【目的】研究水稻花器官数目异常突变体afon1(abnormal floral organ number1)的分子机理,鉴定出控制水稻花器官数目变化的基因。【方法】利用甲基磺酸乙酯(EMS)诱变籼稻品种浙农34获得一个花器官数目异常突变体作为试验材料,命名为afon...【目的】研究水稻花器官数目异常突变体afon1(abnormal floral organ number1)的分子机理,鉴定出控制水稻花器官数目变化的基因。【方法】利用甲基磺酸乙酯(EMS)诱变籼稻品种浙农34获得一个花器官数目异常突变体作为试验材料,命名为afon1。开花期随机取突变体afon1和野生型浙农34的稻穗各5个,利用组织学和扫描电子显微镜等技术研究afon1的花器官表型、细胞学特征和花粉育性。成熟期随机取突变体afon1和野生型浙农34植株各10株,测定株高、分蘖数、穗长、每穗颖花数、每穗实粒数和千粒重等农艺性状。随机取突变体afon1和野生型饱满种子各100粒,测定发芽势和发芽率。以突变体afon1为母本,分别与野生型浙农34和粳稻品种浙农大104杂交构建2个F2群体进行遗传分析和基因定位,筛选候选基因进行DNA测序比对,构建AFON1蛋白质的空间模型并对其结构进行分析,同时对候选基因以及与花器官数目相关的基因进行实时荧光定量PCR分析。【结果】与野生型相比,突变体afon1中59.64%小穗的花器官数目发生异常,其中多数小穗仅在内稃一侧产生一个颖壳状的器官,部分小穗表现2—4轮花器官数目同时增加;株高和千粒重显著增加,而结实率显著降低。遗传分析表明,突变体afon1与野生型浙农34杂交的F1植株小穗花器官数目表现正常,F2群体中小穗花器官数目正常植株与花器官数目异常植株的分离比符合3﹕1,表明突变体afon1性状受一对隐性核基因控制,基因位于水稻第1染色体长臂端In Del标记1M5和1M18之间,物理距离为73 kb,该区间内共有6个注释基因。突变体afon1和野生型的测序比对发现,突变体afon1中的基因LOC_Os01g67430外显子中第565个碱基T突变成A,导致第189个氨基酸由色氨酸突变为精氨酸。蛋白质序列和空间结构分析表明,AFON1蛋白质序列中含有一个Lipase_3结构域,结构域内的突变导致蛋白质的空间结构发生了明显的变化。实时荧光定量PCR结果显示,LOC_Os01g67430在突变体afon1幼穗中的表达量要显著高于野生型,而在根、茎和叶中则无显著差异;穗发育早期FON1和FON2/4等调控花器官数目的基因在突变体afon1花器官中的表达量显著增加。【结论】LOC_Os01g67430为突变基因afon1,该基因通过影响花器官数目相关基因的表达而调控各轮花器官数目。展开更多
fon6是在籼稻恢复系乐恢188/明恢62杂交F3代发现的花器官数目突变体,表型分析结果表明:该突变体小花颖壳畸形扭曲、内颖长于外颖不闭合;每朵小花内外颖壳总数目2～4片;雄蕊数目为1～14枚;雌蕊数目增加,子房数目2～6个,胚囊畸形。突变体...fon6是在籼稻恢复系乐恢188/明恢62杂交F3代发现的花器官数目突变体,表型分析结果表明:该突变体小花颖壳畸形扭曲、内颖长于外颖不闭合;每朵小花内外颖壳总数目2～4片;雄蕊数目为1～14枚;雌蕊数目增加,子房数目2～6个,胚囊畸形。突变体套袋自交结实率为14.06%,花粉活力较高,平均花粉可染率为91.86%。自交种子能正常萌发成苗,突变性状表现稳定的遗传特性。以突变体为父本分别与蜀恢527、明恢63杂交,F2代群体中正常株与突变株的分离均符合3∶1的比例,F3代及BC1F2代进一步的观察与统计结果均表明,该突变性状受1对隐性核基因控制,将该突变基因暂定名为fon6(floral organ number6)。展开更多
The floral-organ-number mutant fon（t） was firstly discovered in the progeny of a cross between a diploid （Chunjiang 683） and a haploid （SARⅣ/-620-A） rice cultivar. The fon（t） mutant showed normal vegetative d...The floral-organ-number mutant fon（t） was firstly discovered in the progeny of a cross between a diploid （Chunjiang 683） and a haploid （SARⅣ/-620-A） rice cultivar. The fon（t） mutant showed normal vegetative development and produced normal inflorescence structures. Difference between the mutant and the wild type was observed when the stamen primordia began to form. The mature flowers offon（t） mutant showed open-hull phenotypes, which resulted in the exposure of stamens and stigmas. Normally, a single fon（t） floret consisted of six to nine stamens and one or two pistils. In addition, stamen/pistil-like structures and bulged tissues near ovaries were also observed in a few fon（t） florets. But homeotic transformation of lodicules into palea/lemma-like organs was observed almost in all the open-hull florets. The phenotypes offon（t） flowers also suggested thatfon（t） gene might affect flower organ identity in the inner whorls. Genetic analysis showed that thefon（t） mutant was controlled by a single recessive gene.展开更多
文摘fon6是在籼稻恢复系乐恢188/明恢62杂交F3代发现的花器官数目突变体,表型分析结果表明:该突变体小花颖壳畸形扭曲、内颖长于外颖不闭合;每朵小花内外颖壳总数目2～4片;雄蕊数目为1～14枚;雌蕊数目增加,子房数目2～6个,胚囊畸形。突变体套袋自交结实率为14.06%,花粉活力较高,平均花粉可染率为91.86%。自交种子能正常萌发成苗,突变性状表现稳定的遗传特性。以突变体为父本分别与蜀恢527、明恢63杂交,F2代群体中正常株与突变株的分离均符合3∶1的比例,F3代及BC1F2代进一步的观察与统计结果均表明,该突变性状受1对隐性核基因控制,将该突变基因暂定名为fon6(floral organ number6)。
基金This work was supported by the Program for Changjiang Scholars and Innovative Research Team in University (No. IRTO453)
文摘The floral-organ-number mutant fon（t） was firstly discovered in the progeny of a cross between a diploid （Chunjiang 683） and a haploid （SARⅣ/-620-A） rice cultivar. The fon（t） mutant showed normal vegetative development and produced normal inflorescence structures. Difference between the mutant and the wild type was observed when the stamen primordia began to form. The mature flowers offon（t） mutant showed open-hull phenotypes, which resulted in the exposure of stamens and stigmas. Normally, a single fon（t） floret consisted of six to nine stamens and one or two pistils. In addition, stamen/pistil-like structures and bulged tissues near ovaries were also observed in a few fon（t） florets. But homeotic transformation of lodicules into palea/lemma-like organs was observed almost in all the open-hull florets. The phenotypes offon（t） flowers also suggested thatfon（t） gene might affect flower organ identity in the inner whorls. Genetic analysis showed that thefon（t） mutant was controlled by a single recessive gene.
