| Summary: | 碩士 === 國立嘉義大學 === 生物農業科技學系研究所 === 106 === Plant growth-promoting rhizobacteria (PGPR) had been applied to plant growth widely. Previously, bacterial strains of genera of Bacillus and Pseudomonas have been isolated from soil based on their ability of secreting plant hormone IAA. Evidence of antimicrobial activity of these bacterial strains included detecting genes involved in synthesis of antimicrobial compounds, colony antagonistic analysis, antimicrobial activity of bacterial culture solution, and ability of secretion of microbial proteases. The antagonism assay of dual culture and volatile compounds of bacteria strains of Bacillus sp. and Pseudomonas sp. showed inhibition effect against Colletotrichum gloeosporioides and Fusarium oxysporum. In bacteria dual culture assay, the results showed that Bacillus sp. and Pseudomonas sp. inhibited the growth of Erwinia chrysanthemi. In soft rot inoculation test, the infected rate were decreased in Phalaenopsis orchid, Brassica rapa, variety chinensis and Brassica campestris, variety chinensis treated with bacteria and soybean fermentation product (SPH). In Fusarium wilt inoculation test, the infected ratio in banana seedlings treated with Pseudomonas sp. and SPH were decreased. In A. thaliana plant test, gene expression associated with Salicylic acid (SA) and Jasmonic acid (JA) pathways was increased after treated with Pseudomonas sp. and SPH. The western blot results showed the higher expression levels of antioxidant enzymes such as Catalase (CAT), and also defense relative protein such as Lipoxygenase (LOX)、Pathogenesis-related protein 2 (PR-2) and Pathogenesis-related protein 3 (PR-3). The results suggested that these PGPR strain and their protein hydrolysate products are potential products for the application of biocontrol.
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