Genetics,resistance mechanism,and breeding of powdery mildew resistance in cucumbers(Cucumis sativus L.)

Cucumber is an important vegetable worldwide,and powdery mildew(PM)is a common and serious disease of cucumbers.Breeding disease-resistant cucumber varieties is the most advantageous strategy to control this disease.In recent years,exploration and identification of cucumber PM resistance genes have achieved great advancement,and many genes have been cloned and verified using different methods.However,the resistance mechanism of cucumber PM is still unclear,and many ambiguities need to be elucidated urgently.In this review,we summarized the research advances in PM resistance in cucumbers,including genetic analysis,quantitative trait locus mapping,map-based cloning,transcriptomics,mlo-mediated PM resistance,and mining of noncoding RNAs involved in resistance.Finally,the research directions and the problems that need to be solved in the future were discussed.

巴西橡胶树(Hevea brasiliensis)HbMlo2基因克隆与表达分析

Mlo (mildew resistance locus O)是一种植物防卫相关基因,对植物的抗病性有负向调控作用。本研究采用基因编辑技术等方法为培育橡胶树抗病品种作出铺垫,进一步填补Mlo家族成员。通过对拟南芥的AtMlo2基因在巴西橡胶树上进行比对,根据同源性克隆得到一个cDNA序列,将其命名为HbMlo2。根据生物信息学分析得出,该基因cDNA全长1 725 bp,编码574个氨基酸,该蛋白的分子量为65.78 kD,等电点为8.98,8个跨膜域,没有信号肽,HbMlo2基因与已知的木薯的Mlo基因相似性达到83%。白粉菌侵染橡胶树叶组织后,通过qRT-PCR发现HbMlo2基因显著上调。本研究结果初步表明,HbMlo2可能参与橡胶树的抗病反应机制,为橡胶树抗病育种的研究提供新思路。