用相互嫁接和定量PCR分析棉花对棉花黄萎病的抗性

为了研究棉花对棉花黄萎病的抗性机制, 本文选用对棉花黄萎病表现抗病的海岛棉(Gossypium barbadense)材料海7124和Pima 90及感病的陆地棉(G. hirsutum)材料冀棉11, 通过相互嫁接的方法构建试验系统, 用棉花黄萎菌对其人工接种, 利用Real-time quantitative PCR (qPCR)技术分析其在感病和抗病棉花中侵染的差别。相互嫁接试验中感/抗和抗/感组合的病情指数介于感/感和抗/抗对照之间, 且相互嫁接棉株各个部位的IC值(侵染系数)也多介于其对照相应部位之间; 并且病情指数与不同部位IC值显著相关, 说明棉花黄萎菌可以通过接口在抗-感之间扩展。感/抗嫁接组合试验说明抗病材料的茎基部在抑制病原菌扩展中起重要的作用, 而抗/感类型试验说明抗病材料接口以上部分也具有抑制病原菌增殖的作用。总之, 抗病海岛棉无论作为砧木还是接穗, 都能有效抑制病原菌的扩展, 说明抗病海岛棉对棉花黄萎菌具全株抗性, 但茎基部在抑制病原菌扩展中起重要的作用; 同样, 感/抗和抗/感组合试验也说明感病材料的各个部位均不能抑制病原菌的定殖和扩展。

Resistance to Verticillium wilt in Cotton by Reciprocal Grafting and Real-time Quantitative PCR

In an attempt to better understand the resistance mechanism of controlling cotton Verticillium wilt by locating responsible for resistance in the plant, reciprocal grafts were made between resistant (Gossypium barbadense, Hai 7124 and Pima 90) and susceptible (G. hirsutum, Jimian 11) genotypes. The grafting combinations were inoculated with Verticillium dahliae. Quantitative monitoring of colonization of V. dahliae in different parts of the plant was analyzed using Real-time quantitative PCR (qPCR). When comparing resistant/susceptible or susceptible/resistant grafted combinations with their resistant and susceptible self-graft checks, respectively, disease index of reciprocal grafts and IC (infection coefficient) values of different parts of the plant were nearly within a range between their corresponding checks, respectively, indicating the pathogens could be transferred through the graft union in reciprocal grafts. The disease index was significantly related with average IC values in different parts of plant in different cotton types. Susceptible/resistant grafted combinations showed basal stem of resistant genotypes had an important role on inhibiting translocation of the pathogens, and resistant/susceptible grafted combinations also showed upper stem above graft union with the resistant ability to V. dahliae in resistant genotypes, which indicated that the resistant genotype G. barbadense has the whole-plant of resistance to V. dahliae. In addition, it seems that all parts of the plant in susceptible genotypes (G. hirsutum) were susceptible to V. dahliae.