Overexpression of a fusion defensin gene from radish and fenugreek improves resistance against leaf spot diseases caused by Cercospora arachidicola and Phaeoisariopsis personata in peanut

Not AvailablePeanut (Arachis hypogaea L.) is one of the important oilseed crops of the Indian subcontinent and fungal diseases like early leaf spot (ELS) and late leaf spot (LLS) caused by Cercospora arachidicola and Phaeoisariopsis personata, respectively, are major peanut cultivation constraints. Defensins are basically antimicrobial peptides that have been implicated in plant defense against various microbial attacks. Transgenic peanut plants, developed through Agrobacterium mediated transformation of de-embryonated cotyledons and overexpressing a synthetic defensin fusion gene from fenugreek (Tfgd2) and radish (RsAFP2) linked by a linker peptide, were found to have enhanced resistance to the ELS and LLS infection over the wild type (cv. GG 20). Both transformed and untransformed lines were characterized for leaf spot diseases using a detached leaf assay. PCR and RT-PCR analyses confirmed stable integration and expression of these genes in peanut transgenics. This investigation provides further evidence that a fusion product of two plant defensins can be successfully implemented as a means of imparting resistance to multiple fungal pathogens through genetic engineering in peanut.ICA

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Not AvailableWe have isolated a strain of Bacillus thuringiensis (Bt) from Indian soil samples that was shown to be toxic to Achaea janata larvae. The isolate, named B. thuringiensis DOR4, serotypically identified with the standard subspecies kurstaki (H3a3b3c) and produced bipyramidal inclusions along with an amorphous type. Although the plasmid pattern of DOR4 was different from that of the reference strain, a crystal protein profile showed the presence of two major bands (130 and 65 kDa) similar to those of Bt subsp. kurstaki HD-1. To verify the cry gene content of DOR4, triplex PCR analysis was performed; it showed amplification of the cry1C gene in addition to cry1Aa, cry1Ac, cry2A, and cry2B genes, but not the cry1Ab gene. RT-PCR analysis showed the expression of cry1Aa and cry1Ac genes. In vitro proteolysis of DOR4 protoxin with midgut extract generated products of different sizes. Zymogram analysis of DOR4 protoxin as substrate pointed to a number of distinct proteases that were responsible for activation of protoxins. Furthermore, toxin overlay analysis revealed the presence of multiple toxin-binding proteins in midgut epithelium. Based on all these characterizations, we suggest that the Bt DOR4 strain can be exploited for an A. janata control program.Not Availabl

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Not AvailableWe have isolated a strain of Bacillus thuringiensis (Bt) from Indian soil samples that was shown to be toxic to Achaea janata larvae. The isolate, named B. thuringiensis DOR4, serotypically identified with the standard subspecies kurstaki (H3a3b3c) and produced bipyramidal inclusions along with an amorphous type. Although the plasmid pattern of DOR4 was different from that of the reference strain, a crystal protein profile showed the presence of two major bands (130 and 65 kDa) similar to those of Bt subsp. kurstaki HD-1. To verify the cry gene content of DOR4, triplex PCR analysis was performed; it showed amplification of the cry1C gene in addition to cry1Aa, cry1Ac, cry2A, and cry2B genes, but not the cry1Ab gene. RT-PCR analysis showed the expression of cry1Aa and cry1Ac genes. In vitro proteolysis of DOR4 protoxin with midgut extract generated products of different sizes. Zymogram analysis of DOR4 protoxin as substrate pointed to a number of distinct proteases that were responsible for activation of protoxins. Furthermore, toxin overlay analysis revealed the presence of multiple toxin-binding proteins in midgut epithelium. Based on all these characterizations, we suggest that the Bt DOR4 strain can be exploited for an A. janata control program.Not Availabl

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Not AvailableAnnexins belong to a plasma membrane binding (in a calcium dependent manner), multi-gene family of proteins, which play ameliorating roles in biotic and abiotic stresses. The expression of annexin AnnBj2 of Indian mustard is tissue specific with higher expression in roots and under treatments with sodium chloride and abscisic acid (ABA) at seedling stage. The effect of constitutive expression of AnnBj2 in mustard was analyzed in detail. AnnBj2 OE (over expression) plants exhibited insensitivity to ABA, glucose and sodium chloride. The insensitivity/ tolerance of the transgenic plants was associated with enhanced total chlorophylls, relative water content, proline, calcium and potassium with reduced thiobarbituric acid reactive substances and sodium ion accumulation. The altered ABA insensitivity of AnnBj2 OE lines is linked to downregulation of ABI4 and ABI5 transcription factors and upregulation of ABA catabolic gene CYP707A2. Furthermore, we found that overexpression of AnnBj2 upregulated the expression of ABA-dependent RAB18 and ABA-independent DREB2B stress marker genes suggesting that the tolerance phenotype exhibited by AnnBj2 OE lines is probably controlled by both ABA-dependent and independent mechanisms.Not Availabl

Pathogen-induced AdDjSKI of the wild peanut, Arachisdiogoi, potentiates tolerance of multiple stresses in E. coli andtobacco

A gene encoding a serine-rich DnaJIII protein called AdDjSKI that has a 4Fe-4S cluster domain was found to be differentially upregulated in the wild peanut, Arachis diogoi in its resistance responses against the late leaf spot causing fungal pathogen Phaeoisariopsis personata when compared with the cultivated peanut, Arachis hypogaea. AdDjSKI is induced in multiple stress conditions in A. diogoi. Recombinant E. coli cells expressing AdDjSKI showed better growth kinetics when compared with vector control cells under salinity, osmotic, acidic and alkaline stress conditions. Overexpression of this type three J-protein potentiates not only abiotic stress tolerance in Nicotiana tabacum var. Samsun, but also enhances its disease resistance against the phytopathogenic fungi Phytophthora parasitica pv nicotianae and Sclerotinia sclerotiorum. In the present study we show transcriptional upregulation of APX, Mn-SOD and HSP70 under heat stress and increased transcripts of PR genes in response to fungal infection. This transmembrane-domain-containing J protein displays punctate localization in chloroplasts. AdDjSKI appears to ensure proper folding of proteins associated with the photosynthetic machinery under stress

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Not AvailablePowdery mildew (PM, caused by Golovinomyces orontii) is one of the major diseases on sunflower that causes severe yield losses in the tropics. Sources of resistance to PM are reported in an exotic accession and some wild Helianthus species. The present study aims at quantitative proteomic analysis of susceptible, resistant, and immune genotypes of sunflower in response to PM infection at 3, 7, 10 days post infection. The majority of differentially expressed proteins in the resistant genotype belonged to oxidative stress (catalase, ATP-sulfurylase, and formate dehydrogenase), defense (HSP-70, heat shock transcription factors), and photosynthesis (LHCB3). In case of immune genotype, 50% of proteins are related to photosynthesis, which play a key role in plant immunity, whereas a few similar proteins are also expressed in the susceptible genotype, but in their reduced abundance besides being inadequate in timing of expression probably leading to its susceptibility to PM. KEGG enrichment analysis shows that carbon metabolism (6-phosphogluconate dehydrogenase, pyruvate dehydrogenase, glutamine synthetase), photosynthesis, and plant–pathogen protein pathways are key pathways governing the resistance. The transcriptional expression of eight of nine differentially expressed proteins are in agreement with the expression of proteins at the corresponding time. The present study provides information on the key proteins that are upregulated in resistant and immune genotypes which restrict the disease progression and constitutes the first quantitative proteomic data of sunflower-PM infection process.Not Availabl

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Not AvailableBackground: Our previous studies have revealed the roles of ribosomal protein (RP)genes in the abiotic stress responses of rice.Methods: In the current investigation, we examine the possible involvement of these genes in in-sect stress responses. We have characterized the RP genes that included both Ribosomal ProteinLarge (RPL) and Ribosomal Protein Small (RPS) subunit genes in response to infestation by twoeconomically important insect pests, the brown planthopper (BPH) and the Asian rice gall midge(GM) in rice. Differential transcript patterns of seventy selected RP genes were studied in a sus-ceptible and a resistant genotype of indica rice: BPT5204 and RPNF05, respectively. An in silicoanalyses of the upstream regions of these genes also revealed the presence of cis-elements that areassociated with wound signaling.Results: We identified the genes that were up or downregulated in either one of the genotypes, orboth of them after pest infestation. The transcript patterns of a majority of the genes were found tobe temporally-regulated by both the pests. In the resistant RPNF05, BPH infestation activatedRPL15, L51 and RPS5a genes while GM infestation induced RPL15, L18a, L22, L36.2, L38, RPS5,S9.2 and S25a at a certain point of time. These genes that were particularly upregulated in the resis-tant genotype, RPNF05, but not in BPT5204 suggest their potential involvement in plant resistanceagainst either of the two pests studied.Conclusion: Taken together, RPL15, L51, L18a, RPS5, S5a, S9.2, and S25a appear to be the geneswith possible roles in insect resistance in riceNot Availabl