交替呼吸途径在油菜素内酯调控本氏烟响应高温胁迫中的作用研究

Role of Alternative Respiratory Pathway in Brassinosteroids Inducing Heat Stress Response in Nicotiana benthamiana

油菜素内酯(Brassinosteroids,BRs)属于甾醇类植物激素,它在植物生长发育及响应逆境过程中发挥着重要作用。然而,目前关于BR与线粒体之间的联系及逆境下BR调控线粒体的信号机制还不是很清楚。本研究探究了线粒体交替呼吸途径在BR调控本氏烟对高温胁迫耐受性中的作用。外施BR能够提高本氏烟对高温胁迫的抗性,同时显著诱导植株交替呼吸途径及上调NbAOX1转录水平。通过化学药剂处理抑制交替呼吸途径或病毒诱导的基因沉默技术抑制NbAOX1表达后,BR诱导的耐热性受到抑制。研究结果证明BR激活的交替呼吸途径能避免植物在高温逆境下积累过量的活性氧以及保护植物光系统在逆境下的正常功能。

Brassinosteroids(BRs),a class of steroid hormones,play important roles in regulation of plant growth and development,as well as the response to stress.To date,the crosstalk between BR and mitochondria and signaling mechanism of BR in regulating mitochondria under stress remain largely unknown.In this study,the role of mitochondrial alternative respiratory pathway in BR inducing heat stress tolerance in Nicotiana benthamiana was investigated.External application of BR increased the resistance of N.benthamiana to heat stress,accompanied by the induction of alternative respiration and up-regulation of NbAOX1 expression.Chemical inhibition of alternative respiration or inhibition of NbAOX1 through virus-induced gene silencing assay compromised BR-induced heat resistance in N.benthamiana.In conclusion,our results indicate that the alternate respiratory pathway induced by BR can avoid the superfluous reactive oxygen species accumulation and protect the photosystems in plants under heat stress condition.