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Pelargonium nurseries in Europe encounter rooting problems due to the low quality of the cuttings supplied during the winter. The problem may be due to the poor quality of the stock plants from which the cuttings are harvested. The main problem that growers have is the prolonged shipping period and its effect on the viability and rootability of the cuttings once they arrive in Europe. We tested the effect of water stressing the stock plants grown grown in random block design in a commercial nursery and checked the rootability of cuttings after storage and the susceptibility of cuttings to rot. We assumed that mild water stress could harden the stock plant and thus the cuttings, and they would survive the journey better. Mild water stress improved the rooting ability of some Pelargonium varieties after days of storage compared to unstressed plants. Cuttings from water-stressed stock plants showed less decay after prolonged storage than unstressed stock plants as measured by percent rotten cutting. Chlorophyll content increased significantly in cuttings from stressed stock plants. The yield and physical parameters of the cuttings from stressed and nonstressed stock plants did not change. Results indicate that applying water stress to stock plants improves the quality of Pelargonium cuttings. Resumo Os viveiros de Pelargonium na Europa enfrentam problemas de enraizamento devido à baixa qualidade das estacas fornecidas durante o inverno. O problema se deve provavelmente à baixa qualidade das plantas matrizes das quais as estacas são colhidas. Concomitantimente, o principal problema que os produtores enfrentam é o período prolongado de envio e seu efeito na viabilidade e enraizamento das mudas quando chegam à Europa. Foi testado o efeito do estresse hídrico nas plantas matrizes cultivadas em blocos aleatórios em um viveiro comercial e verificado o enraizamento das estacas após o armazenamento e a suscetibilidade das estacas ao apodrecimento. A hipótese do trabalho foi que o estresse hídrico moderado poderia enrijecer a planta matriz e, portanto, as estacas sobreviveriam melhor ao transporte. Um baixo estresse hídrico levou a melhora na capacidade de enraizamento de algumas variedades de Pelargonium, após dias de armazenamento, em comparação com plantas não sujeitas ao estresse. As estacas de plantas matrizes sujeitas ao estresse hídrico mostraram menor decomposição após armazenamento prolongado em comparação com plantas não sujeitas ao estresse, conforme medido pela porcentagem de cortes podres. O teor de clorofila aumentou significativamente em estacas de plantas matrizes sob estresse hídrico. Não foi observada diferença na produtividade e parâmetros físicos das estacas de plantas matrizes sujeitas e não sujeitas a estressadas estresse hídrico. Os resultados indicam que o estresse hídrico em plantas matrizes melhora a qualidade das estacas de Pelargonium.

Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roots, and flowers. Tobacco plants transformed with an MYB regulatory gene from either Solanum chilense (Sc) or S. lycopersicum (Sl) demonstrate that ScANT1 induces a higher level of anthocyanin accumulation in comparison to SlANT1 and that this gene is sufficient to promote increased anthocyanin levels. We compared the aptitude of ScANT1 protein to induce anthocyanin accumulation to that of SlANT1 protein in tobacco plants. We also tested the effect of amino acid substitutions in ScANT1 and SlANT1. We examined these synthetic alleles' effect following the over-expression of additional anthocyanin synthesis regulators, such as the tomato bHLH (SlJAF13) protein. Our results show that the amino acid changes that differentiate ScANT1 from SlANT1 are the main contributors to the advantage that ScANT1 has over SlANT1 in anthocyanin accumulation per transcript unit. We further demonstrated that altering the amino acid composition of SlANT1 could increase anthocyanin accumulation, while reciprocally modifying ScANT1 lowers the anthocyanin level. These results confirm the increased anthocyanin level in tobacco is attributed to the amino acid differences between ScANT1 and SlANT1. We also show that the co-expression of SlJAF13 with SlANT1 in tobacco plants represses the anthocyanin production.

Plant pathogens usually originate and diversify in geographical regions where hosts and pathogens co-evolve. Erysiphe necator, the causal agent of grape powdery mildew, is a destructive pathogen of grapevines worldwide. Although Eastern US is considered the centre of origin and diversity of E. necator, previous reports on resistant native wild and domesticated Asian grapevines suggest Asia as another possible origin of the pathogen. By using multi-locus sequencing, microsatellites and a novel application of amplicon sequencing (AmpSeq), we show that the population of E. necator in Israel is composed of three genetic groups: Groups A and B that are common worldwide, and a new group IL, which is genetically differentiated from any known group in Europe and Eastern US. Group IL showed distinguished ecological characteristics: it was dominant on wild and traditional vines (95%); its abundance increased along the season; and was more aggressive than A and B isolates on both wild and domesticated vines. The low genetic diversity within group IL suggests that it has invaded Israel from another origin. Therefore, we suggest that the Israeli E. necator population was founded by at least two invasions, of which one could be from a non-East American source, possibly from Asian origin.

Unprecedented hot and dry spells occurred all over Israel for six days, from May 16 to May 21, 2020. Maximal air temperature reached 46.5 °C and minimal relative humidity reached 10%. The total number of hours with temperature of ≥40 °C was 45 and 41 in the coastal plain and the Judean mountains foothills, respectively. The downy mildew pathogens of cucumber and grapevine survived this extreme event, showing a rapid revival in nature soon after the heat wave. The current isolates of these oomycetes seem to be more tolerant to heat compared to the isolates of the previous century.

Black Sigatoka disease, caused by Mycosphaerella fijiensis, is considered the most damaging and costly disease of commercial banana and plantain and is mainly controlled by intensive sprays of synthetic fungicides. Essential tea tree oil derived from Melaleuca alternifolia plant was found to be effective against a wide range of plant pathogenic fungi including black Sigatoka in conventional production systems and was as effective as synthetic fungicides such as tridemorph, difenoconazole, trifloxystrobin and azoxystrobin. This paper provides evidence that tea tree oil offers an attractive alternative for controlling black Sigatoka in banana plantations.

Ruscus is an evergreen shrub that offers dark-green glossy foliage used as green additions to bouquets and flower arrangements. One of the most significant ways to obtain new varieties of crop and ornamental plants is to induce mutations by radiation. Gamma radiation is most commonly used to obtain mutants in commercial food as well as feed crops and ornamental plants. In this study, we developed tissue culture methods for Ruscus proliferation from rhizomes to obtain rhizomes clusters. These clusters were subsequently irradiated with Gamma rays to obtain unique phenotypes, such as: elongated narrow phylloclades modified stem symmetry and dwarfed growth habit. Such Ruscus types can contribute to the expansion of the floral industry. Resumo Ruscus é um arbusto sempre-verde que oferece folhagem verde-escura brilhante, utilizado como componente de buquês e arranjos de flores. Uma das formas mais significativas de obter novas variedades de plantas e plantas ornamentais é induzir mutações por radiação. A radiação Gama é mais comumente usada para obter mutantes em culturas comerciais, como as destinadas à alimentação e as plantas ornamentais. Neste estudo, foram desenvolvidos métodos de cultura de tecidos para a proliferação de Ruscus a partir de rizomas para obtenção de aglomerados de rizomas. Esses aglomerados foram subsequentemente irradiados com raios Gama para obter fenótipos únicos, tais como: filocládios estreitos e alongados modificando a simetria do caule e o hábito de crescimento anão. Esses tipos de Ruscus podem contribuir para a expansão da indústria da floricultura.

T2 ribonucleases (RNases) are RNA‐degrading enzymes that function in various cellular processes, mostly via RNA metabolism. T2 RNase‐encoding genes have been identified in various organisms, from bacteria to mammals, and are most diverse in plants. The existence of T2 RNase genes in almost every organism suggests an important biological function that has been conserved through evolution. In plants, T2 RNases are suggested to be involved in phosphate scavenging and recycling, and are implicated in defence responses to pathogens. We investigated the function of the tomato T2 RNase LE, known to be induced by phosphate deficiency and wounding. The possible involvement of LE in pathogen responses was examined. Expression analysis showed LE induction during fungal infection and by stimuli known to be associated with pathogen inoculation, including oxalic acid and hydrogen peroxide. Analysis of LE‐suppressed transgenic tomato lines revealed higher susceptibility to oxalic acid, a cell death‐inducing factor, compared to the wild type. This elevated sensitivity of LE‐suppressed lines was evidenced by visual signs of necrosis, and increased ion leakage and reactive oxygen species levels, indicating acceleration of cell death. Challenge of the LE‐suppressed lines with the necrotrophic pathogen Botrytis cinerea resulted in accelerated development of disease symptoms compared to the wild type, associated with suppressed expression of pathogenesis‐related marker genes. The results suggest a role for plant endogenous T2 RNases in antifungal activity., Suppression of the tomato T2 ribonuclease LE expression results in enhanced leaf sensitivity to the pathogen Botrytis cinerea, supporting a role for LE ribonuclease in pathogen defence.

Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this process empirically, very little is known about the early molecular genetic factors and signaling events that lead to shoot regeneration. Using tobacco as a model system, we found that the inductive events required for shoot regeneration occur in the first 4–5 days following incubation on regeneration medium. Leaf segments placed on regeneration medium did not produce shoots if removed from the medium before four days indicating this time frame is crucial for the induction of shoot regeneration. Leaf segments placed on regeneration medium for longer than five days maintain the capacity to produce shoots when removed from the regeneration medium. Analysis of gene expression during the early days of incubation on regeneration medium revealed many changes occurring with no single expression pattern evident among major gene families previously implicated in developmental processes. For example, expression of Knotted gene family members increased during the induction period, whereas transcription factors from the Wuschel gene family were unaltered during shoot induction. Expression levels of genes involved in cell cycle regulation increased steadily on regeneration medium while expression of NAC genes varied. No obvious possible candidate genes or developmental processes could be identified as a target for the early events (first few days) in the induction of shoot regeneration. On the other hand, observations during the early stages of regeneration pointed out that regeneration does not occur from a single cell but a group of cells. We observed that while cell division starts just as leaf segments are placed on regeneration medium, only a group of cells could become shoot primordia. Still, these primordia are not identifiable during the first days.

Regeneration is usually regarded as a unique plant or some animal species process. In reality, regeneration is a ubiquitous process in all multicellular organisms. It ranges from response to wounding by healing the wounded tissue to whole body neoforming (remaking of the new body). In a larger context, regeneration is one facet of two reproduction schemes that dominate the evolution of life. Multicellular organisms can propagate their genes asexually or sexually. Here I present the view that the ability to regenerate tissue or whole-body regeneration is also determined by the sexual state of the multicellular organisms (from simple animals like hydra and planaria to plants and complex animals). The above idea is manifested here by showing evidence that many organisms, organs, or tissues show inhibited or diminished regeneration capacity when in reproductive status compared to the same organism organs or tissues in nonreproductive conditions or by exposure to sex hormones.

Flavonoids are natural pigments occurring in plants and are present in fruits, leaves, stems, roots, and flowers. Tobacco plants transformed with an MYB regulatory gene from either Solanum chilense (Sc) or S. lycopersicum (Sl) demonstrate that ScANT1 induces a higher level of anthocyanin accumulation in comparison to SlANT1 and that this gene is sufficient to promote increased anthocyanin levels. We compared the aptitude of ScANT1 protein to induce anthocyanin accumulation to that of SlANT1 protein in tobacco plants. We also tested the effect of amino acid substitutions in ScANT1 and SlANT1. We examined these synthetic alleles' effect following the over‐expression of additional anthocyanin synthesis regulators, such as the tomato bHLH (SlJAF13) protein. Our results show that the amino acid changes that differentiate ScANT1 from SlANT1 are the main contributors to the advantage that ScANT1 has over SlANT1 in anthocyanin accumulation per transcript unit. We further demonstrated that altering the amino acid composition of SlANT1 could increase anthocyanin accumulation, while reciprocally modifying ScANT1 lowers the anthocyanin level. These results confirm the increased anthocyanin level in tobacco is attributed to the amino acid differences between ScANT1 and SlANT1. We also show that the co‐expression of SlJAF13 with SlANT1 in tobacco plants represses the anthocyanin production.

The essential tea tree oil (TTO) derived from Melaleuca alternifolia plant is widely used as a biopesticide to protect crops from several plant-pathogens. Its activity raised queries regarding its ability to, not only act as a bio-fungicide or bio-bactericide, but also systemically inducing resistance in plants. This was examined by TTO application to banana plants challenged by Fusarium oxysporum f. sp. cubense (Foc, Race 1) causing Fusarium wilt and to tomato plants challenged by Xanthomonas campestris. Parameters to assess resistance induction included: disease development, enzymatic activity, defense genes expression correlated to systemic acquired resistance (SAR) and induced systemic resistance (ISR) and priming effect. Spraying TTO on field-grown banana plants infected with Foc and greenhouse tomato plants infected with Xanthomonas campestris led to resistance induction in both hosts. Several marker genes of salicylic acid, jasmonic acid and ethylene pathways were significantly up-regulated in parallel with symptoms reduction. For tomato plants, we have also recorded a priming effect following TTO treatment. In addition to fungicidal and bactericidal effect, TTO can be applied in more sustainable strategies to control diseases by enhancing the plants ability to defend themselves against pathogens and ultimately diminish chemical pesticides applications.

Downy mildew caused by the oomycete Bremia lactucae Regel is a serious disease of lettuce in field and greenhouse production. Here we report on the antifungal activity of essential Australian tea tree oil (TTO) derived from Melaleuca alternifolia against downy mildew in lettuce. Preventive treatments with Timorex Gold (STK Ltd., Petach Tikva, Israel), fungicide containing TTO, suppressed the development of B. lactucae on cotyledons and young lettuce plants. Epifluorescence microscopy showed that TTO had a moderate inhibitory effect on spore germination of the pathogen but a strong inhibitory effect on sporophore emergence and hence on sporulation. Timorex Gold (22.3 EC W/V) was as effective as copper hydroxide in controlling the disease in organic field plots. It was as effective as the fungicides Bellis (Boscalid + Pyraclostrobin, BASF, Germany) and Commet (pyraclostrobin, BASF, Germany) in conventional production. The results demonstrate that Timorex Gold effectively suppresses the development of downy mildew in lettuce in growth chambers as well as in the field, and thus suitable biopesticide for its control.

Powdery mildew, caused by Pseudoidium anacardii (formerly Oidium mangiferae Berthet), attacks panicles, young fruits, and leaves of mango trees; it may cause considerable crop loss. Mango is the only known host of this pathogen. Disease management in Israel has not been investigated extensively; it is based on field observations by the Agricultural Extension Service, which instructs growers to spray at 14-d intervals, starting from the beginning of bloom when the first flowers appear in the orchard, or after rain events; rain events during flowering promote development of the disease. The present study found that fungicides applied to panicles at 10-d intervals after they reached a length of 5 or 10 cm improved disease control compared with spraying at 14-d intervals. Earlier applications did not improve disease control; later applications, beginning at the first-open-flower stage, were less effective. Foliar sprays applied before rain events provided better disease control than spraying after the rain. In Israel, about 30 fungicides against mango powdery mildew are registered, but no comparative trials for fungicide efficacy have been conducted in recent years. Efficacy trials showed that the most effective fungicides were penconazole, myclobutanil, tetraconazole, and an improved formulation of mineral oil. A tank mixture of systemic fungicide with a reduced sulfur content (up to 60%) was as effective as, or slightly more so than each component applied alone, and provided 70–90% protection compared with control untreated trees. QoI fungicides (strobilurins) were less effective and less consistent. Where there was an existing infection on panicles, two consecutive applications of sulfur or mineral oil, combined with systemic fungicides, suppressed the fungus and inhibited powdery mildew development. The main findings of the present study were implemented by growers and currently are used to develop improved disease management.

Fruit body rot and calyx rot caused by Alternaria alternata f. sp. mali has recently become a severe disease of Pink Lady apple in Israel. Severe fruit rot caused by A. alternata f. sp. mali has not been reported elsewhere in the world, and control measures are not currently known. Our objective was to determine the peak periods of susceptibility and develop methods to manage the disease by timing fungicide applications according to fruit phenological stage. We determined the relationship between fruit phenological stage and rot susceptibility by (i) monitoring the appearance of first fruit symptoms in the orchard; (ii) inoculating detached and attached fruit in the laboratory and orchard, respectively, at various time intervals after petal fall; and (iii) starting fungicide applications at various time intervals after petal fall. Fruit of Pink Lady acquired susceptibility to the disease at about 115 days after petal fall (DAPF) when reaching a diameter of ≥55 mm. Based on these findings, a new spray strategy was adopted involving a limited number of 4 to 6 foliar sprays of azoxystrobin + difenoconazole or tebuconazole + captan, or their alternation, starting at 115 DAPF. This strategy provided excellent control of both body rot and calyx rot in Pink Lady apple fruit in Israel.

Background Characterization and quantification of visual plant traits is often limited to the use of tools and software that were developed to address a specific context, making them unsuitable for other applications. CoverageTool is flexible multi-purpose software capable of area calculation in cm2, as well as coverage area in percentages, suitable for a wide range of applications. Results Here we present a novel, semi-automated and robust tool for detailed characterization of visual plant traits. We demonstrate and discuss the application of this tool to quantify a broad spectrum of plant phenotypes/traits such as: tissue culture parameters, ground surface covered by annual plant canopy, root and leaf projected surface area, and leaf senescence area ratio. The CoverageTool software provides easy to use functions to analyze images. While use of CoverageTool involves subjective operator color selections, applying them uniformly to full sets of samples makes it possible to provide quantitative comparison between test subjects. Conclusion The tool is simple and straightforward, yet suitable for the quantification of biological and environmental effects on a wide variety of visual plant traits. This tool has been very useful in quantifying different plant phenotypes in several recently published studies, and may be useful for many applications. Electronic supplementary material The online version of this article (10.1186/s13007-019-0472-2) contains supplementary material, which is available to authorized users.

Quinone outside inhibitors (QoI) fungicides group were introduced for commercial use against apple scab (Venturia inaequalis) in Israel in 1997. Unlike other regions in the world, in which resistance of V. inaequalis to QoI fungicides was observed within 3–5 years of use, in Israel it only occurred after 14 years of use. Field trials conducted between 2007 and 2017 showed a significant reduction in susceptibility to QoIs in northern Israel only since 2011. The delay in the development of resistance is related to limited fungicidal sprays resulting from unfavorable conditions for the pathogen. Of the 28 isolates collected from infected leaves or fruits of commercial orchards in northern Israel, 27 were resistant to the QoI fungicide Kresoxim-methyl. Amplification of the CYTB gene and sequencing of the G143A mutation region confirmed the resistance of all 27 isolates to QoIs. Resistance is demonstrated in the orchard, in vitro and molecular-based study, which forced the growers to avoid using QoIs against apple scab. We show that foliar applications of tank mixtures of systemic fungicides plus captan or prepacked fungicidal mixtures improved efficacy and can be used as a strategic approach in fungicide resistance management, including in orchards in which resistance to QoIs has been detected.

Severe outbreaks of Alternaria leaf blotch and fruit spot were recently observed in cv. Pink Lady apples in northern Israel, especially on fruit. Such severe outbreaks have not been reported from other countries. Symptoms involved cracks and rot around the calyx and external rot of the fruit body. Up to 80 % of the fruit in some orchards were affected by the disease. Microscopic examinations, fulfillment of Koch’s postulates and molecular (genetic) analyses confirmed the causal agent as Alternaria alternata f. sp. mali. The incidence of Alternaria increased as the degree of calyx cracking increased, or if fruit were both cracked and rotted. Injecting spore suspensions into the fruit produced typical rot symptoms. Injection assays of detached fruit of eight apple cultivars showed that cvs. Pink Lady and Golden Delicious were susceptible whereas cv. Jonathan was resistant. Pink Lady and Golden Delicious produced more fruit rot as the inoculum concentration increased. Rot in all three cultivars was moderate close to the skin but more severe close to the seed locule. Aqueous extracts taken from Jonathan fruit peel inhibited germ tube elongation of A. alternata f. sp. mali in vitro. This is the first report on heavy infection of Pink Lady fruit in Israel caused by A. alternata f. sp. mali.

Annual and perennial plants represent two different evolutionary strategies based on differential synchronization of their reproductive development. The mobile signal protein FLOWERING LOCUS T (FT) plays a central role in mediating the onset of reproduction in both plant types. Two novel FT-like genes from pear (Pyrus communis)-PcFT1 and PcFT2-were isolated, and their expression profiles were determined for one annual cycle. The effects of PcFT2 on flowering were investigated in annual (tobacco) and perennial (apple) plants by means of grafting and generating transgenic plants. Long-distance graft transmission of PcFT2 in both annual and perennial plants was confirmed using a 35S::PcFT2-YFP construct. Ectopic overexpression of PcFT2 caused early flowering in tobacco but not in apple. Transgenic apples were less sensitive to short-day-induced dormancy, and this phenotype was also observed in wild-type apples grafted onto the transgenic plants. Comparison of PcFT2 protein structure to the paralogous FT proteins from apple and pear showed alterations that could influence protein structure and thus the florigen-activation complex. PcFT2 protein seems to function by promoting flowering as all other FT proteins in the annual plant tobacco while in the perennial plant apple PcFT2 does not promote flowering but delays senescence. This observation may hint to a modified function of FT2 in perennial plants.

Fruit body rot and calyx rot caused by Alternaria alternata f.sp. mali recently appeared in Israel as a severe disease of apple, cv. Pink Lady. No such heavy rots of fruits were reported elsewhere, nor are there any known control measures against the disease. We found that the disease may be successfully controlled by application of fungicidal mixtures to the fruit at the proper phenological development stage. Ortiva-Top (azoxystrobin+difenoconazole) and Azimut (azoxystrobin+tebuconazole) effectively inhibited spore germination, mycelial growth, and rot development in detached fruits. Mixtures of Azimut or Ortiva-Top with Captan were synergistically effective in controlling the disease in detached fruits. In seven field trials Ortiva-Top and Orpan (tebuconazole+captan) were the most effective, and reduced calyx and fruit body rot by 60–88 and 58–92%, respectively, compared with untreated trees. Based on these findings a new spray program was adopted, in which only four to six sprays of Ortiva-Top, Orpan or Azimut were employed, starting at about 115 days after petal fall; it effectively controlled Alternaria fruit rot in 'Pink Lady' apples in Israel.

Hazelnuts (Corylus avellana) are widely grown in the Republic of Georgia and considered a major agricultural export product (Gurcan et al. 2010). Powdery mildew in hazelnut trees is a major disease that causes significant yield loss (Sezer et al. 2017). Until recently, Phyllactinia guttata was considered the main causal agent in the neighboring countries of Western Asia and the Caucasus (Abasova et al. 2018; Arzanlou et al. 2018). However, in the last 3 years a new destructive species, Erysiphe corylacearum, has been identified as a pathogen of powdery mildew on hazelnut in the neighboring countries of Iran, Azerbaijan, and Turkey (Abasova et al. 2018; Arzanlou et al. 2018; Sezer et al. 2017). During May and July 2018, powdery mildew symptoms were observed in hazelnut plantations of the cultivar Anakliuri in Adjara region (western Georgia). Symptoms were observed on the upper leaf surface and fruit clusters including husks. Disease incidence reached 100%, and severity ranged between 10 and 70%. On heavily affected leaves, necrotic lesions were observed 9 to 13 days after the first symptoms appeared, followed by leaf curling and defoliation. Morphological characterization of leaf and husk samples showed the following characters: hyphal appressoria (n = 30) were lobed, solitary, 1 to 4 μm in diameter; mycelium was amphigenous, hyaline, branched, septate 1.8 to 5.3 μm wide; conidiophores (n = 35) vertically elevated above the mycelium 53 to 82 μm long and 5 to 12 μm wide; produced solitary conidia (n = 50) on conidiophores, hyaline, ellipsoid to ovoid, 24 to 36 μm long, 14 to 24 μm wide. Chasmothecia appeared in early October. They were spherical, single or in groups, 73 to 104 μm in diameter, appendages six to 15 straight, 72 to 101 μm long, four to five times dichotomous branched, aseptate or one with a septum at the base. In each chasmothecium, there were three to five asci (n = 50) with a width of 38 to 53 μm and a length of 26 to 38 μm of oval-ellipsoid shape. Asci contained four to eight ascospores (n = 50), 18 to 25 μm long and 8 to 12 μm wide. Pathogenicity testing was conducted according to Koсh’s postulates. Two-year-old plants of C. avellana, cultivar Anakliuri, were artificially infected by dusting conidia from infected leaves (n = 25). Inoculated plants were incubated under 20 to 28°C and 70 to 80% humidity. Typical symptoms (fluffy white bloom) appeared on the upper surface of the leaves within 8 to 10 days after inoculation. No symptoms were found on control plants treated with sterile water. The fungus isolated from the inoculated leaves (n = 25) was morphologically identical to the original isolates from natural diseased plants (n = 10). DNA was extracted, and the rDNA internal transcribed spacer region of four isolates was amplified using primers ITS1 and ITS4 and sequenced. BLAST analysis of our 593-bp fragments (all identical and represented by GenBank accession no. MK157199) showed 99% identity to ITS rDNA sequences of E. corylacearum from Azerbaijan (LC270863) and Turkey (KY082910) and only 83% similarity to P. guttata (accession no. AB080558).

Tomato yellow leaf curl virus (TYLCV) is a begomovirus causing significant crop losses in tomatoes worldwide. TYLCV infection has several defined symptoms that are characterized at the whole plant level that include yellowing and curling of the leaves, stunting and growth retardation, and severe yield losses that can reach 100%. While the etiology and phenotypic symptoms of TYLCV infection were characterized, little is known about the cellular basis of these symptoms. Our goal in the present study is to describe some of the microscopic features of the disease while comparing TYLCV-susceptible and resistant near-isogenic tomato plants under infection. We depict the cellular changes that occur in susceptible line as a result of TYLCV infection that include: epidermal cell sizes reduction, accompanied with modifications in cell shape; reduction in plastid number, plastid size and chlorophyll content; diminished expression genes encoding LHC, Rub L, CAB4, and CAB8 and a surge in plasmodesmata number after infection. We conclude that TYLCV affect many targets or that it has a very critical target in cellular development.

The effect of two training systems on the development of powdery mildew caused by Erysiphe necator in berries of Chardonnay and Cabernet Sauvignon grapevines was examined. Disease development was monitored on berries from vines trained to either vertical shoot positioning or as free-positioned, topped vines with no foliage support wires. No fungicides were applied and powdery mildew development was recorded following artificial inoculation of young berries. Disease incidence was higher in berries collected from the vertical shoot system than in berries from the free-canopy vines. Incubating the berries under the reciprocal training system had a slight effect on PM development with the more susceptible berries of the VSP system but not on berries from the free canopy. The data suggest that the training system decreases disease development mainly through an effect on the susceptibility of the berries. The latter were less vulnerable to artificial inoculation performed in the laboratory after prior exposure to higher radiance intensity. The free-position system may therefore be useful in reducing the use of fungicides.

A protocol for plantlet regeneration through shoot formation was developed for the neotropical shrub Brunfelsia calycina. This shrub is unique in its change in flower color from dark purple to white. Explants from young and mature leaves were incubated on MS medium (pH 5.7, 30 g/l sucrose, 7.5 g/l agar) with various combinations of Indole-3-acetic acid (IAA) and 6-Benzyladenine (BA) under a 16 h photoperiod at a constant temperature of 25°C. Shoot emergence was best at 4.44 μM BA and 2.85 μM IAA for young leaf explants, and at 8.88 μM BA, 2.85 μM IAA for mature leaf explants. When shoots were transferred to MS medium supplemented with 1.23–2.46 μM indole butrytic acid (IBA), they developed roots.

The tomato INTENSE PIGMENT (IP) genotype is characterized by intense visual pigmentation of unripe and ripe fruits, not thoroughly analyzed thus far. This study was therefore designed to analyze key morphologic, metabolomic, and photomorphogenic phenotypes of this genotype in comparison to its near-isogenic normal counterpart and to evaluate its significance relative to other tomato mutants known for increased fruit pigmentation. The IP genotype produced smaller and darker red fruits, and a substantially increased chloroplast biogenesis was found in its green fruit and leaf tissues. Ripe-red fruits of the IP genotype produced 34-38% more soluble solids and up to 62.6% more carotenoids, but no differences were found in the concentration of flavonoid compounds in its peel tissue. The IP genotype was found to display a greater hypocotyl inhibition response to blue and yellow light, but a more prominent and novel response to total darkness. As a whole, the IP genotype exhibited highly desirable traits, making it a valuable genotype for tomato breeders attempting to introduce functional and taste qualities into tomato fruits.

Fruits harvested from tomato (Solanum lycopersicum) plants carrying mutations at the DAMAGED DNA BINDING PROTEIN 1 gene (SlDDB1; hp-1 and hp-1w) are characterized by significantly elevated levels of lycopene and several other phytonutrients. We hypothesize that the pleotropic effect on mutant Slddb1 are some general function of DDB1 protein on cell growth. The main objective of this research was to carry out functional analysis of the mutant SlDDB1 alleles both in-planta and ex-planta in comparison to their normal counterparts. Our major results indicate that: mutant Slddb1 seedlings exhibited delayed growth and smaller cell size, greater chloroplast density, smaller chloroplasts and higher concentration of chlorophyll. Cotyledons cells of Slddb1 mutant also displayed abnormal stomatal pattern, reduced content of CDT1 transcript and altered response to cytokinin. Some of these observations were previously described to be connected to defects in cell cycle control. Our results, coupled with former studies, also suggest that the CDD complex (composed of DDB1, DET1 and COP10) mediate the effect of light and cytokinin activity by possibly regulating the replication licensing factor CDT1 thus affecting both cell size and plastid multiplication.

The tomato Anthocyanin fruit (Aft) genotype is characterized by purple color in skin and outer pericarp of its fruits due to higher levels of anthocyanins-flavonoid metabolites. Our objectives were to carry out metabolic and molecular characterization of this genotype, emphasizing its interaction with the high pigment-1 (hp-1) mutation, known to increase flavonoids in tomato fruits. These objectives fit the growing interest in developing tomato fruits with higher levels of functional metabolites. Our results show that 1) Aft fruits are also characterized by significantly higher levels of the flavonols quercetin and kaempferol, thus enhancing their functional value; 2) the tomato Anthocyanin1 (Ant1) gene, encoding a Myb transcription factor, displayed nucleotide and amino acid polymorphisms between the Aft genotype and cultivated genotypes; 3) a DNA marker based on Ant1 showed that the Aft trait is encoded by a single locus on chromosome 10 fully associated with Ant1; and 4) double homozygotes Aft/Aft hp-1/hp-1 plants displayed a more-than-additive effect on the production of fruit anthocyanidins and flavonols. This effect was manifested by approximately 5-, 19-, and 33-fold increase of petunidin, malvidin, and delphinidin, respectively, in the double mutants compared with the cumulative levels of their parental lines.

Phenotypes of the tomato (Solanum lycopersicum) high pigment-2dg (hp-2dg) and hp-2j mutants are caused by lesions in the gene encoding DEETIOLATED1, a negative regulator of light signaling. Homozygous hp-2dg and hp-2j plants display a plethora of distinctive developmental and metabolic phenotypes in comparison to their normal isogenic counterparts. These mutants are, however, best known for the increased levels of carotenoids, primarily lycopene, and other plastid-accumulating functional metabolites. In this study we analyzed the transcriptional alterations in mature-green, breaker, and early red fruits of hp-2dg/hp-2dg plants in relation to their normal counterparts using microarray technology. Results show that a large portion of the genes that are affected by hp-2dg mutation display a tendency for up- rather than down-regulation. Ontology assignment of these differentially regulated transcripts revealed a consistent up-regulation of transcripts related to chloroplast biogenesis and photosynthesis in hp-2dg mutants throughout fruit ripening. A tendency of up-regulation was also observed in structural genes involved in phytonutrient biosynthesis. However, this up-regulation was not as consistent, positioning plastid biogenesis as an important determinant of phytonutrient overproduction in hp-2dg and possibly other hp mutant fruits. Microscopic observations revealed a highly significant increase in chloroplast size and number in pericarp cells of mature-green hp-2dg/hp-2dg and hp-2j/hp-2j fruits in comparison to their normal counterparts. This increase could be observed from early stages of fruit development. Therefore, the molecular trigger that drives phytonutrient overproduction in hp-2dg and hp-2j mutant fruits should be initially traced at these early stages.

The sterol biosynthesis inhibitors bromuconazole and difenoconazole and tank mixes of each fungicide with captan were applied to apples and evaluated as controls for moldy-core and fruit decay caused by Alternaria alternata. Effectiveness of a mixture of bromuconazole and captan in controlling colonization by the fungus was also evaluated. Decay formation by A. alternata on mature detached fruits was partially inhibited by bromuconazole at 0.5 μg ml−1 and was completely inhibited at 50 μg ml−1; it was significantly affected by either bromoconazole at 5 μg ml−1 or captan at 1,250 μg ml−1, and was completely inhibited by their mixture. In general, three foliar applications of bromuconazole or difenoconazole in the field, during the bloom period, reduced the numbers of infected fruits by 40–60% compared with untreated control trees. However, tank mixes of either fungicide with captan improved control of moldy-core in fruits at harvest. Tank mixtures of bromuconazole and captan also significantly reduced the percentage of fruits colonized by A. alternata when sampled at various days after full bloom. Artificial inoculations in the orchard at full bloom did not change the inhibitory effects of the tank mixtures. Large-scale demonstration trials in commercial orchards supported these findings. The inhibitory effects of tank mixes on decay development in detached fruits, and on moldy-core in the field indicate that a control programme based on mixtures of either bromuconazole or difenoconazole with captan during the bloom period can effectively reduce moldy-core on Red Delicious apples.