The Stress Tolerance Characteristics of Plant Growth-Promoting Rhizobacteria JHS0317 and XL0404 and Their Growth-Promoting and Disease Control Effects on Tobacco

LI Xiaojie; QIU Rui; LIU Chang; BAI Jingke; ZHANG Mengdan; CHEN Yuguo; MIAO Shuyue; LI Shujun

doi:10.15933/j.cnki.1004-3268.2025.12.010

Abstract：The aims are to clarify the stress tolerance characteristics,growth-promoting and disease control effects,and mechanisms of Pantoea agglomerans JHS0317 and Enterobacter ludwigii XL0404,which were plant growth-promoting rhizobacteria.The sensitivity of strains JHS0317 and XL0404 to temperature,pH value,and ultraviolet radiation was determined using the plate counting method.The growth-promoting effect on tobacco and the control effect on tobacco root rot caused by Fusarium were determined through indoor pot inoculation experiments.The results showed that the suitable growth temperature for strain JHS0317 was 28-35℃,and the suitable growth temperature for strain XL0404 was 28-45℃,with a lethal temperature of 65℃.Both strains could grow under pH conditions of 5-9,and the optimal pH was 5-7.They were sensitive to ultraviolet radiation.The results of pot experiments showed that the treatment of strains JHS0317 and XL0404 had a significant promoting effect on tobacco plant height,aboveground fresh weight,root fresh weight,total root surface area,and total root volume,which increased by 62.58%,44.76%,55.23%,63.83%,71.43%,and 82.32%,49.84%,43.02%,43.38%,61.11%respectively compared to the control treated with water.The content of plant hormones such as brassinolide,gibberellin,and auxin,and the activity of resistance enzymes such as phenylalanine ammonia lyase,per oxidase,polyphenol oxidase and superoxide dismutase in tobacco leaves were also increased compared to the control.The treatment of strains JHS0317 and XL0404 could reduce the incidence rate and disease index of tobacco Fusarium root rot,and the control effects were 49.99%and 24.98%,respectively.In summary,the plant growth-promoting rhizobacteria strains JHS0317 and XL0404 have good stress resistance to high temperature and acid and alkali,and have significant growth-promoting and disease prevention effects on tobacco,with good application prospects.