不同致病力Rhizoctonia菌株对玉米木质素代谢、总酚含量及相关基因表达的影响

. Effects of different Rhizoctoniaspp.on lignin metabolism,total phenols content and expression of defense related genes in maize

【目的】通过分析不同致病力Rhizoctoniaspp.菌株与玉米互作过程中寄主PAL活性、木质素和总酚含量及PAL、POD、PR-1基因的诱导表达特点,了解玉米对Rhizoctoniaspp.侵染的抗性反应.【方法】采用分光度计法和定量RT-PCR法,分别测定不同菌株接种后玉米叶鞘苯丙氨酸解氨酶(PAL)活性、木质素含量和总酚含量变化及PAL、POD、PR-1基因的表达动态.【结果】玉米对不同致病力的Rhizoctonia solani AG1-IA菌株的反应有明显差异,菌株致病力越强,玉米PAL活性、木质素和总酚含量越高;同一菌株处理的玉米,其木质素含量变化与PAL活性变化呈正相关;强致病力菌株LY1-3-1接种后的48h和96h,PAL和PR-1基因表达量分别达最高;弱致病力菌株NJ002-12和YZ006-14接种96h后,PAL和PR-1基因表达量分别达最大水平;POD在不同处理中的表达趋势与PAL和PR-1类似.【结论】3个Rhizoctonia solani AG1-IA菌株都可增强玉米防御酶活性及基因的表达,并且抗性反应与菌株的致病力成正相关;弱致病力的双核丝核菌BX006-1对玉米的防御酶及相关卫基因的表达无明显影响.

【Objective】To investigate the resistance response of maize to different Rhizoctoniaspp.,activities of PAL,content of lignin and total phenols,and expressions of PAL,PODand PR-1 were analyzed.【Method】Three strains of Rhizoctonia solani AG1-IA with different pathogenicity,named as LY1-3-1,YZ006-14 and NJ002-12 respectively were selected as inoculums with a binucleate Rhizoctonia BX006-1 as a negative control.Dynamic changes of PAL activities,lignin and total phenols content,and expressions of PAL,POD,and PR-1 were detected by Trophotometer and RT-PCR respectively.【Result】The PAL activities and content of lignin and total phenols in maize were much higher after being inoculated by LY1-3-1,being a strain with higher pathogenicity compared with that of other strains.The PAL activities was positively correlated to the total phenols in post inoculation by the same strain.The highest expression of PALand PR-1 were at 48 hand 96 hafter being inoculated by LY1-3-1.However,the maximum expression of PALand PR-1 was at 96 hafter being inoculated by NJ002-12 and YZ006-14 respectively.Dynamic change of PODgene was very similar to that of PALand PR-1.No obvious changes appeared in PAL activities,lignin and total phenols content,and expressions of PAL,PODand PR-1 in maize after being inoculated by BX006-1.【Conclusion】The activity of PAL and expressions of related genes can be induced by Rhizoctonia solani AG1-IA and these defense responses in maize showed positive correlation with virulence of these pathogens.BX006-1 had no obvious effect on expression of related defense enzymes and genes.