【作者】 王宝和；

【导师】 张红生； 张洪熙；

【作者基本信息】 南京农业大学 ， 农学， 2006， 硕士

【摘要】 水稻植株90-95％的干物质来自光合作用，其生物产量和经济产量主要是依靠光合产物。叶片是最主要的光合器官，因此定位和克隆与水稻光合作用相关的新基因、研究其功能，对阐明光合调控机理、提高水稻的光合生产能力和增加水稻产量具有重要的理论价值与实践意义。叶色突变是一类明显的性状突变，不仅在高等植物叶绿素生物合成、叶绿体结构和功能、遗传和分化以及发育等基础研究中具有重要意义，并可作为标记性状在杂交稻种子纯度鉴定中加以利用。本研究以粳稻（Oryza sativa L．ssp．japonica）品种武运粳7号自然突变的黄绿叶突变体ygl2为材料，分别与武运粳7号和江西1587正交、反交，获得杂交F₁及自交F₂。对后代进行系统观察发现：F₁代叶片均表现为正常绿色，F₂代叶色性状发生分离，不同的杂交组合F₂代群体中的叶片都表现出黄绿叶色和正常绿色两种类型，正常绿色植株与黄绿叶植株的比例符合3:1的分离比，表明黄绿叶突变性状受1对隐性核基因控制。利用微卫星标记（SSR）和ygl2／江西1587杂交组合的F₂群体对控制该黄绿叶性状的隐性基因初步定位，确定该基因在水稻第6染色体长臂上，位于RM541和RM30两个标记之间，遗传距离分别是13.13cM和9.09cM。文献检索发现，第6染色体在此位置上没有类似的基因报道，表明该基因为一新的叶色基因。由于在水稻中已有一个黄绿叶基因ygl，位于水稻第10染色体，因此将本研究中所发现的黄绿叶突变体基因暂命名为ygl2（t）（yellow-green，leaf 2）。进一步利用已经公布的水稻基因组序列，在ygl2（t）基因附近区域寻找微卫星序列并发展新的SSR标记，在RM541和RM30之间找到8个连锁多态性分子标记。用这8个分子标记对ygl2／江西1587 F₂群体中的429株黄绿叶单体进行群体分析，将黄绿叶基因ygl2（t）定位在SSR6-16和RM7434之间，与SSR6-16和RM7434的遗传距离分别为0.62 cM和0.74 cM，为进一步克隆该基因奠定基础。以自然突变体ygl2为黄绿叶供体、103S为光温敏不育基因供体，通过杂交、回交和不同生态条件下育性跟踪鉴定，选育出带有黄绿叶标记的新光温敏不育系3290S，并与绿叶恢复系测交筛选优势组合，所配优势组合杂种优势在主要经济性状上与正常叶色不育系103S所配组合无明显差异，表明该黄绿叶性状对杂种优势无显著负效应，同时黄绿叶性状在秧田期易识别，表明了黄绿叶突变体在育种实践中具备可行性。更多还原

【Abstract】 Crop biomass and economic yield mainly depend on the photosynthetic assimilate ofleaves and other photosynthetic organs. 90-95% dry matter accumulation in rice is resultedfrom photosynthetic assimilate of leaves, the main photosynthetic organ. Therefore it isvery important in the theoretical research of photosynthesis regulatory mechanism to mapand clone new rice photosynthetic-related genes and investigate their function. Through thegene engineering approach, the photosynthesis ability and economic efficiency of rice maybe significantly increased. As an obvious trait mutation, leaf color mutation could not onlyused in the research of photosynthesis, chlorophyll biosynthesis, structure, function,inheritance, differentiation and growth of chloroplast, but also in the identification of seedpurity for hybrid rice.Rice cultivar Wuyunjing 7, Jiangxi 1587 （upland rice） and a yellow-green leaf mutantygl2, origined from a Wuyunjing 7, was used in this study.Two reciprocals （Wuyunjing 7×ygl2, Jiangxi1587×ygl2） were made to obtain F₁ andF₂ populations. The observation of leaf color showed that all the F₁ plants were normalgreen, but the leaf color trait in the all F₂ populations was segregated into yellow green andnormal green with a segregation ratio of 3: 1. It indicated that the leaf color of mutant ygl2was controlled by a single recessive nuclear gene.The plants of F2 population, generated from the cross ygl2×Jiangxi 1587, were usedfor molecular mapping of this recessive gene. The preliminary results showed that themutant gene was located on the rice chromosome 6 between two SSR markers, RM541 andRM30, with the genetic distances of 13.13cM and 9.09cM respectively. Since there is nosimilar gene locus reported on this region, it indicates that this is new gene identified andtentatively named as ygl2（t） （yellow-green leaf 2）. In order to establish the fine location ofthe ygl2（t） gene, the public rice genome sequence in the region containing ygl2（t） gene wasused to search new SSR markers. Then eight new SSR markers between RM541 and RM30 were developed. 429 yellow-green leaf plants of F₂ population generated from the crossygl2×Jiangxi 1587 were analyzed with above eight SSR markers, and the gene ygl2（t） wasmapped between SSR6-16 and RM7434 markers, with genetic distances of 0.62cM and0.74cM respectively.A new photo-thermo sensitive genic male sterile line 3290S with the yellow-green leaftag was developed in BC₁F₇ from the yellow-green leaf mutant and the photo-thermosensitive male sterile line 103S via cross, backcross and fertility identification. Goodhybrids were developed by identifying crosses from 3290S and 103S with a series of greenleaf restorer lines, and there were no obvious differences in all the main economiccharacteristics investigated, indicating that the yellow-green leaf trait had no significantnegative effect on the main economic characteristics. Meanwhile the seedlings withyellow-green leaves could be easily distinguished from the normal seedlings. Thus, it wasreasonable to breed japonica sterile lines with the yellow-green leaf tag.更多还原