Ryu Choong-Min, Hu Chia-Hui, Reddy M S, Kloepper Joseph W
Department of Entomology and Plant Pathology, 209 Life Sciences Building, Auburn University, Auburn, AL 36849 USA.
Present address: Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73402 USA.
New Phytol. 2003 Nov;160(2):413-420. doi: 10.1046/j.1469-8137.2003.00883.x.
• The mechanisms by which plant growth-promoting rhizobacteria (PGPR) mediate induced systemic resistance are currently being intensively investigated from the viewpoint of signal transduction pathways within plants. • Here, we determined whether our well-characterized PGPR strains, which have demonstrated induced resistance on various plants, also elicit induced resistance in Arabidopsis thaliana. Nine different PGPR strains were evaluated for their capacity to cause induced resistance on Arabidopsis against two pathovars of Pseudomonas syringae. Six strains significantly reduced severity of P. syringae pv. tomato, whereas seven strains reduced severity of P. syringae pv. maculicola. • From the initial screenings, four strains (90-166, SE34, 89B61 and T4) were selected because of their consistent induced resistance capacity. Elicitation of induced resistance with these strains depended on how disease severity was measured. Three strains (90-166, 89B61 and T4) induced resistance in NahG plants (SA-deficient), indicating a salicylic acid-independent pathway, which agrees with the previously reported pathway for induced resistance by PGPR. However, differences from the reported pathway were noted with strain 89B61, which did not require jasmonic acid or ethylene signaling pathways for induced resistance, and with strain T4, which induced resistance in npr1 plants. • These results indicate that strains 89B61 and T4 induce resistance via a new pathway or possibly a variation of the previously reported pathway. This information will broaden our understanding of ways in which microorganisms can signal physiological changes in plants.
• 目前，从植物体内信号转导途径的角度，对促进植物生长的根际细菌（PGPR）介导诱导系统抗性的机制进行了深入研究。• 在此，我们确定了我们已充分表征的PGPR菌株（这些菌株已在多种植物上证明具有诱导抗性）是否也能在拟南芥中引发诱导抗性。评估了9种不同的PGPR菌株对拟南芥针对丁香假单胞菌两个致病型诱导抗性的能力。6种菌株显著降低了番茄丁香假单胞菌致病型的严重程度，而7种菌株降低了黄斑丁香假单胞菌致病型的严重程度。• 从初步筛选中，选择了4种菌株（90 - 166、SE34、89B61和T4），因为它们具有一致的诱导抗性能力。这些菌株诱导抗性的激发取决于疾病严重程度的测量方式。3种菌株（90 - 166、89B61和T4）在NahG植物（水杨酸缺陷型）中诱导抗性，表明存在水杨酸非依赖途径，这与先前报道的PGPR诱导抗性途径一致。然而，注意到与报道途径的差异在于菌株89B61诱导抗性不需要茉莉酸或乙烯信号途径，以及菌株T4在npr1植物中诱导抗性。• 这些结果表明，菌株89B61和T4通过新途径或可能是先前报道途径的变体诱导抗性。这些信息将拓宽我们对微生物如何向植物发出生理变化信号的理解。
