谷子对黑粉菌侵染的生物学响应

Biological Responses of Millet Plants to Ustilago crameri Infection

研究采用大田试验筛选出黑穗病高抗品种冀谷20(J20)和高感品种长农35(C35),采用室内盆栽试验检测2个品种对黑粉菌的响应。结果表明,谷种拌菌组植株中苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)活性升高,且J20的PAL和PPO活性显著高于C35;J20拌菌组的总酚、类黄酮和木质素含量及几丁质酶活性显著高于未拌菌对照组,β-1,3-葡聚糖酶活性升高不明显;C35拌菌组中木质素含量与几丁质酶活性高于未拌菌对照组,类黄酮含量与β-1,3-葡聚糖酶活性无明显改变,总酚含量显著下降;拌菌组中J20的β-1,3-葡聚糖酶活性显著高于C35;J20拌菌组中抗病相关基因(4CL、CCR、CHIB和WRKY22)和受体蛋白FLS2上调表达。谷子对黑粉菌的抗性涉及植株基因转录应答、次生代谢调控、抗病防御应答等生物学过程,不同品种的遗传基础差异导致植株自身结构、防御应答不同,品种抗性水平表现出显著差异。

In this study,based on the field experiment millet resistant variety Jigu 20(J20)and sensitive variety Changnong 35(C35)were selected for further study on the response mechanism of millet plants to Ustilago crameri infection by indoor pot experiment.The results showed that the activities of phenylalanin ammonia-lyase(PAL)and polyphenol oxidase(PPO)in millet seedlings increased after seeds sowed with the pores of Ustilago crameri,which labeled as I-J20 and I-C35,respectively.The activities of PAL and PPO in I-J20 plants were significantly higher than in I-C35.The contents of total phenols,flavonoids and lignin,as well as chitinase activity in I-J20 plants increased significantly than in the control J20 without Ustilago crameri pores,whileβ-1,3-glucanase activity enhanced a little in I-J20 plants.However,in I-C35 plants,the lignin content and chitinase activity increased,the total phenols content decreased,and no changes was found in flavonoids content andβ-1,3-glucanase activity.Furthermore,theβ-1,3-glucanase activity in I-J20 was higher than in I-C35.Transcriptional levels of resistance-related genes(4CL,CCR,CHIB,and WRKY22)and the FLS2 receptor were up-regulated in I-J20 plants.The results indicated that the disease resistance of millet plants to Ustilago crameri was dependent on the regulation of gene expression,secondary metabolism,and defense response.The differences in the genetic basis of different millet varieties might lead to the differences in plant structure and defense response,resulting in significant differences in the disease resistance level of varieties.