结缕草响应立枯丝核菌侵染的SA合成途径鉴定  

Identification of SA Synthetic Pathways Responding to Rhizoctoniasolani Infection in Zoysia japonica

作　　者：宿强 左慧 晁跃辉[1] 曾会明[1] XU Qiang;ZUO Hui;CHAO Yue-hui;ZENG Hui-ming(School of Grassland Science,Beijing Forestry University,Beijing 100083)

机构地区：[1]北京林业大学草业与草原学院,北京100083

出　　处：《生物技术通报》2020年第10期32-39,共8页Biotechnology Bulletin

摘　　要：为揭示立枯丝核菌(Rhizoctonia solani)侵染条件下结缕草(Zoysia japonica)中水杨酸(SA)合成的主要途径,通过同源比对法识别关键调控基因,依据病程下的转录模式鉴定响应通路,测试SA浓度及苯丙氨酸解氨酶(PAL)活性验证表达效果。ZjPAL1-ZjPAL5作为典型PAL等位基因,对应Unigene于根部发病后呈现持续上调,在转录水平积极响应侵染。异分支酸合成酶基因中仅监测到ZjICS1表达,且丰度始终不足ZjPAL1-ZjPAL5的10%,并随侵染加深趋于下调。菌丝体侵入根部内皮层后引起PAL活性严重减弱,伴随其减弱程度加剧,途径终产物SA浓度的下降也加快;但同时在尚未感染的叶片中SA浓度却随PAL活性提升保持高水平。PAL基因调控的苯丙氨酸途径是R.solani侵染下结缕草SA合成主导途径,响应强度随侵染深入而增强,PAL活性下降会显著降低SA水平。To reveal the main salicylic acid(SA)biosynthetic pathway in Rhizoctonia solani-infected Zoysia japonica,the key genes was recognized with aligned homologous sequences,the responsive pathway was identified according to transcriptional profile during pathogenesis,SA concentration was measured,and phenylalanine ammonia lyase(PAL)activity was verified.As typical alleles of PAL,genes ZjPAL1-ZjPAL5 were up-regulated continuously in the diseased root shown by their corresponding Unigenes,meaning an active response to infection at transcription level.About genes encoding isochorismate synthase,only ZjICS1 transcripts were observed,whose abundance was always less than one-tenth of that of ZjPAL1-ZjPAL5 and tended downwards with infection increasing.The PAL activity in the root reduced after mycelial invasion into the endodermis of the root.The more the activity was weakening,the faster the decrease of synthesized SA concentration was.However,the SA concentration in the non-infected leaves remained high by enhanced PAL activity.Phenylalanine pathway regulated by PAL gene plays a major role in SA synthesis when Z.japonica is infected by R.solani.Responsive intensity increases with the infection deepening,and the reduction of PAL activity will result in SA concentration decreasing.

关 键 词：结缕草 立枯丝核菌 水杨酸合成 苯丙氨酸途径 

分 类 号：S436.8[农业科学—农业昆虫与害虫防治]