【作者】 咸丰；

【导师】 张显；

【作者基本信息】 西北农林科技大学 ， 蔬菜学， 2012， 博士

【摘要】 本研究以高抗白粉病的野生甜瓜材料‘云甜-930’和感病甜瓜品种‘华莱士’及其杂交后代为试材，对野生甜瓜‘云甜-930’抗白粉病的遗传机制和激素变化及其抗病相关基因进行了系统的研究，主要结果如下：1.白粉病抗性室内鉴定进一步表明，野生甜瓜‘云甜-930’高抗白粉病。叶片解剖结构研究表明甜瓜白粉病抗性与甜瓜叶表细胞排列的致密程度和刺毛数存在相关性。2.采用一整套国际通用的甜瓜白粉病生理小种鉴别寄主，对陕西关中地区的不同栽培条件下的瓜类作物上收集到的38份白粉病菌进行了生理小种鉴定、显微和超显微观察。显微和超显微的观察结果表明，收集的38份白粉病菌均为单囊壳白粉菌，其中Nantais Oblong、PMR45、Iran H、Vedrantais和Topmark等5个鉴别寄主高度感病，而WMR29、Edisto47、PMR5和PMR6等4个鉴别寄主免疫，MR1、PI414723、PI124112和PI124111等4个鉴别寄主表现为抗病，与生理小种2F.对这些鉴别寄主的抗感反应一致。初步鉴定为陕西关中地区的瓜类白粉病生理小种是单囊壳白粉菌生理小种2F.，并没有发现其它生理小种。为有效地防治陕西关中地区的瓜类白粉病以及选育抗白粉病新品种奠定了基础。3.采用植物数量性状分析方法，对野生甜瓜‘云甜-930’（P1）和栽培甜瓜品种‘华莱士’（P2）及其杂交后代F1、B1、B2和F2等6个世代群体的白粉病抗性进行了分析。2008年大棚中，B1的主基因遗传率和多基因遗传率分别为73.31%和18.83%，B2的主基因遗传率和多基因遗传率分别为69.15%和25.86%，F2的主基因遗传率和多基因遗传率分别为97.61%和0，环境方差是总表型方差的2.39~7.86%之间；2009年温室中，B1的主基因遗传率和多基因遗传率分别为62.98%和28.93%，B2的主基因遗传率和多基因遗传率分别为58.58%和31.47%，F2的主基因遗传率和多基因遗传率分别为90.89%和3.22%，环境方差是总表型方差的5.89%~9.94%之间。野生甜瓜‘云甜-930’的白粉病抗性遗传由两对加性显性上位性主基因+加性显性上位性多基因控制，同时还受环境变异的影响。在白粉病抗性育种中，选择效率最高的是F2主基因。为抗病基因的选择和甜瓜白粉病抗性育种提供了一定的理论依据，奠定了一定的基础。4.野生甜瓜‘云甜-930’在与甜瓜白粉病菌互作的早期防卫反应阶段，其IAA和ZR的含量增加迅速，GA和JA的含量缓慢下降，且四者都高于未接种对照，其ABA含量比对照上升慢，低于对照，且IAA和ZR可能是野生甜瓜‘云甜-930’抗白粉病的早期关键转导信号，二者协同作用；早期防卫反应期之后，野生甜瓜‘云甜-930’的IAA、ZR、ABA和JA的含量均低于对照，GA含量高于对照，且ZR/IAA与IAA/ABA比值变化平稳，维护着植株正常生长。5.利用cDNA-AFLP技术分析了野生甜瓜‘云甜-930’抗白粉病相关基因的差异表达，256对引物产生了188条TDFs (Transcript-derived fragments)，其中上调表达的有109条，下调表达的有79条。测序了表达稳定、回收质量好的60条TDF，通过BLAST比对分析等，其中有25个TDF在GenBank有较好的同源性。qRT-PCR验证了其中4个候选基因在白粉菌作用下的表达，4个基因在与白粉病互作时起到了重要作用，也表明了cDNA-AFLP的实验结果可靠性，为下一步进行基因全长克隆、亚细胞定位及功能验证提供了铺垫。更多还原

【Abstract】 A highly powdery mildew(PM)-resistant accession ‘Yuntian-930’ of wild melon, aPM-susceptible cultivar ‘Hualaishi’ and their hybrids were used as experimental materials tosystematically investigate the inherited mechanism, hormonal changes and disease-resistantgenes related to PM. The main results are as follows:1. Indoor PM-resistant identification indicated that ‘Yuntian-930’ processes highlyresistant to PM. Anatomic analysis in leaf structure showed that there is a correlation betweenPM resistance and epidermic cell arrangement and bristle number of leaves in melon.2.38pathogen collections of PM were collected from cucurbits crops with differentcultivation conditions from Guanzhong region Shaanxi Province, and further identified thephysiological races using an international common method. Microscopical chatacteristics onPodosphaera xanthii indicated that all38pathogens were P. xanthii, among which Iran H,Topmark, Vedrantais, PMR45and Nantais Oblong were highly susceptible to PM; PMR5,PMR6, Edisto47and WMR29were immune to PM; PI124111, PI124112, PI414723andMR1were resistant to PM with the same disase resistance as2F. It could be preliminarilyconfirmed that physiological race of cucurbits powdery mildew was the race2F. of P. xanthiiand no other races were discovered in Guanzhong areas, Shaanxi Province.3. PM-resistance of ‘Yuntian-930’(P1),‘Hualaishi’(P2) and their hybrids F1, B1, B2andF2were analyzed using plant quantitative analysis method. In2008, the major genesheritability of B1, B2and F2were estimated to be73.31%,69.15%and97.61%respectively,the polygene heritability to be18.83%,25.86%and0, and the ratios of the environmentalvariance to phenotype variance were2.39%-7.86%in the plastic tunnel. In2009, the majorgenes heritability of B1, B2and F2were estimated to be62.98%,58.58%and90.89%respectively, the polygene heritability to be28.93%,31.47%and3.22%, and the ratios of theenvironmental variance to phenotype variance were5.89%-9.94%in the green house. Thepowdery mildew resistance of wild melon ‘Yuntian-930’ was controlled by two pairs ofadditive-dominance-epitasis major genes plus additive-dominant-epitasis polygene, and alsoaffected by environment. In the resistance breeding program, the selection efficiency to major gene of the F2is the highest.4. In the early stage of the interaction with PM, the content of IAA and ZR, increasedquickly but GA and JA decreased slowly. The content of ABA increased slowly in wild melon,‘Yuntian-930’. IAA and ZR may be the early key transduction signal resistant to PM in thewild melon and were a synergistic effect. After the early defense responses, the content ofIAA, ZR, ABA and JA was lower than that of the control; GA content was higher than that ofthe control, the ratio of ZR/IAA and IAA/ABA changed smoothly and maintained the normalgrowth of the plant.5. Differential expression of PM-resistant related genes were analyzed in the interactionbetween ‘Yuntian-930’ and PM using cDNA-AFLP technology.256pairs of primers produced188TDFs (Transcript-derived fragments), which included109inducible expression TDFs and79displayed repression.60TDFs with expression stability and good quality were sequenced.By BLAST analysis in GenBank,25TDFs has high homology. Using qRT-PCR, expressionof four candidate genes was verified. Those laid the foundation for cloning the full-lengthgene, subcellular localization and function verification.更多还原