Studies on systemic resistance induced by Pseudomonas putida A7 and Streptomyces coelicolor in Arabidopsis thaliana

• Main Authors: Han-Tan Cheng, 鄭涵丹
• Other Authors: 林乃君
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/4ppea5

碩士 === 國立臺灣大學 === 農業化學研究所 === 105 === During agricultural practice, chemical fertilizers and pesticides are often applied to enhance crop yield and prevent losses caused by pests and pathogens. However, environmental issues derived from utilization of such chemicals raise concerns about further damage to our ecosystem, and alternative means with similar effects should be developed to lessen the problem. Use of plant growth-promoting rhizobacteria (PGPR) with ability to promote plant growth directly or indirectly becomes a good strategy incorporated into the integrated pest management (IPM) program. In our studies, two soil habitants, Pseudomonas putida A7 and Streptomyces coelicolor strain M145, were proved to be plant growth promoting rhizobacteria, which not only promote plant growth but also induce resistance against Pseudomonas syringae pv. tomato (Pst) DC3000 in Arabidopsis thaliana. Further studies showed that P. putida A7 can induce resistance against Pst DC3000 in the Arabidopsis mutant lines, jar1, pad4 and npr1. By means of semiquantitative RT-PCR, we also found that higher amount and faster expression of the salicylic acid (SA) maker genes PR1 and PR5 were observed in P. putida A7-pretreated Arabidopsis compared to the water-treated control after Pst DC3000 infection. Stronger and faster responses upon Pst DC3000 infection in the A7-pretreated Arabidopsis were also found in the expression of genes involved in jasmonic acid (JA) and ethylene (ET) signaling pathways, such as LOX2, HEL and GST2. These data indicate that SA and JA/ET signaling pathways are involved in P. putida A7-induced systemic resistance to Pst DC3000 in A. thaliana. On the other hand, S. coelicolor M145-treated Arabidopsis mutant lines, jar1, npr1 and etr1, lost their ability to trigger systemic resistance to Pst DC3000. Futhermore, the expressions of PR1 and PR5 as well as PDF1.2, LOX2, HEL and GST2 were also stronger and faster after Pst DC3000 infection. Taking togather, we demonstrated P. putida A7 and S. coelicolor M145 probably can use different mechanisms to affect signaling pathways involving SA, JA and ET, to induce systemic resistance against Pst DC3000 in A. thaliana.