蜡质芽孢杆菌AR156对辣椒的防病促生机理研究

Disease preventing and growth promoting mechanisms of Bacillus cereus strain AR156 on pepper

蜡质芽孢杆菌AR156是南京农业大学与新沂中凯农用化工有限公司合作开发的生物农药。为了解AR156对辣椒的防病促生机制,本文研究了AR156在温室条件下对青枯劳尔氏菌引起的辣椒青枯病的生防效果,对辣椒的促生作用,在辣椒根围的定殖能力,诱导植物细胞防卫反应,如活性氧积累和胼胝质沉积,以及植物防御相关酶的活力。结果表明,蜡质芽孢杆菌AR156对辣椒青枯病的温室防效高达73.31%。AR156的使用使辣椒植株干重增加22.30%,并能稳定的在辣椒根围定殖,接种60 d后,其定殖量为5×105cfu·g-1FW。AR156预处理后挑战接种病原菌能诱导植株更迅速的产生细胞防卫反应,并可显著提高超氧化物歧化酶(SOD)和过氧化物酶(POD)的活力。可见AR156菌株诱导的植物细胞防卫反应,提高植物防御相关酶活和在辣椒根围稳定的定殖能力使其产生对病害的广谱抗性。研究还发现AR156菌剂可增加辣椒叶片叶绿素的含量,这可能是该菌剂促进辣椒生长的原因之一。

Bacillus cereus strain AR156, one kind of biopesticide, was cooperatively developed by Nanjing Agricultural University and Xinyi Zhongkai Agricultural Chemical Industry Co., Ltd. In order to explore the mechanism of this strain in preventing disease and promoting plant growth, biocontrol efficacy of AR156 on pepper wilt disease caused by Ralstonia solanacearum was investigated along with its growth promotion effects on pepper in the greenhouse, colonization ability, activation of the cellular defense responses such as hydrogen peroxide accumulation and callose deposition, and several plant defense related enzymes activity in pepper plants. It was showed that biocontrol efficacy of AR156 on pepper wilt disease was up to 73.31%, meanwhile improving the fresh weight of pepper plants by 22.30%. It was found that strain AR156 could stably colonize in rhizosphere at 5×105 cfu per gram of root fresh weight on the 60th day after inoculation. Faster cellular defense responses were induced and the activity of plant defense related enzymes including superoxide dismutase （SOD） and peroxidase （POD） were significantly enhanced in pepper treated with AR156 and R. solanacearum. In conclusion, the broad spectrum resistance of AR156 to disease was realized by inducing cellular defense responses, enhancing plant defense related enzymes activity and forming robust colonies in the rhizosphere of pepper. In addition, it was found that AR156 treatment could increase the contents of chlorophyll in pepper leaves, which might be one reason that AR156 could promote pepper growth.