Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Nanjing, China.
J Exp Bot. 2021 Jul 28;72(15):5673-5686. doi: 10.1093/jxb/erab210.
Inoculation with pollution-degrading endophytes boosts the catabolism of residual contaminants and promotes the pollution adaptation of host plants. We investigated the interaction pattern between Sphingomonas strain HJY-rfp, a chlorpyrifos-degrading endophytic bacterium, and rice (Oryza sativa) under pesticide stress using hydroponic cultivation. We observed a notable trend of endophytic root colonization in rice plants treated with 10 mg l-1 chlorpyrifos solution, and after 24 h the migration of HJY-rfp enhanced the chlorpyrifos degradation rate in leaves and stems by 53.36% and 40.81%, respectively. Critically, the rice root exudate profile (organic acids and amino acids) changed under chlorpyrifos stress, and variations in the contents of several components affected the chemotactic behaviour of HJY-rfp. HJY-rfp colonization dramatically activated defensive enzymes, which enabled efficient scavenging of reactive oxygen species, and led to 9.8%, 22.5%, and 41.9% increases in shoot length, fresh weight, and accumulation of total chlorophyll, respectively, in rice suffering from oxidative damage by chlorpyrifos. Endophytic colonization caused up-regulation of detoxification genes that have shown a significant positive correlation with chlorpyrifos degradation in vivo. Collectively, our results demonstrate that agrochemical stress causes plants to actively recruit specific symbiotic microbes to detoxify contaminants and survive better under pollution conditions.
接种具有降解污染能力的内生菌可以促进宿主植物对残留污染物的分解代谢和污染适应。我们使用水培培养的方法，研究了在农药胁迫下，具有降解毒死蜱能力的内生细菌 Sphingomonas 菌株 HJY-rfp 与水稻之间的相互作用模式。我们观察到，在 10mg/L 毒死蜱溶液处理的水稻植物中，HJY-rfp 明显表现出内生根定殖的趋势，24 小时后，HJY-rfp 的迁移使叶片和茎中的毒死蜱降解率分别提高了 53.36%和 40.81%。重要的是，水稻根分泌物（有机酸和氨基酸）在毒死蜱胁迫下发生变化，几种成分含量的变化影响了 HJY-rfp 的趋化行为。HJY-rfp 的定殖显著激活了防御酶，使活性氧的有效清除率提高了 9.8%、22.5%和 41.9%，分别使遭受氧化损伤的水稻的苗长、鲜重和总叶绿素积累增加。内生菌的定殖引起了解毒基因的上调，这些基因与体内毒死蜱的降解有显著的正相关。总的来说，我们的研究结果表明，农用化学品胁迫会促使植物主动招募特定的共生微生物来解毒污染物，并在污染条件下更好地生存。
