微生物帮助烟草抗旱的机理及其应用

Microbe-assisted drought resistance for tobacco plants: Mechanisms and applications

干旱是中国烟草种植业面临的较为严重的非生物胁迫.很多与植物共生或联合的根际微生物能帮助植物避旱和耐旱.微生物能通过菌丝吸水并转运到植物,通过产生植物激素或改变植物内源激素的平衡来促进根发育和伸长,或诱导叶片关闭气孔,促进根吸水和减少叶片散失水分来避旱.微生物能通过调整不同激素介导的信号通路,诱导植物产生系统抗逆性,促进植物细胞产生渗透保护剂、抗氧化物和活性氧清除剂而耐旱.微生物还能帮助植物吸收营养,以支持植物在干旱胁迫下的代谢和生长.本文关注丛枝菌根真菌、模式内生真菌印度梨形孢和根际促植物生长细菌帮助烟草和番茄等植物抗旱的机理,探讨如何在烟草育苗和栽培中应用有益微生物来帮助烟草抗旱.

Drought is one of the most destructive abiotic stresses to tobacco farming in China. Many microbes in symbiosis or association with plant roots are able to help plant to avoid and tolerate drought stress. Microbes absorb water via mycelia and transport water to plant hosts; microbes produce plant hormones or change plant endogenous hormones to promote root development and elongation or leaf stomatal closure, leading to drought avoidance via increase of water absorption and decrease of water loss. Microbes modulate plant signal transduction pathways mediated by different plant hormones to induce plant systemic tolerance to abiotic stresses via accumulation of osmoprotectants, antioxidants, and scavengers of reactive oxygen species. Microbes also help plant hosts to absorb nutrients and thus support plant metabolism and growth under drought stress. This paper reviewed the mechanisms of microbe-assisted plant resistance to drought stress based mainly on the studies on tobacco and tomato plants inoculated with arbuscular mycorrhizal fungi, the model endophytic fungus Piriformospora indica, and plant growth-promoting rhizobacteria. This paper also discussed the use of these beneficial microbes to promote tobacco resistance to drought stress for tobacco farming.