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The evolution of reproductive isolation is of central interest in evolutionary biology. In plants, this is typically achieved by a combination of pre- and postpollination mechanisms that prevent, or limit, the amount of interspecific gene flow. Here, we investigated and compared two ecologically defined groups of Mediterranean orchids that differ in pollination biology and pollinator specificity: sexually deceptive orchids versus food-deceptive orchids. We used experimental crosses to assess the strength of postmating prezygotic, and postzygotic reproductive isolation, and a phylogenetic framework to determine their relative rates of evolution. We found quantitative and qualitative differences between the two groups. Food-deceptive orchids have weak premating isolation but strong postmating isolation, whereas the converse situation characterizes sexually deceptive orchids. Only postzygotic reproductive isolation among food-deceptive orchids was found to evolve in a clock-like manner. Comparison of evolutionary rates, within a common interval of genetic distance, showed that the contribution of postmating barriers was more relevant in the food-deceptive species than in the sexually deceptive species. Asymmetry in prezygotic isolation was found among food-deceptive species. Our results indicate that postmating barriers are most important for reproductive isolation in food-deceptive orchids, whereas premating barriers are most important in sexually deceptive orchids. The different rate of evolution of reproductive isolation and the relative strength of pre- and postmating barriers may have implication for speciation processes in the two orchid groups. [ABSTRACT FROM AUTHOR]

In much of Western Europe, orchid species have suffered dramatic declines in abundance, whereas the remaining populations often tend to be small and isolated, occur in ecologically marginal habitats and may show decreased reproductive output due to altered pollinator interactions or the absence of specialized pollinators. Furthermore, small and isolated populations are expected to suffer from genetic erosion and increasing genetic divergence among populations, through the effects of random genetic drift, increased levels of inbreeding and reduced gene flow, potentially leading to reduced possibilities of population recovery in the future. In this study, genetic diversity and fitness variation were studied in nine fragmented populations of the food deceptive orchid Orchis purpurea. Within-population genetic diversity and among-population differentiation were investigated using dominant AFLP markers. All studied populations were relatively small (range 12–302; mean: 90 individuals/population). Despite their small size, genetic diversity within populations was rather high (mean gene diversity H j: 0.21, range: 0.15–0.27) and genetic differentiation among populations was not higher than that typically observed in deceptive orchids (F ST =0.09). Nevertheless, Mantel tests showed a positive correlation between geographical and genetic distances indicating limited gene flow among populations. Fruit set, on the other hand, was very low (average fruit set: 5.5%), suggesting strong pollinator limitation, which, in turn, resulted in very low recruitment rates (average seedling recruitment per flowering individual: 0.12). Both measures significantly increased with increasing population size, indicating that a certain threshold value (>50 flowering individuals) has to be reached to produce a sizeable number of fruits and seedlings. These results suggest that although deceptive pollination clearly results in a fitness cost, it may serve as an effective means to maintain high gene diversity within and to counter high genetic differentiation among small orchid populations. From a genetic point of view, our results further suggest that small populations of orchid species should not be neglected as they may harbour as much genetic diversity as large populations. [Copyright &y& Elsevier]

Two genes encoding starch branching enzyme II (SBEII) have been identified in apple. These genes share 94 and 92% identity in coding DNA sequences and amino acid sequences, respectively; moreover, they have similar expression patterns. Both genes are expressed in vegetative and reproductive tissues, including leaves, buds, flowers, and fruits. Based on genomic Southern blots, there are two copies of SbeII genes in the apple genome. Comparisons of genomic sequences between monocots and eudicots have revealed that the genomic structure of SbeII genes is conserved. However, the 5′-terminal region of coding DNA sequences of SbeII genes shows greater divergence than the 3′-terminal region between monocots and eudicots. Phylogenetic analysis of DNA sequences has demonstrated that the duplication patterns of SbeII genes are different between monocots and eudicots. In monocots, the duplication of SbeII genes must have occurred prior to the radiation of grasses (Poaceae); while, in eudicots, the expansion of SbeII genes must have followed the process of speciation. [ABSTRACT FROM AUTHOR]

Nonrandom patterns of gene dispersal have been identified as possible causes of genetic structuring within populations. Attempts to model these patterns have generally focused solely on the effects of isolation by distance, but the processes involved are more complex than such modeling suggests. Here, we extend considerations of gene dispersal processes beyond simple isolation by distance effects by directly evaluating the effects of kin-structured gene dispersal mediated by the group dispersal of related seeds within fruits (i.e., kin-structured seed dispersal) by birds on genetic structure in Ilex leucoclada, a clonal dioecious shrub. To examine the genetic structure patterns, we established two 30x30 m plots (one with immature soils in old-growth forest and one in secondary forest, designated IM and SC, respectively) with different I. leucoclada stem densities. In these two plots 145 and 510 stems were found, representing 78 and 85 genets, respectively, identified by analyzing their genotypes at eight microsatellite loci. The clonal structure was stronger in the SC plot than in the IM plot. Correlograms of coancestry for genets in both plots exhibited significant, positive, high values in the shortest distance class, indicating the presence of strong genetic structure. However, Sp statistics revealed that the pattern of the genetic structure differed between the plots. In addition, to estimate the family structure within fruits, we sampled forty fruits, in total, from 15 randomly selected plants in the area around the IM and SC plots, and found that 80% of the fruits were multiseeded and 42-100% of the multiseeded fruits contained at least one pair of full sibs. Simulations based on these estimates demonstrated that the group dispersal of related seeds produced through correlated mating both within and across fruits, but not unstructured half-sib dispersal, could generate the observed magnitude and trends of genetic structure found in the IM plot. Furthermore, in addition to kin-structured seed dispersal, isolation by distance processes is also likely to promote genetic substructuring in the SC plot. After discussing possible ecological factors that may have contributed to the observed genetic structure, we contrast our results with those predicted by general isolation by distance models, and propose that kin-structured seed dispersal should promote some evolutionary phenomena, and thus should be incorporated, where appropriate, in models of gene dispersal in natural plant populations. [ABSTRACT FROM AUTHOR]

Abstract: Biological control of fungal plant pathogens appears as an attractive and realistic approach, and numerous microorganisms have been identified as biocontrol agents. There have been many efforts to understand the mechanisms of action of fungal biocontrol agents. Microbiological, microscopic, and biochemical techniques applied over many years have shed light on these mechanisms without fully demonstrating them. More recently, the development of molecular techniques has yielded innovative alternative tools for understanding and demonstrating the mechanisms underlying biocontrol properties. To date, more than 70 publications describe the use of molecular techniques for this purpose. They describe work exploiting targeted or non-targeted gene isolation, gene expression profiling, gene inactivation and/or overexpression, the study of regulatory factors. This work has shed considerable light on mechanisms underlying biocontrol properties. It has also fully demonstrated a number of targeted action mechanisms of some biocontrol agents. This review describes the techniques used in such studies, with their potential and limitations. It should provide a guide for researchers wanting to study the molecular basis of the biocontrol in diverse biocontrol agents. [Copyright &y& Elsevier]

I compare the genetic basis of quantitative traits that potentially contribute to pre- and postzygotic isolation between the plant species Solanum lycopersicum (formerly Lycopersicon esculentum) and Solanum habrochaites (formerly Lycopersicon hirsutum), using quantitative trait loci (QTL) mapping in a set of near-isogenic lines. Putative prezygotic isolating traits include flower size, flower shape, stigma exsertion, and inflorescence length, that can influence pollinator preferences and/or selfing rates, and therefore gene flow between divergent types. Postzygotic isolating traits are hybrid pollen and seed sterility. Three substantive results emerge from these analyses. First, the genetic basis of floral differentiation appears to be somewhat less complex than the genetic basis of postzygotic hybrid sterility, although these differences are very modest. Second, there is little evidence that traits for floral differentiation are causally or mechanistically associated with hybrid sterility traits in this species cross. Third, there is little evidence that hybrid sterility QTL are more frequently associated with chromosomal centromeric regions, in comparison to floral trait QTL, a prediction of centromeric drive models of hybrid sterility. Although genome-wide associations are not evident in this analysis, several individual chromosomal regions that contain clusters of QTL for both floral and sterility traits, or that indicate hybrid sterility effects at centromere locations, warrant further fine-scale investigation. [ABSTRACT FROM AUTHOR]

The fission yeast Schizosaccharomyces pombe was used to identify genes from tobacco BY-2 cells that may play roles in cell cycle regulation. A cDNA encoding a protein homologous to the yeast CDC48 was isolated and the gene was designated as NtCDC48. The cDNA contains an open reading frame coding for a predicted protein of 808 amino acids which comprises of two typical ATPase modules (aa 245-374 and aa 518-646). Overexpression of NtCDC48 in tobacco BY-2 cells led to an increase in the mitotic index as well as to the formation of diffused mitotic spindles. NtCDC48-GFP fusion proteins are distributed ubiquitously through G1 to M phases, yet their subcellular localization varied regularly along with the cell cycle progression. These results indicate that NtCDC48 may play an important role in the regulation of cell cycle in BY-2 cells. [ABSTRACT FROM AUTHOR]

West African okra is an under-exploited vegetable crop with high pod and seed yield potentials. F1 hybrids of eight accessions of West African okra were composited to produce F2 seeds and backcross generations. Field evaluation of six generations (P1, P2, F1, F2, BC1, and BC2) from five crosses was carried out in a randomized complete block design with three replications. The A, B, and C scaling tests were not significant for 100 seed weight, while significant A, B, or C scaling test for seed yield pe r plant was recorded. Additive gene effects [d] appeared to have contributed immensely to the inheritance of both characters. However, a non-significant interaction (i, j, l) for 100 seed weight corroborates with the results of individual A, B, and C scaling tests. A duplicate epitasis (Acc5 × Acc4) implied difficulty in evolving improved varieties. Estimates of genetic effects confirmed the preponderance of additive gene effects for 100 seed weight and seed yield per plant. High narrow sense heritability and genetic advance indicate the possibility of substantial improvement in seed yield. [ABSTRACT FROM AUTHOR]

An undescribed spherical virus ca. 30 nm in diameter was isolated from gladiolus ( Gladiolus spp.) plants in Japan. The virus had a moderate host range within eight families. Purified virus preparations contained two large RNA components and one coat protein with mobility similar to Cycas necrotic stunt virus (CNSV) from cycas ( Cycas revolute). The virus was serologically closely related to CNSV. Its nucleotide sequence of the coat protein gene had 89% common identity with that of CNSV. These results indicated that the virus isolated from gladiolus is a new strain of CNSV. [ABSTRACT FROM AUTHOR]

A novel flavonoid, pinocembrin-7-O-[3″-O-galloyl-4″,6″-hexahydroxydiphenoyl]-β-glucose (1) was isolated from the whole plant of Penthorum chinense P., along with four known compounds, pinocembrin-7-O-β-glucoside, quercitrin, quercetin-3-O-rhamnoside and gallic acid. The structures were established by spectroscopic analysis. [ABSTRACT FROM AUTHOR]

Isolated populations are likely to experience a loss of genetic diversity because of reduced gene flow, and the effects of habitat fragmentation are, therefore, central issues in conservation genetics. Here, we present data on genetic diversity and isolation-by-distance for the rare central Asian plant Potentilla ikonnikovii (Rosaceae), which occurs in naturally fragmented populations. Sampling covered the entire distributional range of this endemic of southern Mongolia, where the species is restricted to archipelago-like mountain systems that emerge from the semidesert lowlands of the Gobi region. Random amplified polymorphic DNA analyses revealed modest levels of genetic diversity at both the population and species level. A ΦST of 0.68 indicates that isolation has strong effects on population genetic structure; most variance is kept among populations rather than within, and the two most remote populations were genetically distinct. Mantel statistics showed that genetic distance was highly correlated to spatial distance (RM > 0.6). We conclude that populations of P. ikonnikovii are severely isolated in terms of genetic structure. This may lead to reduced fitness and a crude monitoring scheme is recommended. [ABSTRACT FROM AUTHOR]

The isolation of cellulosomes from clostridial sources has been extensively studied; however, the isolation of cellulosomes from facultative soil anaerobes of the family Bacillaceae is not as well characterized. The Bacillus cellulosome (celluloxylanosome) essentially consists of two complex components: C-I and C-II. This multi-component complex enables Bacillus to degrade a variety of carbonaceous compounds as it is composed of several enzymes, such as cellulases, xylanases and other degradative enzymes. The cellulosomal cellulases from Bacillus megaterium were purified using cellulose affinity chromatography, followed by Sepharose 4B gel filtration chromatography. The objective of this investigation was to establish the effect of sulfate and sulfide on cellulosomal ‘cellulase’ activity. An increase in sulfide concentration led to a general enhancement of cellulosomal-associated cellulolytic activity, whereas an increase in sulfate concentration resulted in an inhibition of the cellulosome-associated cellulolytic activity. [ABSTRACT FROM AUTHOR]

We cloned lipG, which encoded a lipolytic enzyme, from a Korean tidal fiat metagenomic library. LipG was related to six putative lipases previously identified only in bacterial genome sequences. These enzymes comprise a new family. We partially characterized LipG, providing the first experimental data for a member of this family. [ABSTRACT FROM AUTHOR]

We have isolated and characterised the first set of chitin synthase genes from a rust fungus, a large group of economically highly important, obligately biotrophic plant pathogens. Puccinia graminis was used as a model organism for the rust fungi which are not well investigated on the molecular level today. One of the major structural components of most fungal cell walls is the chitin polymer which is synthesised by a family of enzymes called chitin synthases. In P. graminis, we have isolated five new chitin synthase genes from four different classes, chsII, chsIIIa, chsIIIb, chsIV, and chsV. The genes contain a high number of introns, unusual for other known fungal chitin synthases. The dinucleic stage of the fungus seems to contain two slightly different genes or alleles for four isoforms. One isoform, chsIIIa, seems to be expressed only in the youngest stages of fungal growth. Analysis of the derived proteins shows that together with other basidiomycete CHS, the pgtCHS form separate subgroups in the phylogenetic tree. This set of five rust chitin synthase genes, with some unusual features compared to known fungal chitin synthases, allows new insights into chitin synthase classification, and may help in the development of novel functional fungicides. [ABSTRACT FROM AUTHOR]

We isolated two T-DNA insertion mutants of Arabidopsis thaliana GLUTATHIONE PEROXIDASE3 (ATGPX3) that exhibited a higher rate of water loss under drought stress, higher sensitivity to H2O2 treatment during seed germination and seedling development, and enhanced production of H2O2 in guard cells. By contrast, lines engineered to overexpress ATGPX3 were less sensitive to drought stress than the wild type and displayed less transpirational water loss, which resulted in higher leaf surface temperature. The atgpx3 mutation also disrupted abscisic acid (ABA) activation of calcium channels and the expression of ABA- and stress-responsive genes. ATGPX3 physically interacted with the 2C-type protein phosphatase ABA INSENSITIVE2 (ABI2) and, to a lesser extent, with ABI1. In addition, the redox states of both ATGPX3 and ABI2 were found to be regulated by H2O2. The phosphatase activity of ABI2, measured in vitro, was reduced approximately fivefold by the addition of oxidized ATGPX3. The reduced form of ABI2 was converted to the oxidized form by the addition of oxidized ATGPX3 in vitro, which might mediate ABA and oxidative signaling. These results suggest that ATGPX3 might play dual and distinctive roles in H2O2 homeostasis, acting as a general scavenger and specifically relaying the H2O2 signal as an oxidative signal transducer in ABA and drought stress signaling. [ABSTRACT FROM AUTHOR]

Abstract: A 23-kDa antifungal thaumatin-like protein was isolated and purified from Cassia didymobotrya (Fres.) cell cultures for the first time. The protein was secreted in the culture medium, but it could be also isolated after elution of whole cells with a 0.5 M CaCl2 solution. Treatment of the cells with laminarin oligosaccharides or salicylic acid, but not with NaCl, resulted in enhancement of expression of the protein. A rapid purification protocol was used based on cationic exchange chromatography. The protein, with a highly basic character (pI 10), has an exact molecular mass of 23034 Da, as determined by MALDI-ToF mass spectrometry analysis. N-terminal sequencing of the intact polypeptide and the sequencing of two internal tryptic peptides indicated significant identity with other thaumatin-like proteins (TLP). The protein exerted antifungal activity towards some Candida species showing EC50 values comparable to those of other antifungal TLPs. The collected data lead to classify this TLP as a new PR-5 protein. [Copyright &y& Elsevier]

Abstract: Oligochitosan induces defense responses to pathogenic microbes in a wide variety of plants by acting as an elicitor. In the present study, mRNA differential display was used to investigate oligochitosan-induced transcriptional activation of defense-related genes. Accordingly, a novel Ser/Thr protein kinase gene was isolated and designated as oligochitosan-induced protein kinase (oipk). Molecular cloning showed that oipk contains six introns interrupted by seven exons. The open reading frame (ORF) of the gene is 1848 bp, which encodes a putative protein of 615 amino acids with the predicted molecular mass of 70.96 kDa and a pI of 6.32. A plant oipk antisense expression vector was constructed and transformed into tobacco by Agrobacterium tumefaciens. Decreased phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity and decreased resistance to tobacco mosaic virus (TMV) were observed in transgenic tobacco. RT-PCR analysis revealed that oipk was expressed at high levels after oligochitosan induction in wild-type tobacco, but not in transgenic tobacco. These results indicated that oipk is involved in the signal pathway of oligochitosan-induced resistance in tobacco. [Copyright &y& Elsevier]

Gametophytic self-incompatibility (SI) systems in plants exhibit high polymorphism at the SI controlling S-locus because individuals with rare alleles have a higher probability to successfully pollinate other plants than individuals with more frequent alleles. This process, referred to as frequency-dependent selection, is expected to shape number, frequency distribution, and spatial distribution of self-incompatibility alleles in natural populations. We investigated the genetic diversity and the spatial genetic structure within a Prunus avium population at two contrasting gene loci: nuclear microsatellites and the S-locus. The S-locus revealed a higher diversity (15 alleles) than the eight microsatellites (4–12 alleles). Although the frequency distribution of S-alleles differed significantly from the expected equal distribution, the S-locus showed a higher evenness than the microsatellites (Shannon's evenness index for the S-locus: E = 0.91; for the microsatellites: E = 0.48–0.83). Also, highly significant deviations from neutrality were found for the S-locus whereas only minor deviations were found for two of eight microsatellites. A comparison of the frequency distribution of S-alleles in three age-cohorts revealed no significant differences, suggesting that different levels of selection acting on the S-locus or on S-linked sites might also affect the distribution and dynamics of S-alleles. Autocorrelation analysis revealed a weak but significant spatial genetic structure for the multilocus average of the microsatellites and for the S-locus, but could not ascertain differences in the extent of spatial genetic structure between these locus types. An indirect estimate of gene dispersal, which was obtained to explain this spatial genetic pattern, indicated high levels of gene dispersal within our population (σg = 106 m). This high gene dispersal, which may be partly due to the self-incompatibility system itself, aids the effective gene flow of the microsatellites, thereby decreasing the contrast between the neutral microsatellites and the S-locus. [ABSTRACT FROM AUTHOR]

Linkage maps developed from known-function genes can be valuable in the candidate gene mapping approach. A set of 121 expressed sequence tagged site (E-STS) primer pairs were tested on a framework genetic linkage map of apple (Malus × domestica Borkh.) constructed using simple sequence repeats (SSRs) and randomly amplified polymorphic DNA (RAPD) markers. These known-function gene markers, E-STSs, were supplemented by markers for resistance gene analogues (RGAs), designed based on conserved motifs in all characterized resistance genes isolated from plant species. A total of 229 markers, including 46 apple E-STSs, 8 RGAs, 85 SSRs from apple and peach, and 88 RAPDs, were assigned to 17 linkage groups covering 832 cM of the apple genome, based on 52 individuals originating from the cross 'Antonovka debnicka' (Q12-4) × 'Summerred'. Clusters of E-STS and RGA loci were located in linkage groups previously identified to carry resistance genes, some of which confer resistance to apple scab disease caused by Venturia inaequalis (Cke.) Wint. [ABSTRACT FROM AUTHOR]

Near-isogenic lines (NILs) are ideal materials for precise estimation of quantitative trait loci (QTL) effects and map-based gene isolation. With the completion of the rice genome sequence, QTL isolation based on NILs is becoming a routine. In this study, a trait-performance derived NIL strategy was adopted to develop NILs. Two plants were identified within one inbred line of recombinant inbred lines (RILs, F7 generation), exhibiting a significant difference in panicle size. By marker screening of the whole genome the genetic background of the two plants was estimated to be 98.7% identical. These two plants were selected as parents to produce a near-isogenic F2 (NIL-F2) population, consisting of 125 individuals, in which spikelets per panicle (SPP), grains per panicle (GPP), heading date (HD) and plant height (PH) were recorded. These four traits expressed discontinuous or bimodal distribution in the NIL-F2 population and followed the expected segregation ratios for a single Mendelian factor by progeny tests. A partial dominant QTL for the four traits was mapped to the same interval flanked by RM310 and RM126 on chromosome 8. The QTL region explained 83.0, 80.2, 94.9 and 93.8% of trait variation of SPP, GPP, HD and PH in the progenies, respectively. Progeny tests also confirmed co-segregation of QTL for the four traits, tall plants consistently flowering late and carrying large panicles. Different NILs development strategies are discussed. [ABSTRACT FROM AUTHOR]

Production of hybrid corn (Zea mays L) depends on cross-pollination between male and female inbred parents. As such, reproductive isolation of seed fields is required to ensure genetic purity of the hybrid progeny. Customer demand for improved genetic purity prompted the seed industry to examine the level of genetic purity resulting from current isolation practices. A 3-yr study was conducted to monitor purity of hybrid seed produced in 315 fields from 24 seed companies in North America. Each field was near a commercial corn field shedding pollen synchronously with the seed parent: a worse case scenario. Seed samples were collected at five locations along a 200-m transect established perpendicular to the nearest potential adventitious pollen source, and 100 seed from each location were subjected to isozyme analysis to determine percent out-crossing. Isolation distance, seed field size, field block size, number of border rows, adventitious field size, male:female row ratio, male population, and male pollen class were analyzed as continuous predictors and as variable class predictors of out-crossing at the field margins and field midpoints. Year had a significant (p ≤ 0.05) impact on observed out-crossing. Isolation distance, border rows, and male pollen class were significant predictors of out-crossing at the field margin but not at the field midpoint. A significant interaction between isolation distance and border rows was observed at both the field margin and midpoint. There also was an interaction between male:female ratio and male pollen class on out-crossing at the field margin. These results indicate that current practices used to isolate hybrid seed fields often achieve the goal of producing ≥99% genetically pure seed, but much higher levels of out-crossing can and do occur. Because out-crossing generally was greater and more variable at the field margins than at the field midpoint, adjustments to field management that focus on minimizing out-crossing at the field margins should lead to consistently high levels of genetic purity from hybrid seed fields. [ABSTRACT FROM AUTHOR]

Two hundred and seventy five bacterial strains were isolated from the floodwater of a Japanese paddy field during rice cultivation and the cells from 205 of these strains were negative for Gram stain. One hundred and nineteen isolates negative for Gram stain were randomly chosen and subjected to sequencing of partial 16S rDNA to compare with DNA clones obtained from floodwater using the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) method. The isolates belonged to α-, β-, and γ-Proteobacteria and the Cytophaga–Flavobacterium–Bacteroides (CFB) group as well as high-GC and low-GC Gram-positive bacteria, with proportions of 47.9, 7.6, 11.8, 13.4, 4.2 and 15.1%, respectively. Although their DNA sequences did not match the sequences of the DNA clones obtained from the floodwater of a neighboring paddy field, some isolates showed identical DNA sequences to DNA clones from rice straw in soil and rice roots. Phylogenetic distribution of the isolates was wider than that of the DNA clones obtained from the floodwater using the DGGE method. As the CFB cluster consisted exclusively of the isolates and the DNA clones obtained from the floodwater and from microcrustaceans, and the other isolates shared the α-, β- and γ-Proteobacterial clusters with the DNA clones associated with rice straw in soil, microcrustaceans, percolating water and rice roots, bacterial communities in the floodwater were estimated to include floodwater-specific members as well as members associated with other habitats in the paddy fields. [ABSTRACT FROM AUTHOR]

A major fusarium head blight (FHB) resistance gene Fhb1 (syn. Qfhs.ndsu-3BS) was fine mapped on the distal segment of chromosome 3BS of spring wheat ( Triticum aestivum L.) as a Mendelian factor. FHB resistant parents, Sumai 3 and Nyubai, were used as sources of this gene. Two mapping populations were developed to facilitate segregation of Qfhs.ndsu-3BS in either a fixed resistant (Sumai 3*5/Thatcher) (S/T) or fixed susceptible (HC374/3*98B69-L47) (HC/98) genetic background (HC374 = Wuhan1/Nyubai) for Type II resistance. Type II resistance (disease spread within the spike) was phenotyped in the greenhouse using single floret injections with a mixture of macro-conidia of three virulent strains of Fusarium graminearum. Due to the limited heterogeneity in the genetic background of the crosses and based on the spread of infection, fixed recombinants in the interval between molecular markers XGWM533 and XGWM493 on 3BS could be assigned to discrete “resistant” and “susceptible” classes. The phenotypic distribution was bimodal with progeny clearly resembling either the resistant or susceptible parent. Marker order for the two maps was identical with the exception of marker STS-3BS 142, which was not polymorphic in the HC/98 population. The major gene Fhb1 was successfully fine mapped on chromosome 3BS in the same location in the two populations within a 1.27-cM interval (S/T) and a 6.05-cM interval (HC/98). Fine mapping of Fhb1 in wheat provides tightly linked markers that can reduce linkage drag associated with marker-assisted selection of Fhb1 and assist in the isolation, sequencing and functional identification of the underlying resistance gene. [ABSTRACT FROM AUTHOR]

Abstract: Heat-shock (HS) response is universal and many HS protein (Hsp) genes are highly conserved in all organisms. Plants, being sessile, may require unique genes to tolerate frequent temperature fluctuation in nature environment. However, this aspect has not been well explored. Here, we report the study on a novel Hsp gene, Hsa32, which encodes a HS-associated 32kDa protein. Hsa32 cDNA was isolated from a subtractive library prepared from tomato HS-induced versus control mRNA. Unlike the multigene families of many well-characterized Hsps, only one copy of Hsa32 exists in the tomato genome as shown by Southern blot. In addition to HS, the gene was also induced by salt, osmotic and oxidative stresses but to a much lower extent than by heat. Under non-HS conditions, LeHsa32 transcripts were more abundant in fruits, flowers and cultured cells. Multiple alternatively spliced forms of Hsa32 transcripts were observed in the HS-treated tomato flower but not in the leaf. Heterologous expression of a fusion protein of Arabidopsis HsfA1b and GUS in tomato results in the up-regulation of Hsa32 without heat treatment. So far, homologs of tomato Hsa32 could be found mainly in land plants and some microbes. Phylogenic analysis suggests that Hsa32 shares a common ancestor with bacterial phosphosulfolactate synthase. Identification of Hsa32 supports the idea that plants possess special features in HS response. [Copyright &y& Elsevier]

Abstract: We report the cloning of a cDNA from TcAG, an AG (Arabidopsis thaliana MADS-box C-type transcription factor gene AGAMOUS) homologue from cocoa (Theobroma cacao L.). TcAG was in the cocoa flower expressed primarily in stamens and ovaries, comparable to AG in Arabidopsis. Additionally, we found that TcAG is also expressed in the fruit (pod) wall and during its entire development, as well as in the fruit pulp. Ectopic expression of TcAG in transgenic A. thaliana plants resulted in a range of weak to strong apetala2 (ap2) mutant-like phenotypes as well as early flowering and curly leaves, as observed in other studies of plants overexpressing a functional AG homologue. The severity of the phenotypes correlated positively with the TcAG transcript level in the transgenic plants. [Copyright &y& Elsevier]

Determining the genetic structure of an in situ conserved population can provide insight into the dynamics of population genetic processes associated with successful plant conservation. We used 21 microsatellite loci to analyse the genetic relationships among individuals ( n= 813) collected from a small Oryza rufipogon population conserved since 1993 in Hunan Province of China. The analysis revealed four distinct genetic subpopulations ( FST= 0.145) without geographic isolation. One subpopulation was composed of possible introgressed individuals, two subpopulations were composed of seed recruits and their descendants, and the fourth subpopulation consisted of reintroduced individuals, seed recruits and their descendants. Positive spatial genetic structures were detected by spatial autocorrelation statistics at the population ( c. 63 m) and subpopulation levels (11–30 m), but the degree of autocorrelation was stronger at the population level. These results showed that prejudging the cryptic structure is important before autocorrelation analysis for the entire population. Our study suggests that population history can be a significant determinant on population structure for plant restoration projects. [ABSTRACT FROM AUTHOR]

Races and vegetative compatibility groups (VCGs) in Greek isolates of Fusarium oxysporum f. sp. melonis (Fom) were characterized. Three races (0, 2 and 1–2) among 12 isolates tested and two VCGs among 19 isolates tested, were identified. Race 1–2 was the most common and race 1 was not detected. One widespread VCG corresponded to a VCG previously reported from Israel (coded 0138), and included seven isolates of races 0 and 1–2. The other VCG, which was unclassified, included four isolates of races 0, 2 and 1–2. The latter VCG was detected only in a specific melon-growing location of Evros. The remaining eight isolates tested for VCG did not show positive reactions with other isolates, with each other or with the testers of VCGs 0135 or 0138, although they produced complementary mutants. Using two inoculation methods, the local cv. ‘Golden Head’ was found susceptible to all known Fom races, and especially to race 1–2. These results show the presence of more than one VCG and the widespread distribution of the race 1–2, in Greece. [ABSTRACT FROM AUTHOR]

Abstract: Searching for anti-HIV-1 protease (PR) inhibitors of Thai medicinal plants led to the isolation of a new cyclohexenyl chalcone named panduratin C (1) and chalcone derivatives (2–6) from the methanol extract of Boesenbergia pandurata rhizomes. The known compounds were identified to be panduratin A (2), hydroxypanduratin A (3), helichrysetin (4), 2′,4′,6′-trihydroxyhydrochalcone (5), and uvangoletin (6). The structures of all compounds were elucidated on the basis of chemical and spectroscopic methods. It was found that 3 possessed the most potent anti-HIV-1 PR activity with an IC50 value of 5.6μM, followed by 2 (IC50 =18.7μM), whereas other compounds exhibited only mild activity. Structure–activity relationships of these compounds on anti-HIV-1 PR activity are summarized as follows: (1) hydroxyl moiety at position 4 conferred higher activity than methoxyl group; (2) prenylation of dihydrochalcone was essential for activity; (3) hydroxylation at position 4‴ reduced activity; and (4) introduction of double bond at C1′ and C6′ of chalcone gave higher activity. As regards active constituents contained in B. pandurata rhizomes, hydroxypanduratin A (3) and panduratin A (2) are active principles against HIV-1 PR. [Copyright &y& Elsevier]

Abstract: Polymeric polyphenols are the most abundant pigments in black tea. Very limited information is available on the isolation and chemical characterization of these compounds. The present paper reports the comparative yields, physicochemical properties and preliminary biological activities of five polymeric black tea polyphenol (PBP) fractions isolated by liquid–liquid and Soxhlet-based solid (tea powder)–liquid extraction methods. The two methods have also been comparatively evaluated as regards cost, time, labour and practicality of scale-up. Overall, results show that PBP fractions, isolated by both the procedures, were free of other known biologically active monomeric and oligomeric components, and have similar physicochemical properties and biological effect(s). Solid–liquid extraction results in a relatively greater yield of PBP-1 to -3, significant reduction in cost, time and labour and also makes scale-up relatively easier. [Copyright &y& Elsevier]

Background: Transient assays using protoplasts are ideal for processing large quantities of genetic data coming out of hi-throughput assays. Previously, protoplasts have routinely been prepared from dicot tissue or cell suspension cultures and yet a good system for rice protoplast isolation and manipulation is lacking. Results: We have established a rice seedling protoplast system designed for the rapid characterization of large numbers of genes. We report optimized methods for protoplast isolation from 7-14 day old etiolated rice seedlings. We show that the reporter genes luciferase GL2 and GUS are maximally expressed approximately 20 h after polyethylene glycol (PEG)-mediated transformation into protoplasts. In addition we found that transformation efficiency varied significantly with plasmid size. Five micrograms of a 4.5 kb plasmid resulted in 60-70% transformation efficiency. In contrast, using 50 μg of a 12 kb plasmid we obtained a maximum of 25-30% efficiency. We also show that short interfering RNAs (siRNAs) can be used to silence exogenous genes quickly and efficiently. An siRNA targeting luciferase resulted in a significant level of silencing after only 3 hours and up to an 83% decrease in expression. We have also isolated protoplasts from cells prepared from fully green tissue. These green tissue-derived protoplasts can be transformed to express high levels of luciferase activity and should be useful for assaying light sensitive cellular processes. Conclusion: We report a system for isolation, transformation and gene silencing of etiolated rice leaf and stem-derived protoplasts. Additionally, we have extended the technology to protoplasts isolated from fully green tissue. The protoplast system will bridge the gap between hi-throughput assays and functional biology as it can be used to quickly study large number of genes for which the function is unknown. [ABSTRACT FROM AUTHOR]

Anionic peroxidase (p I ∼ 3.5) and oxalate oxidase (p I ∼ 7.0) were isolated from wheat seedlings using chitin. The strength of binding of enzymes with chitin depended on the degree of its acetylation and the ionic strength of the buffer. It was assumed that the acetyl groups of chitin are involved in sorption of enzymes on this biopolymer. The ability of anionic peroxidase and oxalate oxidase for sorption on chitin allows this biopolymer to be used for isolation of these proteins from plants. Coadsorption of anionic peroxidase and oxalate oxidase on chitin suggests that these enzymes cooperate to ensure a defensive response of wheat against chitin-containing pathogens. [ABSTRACT FROM AUTHOR]

Development of improved genetic traits in maize (Zea mays L.) requires robust measures to prevent pollen-mediated gene flow (PMGF) and assure isolation of new traits, whether these traits are the result of conventional breeding or of modern genetic techniques. Studies were conducted in California and Washington to evaluate the relationship of distance and temporal separation for isolation from PMGF. Kernel color was used to detect outcrossing from source plots of 0.4 to 1.2 ha in size to receptor plots planted at distances up to 750 m and planting intervals of up to 3 wk from the pollen source. Outcrossing from source to receptor plots was observable to 0.0002% (1 kernel in ≈500 000 kernels). Increasing temporal separation reduced the distance required to achieve genetic isolation. Outcrossing was <0.01% at 500 m when source and receptors flowered at the same time, whereas this level of confinement was achieved at 62 m or less when 2 wk of temporal separation was used. No outcrossing was detected at 750 m and 2 wk of temporal separation. This is the first practical evaluation of time and distance acting together to achieve genetic purity in maize. [ABSTRACT FROM AUTHOR]

The nirS nitrite reductase genes were studied in two strains (strains 27 and 28) isolated from two denitrifying reactors and characterized as Thauera according to their 16S rRNA gene sequences. Strain 28 contains a single nirS sequence, which is related to the nirS of Thauera mechernichensis, and strain 27 contains two nirS sequences; one is similar to the nirS sequence from Thauera mechernichensis (gene 2), but the second one (gene 8) is from a separate clade with nirS from Pseudomonas stutzeri, Azoarcus species, Alcaligenes faecalis, and other Thauera species. Both genes were expressed, but gene 8 was constitutively expressed while gene 2 was positively regulated by nitrate. [ABSTRACT FROM AUTHOR]

Habitat fragmentation can affect levels of herbivory in plant populations if plants and herbivores are differentially affected by fragmentation. Moreover, if herbivores are top–down controlled by predators or parasitoids, herbivory may also be affected by differential effects of fragmentation on herbivores and their natural enemies. We used natural Silene latifolia populations to examine the effects of plant population size and isolation on the level of herbivory by the seed predating noctuid Hadena bicruris and the rate of parasitism of the herbivore by its parasitoids. In addition, we examined oviposition rate, herbivory and parasitism in differently sized experimental populations. In natural populations, the level of herbivory increased and the rate of parasitism decreased with decreasing plant population size and increasing degree of isolation. The number of parasitoid species also declined with decreasing plant population size. In the experimental populations, the level of herbivory was also higher in smaller populations, in accordance with higher oviposition rates, but was not accompanied by lower rates of parasitism. Similarly, oviposition rate and herbivory, but not parasitism rate, increased near the edges of populations. These results suggests that in this system with the well dispersing herbivore H. bicruris, habitat fragmentation increases herbivory of the plant through a behavioural response of the moth that leads to higher oviposition rates in fragmented populations with a reduced population size, increased isolation and higher edge-to-interior ratio. Although the rate of parasitism and the number of parasitoid species declined with decreasing population size in the natural populations, we argue that in this system it is unlikely that this decline made a major contribution to increased herbivory. [ABSTRACT FROM AUTHOR]

Describes the isolation of ZKT (for the protein containing a PDZ domain, a K-box region, and a TPR region), in Arabidopsis and its expression pattern in response to wounding. Demonstration of the phosphorylation status of the ZKT protein after wounding; Results suggesting that the ZKT protein may act as a molecular adaptor regulated by phosphorylation in wound responses; Expression of the ZKT gene in Escherichia coli and antibody production; Indication that the level of ZKT protein does not change after wounding.

Novel eukaryotic chlorophyll–carotenoid proteins have evolved at least twice following the origin of the plastid and include the widely distributed integral membrane light-harvesting complexes (LHCs) and the dinoflagellate-specific soluble peridinin–chlorophyll proteins. In the glaucophytes, homologs of these proteins are reportedly absent. We have identified a novel carotenoid-rich protein (CRP) in the glaucophyte Cyanophora paradoxa that is 28 kDa and immunologically related to the family of LHCs. CRP is associated with the thylakoid membrane, though it can be removed by stringent washes, suggesting that there are probably significant structural differences between CRP and the LHCs. CRP co-localizes with a zeaxanthin-rich thylakoid membrane fraction that also contains β-carotene, chlorophyll and an unidentified carotenoid. Despite this, we found no evidence for carotenoid–chlorophyll energy transfer in the isolated complex, suggesting that light harvesting may not be a primary function. The presence of CRP in C. paradoxa is evidence for the evolution of a novel pigment-binding protein in the glaucophytes. [ABSTRACT FROM AUTHOR]

A collection of Activator (Ac)-containing, near-isogenic W22 inbred lines has been generated for use in regional mutagenesis experiments. Each line is homozygous for a single, precisely positioned Ac element and the Ds reporter, r1-sc:m3. Through classical and molecular genetic techniques, 158 transposed Ac elements (tr-Acs) were distributed throughout the maize genome and 41 were precisely placed on the linkage map utilizing multiple recombinant inbred populations. Several PCR techniques were utilized to amplify DNA fragments flanking tr-Ac insertions up to 8 kb in length. Sequencing and database searches of flanking DNA revealed that the majority of insertions are in hypomethylated, low- or single-copy sequences, indicating an insertion site preference for genic sequences in the genome. However, a number of Ac transposition events were to highly repetitive sequences in the genome. We present evidence that suggests Ac expression is regulated by genomic context resulting in subtle variations in Ac-mediated excision patterns. These tr-Ac lines can be utilized to isolate genes with unknown function, to conduct fine-scale genetic mapping experiments, and to generate novel allelic diversity in applied breeding programs. [ABSTRACT FROM AUTHOR]

This study demonstrates that the putative ER-located Hsp90, XVGrp94, is upregulated under conditions of stress, and is the first report of such upregulation in response to desiccation stress. XVGrp94 was identified by differential screening of a cDNA library from a dehydrated resurrection plant Xerophyta viscosa Baker. Sequence analysis revealed that the cDNA potentially encoded a protein of 812 amino acids with a calculated molecular weight of 92.83kDa. Amino acid sequence comparisons revealed significant homology to several Grp94s from plants with the highest similarity to Grp94 from Oryza sativa (82.74%), Catharanthus roseus (81.97%), Hordeum vulgare (80.10%) and Arabidopsis thaliana (77.45%). The sequence contains the Hsp90 protein family signature, NKDIFL, a putative eukaryotic secretory signal, and the endoplasmic reticulum targeting and retention signal, KDEL. Residues that interact with ATP within the N-terminal domain of Hsp90s are conserved in the N-domain of the putative XVGrp94, indicating that it is potentially capable of ATP binding and hydrolysis. Southern blot analysis confirmed the presence of the XVGrp94 gene within the X. viscosa genome and the results suggest the possibility of homologues. Western blot analysis showed that the XVGrp94 expression increased significantly in response to heat and dehydration, and slightly in response to high salinity. No response was seen in response to high light, cold treatment or exogenous ABA (abscisic acid) application. [ABSTRACT FROM AUTHOR]

Bleomycin is an antitumor agent believed to act by damaging DNA. It is currently used for treating testicular carcinomas, but other types of cancers such as ovarian and colon are resistant to the drug from the outset. The mechanism involved in allowing cells to confer resistant to bleomycin is not known. We exploited the power of yeast genetics to isolate for the first time several bleomycin-resistant mutants derived from a strain deleted for the IMP2 gene encoding a transcriptional co-activator. imp2Δ mutants are known to be hypersensitive to bleomycin, monovalent and divalent cations, and high pH. The suppressors of imp2Δ showed extreme resistance to bleomycin and also either fully or partially rescued the phenotypes associated with the imp2Δ mutant, suggesting that bleomycin resistance is linked to other phenotypes. Using fluorescently labeled bleomycin, we demonstrated that two bleomycin-resistant variants, MAY1 and MAY2, were compromised for uptake of the drug, as compared with the parent. In contrast, the imp2Δ mutant showed a substantial increase in the uptake of fluorescently labeled bleomycin. We further showed that strains MAY1 and MAY2 contain a reduced amount of a plasma membrane protein, which binds to 57Co-labeled bleomycin and is believed to mediate drug entry into the cell. We propose that the bleomycin-resistant mutants are likely defective in a process responsible for transporting the drug into the cell. [ABSTRACT FROM AUTHOR]

A synthetic gene encoding the tandem affinity purification (TAP) tag has been constructed, and the TAP tag assayed for its effects on expression levels and subcellular localization by fusion to green fluorescent protein (GFP) as well as for its effects on steroid-dependent translocation to the nucleus and transcription when fused to a hybrid glucocorticoid receptor. A nuclear localization signal (NLS) was detected in the calmodulin-binding protein (CBP) domain and removed by mutation to improve the usefulness of the TAP tag. Additionally, purification improvements were made, including inhibition of a co-purifying protease, and adding a protein cross-linking step to increase the recovery of interacting proteins. The improved synthetic TAP tag gene and methods were used to isolate proteins interacting with the hybrid glucocorticoid receptor and to identify them by mass spectrometry. The two proteins identified, HSP70 and HSP90, are known to interact with the glucocorticoid receptor in vivo in mammalian cells and in vitro in plants. [ABSTRACT FROM AUTHOR]

• Background and Aims Isolation and drift are the main causes for geographic structure of molecular variation. In contrast, the one found in a previous survey in Armeria (Plumbaginaceae) for nuclear ribosomal ITS multicopy regions was species-independent and has been hypothesized to be due to extensive gene-flow and biased concerted evolution. Since this was inferred from a genus-level phylogenetic analysis, the aim of this study was to check for the occurrence of such structure and the validity of the proposed model at a local scale, in a southern Spanish massif (Sierra Nevada), as well as to examine the evolutionary implications at the organism level. • Methods In addition to 117 sequences of direct PCR products from genomic DNA, 50 sequences of PCR products from cloned DNA were obtained to analyse cases of intragenomic polymorphisms for the ITS regions. • Key Results Sequence data confirm the occurrence of a species-independent structure at a local scale and reveal insights through the analysis of contact areas between different ITS copies (ribotypes). A comparison between cloned and direct sequences (a) confirms that, within these contact areas, ITS copies co-occur both in different individuals and within single genomes; and (b) reveals recombination between different copies. • Conclusions This study supports the utility of direct sequences for detecting intra-individual polymorphism and for partially inferring the ITS copies involved, given previous knowledge of the variability. The main evolutionary implication at the organism level is that gene-flow and concerted evolution shape the geographic structure of ITS variation. [ABSTRACT FROM AUTHOR]

Gene isolation from plants by positional cloning frequently requires several rounds of transformation. To reduce the resources invested and to accelerate the process, we have used large DNA fragments in transformation experiments, followed by analysis of transgenic plants to assess functional complementation. Specifically, the transformation of potato with DNA from the 106 kb BAC plasmid BA87d17 is described. The large fragment was introduced into the potato genome by biolistic transformation, while attempting to clone the R1 gene conferring a race specific resistance to Phytophthora infestans. Thirty-one kanamycin resistant plants were regenerated of which thirteen showed the necrotic lesions typical for the hypersensitive response after infection with the incompatible P. infestans race 4, which carries the avirulence gene Avr1. The successful complementation supported the location of the R1 gene in the BAC insertion of the BA87d17 plasmid. Based on PCR and Southern gel blot analysis, both complete and incomplete integrations of the large construct into the recipient genome were demonstrated. [ABSTRACT FROM AUTHOR]

Background: Mutagenesis of yeast artificial chromosomes (YACs) often requires analysis of large numbers of yeast clones to obtain correctly targeted mutants. Conventional ways to isolate yeast genomic DNA utilize either glass beads or enzymatic digestion to disrupt yeast cell wall. Using small glass beads is messy, whereas enzymatic digestion of the cells is expensive when many samples need to be analyzed. We sought to develop an easier and faster protocol than the existing methods for obtaining yeast genomic DNA from liquid cultures or colonies on plates. Results: Repeated freeze-thawing of cells in a lysis buffer was used to disrupt the cells and release genomic DNA. Cell lysis was followed by extraction with chloroform and ethanol precipitation of DNA. Two hundred ng - 3 µg of genomic DNA could be isolated from a 1.5 ml overnight liquid culture or from a large colony. Samples were either resuspended directly in a restriction enzyme/ RNase coctail mixture for Southern blot hybridization or used for several PCR reactions. We demonstrated the utility of this method by showing an analysis of yeast clones containing a mutagenized human β-globin locus YAC. Conclusion: An efficient, inexpensive method for obtaining yeast genomic DNA from liquid cultures or directly from colonies was developed. This protocol circumvents the use of enzymes or glass beads, and therefore is cheaper and easier to perform when processing large numbers of samples. [ABSTRACT FROM AUTHOR]

Fifty-one endophytic isolates of Aureobasidium pullulans were obtained from the flesh of sweet cherries and extensively screened to evaluate their biocontrol activity against postharvest rots of sweet cherries and table grapes. Preliminary analysis of all isolates by randomly amplified polymorphic DNA (RAPD) with three different primers showed the presence of a high genetic variability and enabled isolates not showing any genetic difference to be discarded. Thirty-five isolates with different RAPD electrophoresis patterns had a wide range of biocontrol activity against Botrytis cinerea and Monilinia laxa on single-wounded berries of sweet cherries and table grapes with a reduction of decay from 10 to 100%. Two isolates (533 and 547) significantly reduced B. cinerea on table grape berries also when applied 6, 12, and 24 h after the pathogen inoculation. In a 2-year period of investigation (1998–1999), a reduction of total rots ranging from 32 to 80% (sweet cherries) and from 59 to 64% (table grape) was achieved with isolates 533 and 547 applied after harvest. Preharvest applications of isolate 547 significantly reduced postharvest rots of sweet cherries and table grapes by 47 and 38%, respectively. On the whole, isolates 533 and 547 were more effective than A. pullulans L47, a biocontrol agent of postharvest diseases with a known activity. Population studies demonstrated that isolate 547 was able to survive under field conditions, to increase its population during cold storage, and to penetrate the flesh of sweet cherries when applied during flowering. [Copyright &y& Elsevier]

To develop simple sequence repeat (SSR) markers for the hexaploid forage grass timothy (Phleum pratense L.), we used four SSR-enriched genomic libraries to isolate 1,331 SSR-containing clones. All four libraries contained a high percentage of perfect clones, ranging from 78.1% to 91.6%. From these clones, we developed 355 SSR markers when tested from 502 SSR primer pairs. Using all 355 SSR markers we tested one screening panel consisting of eight timothy clones to detect the level of polymorphism and identify a set of loci suitable for framework mapping. The SSR markers detected 90.4% polymorphism between the parents of a pseudo-testcross F1 population. These SSR markers will provide an ideal marker system to assist with gene targeting, QTL (quantitative trait locus) mapping, and marker-assisted selection in timothy. [ABSTRACT FROM AUTHOR]

MsPG3 is a Medicago sativa polygalacturonase gene isolated in our laboratory, its expression during nodule development is associated with the presence of Sinorhizobium meliloti. By RT-PCR and in situ hybridization studies we showed the early induction of MsPG3 expression after inoculation of M. sativa plants with the microsymbiont, suggesting a role for MsPG3 product in the early stages of the interaction. To localize its expression in nodule as well as to characterize the transcriptional regulation of MsPG3, Medicago truncatula transgenic plants containing a 2.7 kb MsPG3 promoter-β-glucuronidase (gus) gene fusion have been obtained. These transgenic plants showed nodule-specific gus expression pattern. Five MsPG3 promoter fragments of different length (from 600 to 92 bp) fused to gus gene have been used to transform M. truncatula in order to determine the promoter regions responsible of this nodule specificity. The region between 600 and 413 bp of MsPG3 promoter was found necessary for transgenic gus expression in nodules. This result was also confirmed in V. hirsuta transgenic `hairy roots'. At position -474/-492 bp upstream of the start codon a sequence was identified that is homologous to the binding site of the transcription factor ENBP1. Our results suggest that MsPG3 expression in nodules could be regulated through this element. [ABSTRACT FROM AUTHOR]

The genetic analyses of nine Far East Asian Saccharomyces isolates allowed us to identify three species (S. cerevisiae, S. paradoxus, and S. bayanus). The occurrence of the last species in Far East Asia was shown for the first time. A new methodology for the molecular genetic differentiation of Saccharomyces sensu stricto species is described. The ecogeographical distribution of Saccharomyces yeasts is discussed. [ABSTRACT FROM AUTHOR]

Focuses on the isolation and characterization of RH3 gene in rice using RNA gel blotting and RNA hybridization. Expression regulations of the gene in response to hormones and abiotic stress treatments; Defense mechanism of the rice to brown planthopper.

Presents a study which investigated the nature of reproductive isolation between Mimulus lewisii and M. cardinalis, sister species of monkeyflowers. Review of related literature; Data and methods used; Results and discussion.

Summary We describe the isolation and characterization of ICL1 from the rice blast fungus Magnaporthe grisea , a gene that encodes isocitrate lyase, one of the principal enzymes of the glyoxylate cycle. ICL1 shows elevated expression during development of infection structures and cuticle penetration, and a targeted gene replacement showed that the gene is required for full virulence by M. grisea . In particular, we found that the prepenetration stage of development, before entry into plant tissue, is affected by loss of the glyoxylate cycle. There is a delay in germination, infection-related development and cuticle penetration in Δicl1 mutants. Recent reports have shown the importance of the glyoxylate cycle in the virulence of the human pathogenic fungus Candida albicans and the bacterial pathogen Mycobacterium tuberculosis . Our results indicate that the glyoxylate cycle is also important in this plant pathogenic fungus, demonstrating the widespread utility of the pathway in microbial pathogenesis. [ABSTRACT FROM AUTHOR]