细胞乳突的形成和小麦白粉菌成功侵染的关系

THE RELATION BETWEEN PAPILLAE FORMATION AND SUCCESSFUL INFECTION BY ERYSIPHE GRAMINIS TRITICI IN WHEAT

用一套己知抗白粉病单基因的小麦材料,研究了小麦白粉菌诱发寄主表皮细胞产生的乳突与成功侵染的关系。抗病小麦叶片上,诱发产生乳突的分生孢子占测定分生孢子数的58.8%,感病品种为63.8%。这表明抗性不同的小麦材料接种白粉菌之后,叶表皮细胞内形成乳突的百分率相近,然从在抗病材料和感病材料中形成的乳突阻止病原物发育和成功侵染的作用不相同,在抗病叶片上,诱发产生乳突的分生孢于中有88%停留在压力孢阶段,不继续发育,仅有12%能突破乳突形成吸器,使得侵染成功。与此对照,在感病叶片上只有32%诱发乳突的分生孢子不能穿透乳突,而68%则能突破乳突。成功地与寄主建立寄生关系。我们的研究表明,乳突能否成功地阻止白粉菌侵入可能与乳突形成的迟早有关。

Relation between papillae formation induced in epidermal cells of host and infection by Erysiphe graminis tritici was studied by using the leaves of the wheat lines which have single genes for resistance to the pathogen of powdery mildew in wheat.The percentage of conidia that induced papillae in the total test conidia were 58.8% on the resistant wheat lines,slightly less than 63.6% on the susceptible ones.This suggests that the frequency of papillae formation is not associated with degree of host resistance to powdery mildew.However,the papilla formed in the resistant and susceptible wheat lines had different capacity for stopping the development of the pathogen.In the leaves of the resistant line-s,88% of the conidia that induced papilla did not develop further after the stage of appressoria,only 12% of them could break through papilla and produce hau-storia.In contrast with this,for the susceptible lines 32% of such conidia did not develop after appressoria,but 68% of them could pass through papilla to form haustoria and infect host successfully.The present study shows that whet-her or not the papillae can obstruct the penetration of the pathogen might be related of time in which papillae appeared in host cells.