The Korean Soclety of Plant Pathology : B ; Biological Control : B-8 ; Versatile functions of field application of Bacillus vallismortis strain EXTN-1 and a dipeptide in Chinese cabbage

It has been known that Bacillus vallismortis strain EXTN-1 (EXTN-1), which was originally isolated from the rhizosphere of chili pepper, en-hanced plant growth promotion in diverse crop plants. In this study, the potential physiological role of EXTN-1 and a dipeptide (Q3, cyclic Proline-Glycine) in plant growth promotion, disease management, and improve-ment of abiotic stress tolerance was elucidated in Chinese cabbage under field conditions. The length of width and height of leaves were phenotypi-cally longer after application of a combination treatment. Moreover, total biomass of Chinese cabbage was significant increased by approximately 2-fold change. In addition to developmental alteration, elicitation of induced systemic resistance (ISR) was appeared by a combination treat-ment in response to soft rot caused by Pectobacterium carotovora subsp. carotovorum SCC1, relative to control plants. Intriguingly, plants applied to a combination treatment displayed an improvement of heat toler-ant, which was accompanied by up-regulation of stress tolerance genes. Taken together, our results strongly suggest that EXTN-1 and Q3 are nor-mally required in plant growth promotion, induced systemic resistance to bacterial soft rot and abotic stress tolerance. Our data provide a new paradigm in interconnection between EXTN-1 and Q3 and plant growth, disease management, and abiotic stresses on a large scale under high land field conditions.