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Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40 g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) 1. Translocation factor values were, The authors extend their appreciation to the Deputyship for Research and Innovation, Ministry of Education in Saudi Arabia for funding this research work through the project number IFP-KKU-2020/3.

The aim of this study was to evaluate the pathogenicity of Bipolaris oryzae, the causal agent of brown spot disease on Egyptian rice cultivars. Sample of rice were collected from 10 cultivars namely (Sakha 101, Sakha 104, Sakha 106, Giza 176, Giza 177, Giza 178, Giza 182, Egyptian hybrid and Egyptian Yasmin). Fungal genera were recovered from the rice samples. These fungi were identified as(Curvularia lunata, Asprgillus niger, Asprgillus flavus, Penicillium sp., Trichoderma, Alternaria alternata, Bipolaris oryzae, Fusarium verticillioides, Fusarium chlamydosporum, Rhizopus oryzae, Curvularia tuberculate, Bipolaris hawaiiensis, Cephaliophora tropica and Negrospora sp.). Out of the fourteen fungi,Bipolaris oryzae (B. oryzae) was characterized as one of the highest frequently exists fungus. Ten isolates of B. oryzae were investigated in terms of spore dimension, number of septa of conidia, linear growth and culture color. These ten B. oryzae isolates were used in the pathogenicity test on five commercial rice cultivars (Sakha 108, Sakha super 300, Giza 177, Giza 182 and Egyptian hybrid. The disease severity was assessed 7days after inoculation, 21-days-old rice plants. The most aggressive B. oryzae isolates were B.o10, B.o7, B.o9 and B.o8. On the other hand, the lowest aggressive once were B.o2, and B.o1. Screening of the B. oryzae isolates on the commercial rice cultivars in the rice cultivation area in Egypt could help develop prediction plane of brown spot disease, ultimately, facilitate the most proper decision for rice cultivars to be cultivated.

The current study aims at forming new prediction models to be employed in the approximating the possible uptake of a range of 10 heavy metals (HMs) (Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) by Hordeum vulgare tissues including roots, shoots and grains following its growth in soil amended with sewage sludge (SS) using conditions employed in greenhouses. The present study determined an insignificant difference between the actual and predicted quantities of the HMs in the three tissues using t values. The majority of the predicted quantities of the HMs were acceptable with the exception of Cd in the shoots, Cu in grains and Pb in roots. Consequently, it is possible to use these models in assessing the cultivation of barley plants in soil amended with SS in a safe way, while simultaneously monitoring any potential risks to the health of humans.

Prediction of heavy-metal concentration in the edible parts of economic crops, based on their concentration in soil and other environmental factors, is urgently required for human risk assessment. The present investigation aimed to develop regression models for predicting heavy-metal concentration in wheat plants via their contents in sewage sludge amended soil, organic matter (OM) content and soil pH. The concentration of heavy metals in the plant tissues reflected its concentration in the soil with high Fe followed by Al, Mn, Cr, Zn, Ni, Co, Cu, and Pb. Soil OM content had a significant positive correlation with all investigated heavy-metal concentrations in the different tissues of wheat plants, while soil pH was negatively significant with most heavy metals except spike Pb and grain Cr. The bio-concentration factor of Al, Cu, and Zn from soil to wheat root was >1, while that of shoot, spikes, and grains was

The aim of this study was to investigate the feasibility of using sewage sludge (SS) biosolids as a low-cost soil fertilizer to improve soil characteristics and crop yields. Okra (Abelmoschus esculentus (L.) Moench) plants were grown in soil supplemented with different concentrations of SS (0, 10, 20, 30, 40, and 50 g/kg). The results showed that SS soil application led to improved soil quality with a 93% increase of organic matter (at SS dose of 10 g/kg), decreased pH (a reduction from 8.38 to 7.34), and enhanced macro- and micro- nutrient contents. The levels of all the investigated heavy metals (HMs; Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the postharvest SS-amended soil were within the prescribed safe limits. The application of SS to soil considerably enhanced the growth parameters of okra plants. Total biomass increased 13-fold and absolute growth rate increased 10-fold compared to plants grown in nonamended (control) soils. Among the applied SS doses, the 10 g/kg SS dose led to the highest values of the measured growth parameters, compared to those of plants grown in control soils. The induced growth at 10 g/kg SS was accompanied by a substantial increase in metal content in roots, stems, leaves, and fruits; however, all levels remained within safe limits. Consequently, the data presented in this study suggest that SS could be used as a sustainable organic fertilizer, also serving as an ecofriendly method of SS recycling.

The bacterial genera Pectobacterium, Dickeya and Enterobacter are plant pathogens that cause soft rot and blackleg of potato. In the present study, 25 soft rot bacteria were isolated from potato tubers and stems showing typical tuber soft rot and blackleg symptoms. The samples were obtained from different locations in Egypt. Initial identification was based on morphological, physiological and biochemical characteristics. Pathogenicity of the identified isolates was assessed on potato tuber slices. Molecular techniques (16S rRNA sequencing and PCR analysis) revealed the identification of new clades of D. solani and E. cloacae. The primers (Eca1f/Eca2r) selected for the detection of P. atrosepticum specifically amplified a 690-bp region in only two out of 25 soft rot isolates. A single 550-bp band was produced from 14 isolates of P. carotovorum subsp. carotovorum using the species-specific primer EXPCC. Out of 23 isolates, 12 isolates gave a 666-bp band using primers to detect pmrA. Moreover, D. solani isolates were confirmed by the PCR amplification of a 420-bp region using specific primers (ADE1/ADE2). Nested PCR using the primer set EXPCCF/EXPCCR followed by INPCCF/INPCCR produced a 400-bp band from all P. c. subsp. carotovorum isolates tested. Nested PCR and multiplex PCR assays provided fast and reliable detection of the major soft rot and blackleg potato pathogens using three pairs of primers (Df/Dr, Y45/46 and EXPCCF/EXPCCR) and enabled the simultaneous detection of four pectinolytic bacteria found in potato: P. atrosepticum, P. c. subsp. carotovorum, D. solani and E. cloacae.

The risk evaluation of polluted soil requires the application of precise models to predict the heavy metal uptake by plants so possible human risks can be identified. Therefore, the present work was conducted to develop regression models for predicting the concentrations of heavy metals in spinach plants from their concentration in the soil by using the organic matter content and soil pH as co-factors. The soil improved with sewage sludge was slightly alkaline and had a relatively high organic matter content. Similar to the soil analysis, Fe had the highest median concentration, while Cd had the lowest concentration in the roots and leaves. Heavy metals accumulated in the roots and leaves in the order Fe Mn Zn Cu Cr Ni Co Pb Cd. The bio-concentration factor of the investigated heavy metals, from soil to roots, did not exceed one. The spinach was recognized by a translocation factor1.0 for all of the heavy metals except Zn. Plant heavy metal concentrations were positively correlated with the soil organic matter content and negatively correlated with soil pH. The leaf Cr, Fe and Zn and the root Cr, Fe, Pb and Zn concentrations were positively correlated with the respective soil heavy metals. In addition, a linear correlation was found between the bio-concentration factor of heavy metals and soil pH and organic matter content. Regression models with high model efficiency and coefficients of determination and low mean normalized average errors, which indicate the efficiency of the models, were produced for predicting the plant heavy metal contents by using the soil pH and organic matter content as co-factors.

A greenhouse experiment was performed to assess the soil heavy metal pools, growth, yield, and heavy metal uptake of wheat plants (Triticum aestivum L.) that are grown at different rates in soils supplemented with sewage sludge (SS). The experimental design was completely randomized, with six replicates per treatment. The application of SS significantly increased the soil organic matter content. Generally, most growth parameters, as well as the biomass of treated wheat, were significantly increased with the amendment of SS, up to the addition rate of 40 g kg−1. The content of all heavy metals (except Cr in grains and Pb in spikes) significantly increased in different tissues of treated wheat with the increasing rate of SS application. However, all heavy metal concentrations (except for Al, Cr, Fe, and Mn in the roots) were normal and did not overcome the phytotoxic levels. The wheat was recognized by a bioaccumulation factor

The current study aims at forming new prediction models to be employed in the approximating the possible uptake of a range of 10 heavy metals (HMs) (Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb and Zn) by

Aspergillus flavus is a phytopathogenic fungus that produces toxic compounds, aflatoxins, in infected plant tissues which harm human and animal health. In this study, 57 food/feed products were col...

The aim of this study is to design de novo prediction models in order to gauge the likely uptake of eight heavy metals (Al, Cr, Cu, Fe, Mn, Ni, Pb and Zn) by Lycopersicon esculentum, the tomato plant. Uptake was assessed within the plant’s root, stem, leaf and fruit tissues, respectively. The plant was cultivated in soil amended by different application rates of sewage sludge, i.e. 0, 10, 20, 30 and 40 g/kg. The roots exhibited markedly elevated heavy metal concentrations compared to the above-ground plant components, with the exception of the quantity of Ni in the leaves. Apart from Al, Fe and Mn, a bioconcentration factor >1 was identified for all heavy metals. Excluding Ni in the leaves, all tested heavy metals exhibited a translocation factor < 1. The regression models were deployed to predict the accretion of the heavy metals under investigation within the various parts of L. esculentum. These were founded on the parameters of the equivalent eight heavy metals within the soil, pH and organic matter content. Student’s unpaired t-tests revealed no differences between the actual and predicted heavy metal concentrations in the roots, stems, leaves or fruits of the tomato plant. These data suggest an excellent model goodness of fit in terms of its accuracy to forecast the degree of heavy metal uptake. The constructed models may therefore facilitate the safe propagation of L. esculentum in growing media amended with sewage sludge, and concurrently provide a risk assessment with respect to human well-being., The authors extend their appreciation to the Scientific Research Deanship at King Khalid University and the Ministry of Education in Saudi Arabia for funding this research work through the project number IFP-KKU-2020/3.

This study was carried out to develop mathematical regression equations for predicting the uptake of ten heavy metals (HMs) (cadmium, Cd; cobalt, Co; chromium, Cr; copper, Cu; iron, Fe; manganese, Mn; molybdenum, Mo; nickel, Ni; lead, Pb; zinc, Zn) by a vegetable species (Eruca sativa Mill.) in the Abha region (Saudi Arabia) based on the concentration of these HMs in soils amended with sewage sludge, organic matter (OM) content and soil pH. The resultant regression equations indicated that the three soil factors were significant predictors for the uptake of the ten HMs in the plant tissues. By applying a t test, we found that there are no significant differences between the actual and predicted values of the ten HMs in the E. sativa roots and leaves (P > 0.05), which reflects the goodness of fit of these equations for predicting the uptake of these HMs. Such types of equations may be helpful for evaluating the risk of cultivation of E. sativa plants in soils amended with sewage sludge.

The present study was conducted using a pot experiment to develop regression models for the prediction of trace metal concentrations in faba bean (Faba sativa Bernh.) plants cultivated in soils amended with different rates of sewage sludge to monitor possible human health risks. The trace metal concentrations in the different tissues of faba bean showed that most of the investigated trace metals were accumulated in the plant roots rather than in the other tissues. Meanwhile, the fruits accumulated the lowest concentration of most trace metals. The trace metal concentrations of the faba bean plants had a significant positive correlation with the organic matter content and a significant negative correlation with the soil pH. Transfer of trace metals from the soil to faba bean roots indicated that Al, Cu, Pb and Zn had a transfer factor that exceeded one, whereas the TF of the investigated trace metals from the roots to the fruits did not exceed one. The daily intake rate of the investigated trace metals did not exceed one in both adults and children. On the other side, the hazard quotient of trace metals from consuming faba bean fruits had values P > 0.05). Therefore, these developed models will be useful for prediction of trace metals uptake by faba bean grown in soil amended with sewage sludge so possible human risks can be identified.

In the present study, growth and productivity of hot pepper planted in the two successive summer seasons of 2017 and 2018 were evaluated under the effect of foliar spray of variable doses of potassium silicate (PS), and clove water extract (CWE) with different rates of nitrogen (N) fertilization application. The post-harvest resistance of hot pepper fruits to Alternaria alternata fungal infection, was also evaluated. Maximum plant height was achieved with the application of the highest rates of N, PS and CWE, while the intermediate rates were sufficient to reach the maximum number of branches, the highest leaf dry matter and chlorophyll accumulation. Fruit yield progressively increased with increasing the applied N rate. The foliar application of PS and CWE exerted a limited, yet positive effect on fruit yield. Generally, the least amount of fruit yield, amounting to 18.84 and 18.00 t ha−1, resulted from the application of the lowest N rate (144 kg ha−1) in the absence of PS and CWE. The highest significant fruit yield, amounting to 31.71 and 31.22 t ha−1, for 2017 and 2018, respectively, accompanied the application of the maximum levels of the three factors. The application of high N rates increased the post-harvest Alternaria fruit rot severity. The positive effect of CWE application in counterbalancing the negative effects associated with the high rates of N and PS may be related to the presence of phenolic and flavonoid compounds ellagic acid, benzoic acid, catechol gallic acid, rutin, myricetin, quercetin, apigenin and kaempferol as identified by High Performance Liquid Chromatography (HPLC).

In this study, we present the response of spinach to different amendment rates of sewage sludge (0, 10, 20, 30, 40 and 50 g kg−1) in a greenhouse pot experiment, where plant growth, biomass and heavy metal uptake were measured. The results showed that sewage sludge application increased soil electric conductivity (EC), organic matter, chromium and zinc concentrations and decreased soil pH. All heavy metal concentrations of the sewage sludge were below the permissible limits for land application of sewage sludge recommended by the Council of the European Communities. Biomass and all growth parameters (except the shoot/root ratio) of spinach showed a positive response to sewage sludge applications up to 40 g kg−1 compared to the control soil. Increasing the sewage sludge amendment rate caused an increase in all heavy metal concentrations (except lead) in spinach root and shoot. However, all heavy metal concentrations (except chromium and iron) were in the normal range and did not reach the phytotoxi...

Climate change is an issue that has huge concerns worldwide. Carbon dioxide (CO2) emission is one of the important factors in global climate change. Carbon sequestration potential (CSP) of various terrestrial ecosystems, especially wetlands, play a role in manipulating the excessive increase of CO2 in the atmosphere. In the current investigation, we report on the efficiency of mangrove forests located in the southern Saudi Arabian Red Sea coast in carbon sequestration and establishment of a baseline data on soil organic carbon (SOC) pools for future studies on SOC dynamics. Sampling was carried out in three locations along the southern Saudi Arabian Red Sea coast. The sampled locations were classified into landward and seaward stands. In each of the sampling location, ten sampling sites were selected to assure representative samples to each of the landward and seaward stands. Three soil cores were taken in each sampling site and were pooled together into one composite core per sampling site. A total of 480 soil samples were collected. The mean distribution of soil bulk density in the landward and seaward stands increased significantly with depth reaching the maximum at a depth of 20–25 cm. SOC concentration in the landward stands declined significantly with depth from 35.8 g C kg−1 at depth 0–5 cm to 20.9 g C kg−1 at depth 20–25 cm. SOC concentration in the seaward stands declined significantly with depth from 35.7 g C kg−1 at depth 0–5 cm to 24.8 g C kg−1 at depth 20–25 cm. The carbon sequestration rate (CSR) ranged between 11.7 g C m−2 year−1 in the landward stands and 12.0 g C m−2 year−1 in the seaward stands. Based on the area of mangrove stands (292 km2) and CSR, the total CSP of mangroves in Saudi Arabia was 3.47 ± 0.05 Gg C year−1.

Heavy metal (HM) concentrations in edible plants can develop many serious health risks to humans. The precise prediction of plant uptake of HMs is highly important. Thus, the present investigation was carried out to develop regression models for predicting the concentrations of HMs in cucumbers (Cucumis sativus L.) from their concentration in the soil and using the organic matter (OM) content and soil pH as co-factors. The results showed that cucumber roots had the highest significant concentrations of all HMs at P

Leaf rust caused by Puccinia triticina Eriks., is one of the main diseases of wheat (Triticum aestivum L.) in Egypt, causing up to 50% of yield losses. Genetic resistance is the most economic and effective means of reducing yield losses caused by the disease. However, breeding genotypes for disease resistance is a continuous process and plant breeders need to add new effective sources to their breeding materials. Among 42 Egyptian wheat varieties screened for leaf rust resistance, only 9 varieties (Sakha94, Giza168, Gemmiza9, Gemmiza10, Gemmiza11, Sids12, Sids13, Misr1 and Misr2) exhibited seedling and adult plant resistance during 2010/11 and 2011/12 growing seasons. Out of 41 monogenic line (Lr genes) tested, only 13 Lr genes (Lr9, Lr10, Lr11, Lr16, Lr18, Lr19, Lr26, Lr27, Lr29, Lr30, Lr34, Lr42 and Lr46) exhibited seedling resistance while, 9 Lr genes (Lr19, Lr20, Lr21, Lr24, Lr29, Lr30, Lr32, Lr34 and Lr44) showed adult plant resistance at both growing seasons. This result may add a depth of their resistance to be exploited as good sources of resistance. Partial resistance traits of wheat seedlings were present in 12 varieties (Sids12, Misr2, Sakha94, Misr1, Sids13, Giza168, Gemmiza9, Sids7, Beniswef4, Sakha93, Gemmiza11 and Sids6), recording the longest incubation and latent period. However, 10 varieties (Sakha8, Sakha93, Giza144, Giza155, Giza156, Giza157, Sids4, Sids5, Sids8 and Beniswef4) were marked as having high level of partial resistance of adult plant, recording ACI less than 20%, AUDPC less than 332.5 and r-value less than 0.101. The highest significant loss percentages were found in susceptible wheat cultivars i.e. Gemmiza7, Sakha61 and Giza164 (12.24%, 12.10% and 9.08%, respectively). However, insignificant loss percentages were found in resistant cultivars i.e. Giza168 (1.87%), Misr2 (2.44%) Sakha94 (2.46%). Inverse relation was present between the disease level and grain yield. Cultivating of resistant cultivars such as Misr2, Giza168 and Sakha94 is recommended to escape heavy yield losses wreaked by the leaf rust disease.

Plant NADPH oxidases are key regulators of plant–microbe interactions and reactive oxygen species (ROS) are essential to plant defences against pathogens. A significant part in the role played by ROS has been ascribed to plant respiratory burst oxidase homologs (RBOHs). In potato ( Solanum tuberosum ), where RBOHs were previously shown to be involved in wound-induced oxidative burst, we assessed their expression after inoculation with Verticillium dahliae Kleb. and showed that StRbohA was the only homolog to be differentially induced in potato in response to inoculation. In order to investigate the potential role of this gene in plant protection against wilt diseases, we used Agrobacterium -mediated transformation of Arabidopsis to assess the effects of its overexpression on plant responses to V. dahliae . After inoculation with this pathogen, the transformed Arabidopsis line overexpressing StRbohA showed lower disease severity (percent damaged leaf area and vascular discoloration) as compared to the wild type. It also had higher ROS production and more cell death caused by hydrogen peroxide (H 2 O 2 ), compared to the wild type. Suberization of root cells was also more pronounced in the line overexpressing StRbohA , and supports a possible role for StRBOHA in plant resistance to V. dahliae . Together, these findings indicate that overexpressed StRbohA in Arabidopsis enhances the ROS-mediated defence mechanisms against V . dahliae and can be a potential tool to improve plant resistance to this and other soilborne pathogens that cause wilts in economically important crops.

When sewage sludge is incorrectly applied, it may adversely impact agro-system productivity. Thus, this study addresses the reaction of Cucumis sativus L. (cucumber) to different amendment rates (0, 10, 20, 30, 40 and 50 g kg−1) of sewage sludge in a greenhouse pot experiment, in which the plant growth, heavy metal uptake and biomass were evaluated. A randomized complete block design with six treatments and six replications was used as the experimental design. The soil electrical conductivity, organic matter and Cr, Fe, Zn and Ni concentrations increased, but the soil pH decreased in response to the sewage sludge applications. As approved by the Council of European Communities, all of the heavy metal concentrations in the sewage sludge were less than the permitted limit for applying sewage sludge to land. Generally, applications of sewage sludge of up to 40 g kg−1 resulted in a considerable increase in all of the morphometric parameters and biomass of cucumbers in contrast to plants grown on the control soil. Nevertheless, the cucumber shoot height; root length; number of leaves, internodes and fruits; leaf area; absolute growth rate and biomass decreased in response to 50 g kg−1 of sewage sludge. All of the heavy metal concentrations (except the Cu, Zn and Ni in the roots, Mn in the fruits and Pb in the stems) in different cucumber tissues increased with increasing sewage sludge application rates. However, all of the heavy metal concentrations (except the Cr and Fe in the roots, Fe in the leaves and Cu in the fruits) were within the normal range and did not reach phytotoxic levels. A characteristic of these cucumbers was that all of the heavy metals had a bioaccumulation factor

Verticillium wilt, caused by the soilborne pathogen Verticillium dahliae (Kleb.), is an important disease affecting more than 400 plant species, including many economic crops. This study explored differential accumulation of phenolic compounds in potato in response to weakly and highly aggressive isolates of this pathogen. After phenolic compounds were extracted from roots, stems and leaves of inoculated plants, those showing differential accumulation were identified using high performance liquid chromatography (HPLC) equipped with a photodiode array detector, a fluorescence detector, and co-elution with commercial standards. Profiling of phenolic compounds during the potato–V. dahliae interaction confirmed previous observations on rutin accumulation in response to infection and showed differential accumulation of hydroxycinnamic acids in different tissues in response to two isolates possessing different levels of aggressiveness. In particular, differential accumulation of caffeic and ferulic aci...

Vegetative compatibility groups (VCGs) of 12 potato and nine sunflower isolates of Verticillium dahliae were determined using both nitrate non-utilizing (nit) mutants and multiplex-nested-PCR approaches. Based on analysis of nit mutants, most potato isolates showed strong compatibility with VCG 4A and weak compatibility with VCG 4B; one potato isolate was also weakly compatible with VCGs 2A, 2B and 3. Sunflower isolates were more variable and most of them showed weak reactions with VCG 4A and 4B. One sunflower isolate, Vs06-14, was compatible only with VCG3 testers, whereas another isolate, Vs06-20, was compatible with all VCG groups except VCG2A. Vegetative compatibility of four selected isolates, two from potato and two from sunflower, was also investigated after passing them through potato or sunflower for four generations. The VCG of one potato isolate did not change, whereas the other one changed from VCG4B to 4A. One sunflower isolate, initially compatible with both VCG4A and 4B, became inc...

Verticillium wilt is a vascular disease affecting hundreds of important dicotyledonous crops worldwide. Its main causal agent in potato is Verticillium dahliae Kleb. A differential potato-V. dahliae system consisting of two cultivars of potato (susceptible; S and moderately resistant; MR) and two V. dahliae isolates (weakly, WA and highly aggressive, HA), was used to evaluate the expression of five defence-related genes, PAL1, PAL2, PR-1, PR-2 and PR-5. These genes were selected because they are in general associated with the salicylic acid defence signalling pathway. Expression levels of these genes were assessed in potato roots and leaves at 0, 4 and 21 h (hpi), and 3, 7 and 14 days postinoculation (dpi). In the roots, the expression of PAL1, PR-1 and PR-2 in the MR was higher than in the susceptible cultivar in response to inoculation with either one of the tested V. dahliae isolates. PAL2 gene expression increased gradually starting at 21 hpi in the MR cultivar as opposed to the susceptible one. Higher expression of PR-1 was detected at 7 dpi in roots. In the leaves, both PAL1 and PAL2 genes showed higher expression in the MR cultivar relative to the susceptible one. Interestingly, the expression of PR-2 was slightly higher in the susceptible cultivar. Combined data analyses revealed that PAL1, PAL2, PR-1 and PR-2 genes are regulated at the transcriptional level in response to infection by V. dahliae. These results indicate that the salicylic acid pathway is also involved in potato defence against V. dahliae and add to the data gathered to elucidate the signalling mechanisms in this host–pathogen interaction.

Plant-fungi and plant-oomycete interactions have been studied at the proteomic level for many decades. However, it is only in the last few years, with the development of new approaches, combined with bioinformatics data mining tools, gel staining, and analytical instruments, such as 2D-PAGE/nanoflow-LC-MS/MS, that proteomic approaches thrived. They allow screening and analysis, at the sub-cellular level, of peptides and proteins resulting from plants, pathogens, and their interactions. They also highlight post-translational modifications to proteins, e.g., glycosylation, phosphorylation or cleavage. However, many challenges are encountered during in planta studies aimed at stressing details of host defenses and fungal and oomycete pathogenicity determinants during interactions. Dissecting the mechanisms of such host-pathogen systems, including pathogen counter-defenses, will ensure a step ahead towards understanding current outcomes of interactions from a co-evolutionary point of view, and eventually move a step forward in building more durable strategies for management of diseases caused by fungi and oomycetes. Unraveling intricacies of more complex proteomic interactions that involve additional microbes, i.e., PGPRs and symbiotic fungi, which strengthen plant defenses will generate valuable information on how pathosystems actually function in nature, and thereby provide clues to solving disease problems that engender major losses in crops every year.

Verticillium dahliae is the main pathogen causing Verticillium wilt in potato. Management of this vascular disease is very challenging due to the soilborne nature of the pathogen. A better understanding of the molecular host–pathogen interactions is important for the development of novel strategies to control Verticillium wilt. In this pathosystem, the disease cycle starts with stimulation and germination of the V. dahliae microsclerotia through host root exudates. The present study reports on the use of potato root extracts derived from a susceptible (Kennebec) and a moderately resistant (Ranger Russet) cultivar to elicit pathogenicity-related genes in highly and weakly aggressive isolates of V. dahliae. Using a combined approach of subtractive hybridization and cDNA-AFLP, 573 transcripts differentially accumulated in one or the other isolate in response to root extracts were detected. Sixteen primer combinations representing EcoRI/MseI AFLP primers + A, T, C, or G were used to provide a complete coverage of the subtractive hybridization products. The detected differentially expressed transcripts in the highly and weakly aggressive isolates were 301 and 272, respectively. Among the amplified transcripts, 185 were recovered from the PAGE gel then re-amplified by PCR and further sequenced. BLAST search against the NCBI, the Broad Institute V. dahliae genome, and V. dahliae ESTs collection COGEME databases showed that some of the differentially expressed transcripts matched with known sequences, with assigned functions in V. dahliae such as polygalacturonases or with conserved hypothetical proteins. The remaining sequences had no match in these databases. The results are discussed based on the potential involvement of these genes in V. dahliae's pathogenesis.

Verticillium dahliae is a soilborne fungus that causes a vascular wilt disease of plants and losses in a broad range of economically important crops worldwide. In this study, we compared the proteomes of highly (Vd1396-9) and weakly (Vs06-14) aggressive isolates of V. dahliae to identify protein factors that may contribute to pathogenicity. Twenty-five protein spots were consistently observed as differential in the proteome profiles of the two isolates. The protein sequences in the spots were identified by LC-ESI-MS/MS and MASCOT database searches. Some of the identified sequences shared homology with fungal proteins that have roles in stress response, colonization, melanin biosynthesis, microsclerotia formation, antibiotic resistance, and fungal penetration. These are important functions for infection of the host and survival of the pathogen in soil. One protein found only in the highly aggressive isolate was identified as isochorismatase hydrolase, a potential plant-defense suppressor. This enzyme may inhibit the production of salicylic acid, which is important for plant defense response signaling. Other sequences corresponding to potential pathogenicity factors were identified in the highly aggressive isolate. This work indicates that, in combination with functional genomics, proteomics-based analyses can provide additional insights into pathogenesis and potential management strategies for this disease.

A total of twenty leaf rust resistance genes (Lr genes) were postulated in nine Egyptian wheat cultivars based on infection types (ITs) expressed on the tested cultivars by 72 Puccinia triticina pathotypes compared with the ITs expressed on the monogenic lines. The most carrier genes cultivars were Giza168 and Misr1 each may contain five genes i.e. Lr2c, 10, 18, 24, 41 and Lr3, 10, 19, 22b, 24, respectively. Five cultivars, Sakha94, Gemmeiza9, Gemmeiza10, Sids12 and Misr2 each probably contain four genes i.e. Lr9, 19, 29, 37; Lr18, 21, 24, 41; Lr3, 9, 19, 29; Lr9, 19, 26, 29 and Lr3, 10, 19, 26, respectively. Gemmeiza11 was the least cultivar carrying genes; it probably carries just two genes i.e. Lr24 and Lr41. The most postulated genes were Lr19 and Lr24, each postulated within five cultivars followed by Lr41 within four cultivars. Five Lr genes, Lr3, Lr9, Lr10, Lr26 and Lr29 each within three cultivars. The lowest postulated genes were Lr2c, Lr21, Lr22b and Lr37 each of them was postulated within only one cultivar. Five Lr genes, Lr9, Lr10, Lr19, Lr24 and Lr26 were identified by PCR-based molecular marker. The Lr9 gene was identified in cultivar Sids12 while, Lr10 was identified in cultivar Misr1. The Lr19 was present in two cultivars, Misr1 and Misr2. The Lr24 and Lr26 were absent in all the screened Egyptian cultivars. The obtained results for Lr9, Lr10, Lr19, Lr24 and Lr26 marker were in agreement with and confirm their identification by gene postulation. Markers for Lr9, Lr10 and Lr19 may be useful in marker-assisted breeding. Our findings showed the usefulness of the molecular marker in identifying leaf rust resistance genes in wheat cultivars, especially when used in conjunction with multipathotypes test at the pre-breeding stage. This approach may help understanding the wheat - P. triticina interaction and provide information to build an effective management program for leaf rust disease.