细胞微丝骨架在玉米抗纹枯病菌Rhizoctonia solani侵染中的作用

Roles of actin filaments in defense against Rhizoctonia solani causing banded leaf and sheath blight of maize

为探究细胞微丝骨架在玉米抗纹枯病侵染过程中的作用,采用微丝骨架解聚剂LatB预处理玉米离体叶片后接种立枯丝核菌Rhizoctonia solani AG1-IA,显微观察病原菌的侵染过程,并检测活性氧(ROS)、细胞坏死及抗病基因(PR1、ZmDREB2A)表达等抗病反应情况。结果显示,与未经LatB预处理相比,LatB预处理加快了R.solani侵染后玉米病斑的形成,并影响了侵染结构的发育;在侵染后期,LatB促进了R.solani诱导的玉米叶片中ROS积累、细胞坏死反应和PR1基因表达;溶剂DMSO预处理与未经LatB预处理的结果类似,表明DMSO对本试验的影响较小。研究表明,细胞微丝骨架不仅参与玉米抗R.solani的侵入,而且通过调控ROS、PR1基因表达,细胞死亡等抗病信号提高玉米抗病防御能力。本研究为进一步研究细胞微丝骨架在玉米对纹枯病的抗病机理中的作用提供了重要参考。

In order to find out the role of cellular actin filaments in maize resistance to Rhizoctonia solani causing banded leaf and sheath blight,detached maize leaves were pretreated with the actin filament depolarization,latrunculin B(LatB),before inoculation with R.solani AG1-IA,and then collected at different time points in this study.Disease development and pathogen infectious structures were observed through the microscope,and meanwhile,defense responses including ROS accumulation,cell death and defense gene expression(PR1 and ZmDREB2A)were also examined.The results showed that,compared to inoculation with R.solani alone,pretreatment with LatB led to an earlier disease lesions and development of infectious structures.Additionally,ROS accumulation,cell death and defense gene expression were much higher than that without LatB pretreatment.In addition,pretreatment with the solvent DMSO showed similar results to the control without LatB treatment,indicating that DMSO had little effect on the LatB treatment.These data demonstrated that cellular cytoskeletal actin filaments not only functioned on pathogen invasion,but also regulated ROS accumulation,PR1 expression and cell death,all of which worked together to suppress pathogen spread on maize leaves and enhance maize resistance.This study provides important information for further studies on the role of actin filaments in maize resistance.