外源水杨酸对水稻苗期生长与防卫相关基因表达的影响

Effects of exogenous salicylic acid on growth and defense-related genes of rice seedlings

为探究外源水杨酸(SA)对水稻苗期生长与SA相关防卫反应的影响,用不同浓度外源SA喷施苗期日本晴水稻,利用分光光度计测定水稻苗期生长关键指标叶绿素含量,采用qRT-PCR定量分析外源SA对水稻苗期SA合成基因PAL1、SA受体基因NPR1、SA信号途径下游的转录因子WRKY45/WRKY76和防卫基因PR1a/PR1b的表达水平。结果表明,外源SA对上述水稻基因的影响不同,即低浓度SA在一定程度上促进水稻苗期叶绿素积累,并显著影响水稻苗期防卫相关基因的表达水平;高浓度SA抑制叶绿素的积累,影响水稻的正常生长。综合比较结果显示,喷施2.0 mmol·L-1外源SA对水稻苗期防卫相关基因表达的影响最为有效,该结果为进一步探索外源SA促进水稻苗期生长并提高水稻苗期防卫能力的作用研究奠定基础。

To explore the effects of exogenous salicylic acid(SA)on plant growth and SA-related defense responses at the stage of rice seedlings,gradient concentrations of exogenous SA were used to spray rice seedlings of Nipponbare.Spectrophotometer was applied to measure the content of chlorophyll,a key indicator of rice seedling growth,and qRT-PCR was further used to analyze the expression levels of SA-biosynthesis gene PAL1,SA-receptor gene NPR1,and transcription factors WRKY45/WRKY76 and defense genes PR1a/PR1b at the downstream of SA signal pathway.It was found that different concentrations of exogenous SA exerted varying influences on expression patterns of tested genes,i.e.lower concentrations of exogenous SA promoted chlorophyll accumulation a certain extent and markedly affected on the expression of defense-related genes,while high concentrations of SA inhibited the accumulation of chlorophyll and induced abnormal growth at the stage of rice seedlings.Comprehensive comparison of quantitative results suggested that 2.0 mmol·L-1 of SA could be most effective in inducing the expression of defense-related genes by spraying rice seedlings.These results laid the foundation for further investigating roles of exogenous SA in promotion of plant growth and defense responses at the stage of rice seedlings.