水稻和稻瘟病菌互作中的信号传导及防御反应基因诱导表达的研究

 水稻和稻瘟病菌互作是研究植物与病原菌互作的模式体系。本文利用3个水稻抗稻瘟病近等基因品系(CO39、C101LAC和C101A51)和2个特异性菌株(M209和M210)构成不同亲和程度的互作关系,研究了稻瘟病菌对3个水稻信号传导途径关键酶合成基因、5个防御反应病程相关蛋白基因和1个防御反应转录因子调控基因诱导表达的作用。结果表明:稻瘟病菌诱导了各种互作关系中水稻OsLOX、OsAOS和OsPAL酶合成基因的表达,水稻启动了茉莉酸和水杨酸防御反应信号传导途径。在不亲和的互作反应中,稻瘟病菌能不同程度地诱导水稻OsPR1a、OsPR2、OsPR3-1、OsPR3-2和OsPR4基因的表达,从而有效激活了防御反应系统,使水稻植株表现为抗病;而在亲和的互作反应中,多数OsPR基因的表达水平低、时间短或没有表达,水稻植株表现为感病。OsMyb基因在各种互作关系中有不同的诱导表达。说明这些防御相关基因的诱导表达可能与水稻抗稻瘟病性相关。     

Comparative study of morphological,cultural and molecular markers for the characterization ofPseudocercosporella herpotrichoides isolates

Nirenberg's classification system and the polymerase chain reaction (PCR) combined with restriction enzyme digestion of an amplified ribosomal DNA fragment, were compared for the characterization of sixty isolates ofPseudocercosporella herpotrichoides, from various geographical areas and with differing fungicide sensitivity. With Nirenberg's system, it was possible to identify most isolates asP. herpotrichoides var.herpotrichoides orP. herpotrichoides var.acuformis. However, identification was slow and sometimes inconclusive as overlap occurred between the two varieties for all criteria examined. Molecular markers identified two distinct types among the isolates tested and generally good correlation was found between the PCR-based assay and Nirenberg's system, but the molecular assay was more accurate and faster.