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Summary: Heritable fungal endosymbiosis is underinvestigated in plant biology and documented in only three plant families (Convolvulaceae, Fabaceae, and Poaceae). An estimated 40% of morning glory species in the tribe Ipomoeeae (Convolvulaceae) have associations with one of two distinct heritable, endosymbiotic fungi (Periglandula and Chaetothyriales) that produce the bioactive metabolites ergot alkaloids, indole diterpene alkaloids, and swainsonine, which have been of interest for their toxic effects on animals and potential medical applications. Here, we report the occurrence of ergot alkaloids, indole diterpene alkaloids, and swainsonine in the Convolvulaceae; and the fungi that produce them based on synthesis of previous studies and new indole diterpene alkaloid data from 27 additional species in a phylogenetic, geographic, and life‐history context. We find that individual morning glory species host no more than one metabolite‐producing fungal endosymbiont (with one possible exception), possibly due to costs to the host and overlapping functions of the alkaloids. The symbiotic morning glory lineages occur in distinct phylogenetic clades, and host species have significantly larger seed size than nonsymbiotic species. The distinct and widely distributed endosymbiotic relationships in the morning glory family and their alkaloids provide an accessible study system for understanding heritable plant–fungal symbiosis evolution and their potential functions for host plants. [ABSTRACT FROM AUTHOR]

Gene flow is thought to impede genetic divergence and speciation by homogenizing genomes. Recent theory and research suggest that sufficiently strong divergent selection can overpower gene flow, leading to loci that are highly differentiated compared to others. However, there are also alternative explanations for this pattern. Independent evidence that loci in highly differentiated regions are under divergent selection would allow these explanations to be distinguished, but such evidence is scarce. Here, we present multiple lines of evidence that many of the highly divergent SNPs in a pair of sister morning glory species, Ipomoea cordatotriloba and I. lacunosa, are the result of divergent selection in the face of gene flow. We analysed a SNP data set across the genome to assess the amount of gene flow, resistance to introgression and patterns of selection on loci resistant to introgression. We show that differentiation between the two species is much lower in sympatry than in allopatry, consistent with interspecific gene flow in sympatry. Gene flow appears to be substantially greater from I. lacunosa to I. cordatotriloba than in the reverse direction, resulting in sympatric and allopatric I. cordatotriloba being substantially more different than sympatric and allopatric I. lacunosa. Many SNPs highly differentiated in allopatry have experienced divergent selection, and, despite gene flow in sympatry, resist homogenization in sympatry. Finally, five out of eight floral and inflorescence characteristics measured exhibit asymmetric convergence in sympatry. Consistent with the pattern of gene flow, I. cordatotriloba traits become much more like those of I. lacunosa than the reverse. Our investigation reveals the complex interplay between selection and gene flow that can occur during the early stages of speciation. see also the Perspective by Field and Fraïsse [ABSTRACT FROM AUTHOR]

Morning glories (Ipomoea spp.) are important weeds in non-burning sugarcane farming in Brazil, and their chemical control has low efficacy due to the straw mulching. The purpose of this work was to determine the effect of epidemiological parameters on the development of Cercospora leaf spot (Cercospora aff. canescens Ellis & G. Martin) on four Ipomoea weed species, as well as on the host range. The results demonstrated that the use of a suspension of 2 × 107 conidia ml−1 on specific host phenological stages (3-5 leaves, open flowers, and with fruit), with a minimum of a 24 h dew period, induces plant defoliation and a higher disease incidence on Ipomoea nil L. (Roth). However, the same disease incidence and defoliation on I. grandifolia (Dammer) O'Donell, I. quamoclit L., and I. hederifolia L. were not achieved. The pathogen was specific to these four Ipomoea species among 18 plant species. These results represent an important step in the development of a mycoherbicide to control morning glories. [ABSTRACT FROM AUTHOR]

The Japanese morning glory (Ipomoea nil) and petunia (Petunia hybrida), locally called "Asagao" and "Tsukubane-asagao", respectively, are popular garden plants. They have been utilized as model plants for studying the genetic basis of floricultural traits, especially anthocyanin pigmentation in flower petals. In their long history of genetic studies, many mutations affecting flower pigmentation have been characterized, and both structural and regulatory genes for the anthocyanin biosynthesis pathway have been identified. In this review, we will summarize recent advances in the understanding of flower pigmentation in the two species with respect to flower hue and color patterning. Regarding flower hue, we will describe a novel enhancer of flavonoid production that controls the intensity of flower pigmentation, new aspects related to a flavonoid glucosyltransferase that has been known for a long time, and the regulatory mechanisms of vacuolar pH being a key determinant of red and blue coloration. On color patterning, we describe particular flower patterns regulated by epigenetic and RNA-silencing mechanisms. As high-quality whole genome sequences of the Japanese morning glory and petunia wild parents (P. axillaris and P. inflata, respectively) were published in 2016, further study on flower pigmentation will be accelerated. [ABSTRACT FROM AUTHOR]

Human-mediated selection can strongly influence the evolutionary response of natural organisms within ecological timescales. But what traits allow for, or even facilitate, adaptation to the strong selection humans impose on natural systems? Using a combination of laboratory and greenhouse studies of 32 natural populations of the common agricultural weed, Ipomoea purpurea, we show that herbicide-resistant populations self-fertilise more than susceptible populations. We likewise show that anther-stigma distance, a floral trait associated with self-fertilisation in this species, exhibits a nonlinear relationship with resistance such that the most and least resistant populations exhibit lower anther-stigma separation compared to populations with moderate levels of resistance. Overall, our results extend the general finding that plant mating can be impacted by human-mediated agents of selection to that of the extreme selection of the agricultural system. This work highlights the influence of human-mediated selection on rapid responses of natural populations that can lead to unexpected long-term evolutionary consequences. [ABSTRACT FROM AUTHOR]

Morning glory (MG, Ipomoea aquatica ) with water hyacinth (WH, Eichhornia crassipes ) were co-digested for 17 weeks at five different MG:WH ratios of 100:0, 70:30, 50:50, 30:70 and 0:100 (w:w dry basis). Fixed quantity of cow dung slurry was added to each treatment as inoculum to seed the digesters. Biodegradation and maximum biogas yield models based on first-order kinetics were fitted to the experimental biogas yields to describe the cumulative and predict maximum biogas yields, respectively from each treatment. From the results, it was observed that MG was viable and prolific for biogas production. Although co-digestion did not have significant ( p > 0.05) effect on biogas yield, MG:WH (50:50) recorded the highest yield (0.29 dm 3 kg −1 vs fed day −1 ). However, co-digestion affected ( p ≤ 0.05) total bacterial count. The biodegradation model described the observed biogas yields satisfactorily as indicated by the high R 2 . Similarly, the high R 2 values and percentages of predicted maximum yield/observed maximum yield showed that the maximum biogas yield model predicted the maximum yields satisfactorily. Biogas yield from MG:WH (100:0) was the best described and predicted by the biodegradation and maximum yield models, respectively. [ABSTRACT FROM AUTHOR]

One of the most striking and consistent results in speciation genomics is the heterogeneous divergence observed across the genomes of closely related species. This pattern was initially attributed to different levels of gene exchange—with divergence preserved at loci generating a barrier to gene flow but homogenized at unlinked neutral loci. Although there is evidence to support this model, it is now recognized that interpreting patterns of divergence across genomes is not so straightforward. One problem is that heterogenous divergence between populations can also be generated by other processes (e.g. recurrent selective sweeps or background selection) without any involvement of differential gene flow. Thus, integrated studies that identify which loci are likely subject to divergent selection are required to shed light on the interplay between selection and gene flow during the early phases of speciation. In this issue of Molecular Ecology, Rifkin et al. () confront this challenge using a pair of sister morning glory species. They wisely design their sampling to take the geographic context of individuals into account, including geographically isolated (allopatric) and co‐occurring (sympatric) populations. This enabled them to show that individuals are phenotypically less differentiated in sympatry. They also found that the loci that resist introgression are enriched for those most differentiated in allopatry and loci that exhibit signals of divergent selection. One great strength of the study is the combination of methods from population genetics and molecular evolution, including the development of a model to simultaneously infer admixture proportions and selfing rates. [ABSTRACT FROM AUTHOR]

Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors. [ABSTRACT FROM AUTHOR]

Fitness costs are frequently invoked to explain the presence of genetic variation underlying plant defense across many types of damaging agents. Despite the expectation that costs of resistance are prevalent, however, they have been difficult to detect in nature. To examine the potential that resistance confers a fitness cost, we examined the survival and fitness of genetic lines of the common morning glory, Ipomoea purpurea, that diverged in the level of resistance to the herbicide glyphosate. We planted a large field experiment and assessed survival following herbicide application as well as fitness of the divergent selection lines in the absence of the herbicide. We found that genetic lines selected for increased resistance exhibited lower death compared to control and susceptible lines in the presence of the herbicide, but no evidence that resistant lines produced fewer seeds in the absence of herbicide. However, susceptible lines produced more viable seeds than resistant or control lines, providing some evidence of a fitness cost in terms of seed germination, and thus potential empirical support for the expectation of trait trade-offs as a consequence of adaptation to novel environments. [ABSTRACT FROM AUTHOR]

Periglandula ipomoeae and P. turbinae (Ascomycota, Clavicipitaceae) are recently described fungi that form symbiotic associations with the morning glories (Convolvulaceae) Ipomoea asarifolia and Turbina corymbosa, respectively. These Periglandula species are vertically transmitted and produce bioactive ergot alkaloids in seeds of infected plants and ephemeral mycelia on the adaxial surface of young leaves. Whether other morning glories that contain ergot alkaloids also are infected by Periglandula fungi is a central question. Here we report on a survey of eight species of Convolvulaceae (Argyreia nervosa, I. amnicola, I. argillicola, I. gracilis, I. hildebrandtii, I. leptophylla, I. muelleri, I. pes-caprae) for ergot alkaloids in seeds and associated clavicipitaceous fungi potentially responsible for their production. All host species contained ergot alkaloids in four distinct chemotypes with concentrations of 15.8-3223.0 μg/g. Each chemotype was a combination of four or five ergot alkaloids out of seven alkaloids detected across all hosts. In addition, each host species exhibited characteristic epiphytic mycelia on adaxial surfaces of young leaves with considerable interspecific differences in mycelial density. We sequenced three loci from fungi infecting each host: the nuclear rDNA internal transcribed spacer region (ITS), introns of the translation factor 1-α gene (tefA) and the dimethylallyl-tryptophan synthase gene (dmaW), which codes for the enzyme that catalyzes the first step in ergot alkaloid biosynthesis. Phylogenetic analyses confirmed that these fungi are in the family Clavicipitaceae and form a monophyletic group with the two described Periglandula species. This study is the first to report Periglandula spp. from Asian, Australian, African and North American species of Convolvulaceae, including host species with a shrub growth form and host species occurring outside of the tropics. This study demonstrates that ergot alkaloids in morning glories always co-occur with Periglandula spp. and that closely related Periglandula spp. produce alkaloid chemotypes more similar than more distantly related species. [ABSTRACT FROM AUTHOR]

The article presents a study on the occurrence of pink morning glory (Ipomoea carnea) intoxication in goats found in northern Argentina. Topics include the clinical signs, biochemical alterations and histopathological and lectin-histochemical analysis of the spontaneous intoxication by I. carnea, a comparison of clinical signs in naturally-occurring and experimental cases of I. carnea, and the need for further research on the impact of swainsonine-containing plants on livestock production.

A global revision of Convolvulus L. is presented, Calystegia R.Br. being excluded on pragmatic grounds. One hundred and ninety species are recognised with the greatest diversity in the Irano-Turanian region. All recognised species are described and the majority are illustrated. Distribution details, keys to species identification and taxonomic notes are provided. Four new species, Convolvulus austroafricanus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvulus iranicus J.R.I.Wood & R.W.Scotland, sp. nov., Convolvulus peninsularis J.R.I.Wood & R.W.Scotland, sp. nov. and Convolvulus xanthopotamicus J.R.I.Wood & R.W.Scotland, sp. nov., one new subspecies Convolvulus chinensis subsp. triangularis J.R.I.Wood & R.W.Scotland, subsp. nov., and two new varieties Convolvulus equitans var. lindheimeri J.R.I.Wood & R.W.Scotland, var. nov., Convolvulus glomeratus var. sachalitarum J.R.I.Wood & R.W.Scotland, var. nov. are described. Convolvulus incisodentatus J.R.I.Wood & R.W.Scotland, nom. nov., is provided as a replacement name for the illegitimate Convolvulus incisus Choisy. Several species treated as synonyms of other species in recent publications are reinstated including C. chinensis Ker-Gawl., C. spinifer M.Popov., C. randii Rendle and C. aschersonii Engl. Ten taxa are given new status and recognised at new ranks: Convolvulus namaquensis (Schltr. ex. A.Meeuse) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hermanniae subsp. erosus (Desr.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus crenatifolius subsp. montevidensis (Spreng.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus fruticulosus subsp. glandulosus (Webb) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus capituliferus subsp. foliaceus (Verdc.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hystrix subsp. ruspolii (Dammer ex Hallier f.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus hystrix subsp. inermis (Chiov.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus rottlerianus subsp. stocksii (Boiss.) J.R.I.Wood & R.W.Scotland, comb. et stat. nov., Convolvulus calvertii subsp. ruprechtii (Boiss.) J.R.I.Wood & R.W.Scotland, stat. nov., Convolvulus cephalopodus subsp. bushiricus (Bornm.) J.R.I.Wood & R.W.Scotland, stat. nov. The status of various infraspecific taxa is clarified and numerous taxa are lectotypified. This account represents a new initiative in terms of taxonomic monography, being an attempt to bring together the global approach of the traditional monograph with the more pragmatic and identification-focussed approach of most current floras while at the same time being informed by insights from molecular systematics. [ABSTRACT FROM AUTHOR]

* Premise of the study: Morning glories are an emerging model system, and resolving phylogenetic relationships is critical for understanding their evolution. Phylogenetic studies demonstrated that the largest morning glory genus, lpomoea, is not monophyletic, and nine other genera are derived from within lpomoea. Therefore, systematic research is focused on the monophyletic tribe Ipomoeeae (ca. 650-900 species). We used whole plastomes to infer relationships across Ipomoeeae. * Methods: Whole plastomes were sequenced for 29 morning glory species, representing major lineages. Phylogenies were estimated using alignments of 82 plastid genes and whole plastomes. Divergence times were estimated using three fossil calibration points. Finally, evolution of root architecture, flower color, and ergot alkaloid presence was examined. * Key results: Phylogenies estimated from both data sets had nearly identical topologies. Phylogenetic results are generally consistent with prior phylogenetic hypotheses. Higher-level relationships with weak support in previous studies were recovered here with strong support. Molecular dating analysis suggests a late Eocene divergence time for the Ipomoeeae. The two clades within the tribe, Argyreiinae and Astripomoeinae, diversified at similar times. Reconstructed most recent common ancestor of the Ipomoeeae had blue flowers, an association with ergot-producing fungi, and either tuberous or fibrous roots. * Conclusions: Phylogenetic results provide confidence in relationships among Ipomoeeae lineages. Divergence time estimation results provide a temporal context for diversification of morning glories. Ancestral character reconstructions support previous findings that morning glory morphology is evolutionarily labile. Taken together, our study provides strong resolution of the morning glory phylogeny, which is broadly applicable to the evolution and ecology of these fascinating species. [ABSTRACT FROM AUTHOR]

Observations and analyses of low-level convergence lines over the Gulf of Carpentaria region of northeastern Australia made during the second and third Gulf Lines EXperiments (GLEX II and GLEX III) are reported. During GLEX II, the initiation of the North Australian Cloud Line (NACL) was documented using a small autonomous aircraft and two Doppler sodars. NACLs are long convergence lines that form on the western side of northern Cape York Peninsula and are typically marked by a line of contiguous cumulus or cumulus congestus cloud. The observations show that the degree of asymmetry between west-coast and east-coast sea breezes (as characterized by the wind field) depends on the strength of the background easterlies, and that NACLs develop only when the background easterlies are sufficiently large (≥ 5 m s−1). GLEX III focused on morning glories, which are (mostly) southwestward-moving bore-like convergence lines that originate over the southern part of the gulf region. The field experiment involved Doppler sodar measurements as well as high-temporal-resolution data from operational automatic weather stations. The sodar measurements showed that undular bore-like morning glory cloud lines develop only when the background easterlies are sufficiently weak (≤ 10 m s−1) and that strong bore-like morning glories develop when the background winds exceed about 10 m s−1. If the background easterlies are too strong, no morning glories develop. Numerical simulations show that the structure of convergence line produced depends on the strength of the collision between the sea breezes from each side of the Cape York Peninsula, which in turn depends on the strength of the background easterlies. When the easterlies are weak (≤ 10 m s−1), the sea breezes have similar depths and strengths, and their collision is relatively violent, whereas when the background easterlies are strong (> 10 m s−1) the sea breezes have very different depths and strengths and their collision is comparatively benign. [ABSTRACT FROM AUTHOR]

Ergot alkaloids are mycotoxins that can increase host plant resistance to above- and below-ground herbivores. Some morning glories (Convolvulaceae) are infected by clavicipitaceous fungi ( Periglandula spp.) that produce high concentrations of ergot alkaloids in seeds-up to 1000-fold greater than endophyte-infected grasses. Here, we evaluated the diversity and distribution of alkaloids in seeds and seedlings and variation in alkaloid distribution among species. We treated half the plants with fungicide to differentiate seed-borne alkaloids from alkaloids produced de novo post-germination and sampled seedling tissues at the cotyledon and first-leaf stages. Seed-borne alkaloids in Ipomoea amnicola, I. argillicola, and I. hildebrandtii remained primarily in the cotyledons, whereas I. tricolor allocated lysergic acid amides to the roots while retaining clavines in the cotyledons. In I. hildebrandtii, almost all festuclavine was found in the cotyledons. These observations suggest differential allocation of individual alkaloids. Intraspecific patterns of alkaloid distribution did not vary between fungicide-treated and control seedlings. Each species contained four to six unique ergot alkaloids and two species had the ergopeptine ergobalansine. De novo production of alkaloids did not begin immediately, as total alkaloids in fungicide-treated and control seedlings did not differ through the first-leaf stage, except in I. argillicola. In an extended time-course experiment with I. tricolor, de novo production was detected after the first-leaf stage. Our results demonstrate that allocation of seed-borne ergot alkaloids varies among species and tissues but is not altered by fungicide treatment. This variation may reflect a response to selection for defense against natural enemies. [ABSTRACT FROM AUTHOR]

Purpose: To report an association of congenital optic nerve anomalies with peripheral retina nonperfusion and to describe the clinical manifestations and treatment. Design: Retrospective, observational case series. Participants: Fifteen patients with congenital optic nerve anomalies referred for pediatric retina consultation were studied. Sixteen eyes of 9 patients with optic nerve hypoplasia and 8 eyes of 6 patients with other congenital optic nerve anomalies, including optic nerve coloboma, morning glory disc, and peripapillary staphyloma, were included. Methods: All patients underwent examinations under anesthesia. Wide-angle retina photographs and fluorescein angiograms were reviewed. The severity of nonperfusion was graded. The presence of fibrovascular proliferation (FP), vitreous hemorrhage (VH), and tractional retinal detachment (TRD) were documented. Anatomic outcome after treatment was recorded. Main Outcome Measures: Severity of nonperfusion, occurrence of secondary complications, and the anatomic outcome of patients who underwent laser treatment. Results: In patients with optic nerve hypoplasia, 12 of 16 eyes (75%) had severe peripheral nonperfusion, 12 of 16 eyes (75%) had FP, 3 of 16 eyes (19%) had VH, and 10 of 16 eyes (63%) had TRD. Six of these eyes with severe nonperfusion received laser photocoagulation to the nonperfused retina; laser-treated retinas remained attached in all 6 eyes. In patients with the other optic nerve anomalies, 7 of 8 eyes (88%) had mild to moderate nonperfusion, 2 of 8 eyes (25%) had FP, 1 of 8 eyes (12%) had VH, and 2 of 8 eyes (25%) had TRD. Six of 9 patients (67%) with optic nerve hypoplasia and 1 of 6 patients (17%) with other anomalies had a coexisting congenital brain disease. Conclusions: Congenital optic nerve anomalies may be associated with peripheral retina nonperfusion and the secondary complications of FP, VH, and TRD. In this select group of patients, the nonperfusion associated with optic nerve hypoplasia seemed to be more severe and associated more frequently with secondary complications. Peripheral retina examination in eyes with optic nerve anomalies may identify nonperfusion or FP. Laser treatment of the avascular retina may have helped prevent complications from proliferative retinopathy in eyes clinically observed to have progressed or considered at risk for progression to proliferative retinopathy. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. [Copyright &y& Elsevier]

Clines in phenotypic traits with an underlying genetic basis potentially implicate natural selection. However, neutral evolutionary processes such as random colonization, spatially restricted gene flow, and genetic drift could also result in similar spatial patterns, especially for single-locus traits because of their susceptibility to stochastic events. One way to distinguish between adaptive and neutral mechanisms is to compare the focal trait to neutral genetic loci to determine whether neutral loci demonstrate clinal variation (consistent with a neutral cline), or not. Ivyleaf morning glory, Ipomoea hederacea, exhibits a latitudinal cline for a Mendelian leaf shape polymorphism in eastern North America, such that lobed genotypes dominate northern populations and heart-shaped genotypes are restricted to southern populations. Here, we evaluate potential evolutionary mechanisms for this cline by first determining the allele frequencies at the leaf shape locus for 77 populations distributed throughout I. hederacea's range and then comparing the geographical pattern at this locus to neutral amplified fragment length polymorphism ( AFLP) loci. We detected both significant clinal variation and high genetic differentiation at the leaf shape locus across all populations. In contrast, 99% of the putatively neutral loci do not display clinal variation, and I. hederacea populations show very little overall genetic differentiation, suggesting that there is a moderate level of gene flow. In addition, the leaf shape locus was identified as a major FST outlier experiencing divergent selection, relative to all the AFLP loci. Together, these data strongly suggest that the cline in leaf shape is being maintained by spatially varying natural selection. [ABSTRACT FROM AUTHOR]

* Premise of the study: Many reports have cited Baker's list of weediness traits, or those that exemplify the "ideal" weed, yet few have considered the evolutionary potential of such traits as a group. Thus, it is unknown whether constraints on the evolution of increased weediness, such as a lack of genetic variation or genetic correlations between the traits, are present. Ipomoea purpurea, the common morning glory, is a problematic weed that exhibits many of Baker's ideal weed traits. * Methods: We used progeny from a half/full-sib breeding design in a series of three greenhouse experiments to assess the presence of genetic variation, narrow sense heritabilities, and genetic correlations in Baker's growth, competition, and fitness "weediness" traits in two populations of I. purpurea. * Key results: We uncovered genetic variation underlying reproductive fitness traits and competitive ability in at least one population, but no evidence of genetic variation underlying growth rate in either population. Genetic correlations between many of the weediness characters differed significantly from zero; however, their direction and/or magnitude differed between populations. * Conclusions: We found that increased weediness in the common morning glory is more likely to occur through selection on reproductive output and competitive ability rather than through selection on growth rate. Assessing Baker's traits in a quantitative genetics framework can provide a solid perspective on their evolutionary potential and a unique framework within which to determine how weeds will respond to different environmental stresses and/or scenarios of global climate change. [ABSTRACT FROM AUTHOR]

Although Japanese morning glory (Ipomoea nil (L.) Roth.) has been used intensively for genetic studies, DNA markers have not been developed in Ipomoea nil sufficient to cover all chromosomes. Therefore, we conducted microsatellite (simple sequence repeats, SSR) marker development in I. nil for future genetic studies. From 92,662 expressed sequence tag (EST) sequences, 514 unique microsatellite-containing ESTs were identified. Primer pairs were designed automatically in 326 SSRs. Of 150 SSRs examined, 75 showed polymorphisms among strains. A phenogram based on the SSR genotypes revealed the genetic relation among seven Japanese morning glories from five different regions of the world and an ivyleaf morning glory (I. hederacea Jacq.). The developed SSR markers might be applicable for genetic studies of morning glories and their relatives. [ABSTRACT FROM AUTHOR]

Many diverse questions in ecology and evolution have been addressed using species belonging to the genus Ipomoea, commonly referred to as the morning glory genus. Ipomoea exhibits a wide range of diversity in floral color, growth form, mating system and tolerance to environmental factors, both within and among species, and as such has been a focal group of many investigations in the last 80 years. In this review, we highlight recent work to which Ipomoea species have contributed-from studies of the mating system, molecular evolution, plant-herbivore and plant-parasite interactions to their impact on and importance to agriculture. Genomic resources for this group are currently under development, and given the breadth of studies and history of this group, combined with an expanding genetics toolkit, we argue that Ipomoea should provide the next model organism for ecological genomics. [ABSTRACT FROM AUTHOR]

In order to develop new natural dyes and enrich the hue of natural dyes, onion, morning glory, purple cabbage, grape skin, black rice and other new natural dyes were selected to dye on silk and wool fabrics. After dyeing, the color fastness was evaluated. The results showed that the dyes from onion skins had a strong affinity for protein fibers. The dyes from grape skin, morning glory, black rice and purple cabbage had a poorer affinity for protein fibers than onion. The mordant can improve the depth of color. In the experiment, wool and silk fabrics were dyed into blue tone by the purple cabbage dye, green tone by the purple onion and morning glory dyes; purple gray tone by the dyes from black rice and the grape skin. Be testing, the dry rubbing fastness of all fabrics was better; however, the grade of wet rubbing fastness was lower than that of dry rubbing fastness. The level of color fastness to sunlight of the onion skin dyes was higher. [ABSTRACT FROM AUTHOR]

Abstract: This paper was designed to study metabonomic characters of the nephrotoxicity induced by Morning Glory Seed (MGS), a well-known traditional Chinese medicine which was used for the treatment of edema, simple obesity and lung fever. Urinary samples from control and MGS treated rats were analyzed by ultra-performance liquid chromatography/mass spectrometry (UPLC–MS) in positive ionization mode. Blood biochemistry and histopathology were examined to identify specific changes of renal damage. The results affirmatively suggested that ethanol extract of Morning Glory Seed (EMGS), instead of water extract of Morning Glory Seed (WMGS), should be responsible for the nephrotoxicity caused by this herbal medicine. The UPLC–MS analysis revealed that the levels of 8 endogenous metabolites as biomarkers were significantly changed in urine from EMGS treated rats. The underlying regulations of EMGS-perturbed metabolic pathways were discussed according to the identified metabolites. The present study proves the potential of UPLC–MS based metabonomics in mapping metabolic response for toxicology. [Copyright &y& Elsevier]

Ethnopharmacological relevance: Morning Glory Seed (MGS) is a valuable traditional Chinese medicine which is widely used for the treatment of edema, ascites, hydroncus, simple obesity, lung fever and ardent fever. In recent years, long-term exposure to Morning Glory Seed (MGS) has shown to pose progressive renal damage in clinical practice. We hypothesize that changes in metabolic profile could have occurred before symptoms were observed, which may allow early treatment. Aim of the study: To investigate the metabolic changes caused by Morning Glory Seed-induced renal damage. Method: Metabonomics method was used for chronic toxicology study of MGS in Wistar rats. With a therapeutic dose, the model rats were orally administered the extract of MGS for 10 weeks continuously. The urine samples of model and control rats were collected in various time-points and the endogenous metabolites were analyzed by ultraperformance liquid chromatography coupled with mass spectrometry. The identification of all the potential biomarkers was performed using reference standard by comparing their mass spectra, MS/MS fragmentation and retention time. Furthermore, histopathology and clinical chemistry studies were carried out to ensure the success of MGS-induced nephrotoxicity model. Results: The difference in metabolic profiles between the control and the dosed rats was well observed by the principal component analysis (PCA) of the MS spectra. Significant changes of 12 metabolite biomarkers were detected in the rat urine samples. Metabonomics method could discriminate the model rats from the control rats in 2nd, 6th and10th week respectively before serious organic damage of kidney was found in 10th week by histopathology method. Conclusion: We believe that metabolic profiling may act as a preclinical protocol for MGS exposure before symptoms are observed. [Copyright &y& Elsevier]

Field research conducted over 3 years evaluated red morningglory seedling emergence from June through September in a fallowed sugarcane field. Tillage to a 10.2 cm depth was compared with no tillage where glufosinate at 0.37 kg ai/ha was used to eliminate red morningglory. In July, 4 weeks after initial tillage, red morningglory seedling emergence was equal whether soil was tilled or not tilled. Seedling emergence in August and September, however, was 1.5 and 3.9 times greater, respectively, for the tillage treatment. Total season emergence of red morningglory was 34% greater where soil was tilled compared with no- tillage. In October, seed population in soil for the tilled and no tillage treatments was equivalent and had decreased an average of 35% from June. For the undisturbed control where seed production occurred, seed population in soil increased 1.4 fold across the growing season. Red morningglory emergence and growth in response to 0, 30, 50, 70, or 90% shade established using enclosures covered with shade cloth was evaluated in three years of field research. Red morningglory seedling emergence 20 to 41 days after soil was tilled to a 10.2 cm depth decreased 5 and 8% for the 30 and 50% shade treatments, respectively, compared with no shade (full sunlight). Increasing shade to 70 and 90% decreased seedling emergence 37 and 43%, respectively. Shade did not affect red morningglory height , but biomass per plant decreased 27 and 48% as shade level increased to 70 and 90%, respectively. Leaf and stem weight was lower when red morningglory plants were grown under 90% shade compared with 30%. Plant leaf area was greater under all shade levels compared with that for plants grown in full sunlight. Red morningglory tolerance to a shade environment stresses the need for effective weed control programs at the layby cultivation and later in the growing season to prevent climbing and wrapping of sugarcane stalks and reduced harvest efficiency. [ABSTRACT FROM AUTHOR]

The article discusses a study which examined the transcriptome of the beach morning glory, a wild relative of the salt-sensitive sweet potato.

The existence of eastward-propagating bores over Cape York Peninsula is shown from data obtained during the Gulf Lines Experiment (GLEX) conducted during September and October 2002 and from numerical modeling experiments. The disturbances were detected regularly at two stations, observable on 24 days during the 40-day experiment. The passage of a typical disturbance exhibits a sudden increase in pressure of around 1 hPa, often accompanied by undulations, and a change in the wind speed and direction from an easterly to a westerly flow. Disturbances were not observed during days of strong easterly flow. A two-dimensional nonhydrostatic mesoscale model is used to examine the formation of these disturbances. It is shown that the west coast sea breeze is shallow and does not penetrate far inland because of the opposing low-level easterly flow. In contrast, the east coast sea breeze is deeper and is less stable because it is modified by daytime convective mixing as it crosses the peninsula. As the east coast sea breeze overrides the west coast sea breeze, the west coast sea breeze produces an eastward-propagating bore on the stable layer laid down by the east coast sea breeze. About 2 h after generation, the bore becomes undular. These eastward-propagating disturbances are shown to be associated with the westward-propagating north Australian cloud line and the northeasterly morning glory. In addition, it is shown here that an undular bore can be formed when cold-air downdrafts from afternoon deep convection enter the stable layer created by the east coast sea breeze. Four events from GLEX are believed to have been formed in this way. The eastward-propagating disturbances produced in this way are accompanied neither by the north Australian cloud line nor by the northeasterly morning glory. [ABSTRACT FROM AUTHOR]

Abstract: Resource availability may limit plant tolerance of herbivory. To predict the effect of differential resource availability on plant tolerance, the limiting resource model (LRM) considers which resource limits plant fitness and which resource is mostly affected by herbivore damage. We tested the effect of experimental drought on tolerance of leaf damage in Ipomoea purpurea, which is naturally exposed to both leaf damage and summer drought. To seek mechanistic explanations, we also measured several morphological, allocation and gas exchange traits. In this case, LRM predicts that tolerance would be the same in both water treatments. Plants were assigned to a combination of two water treatments (control and low water) and two damage treatments (50% defoliation and undamaged). Plants showed tolerance of leaf damage, i.e., a similar number of fruits were produced by damaged and undamaged plants, only in control water. Whereas experimental drought affected all plant traits, leaf damage caused plants to show a greater leaf trichome density and reduced shoot biomass, but only in low water. It is suggested that the reduced fitness (number of fruits) of damaged plants in low water was mediated by the differential reduction of shoot biomass, because the number of fruits per shoot biomass was similar in damaged and undamaged plants. Alternative but less likely explanations include the opposing direction of functional responses to drought and defoliation, and resource costs of the damage-induced leaf trichome density. Our results somewhat challenge the LRM predictions, but further research including field experiments is needed to validate some of the preliminary conclusions drawn. [Copyright &y& Elsevier]

The wild-type Japanese morning glory [ Ipomoea nil (L.) Roth.] exhibits blue flowers with red stems, and spontaneous r mutants display white flowers with green stems. We have identified two r mutations, r1-1 and r1-2, that are caused by insertions of Tpn1-related DNA transposable elements, Tpn3 (5.6 kb) and Tpn6 (4.7 kb), respectively, into a unique intron of the CHS-D gene, which is responsible for flower and stem pigmentation. Both Tpn3 and Tpn6, which belong to the En/Spm or CACTA superfamily, are nonautonomous elements lacking transposase genes but containing unrelated cellular DNA segments including exons and introns. Interestingly, r1-2 contains an additional 4-bp insertion at the Tpn3 integration site in r1-1, presumably a footprint caused by the excision of Tpn3. The results strengthen the previous notion that Tpn1 and its relatives are major spontaneous mutagens for generating various floriculturally important traits in I. nil. Since I. nil has an extensive history of genetic studies, molecular identification of classical spontaneous mutations would also facilitate reinterpretation of the abundant classical genetic data available. [ABSTRACT FROM AUTHOR]

The onset and progression of petal senescence, which is a type of programmed cell death (PCD), are highly regulated. Genes showing changes m expression during petal senescence in Japanese morning glory (Ipomoea nil) were isolated and examined to elucidate their function in PCD. We show here that a putative membrane protein, InPSR26, regulates progression of PCD during petal senescence in Japanese morning glory. InPSR26 is dominantly expressed in petal limbs and its transcript level increases prior to visible senescence symptoms. Transgenic plants with reduced InPSR26 expression (PSR26r lines) showed accelerated petal wilting, with PCD symptoms including cell collapse, ion and anthocyanin leakage, and DNA degradation accelerated in petals compared to wild-type plants. Transcript levels of autophagy- and PCD-related genes (InATG4, InATG8, InVPE, and InBI-1) were reduced in the petals of PSR26r plants. Autophagy visualized by monodansylcadaverine staining confirmed that autophagy is induced in senescing petal cells of wild-type plants and that the percentage of cells containing monodansylcadaverine-stained structures, most likely autophagosomes, was significantly lower in the petals of PSR26r plants, indicating reduced autophagic activity in the PSR26r plants. These results suggest that InPSR26 acts to delay the progression of PCD during petal senescence, possibly through regulation of the autophagic process. Our data also suggest that autophagy delays PCD in petal senescence. [ABSTRACT FROM AUTHOR]

Evolutionary theory predicts that interactions between species such as resource competition or reproductive interference will generate selection for character displacement where similar species co-occur. However, the rate and direction of character displacement will depend not only on the strength of selection for trait divergence, but also on the amount of genetic variation for selected traits and the nature of genetic correlations between them. To assess the importance of genetic constraints for the evolution of character displacement, we examined the genetic architecture of a suite of floral traits previously shown to be under selection in the annual plant Ipomoea hederacea when this species co-occurs with Ipomoea purpurea. We found that the six floral traits we measured are all positively genetically correlated. We also demonstrate, using new statistical approaches, that the predicted response to selection for four of these six traits is substantially constrained by their genetic correlation structure. Most notably, the response to selection for reduced separation of the tallest and shortest anthers, which reduces the degree of detrimental heterospecific pollen flow, is substantially constrained. Our results suggest that the rate of evolution of reproductive character displacement in I. hederacea is limited by the genetic architecture of floral traits. [ABSTRACT FROM AUTHOR]

Evolutionary biologists explain the maintenance of intermediate levels of defense in plant populations as being due to trade-offs, or negative genetic covariances among ecologically important traits. Attempts at detecting trade-offs as constraints on the evolution of defense have not always been successful, leading some to conclude that such trade-offs rarely explain current levels of defense in the population. Using the agricultural pest Ipomoea purpurea, we measured correlations between traits involved in defense to glyphosate, the active ingredient in Roundup, a widely used herbicide. We found significant allocation costs of tolerance, as well as trade-offs between resistance and two measures of tolerance to glyphosate. Selection on resistance and tolerance exhibited differing patterns: tolerance to leaf damage was under negative directional selection, whereas resistance was under positive directional selection. The joint pattern of selection on resistance and tolerance to leaf damage indicated the presence of alternate peaks in the fitness landscape such that a combination of either high tolerance and low resistance, or high resistance and low tolerance was favored. The widespread use of this herbicide suggests that it is likely an important selective agent on weed populations. Understanding the evolutionary dynamics of herbicide defense traits is thus of increasing importance in the context of human-mediated evolution. [ABSTRACT FROM AUTHOR]

Leaf shape is one of the most variable plant traits. Previous work has provided much indirect evidence that leaf-shape variation is adaptive and that leaf shape influences thermoregulation, water balance, and resistance to natural enemies. Nevertheless, there is little direct evidence that leaf shape actually affects plant fitness. In this study, we first demonstrate that populations of the ivyleaf morning glory, Ipomoea hederacea, in North and South Carolina are frequently polymorphic at a locus that influences leaf shape. We then employ several field experiments to show that this polymorphism is subject to selection. In two of the experiments, at different sites, heterozygotes enjoyed a fitness advantage over both homozygotes. At a third site, in one year directional selection favored lobed leaves, whereas in a second year the pattern of fitnesses was consistent with similar directional selection or heterozygote superiority. Computer simulations of heterozygote advantage under the high selfing rates of I. hederacea indicate that balancing selection of the magnitude observed can by itself stabilize the polymorphism, although spatially and temporally variable selection may also contribute to its long-term maintenance. [ABSTRACT FROM AUTHOR]

In self-compatible, hermaphroditic plants, display size- the number of flowers open on a plant at one time-is believed to be influenced by trade-offs between increasing geitonogamous selfing and decreasing per-flower pollen export as display size increases. Experimental results presented here indicate that selection through male function favors smaller display sizes in Ipomoea purpurea. In small arrays, plant display size was manipulated experimentally, and female selfing rate, male outcross success, and total male fitness were estimated using genetic markers and likelihood and regression analyses. As would be expected if larger displays experience greater geitonogamy, selfing rate increased with display size. However, the perflower amount of pollen exported to other plants decreased with display size. The magnitude of this effect is more than sufficient to offset the increase in selfing rate, resulting in reduced per-flower total male fitness with increasing display size. The low values of inbreeding depression previously reported for this species would enhance this effect. [ABSTRACT FROM AUTHOR]

El artículo enfoca en el género de plantas herbáceas Cressa L. y una de sus especies, Cressa truxillensis. Se indican sus características morfológicas y anatómicas, se cita su distribución geográfica general y se describe su escasa presencia y vulnerabilidad a extinción en la zona del Bajío de México y alrededores.

Although it is generally believed that pollinators are the primary selective agents driving flower-color evolution, it has recently been suggested that pleiotropic effects of mutations affecting flower color may serve as important constraints on floral evolution. We examined this hypothesis using white-flowered variants of the common morning glory, Ipomoea purpurea. Previous experiments indicate that the white-flowered a allele has a transmission advantage because of increased selfing and no detectable pollen discounting. We confirm this transmission advantage using a large field experiment in which both selfing rate and outcross success were measured for all three genotypes at the A locus. We also demonstrate that this transmission advantage is opposed by apparent pleiotropic effects in aa individuals manifested as reduced survival from germination to flowering. The magnitude of this effect, in combination with the known magnitude of inbreeding depression, more than compensates for the transmission advantage. Our results thus support the notion that deleterious pleiotropy may influence the evolutionary trajectory of flower-color mutants. [ABSTRACT FROM AUTHOR]

Abstract: Five different genotypic cultivars of Ipomoea aquatica commonly grown in Southeast Asia were cultivated to investigate their accumulation variation of di-n-butyl phthalate (DBP) and their potential for phytoremediation of three soils contaminated with DBP (4.5, 10.3 and 22.5mgkg−1). The results indicated different cultivar tolerance to DBP. DBP concentration in the shoots of the cultivars and residual DBP concentration in the soil were proportional to initial DBP concentrations in the soil and significantly different with different genotypic cultivars, indicating that the removal of DBP is cultivar-specific. DBP removal in the soil with indigenous DBP was higher than that in freshly DBP-spiked soils. The cultivars of local white-skin I. aquatica (cultivar V5) and Taiwan filiform-leaf I. aquatica (cultivar V1) presented the highest phytoremediation potential in the soil containing indigenous DBP and in freshly DBP-spiked soil, respectively. The translocation factor (TF, DBP concentration ratio of the shoots to the roots) and bioconcentration factor (BCF, DBP concentration ratio of the plant to the soil) also significantly varied with different cultivars, and they did not follow distribution profiles correlated to DBP removal indicating that phytoextraction was not the dominant DBP removal mechanism. Finally, the potential ability of different cultivars of enhancing biodegradation varied widely. [Copyright &y& Elsevier]

The responses of individual stomata to CO2 concentrations ranging from 0 to 900 μmol mol−1 air were analysed in Ipomoea pes-caprae L. Sweet (Convolvulaceae). The stomata were directly observed using a measurement system that permitted continuous observation of stomatal movement under controlled light and CO2 conditions. A CO2 concentration of 350 μmol mol−1 or higher induced stomatal closure, whereas concentrations below 350 μmol mol−1 did not. The time lag before stomatal closure decreased with increasing CO2 concentration, as did the steady-state aperture of the stomata after a change in CO2 concentration. However, the rate of stomatal closure increased with increasing CO2 concentration. Therefore, not only the stomatal closure rate but also the time from the CO2 concentration change to the beginning of stomatal closure changed with increasing CO2 concentration. These results suggest that atmospheric CO2 may be the stimulus for the closure of guard cells. No significant differences were observed between adaxial and abaxial stomata in terms of their responses to CO2. However, heterogeneous responses were detected between neighbouring stomata on each leaf surface. [ABSTRACT FROM AUTHOR]

While there is abundant evidence to suggest that pollinators influence the evolution of plant floral traits, there is little direct evidence that interactions between plant species shape the evolution of such characteristics. The purpose of this study was to determine whether the presence of the morning glory Ipomoea purpurea alters patterns of selection on floral traits of its congener, Ipomoea hederacea. We show that while selection on I. hederacea floral traits is effectively neutral when I. purpurea flowers are absent, selection acts to increase clustering of anthers about the stigma when I. purpurea flowers are present. Our results provide direct experimental evidence that the presence of flowers of a co-occurring congener can influence patterns of natural selection on floral traits that influence the mating system and contribute to prezygotic isolation. To the extent that this result is general, it also lends support to the claim that distributional patterns interpreted as ecological and reproductive character displacement in other plant species have been caused by natural selection generated by interactions among plant species. [ABSTRACT FROM AUTHOR]

Understanding how genetic variation is organized over geography has long been of interest to evolutionary biologists given that traits can vary within and among populations, across regions, and at continental or global scales. The pattern of regional variation can have an important impact on trait evolution at the local or population level. Using a common garden, we asked whether a geographically variable mosaic of tolerance to the widely applied herbicide RoundUp® existed in two closely related co-occurring species of morning glory, Ipomoea purpurea and I. hederacea. We assayed RoundUp tolerance in over 1,700 plants representing 290 families from 29 populations in the southeastern United States. Our findings suggest that the two species of morning glory partition their respective levels of genetic variation for tolerance to glyphosate differently. Variation for tolerance in I. purpurea appears to exist among maternal lines and regions, whereas in I. hederacea, variation in tolerance existed only among populations. In addition, we find a significant hotspot of tolerance or positive spatial aggregation of this trait on a local scale in I. purpurea populations from the Coastal Plain. This suggests that either similar regimes of selection or gene flow between populations can produce a geographic mosaic of tolerance. These results highlight the fact that the genetic variation underlying an adaptive trait can exist at many different scales, whether it be within- or among-populations, among geographical 'hotspots,' or among distinct ecological regions. Given these results, the partitioning of genetic variation should be considered before making predictions about an adaptive trait's evolutionary trajectory. [ABSTRACT FROM AUTHOR]

Under 30-min high irradiance (1500 μmol m−2 s−1), the roles of the xanthophyll cycle and D1 protein turnover were investigated through chlorophyll fluorescence parameters in morning glory ( Ipomoea setosa) leaves, which were dipped into water, dithiothreitol (DTT) and lincomycin (LM), respectively. During the stress, both the xanthophyll cycle and D1 protein turnover could protect PSI from photoinhibition. In DTT leaves, non-photochemical quenching (NPQ) was inhibited greatly and the oxidation level of P700 (P700+) was the lowest one. However, the maximal photochemical efficiency of PSII (Fv/Fm) in DTT leaves was higher than that of LM leaves and was lower than that of control leaves. These results suggested that PSI was more sensitive to the loss of the xanthophyll cycle than PSII under high irradiance. In LM leaves, NPQ was partly inhibited, Fv/Fm was the lowest one among three treatments under high irradiance and P700+ was at a similar level as that of control leaves. These results implied that inactivation of PSII reaction centers could protect PSI from further photoinhibition. Additionally, the lowest of the number of active reaction centers to one inactive reaction center for a PSII cross-section (RC/CSo), maximal trapping rate in a PSII cross-section (TRo/CSo), electron transport in a PSII cross-section (ETo/CSo) and the highest of 1-qP in LM leaves further indicated that severe photoinhibition of PSII in LM leaves was mainly induced by inactivation of PSII reaction centers, which limited electrons transporting to PSI. However, relative to the LM leaves the higher level of RC/CSo, TRo/CSo, Fv/Fm and the lower level of 1-qP in DTT leaves indicated that PSI photoinhibition was mainly induced by the electron accumulation at the PSI acceptor side, which induced the decrease of P700+ under high irradiance. [ABSTRACT FROM AUTHOR]

Abstract  We isolated several senescence-associated genes (SAGs) from the petals of morning glory (Ipomoea nil) flowers, with the aim of furthering our understanding of programmed cell death. Samples were taken from the closed bud stage to advanced visible senescence. Actinomycin D, an inhibitor of transcription, if given prior to 4 h after opening, suppressed the onset of visible senescence, which occurred at about 9 h after flower opening. The isolated genes all showed upregulation. Two cell-wall related genes were upregulated early, one encoding an extensin and one a caffeoyl-CoA-3-O-methyltransferase, involved in lignin production. A pectinacetylesterase was upregulated after flower opening and might be involved in cell-wall degradation. Some identified genes showed high homology with published SAGs possibly involved in remobilisation processes: an alcohol dehydrogenase and three cysteine proteases. One transcript encoded a leucine-rich repeat receptor protein kinase, putatively involved in signal transduction. Another transcript encoded a 14-3-3 protein, also a protein kinase. Two genes have apparently not been associated previously with senescence: the first encoded a putative SEC14, which is required for Golgi vesicle transport, the second was a putative ataxin-2, which has been related to RNA metabolism. Induction of the latter has been shown to result in cell death in yeast, due to defects in actin filament formation. The possible roles of these genes in programmed cell death are discussed. [ABSTRACT FROM AUTHOR]

Helitrons are newcomers among eukaryotic DNA transposons and have originally been identified by computational analysis in the genomes of Arabidopsis, rice and nematode. They are distinguished from other transposons in their structural features, and their proposed transposition mechanisms are involved in rolling circle replication. Computer-predicted autonomous Helitrons with conserved terminal sequences 5′-TC and CTRR-3′ are presumed to encode a putative transposase, Rep/Hel-TPase, which contains a characteristic nuclease/ligase domain for the replication-initiation protein (Rep) and a DNA helicase domain (Hel). Plant Helitrons are thought to encode an additional transposase, RPA-TPase, which is related to the largest subunit of the replication protein A (RPA70). Although Helitrons are found in diverse genomes, neither an autonomous element nor a transposition event has been reported. Here we show that a spontaneous pearly-s mutant of Ipomoea tricolor cv. Pearly Gates, exhibiting white flowers and isolated in approximately 1940, has an 11.5-kbp novel Helitron, named Hel-It1, integrated into the DFR-B gene for anthocyanin pigmentation. Hel-It1 shows the predicted plant Helitron structure for an autonomous element with the conserved termini and carrying the two putative transposase genes, Rep/Hel-TPase and RPA-TPase, which contain a nonsense and a frameshift mutation, respectively. Hel-It1-related elements are scattered in the Ipomoea genome, and only a fraction of the pearly-s plants were found to carry Hel-It1 at another insertion site. The pearly-s mutant appears to bear an autonomous element and to express the wild-type RPA-TPase transcripts. The structures of a putative autonomous element and its transposase genes are discussed. [ABSTRACT FROM AUTHOR]

• Theory predicts that, for taxa that are already substantially postzygotically isolated but for which hybrid mating is still costly, enhanced prezygotic isolation will be favored. Here, we tested this hypothesis by examining the potential contribution of one particular floral trait, herkogamy, to prezygotic isolation between two species of morning glory, Ipomoea hederacea and Ipomoea purpurea. • This trait was experimentally manipulated to determine whether it is a likely prezygotic isolating barrier in naturally pollinated arrays in the field. • Emasculated I. hederacea flowers set significantly fewer seeds than did control flowers, indicating that clustering of anthers and stigma in I. hederacea enhances prezygotic isolation from I. purpurea. We hypothesize that this occurs through some combination of mechanical protection and increased self-pollination, with the effect of mechanical protection estimated to be 30% greater than the effect of increased selfing. • Our results identify stigma–anther proximity as a likely prezygotic isolating barrier and target of selection in the presence of heterospecific pollen flow, and provide motivation for further study of the role of floral morphology in reproductive isolation in this system. [ABSTRACT FROM AUTHOR]