جستجوی مقالات مرتبط با کلیدواژه « induced systemic resistance » در نشریات گروه « گیاهپزشکی »

Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (Fol) is one of the most destructive tomato diseases. The disease control through induction of resistance by biocontrol agents is a management strategy to reduce application of chemical fungicides. So, in this study the efficacy of 10 native Trichoderma isolates in induction of resistance against the pathogen was evaluated. In greenhouse, phenotypic evaluation of induction of resistance by Trichoderma isolates with stem-injection and split-root bioassay methods showed the least disease severity and incidence significantly (p≤0.05) in Trichoderma harzianum Th-14ᚉ and Trichoderma atroviride Ta-30ᚉ treatments. The results of study of rhizosphere colonization ability of Trichoderma isolates by serial dilution method, revealed maximum population density in these two isolates. The disease severity showed negative correlation with Trichoderma population density. The activity of polyphenol oxidase and peroxidase increased significantly (p≤0.05) in the plants treated with Th-14 and Ta-30 isolates compared to control (Fol). The results of this study can be applied in integrated management of tomato Fusarium wilt.

Microbial volatiles have an important role in plant growth promotion and protecting them against plant pathogens. In this work, we evaluated whether B. subtilis volatiles promote plant growth and induce resistance against P. syringae pv. tomato DC3000. Arabidopsis seedlings exposed to bacterial volatiles in two compartments I-plate system. Volatiles increased plant growth significantly compared to control. Exposure of plant with bacteria volatiles reduced disease index from 80% to 40%. Pathogenic bacteria population in plant leaves reached up to 1.1×106 CFU/g aerial part wet weight, in volatile treatment, however pathogen population reached up to 1.3×108 in control plants. Expressions of PR-1, PDF1.2, and ChiB have been evaluated as marker genes for salicylic acid, jasmonic acid and ethylene-depended pathways, respectively. Bacteria volatiles boosted the expression of PR-1 and PDF1.2, significantly. These genes expressed strongly and rapidly which represent plant defense priming by bacteria volatiles. In conclusion, volatiles from B. subtilis GB03 not only improved plant growth significantly but also increased expression of defense-related genes and eventually suppressed disease in Arabidopsis.