scholarly journals Characteristic of the Pepper CaRGA2 Gene in Defense Responses against Phytophthora capsici Leonian

2013 ◽  
Vol 14 (5) ◽  
pp. 8985-9004 ◽  
Author(s):  
Ying-Li Zhang ◽  
Qing-Li Jia ◽  
Da-Wei Li ◽  
Jun-E Wang ◽  
Yan-Xu Yin ◽  
...  
Author(s):  
Zi-Hui Zhang ◽  
Jinghao Jin ◽  
Gui-Lin Sheng ◽  
Yu-Ping Xing ◽  
Wang Liu ◽  
...  

Small cysteine-rich (SCR) proteins including fungal avirulence proteins play important roles in the pathogen-plant interactions. SCR protein-encoding genes have been discovered in the genomes of Phytophthora pathogens, but their functions during the pathogenesis remain obscure. Here, we report the characterization of one Phytophthora capsici SCR protein, namely SCR82 with similarity to Phytophthora cactorum phytotoxic protein PcF. The scr82 gene has 10 allelic sequences in the P. capsici population. Homologues of SCR82 were not identified in fungi or other organisms but in Phytophthora relative species. Initially scr82 was weakly expressed during the mycelium, sporangium and zoospore stages, but quickly upregulated when the infection initiated. Both ectopic expression of SCR82 and recombinant yeast-expressed protein (rSCR82) caused cell death on tomato leaves. Upon treatment, rSCR82 induced plant defense responses including the induction of defense gene expression, reactive oxygen species burst and callose deposition. Knockout of scr82 in P. capsici by CRISPR/Cas9 severely impaired its virulence on host plants and reduced significantly its resistance againstoxidative stress. Inversely, its overexpression increased the pathogen’s virulence and tolerance to oxidative stress. Our results collectively demonstrate that SCR82 functions as both an important virulence factor and plant defense elicitor, which is conserved across Phytophthora species.


Author(s):  
Tianli Li ◽  
Gan Ai ◽  
Xiaowei Fu ◽  
Jin Liu ◽  
Hai Zhu ◽  
...  

The oomycete pathogen Phytophthora capsici encodes hundreds of RXLR effectors to enter plant cells and suppress host defense responses. Only few of them are conserved across different strains and species. Such ‘core effectors’ may target hub immunity pathways that are essential during Phytophthora pathogens interacting with their hosts. However, the underlying mechanisms of core RXLRs-mediated host immunity manipulation are largely unknown. Here, we report the functional characterization of a P. capsici RXLR effector, RXLR242. RXLR242 expression is highly induced during the infection process. Its ectopic expression in Nicotiana benthamiana promotes Phytophthora infection. RXLR242 physically interacts with a group of RAB proteins, which belong to the small GTPase family and function in specifying transport pathways in the intracellular membrane trafficking system. RXLR242 impedes the secretion of PATHOGENESIS-RELATED 1 (PR1) protein to the apoplast by interfering the formation of RABE1-7-labeled vesicles. Further analysis indicated that such phenomenon is resulted from competitive binding of RXLR242 to RABE1-7. RXLR242 also interferes trafficking of the membrane-located receptor FLAGELLIN-SENSING 2 (FLS2) through competitively interacting with RABA4-3. Taken together, our work demonstrates that RXLR242 manipulates plant immunity by targeting RAB proteins and disturbing vesicle-mediated protein transporting pathway in plant hosts.


2020 ◽  
Author(s):  
Divya Kattupalli ◽  
Asha Sriniva ◽  
Soniya E V

Abstract Background: Black pepper is a prominent spice which is an indispensable ingredient in culinary and traditional medicine. Phytophthora capsici, the causative agent of foot rot disease causes drastic constraint in black pepper cultivation and productivity. To counterattack various biotic and abiotic stresses plants employ a broad array of mechanisms one such includes the accumulation of pathogenesis-related (PR) proteins. Several studies have reported the role of PR-1 proteins in triggering the plant defenses during plant-oomycete interaction.Results: Through the genome-wide survey, eleven PR-1 genes that belongs to a CAP superfamily protein with Caveolin-Binding Motif (CBM) and CAP-derived peptide (CAPE) were identified from P. nigrum. Despite the critical functional domains, PnPR1 homologs differ in their signal peptide motifs, and core amino acid sequence composition in the functional protein domains. The GO, biological function analysis reveals their role in defense responses and response to biotic stimulus whereas the KEGG functional annotation predicted their function in the plant-pathogen interactions. Furthermore, transcriptome-assisted FPKM analysis revealed PnPR-1 genes mapped to P. nigrum - P. capsici interaction pathway. The differentially expressed pathogen-responsive PR-1 gene was validated through qRT-PCR. Subsequent analysis revealed the structural details, phylogenetic relationships, conserved sequence motifs and critical cis-regulatory elements of PnPR-1 genes.Conclusion: This is the first genome-wide study that identified the role of PR-1 genes during P. nigrum - P. capsici interactions. The detailed in silico experimental analysis revealed the vital role of PnPR-1 genes in regulating the first layer of defense towards P. capsici infection in Panniyur-1 plants.


Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 829-835 ◽  
Author(s):  
L. M. Quesada-Ocampo ◽  
A. M. Vargas ◽  
R. P. Naegele ◽  
D. M. Francis ◽  
M. K. Hausbeck

Phytophthora capsici causes devastating disease on many vegetable crops, including tomato and other solanaceous species. Solanum habrochaites accession LA407, a wild relative of cultivated tomato, has shown complete resistance to four P. capsici isolates from Michigan cucurbitaceous and solanaceous crops in a previous study. Greenhouse experiments were conducted to evaluate 62 lines of a tomato inbred backcross population between LA407 and the cultivated tomato ‘Hunt 100’ and ‘Peto 95-43’ for resistance to two highly virulent P. capsici isolates. Roots of 6-week-old seedlings were inoculated with each of two P. capsici isolates and maintained in the greenhouse. Plants were evaluated for wilting and plant death three times per week for 5 weeks. Significant differences were observed in disease response among the inbred tomato lines. Most lines evaluated were susceptible to P. capsici isolate 12889 but resistant to isolate OP97; 24 tomato lines were resistant to both isolates. Heritability of Phytophthora root rot resistance was high in this population. Polymorphic molecular markers located in genes related to resistance and defense responses were identified and added to a genetic map previously generated for the population. Resistant lines and polymorphic markers identified in this study are a valuable resource for development of tomato varieties resistant to P. capsici.


2021 ◽  
Author(s):  
Sahar Alipour Kafi ◽  
Ebrahim Karimi ◽  
Mahmood Akhlaghi ◽  
Zahra Amini ◽  
Ali Mohammadi ◽  
...  

Abstract Background and aimsThe application of chemical fungicides is the first strategy to control plant fungal diseases. This approach is highly polluting for the environment and affects human health. Artificial introduction of beneficial rhizobacteria into the soil can be an economical and practical way to control phytopathogenic fungi in commercial greenhouses. Here, we recount the travel of a rare Actinomycete (Amycolatopsis strain 1119) from a maize field to a commercial cucumber greenhouse.Methods and resultsCulturable bacteria from rhizosphere and bulk soils of dicot and monocot crops were isolated and screened. About 20% of the representative colonies showed Actinomycetes appearance. 106 Actinomycetes that had antagonistic activity against Phytophthora capsici and were able to produce IAA were selected for further analysis. Two Streptomyces strains (432 and 615) and 2 Amycolatopsis strains (3513 and 1119) that showed a positive effect on plant growth in greenhouse conditions were selected to evaluate for biocontrol potential. Strains 432, 3513, 615 and 1119 controlled incidence of the damping-off by 65%, 42%, 83% and 100% respectively. Application of strain 1119 under commercial greenhouse conditions resulted in an increase in fruit yield (20%) and a decrease in fruit nitrate content (70%). Increased antioxidant enzymes activity and increased LOX and APX transcription and also, increased expression of two genes PR1-1a and GLU (SAR genes) showed that strain 1119 could induce both ISR and SAR in cucumber without pathogen exposure. Conclusion Our results demonstrate that the Amycolatopsis strain 1119, has a great potential to enter the market as a bio-stimulator.


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