【作者】 王伟平；

【导师】 武小金； 陈立云；

【作者基本信息】 湖南农业大学 ， 种子科学与工程， 2010， 博士

【摘要】 在构建水稻突变体库的研究中,通过组织培养诱变,在恢复系T893中发现一株突变体,该突变体在连续两年4代的异地栽培中始终不抽穗,幼穗紧包在叶鞘内不伸出,性状稳定,命名为M893。本研究以包穗突变体M893为试验材料,分别从农艺学、遗传学、生理学及分子生物学等方面进行了研究,主要结果如下：1、M893形态特性表现为：植株矮化、每穗颖花数减少,上3叶明显缩短,幼穗被叶鞘紧包,始终不能抽穗。主茎节间数与T893(对照)相比无显著变化,大多数为5个,但节间长度呈极显著缩短,倒1～倒5节间分别比对照缩短88.40%、83.92%、65.55%、45.04%和32.79%,倒1节间缩短长度和比例均为最大。2、倒1茎秆显微结构观察表明,M893居间分生组织区域细胞排列紧密整齐,类似于对照对应节间的细胞,M893与对照此部位的细胞长度无显著性差异。但节间中部突变体薄壁细胞纵向长度与对照相比呈极显著差异,M893平均10个细胞的长度为205.90μm,而野生型为309.37μm,表明M893倒1节由居间分生组织细胞分化的细胞延伸受阻,导致幼穗分化末期节间不能有效伸长。3、在幼穗分化Ⅳ期、Ⅵ期和Ⅷ期,对M893主茎倒1节间茎秆和叶片赤霉素(GA4)、吲哚乙酸(IAA)、脱落酸(ABA)及玉米素(Z)的测定结果表明：与对照相比,M893倒1节间茎秆中GA4和IAA含量均呈显著或极显著下降；ABA含量在幼穗分化Ⅳ期、Ⅵ期呈显著下降,但到了幼穗分化Ⅷ期,其含量极显著上升；Z的含量在两组材料中无显著变化。M893倒1叶的GA4、ABA及Z的含量与茎秆分析结果一致。4、幼穗分化Ⅷ期末分别用80 mg/L、120 mg/L、160 mg/L、200 mg/L四种浓度的赤霉素(GA3)溶液处理M893植株,倒1～倒3各节间长度在不同浓度处理间无显著性差异,节间未显著伸长,M893对赤霉素(GA3)的诱导呈钝感。5、通过长沙和海南两地共4季种植,M893均表现包穗特性,表明M893具有遗传稳定性。用M893与恢复系丙5060、丙4170、明恢81及T893、轮回422等杂交,Fl均表现抽穗结实正常,表明该突变性状为隐性。通过长沙和海南两地共6个F2群体以及突变体／丙5060的F3、F4代群体的遗传追踪分析,结果表明各个群体中正常株与包穗株数值均符合3：1的分离比例。由此证实该突变性状受1对隐性基因控制,并将该基因命名为Shpx。6、利用SSR标记,将Shpx定位于第2号染色体上,位于RM12680和RM12685二个标记之间,二个标记与基因的遗传距离分别是0.2cM、1.2cM；另一个标记RM6247与Shpx的遗传距离是0cM,表明RM6247与基因呈共分离,连锁紧密。7、通过M893及对照的基因表达图谱比较分析,获得了4个可能与包穗突变体形成的侯选相关基因：AK063150.1、9630.m04842、AF056027.1和AK070347.1,其中前3个基因为生长素调控相关基因,在突变体内处于低表达水平,其中AK063150.1在突变体的表达水平最低。AK070347.1为上调基因,具有类似脱落酸的抑制伸长功能。更多还原

【Abstract】 A rice mutant with sheathed panicle from a restorer line T893 was obtained in tissue culture induction. The mutant, named as M893, kept sheathed panicle characteristics for four generations at two locations in two years, indicating that the character was genetically stable. In this paper, the morphological, physiological and genetic studies were carried out on the character, respectively. And the results are as follows:1. The main morphological, characteristics of M893 were:fully sheathed panicle, dwarf, small panicles, shortened upper 3 leaves. Compared with T893 (Check), the internode number of main stem of M893, which was almost 5, wasn’t significantly different. But the length of all the 5 internodes from top first to top fifth, was shortened by 88.40%、83.92%、65.55%、45.04%and 32.79%at extremely significance, respectively. And the shortened length and proportion of top-first internode was the most.2. It showed that, compared with T893, the length of cell in intercalary meristem in top-first culm of M893 wasn’t significantly different under microscope. And the cells in intercalary meristem arranged in line, similar to that of T893. However, the longitudinal length of parenchyma cell in top-first internode of M893 was extremely significantly different from that of T893. And the average length of 10 cells of M893 was 205.90μm, but that of T893 was 309.37μm. The result suggested that the cells in top-first internode of M893, which were originated from intercalary meristem by differentiation, didn’t extend. Accordingly, the top-first internode didn’t elongate effectively. 3. At stageⅣ、ⅥandⅧof panicle differentiation, the contents of hormones in top-first internode and flag leaf of main stem, including GA4、IAA、ABA and Z, were determined, respectively. The result showed that, compared with the check, the content of GA4 and IAA in culm of M893 decreased significantly or extremely significantly, respectively. And the content of ABA decreased significantly at stageⅣand VI of panicle differentiation, but increased extremely significantly atⅦof panicle differentiation. The content of Z wasn’t significantly different between M893 and T893. The results of analysis on the content of GA4、ABA and Z in flag leaf were similar to that in the culm.4. At the end of stageⅦof panicle differentiation, a population of M893 had been treated by gibbrellic acid(GA3) solution with different concentrations by 80mg/L、120mg/L、160mg/L and 200mg/L, respectively. The length of internode from top first to top third wasn’t significantly different compared with T893, and the internode didn’t elongate significantly. It showed that M893 was insensitive to gibberillic acid (GA3) induction.5. The trait of sheathed panicle was stable genetically during four-generation cultivation in Changsha and Hainan. All 6 populations of F1, originated from the crossing between the mutant and Bing5060、Bing4170、Minghui81、T893(wild type)、Lunhui422 respectively, headed normally, and it indicated that the trait was genetically recessive. The segregation ratio of 8 populations, including 6 populations of F2 and 2 populations of F3、F4 from the crossing between M893 and Bing5060, fitted the expected ratio of 3:1, which suggested that the trait of sheathed panicle was controlled by a pair of recessive genes. And the mutant gene was named as Shpx.6.The mutant gene shpx was mapped on the rice chromosome 2 by SSR markers. And it located among RM12680、RM6247 and RM12685. The genetic distances from the target gene to the markers RM12680、RM6247、RM12685 were 0.2cM、0cM and 1.2cM, respectively. The co-segregation between the marker RM6247 and the gene shpx indicated that RM6247 was linked tightly with shpx.7. The technology of cDNA chip was used to analyze gene expression difference between M893 and T893. Four candidate genes, including AK063150.1、9630.m04842、AF056027.1 (REH1) and AK070347.1, were selected preliminary, and it suggested that they are related to the mutant probably. Further analysis showed that AK063150.1、9630.m04842、AF056027.1 (REH1), which were classified as the regulatory gene of auxin, expressed very lower in M893, and AK063150.1 was the one expressed lowest. AK070347.1, classified as up-regulated gene, had a function on inhibitting to elongate, which was similar to ABA.更多还原