肉桂醛对辣椒疫霉的抑制作用

Inhibition of Phytophthora capsici by cinnamaldehyde

为了探讨肉桂醛对辣椒疫霉的抑制机制,研究了肉桂醛作用下辣椒疫霉菌丝的径向生长、辣椒疫霉孢子的萌发与活力、辣椒疫霉孢子内活性氧(ROS)含量和NADPH氧化酶基因(nox)的表达以及外援ROS清除剂谷胱甘肽(GSH)存在下肉桂醛对辣椒疫霉孢子生长的影响。结果显示:肉桂醛能够有效地抑制辣椒疫霉菌丝的径向生长和孢子的萌发,抑制辣椒疫霉菌丝径向生长的EC50值为1.0 mmol/L,完全抑制辣椒疫霉孢子萌发的MIC值为0.4 mmol/L,并且Almar blue染色发现此时辣椒疫霉孢子几乎没有活力;0.4 mmol/L肉桂醛处理辣椒疫霉孢子0.50h时,孢子内ROS含量明显增加;GSH能够明显缓解肉桂醛对辣椒疫霉孢子的抑制作用;0.4 mmol/L肉桂醛处理辣椒疫霉孢子0.25 h,孢子内nox1基因表达上调,表明肉桂醛可能是通过上调nox1基因的表达从而产生大量的抑制辣椒疫霉的ROS。

In order to study the inhibition mechanism of cinnamaldehyde to Phytophthora capsici, the P. capsicimycelial radial growth, zoospore germination and viability, reactive oxygen species（ROS） content and nox expression inzoospore induced by cinnamaldehyde were measured, and the effect of cinnamaldehyde on P. capsici zoospore growth inthe presence of exogenous ROS scavenger GSH were investigated. Cinnamaldehyde efficiently inhibited the P. capsicimycelial radial growth, with the EC50 value of 1.0 mmol/ L. It impaired the zoospore germination as well, with the MICvalue of 0.4 mmol/ L. P. capsici zoospore almost lost viability with 0.4 mmol/ L cinnamaldehyde by Almar blue staining.ROS content in P. capsici exposed to 0.4 mmol/ Lcinnamaldehyde significantly increased at 0.50 h. GSHobviously relieved the inhibitory effect of cinnamaldehydeon the growth of P. capsici zoospore. Nox1 gene expres-sion in P. capsici zoospore exposed to 0.4 mmol/ L cin-namaldehyde was up-regulated at 0.25 h. These resultsindicated that cinnamaldehyde might boost ROS content through up-regulating nox1 expression.