Biological control of Fusarium wilt of pea plant grown on soil amended with chitin waste by application of Rhizobacteria for chitinolytic activity and induced resistanceAzhar A. Hussain ; Yassin, Sahar ; aboghalia, hoda
AbstractAbstract Isolation of microorganisms from the rhizosphere f healthy pea plants was carried out to select the most antagonistic ones to be used in biological control of Fusarium wilt of pea (Pisum sativum L.) caused by Fusarium oxysporum f. sp.pisi, Bacillus circulans M 21 and Streptomyces rameus B 10 were the most frequently isolated microorganisms. In vitro, the two selected organisms exhibited antagonistic effect against the pathogen, and Streptomyces rameus B 10 showed the best extracellular chitinolytic activity and gave significant reduction in pathogen mycelial growth. SEM examination revealed complete inhibition of conidia germination of F. oxysporum by B. circulans, while S. rameus caused breakage and disintegration of conidia with marked collapse, Ioss of turgor and reduction of hyphae. In vivo, preliminary tests were carried out to evaluate the efficacy of the inoculum size and period of soil infestation by the two selected bioagents when added singly or in combination of biocontrol of the disease. Mixture of the two antagonistic strains at 1:1 (v/v) ratio when added to the soil at planting time gave significantly (P<0.05) control of the disease. Application of combination of the two selected organisms as well as amendment of soil with chitin waste statistically enhanced pea plant growth (root and shoot height, a number of leaves and fresh and dry weights of root and shoot systems). AIso, chitin amendment of the soil increased the microbial population in the rhizosphere resulting in suppression of plant invasion by the pathogen. Bacillus circulans strain showed low effect on fungal growth but suppressed.Fusarium wilt of pea, Estimation of the phenolic compounds in treated and nontreated plants showed accumulation of these compounds in plants treated by B. cireulans strain as compared with nontreated plants, suggesting a role in increasing disease resistance of the plant against pathogen infection. Gel electrophoretic patterns of soluble proteins of pea plants, revealed induction of novel proteins with different molecular weights not only in the infected plants,.but also after treatments with the antagonists.These new structural proteins might play an integral role in increasing plant protection against pathogenicity.
|Keywords||Pea wilt, biological control, Bacillus circulans, Streptomyces rameus, Fusarium oxysporum, chitinase, induced resistance, phenolic compounds and pathogenesis proteins||Issue Date||Dec-2003||Journal||The African Journal of Mycology and Biotechnology||URI||http://research.asu.edu.eg/handle/123456789/1892|
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