水稻胚胎和胚乳双缺陷突变体eed1的表型与遗传分析

从由化学诱变剂甲基磺酸乙酯(ethylmethane sulfonate,EMS)处理的粳稻品种中花11突变体库中,筛选到一个可稳定遗传的胚胎和胚乳发育缺陷的突变体,命名为embryo and endosperm defective 1 (eed1)。eed1籽粒千粒重、颖果的粒长、粒宽、粒厚、萌发率、总淀粉、直链淀粉和贮藏蛋白系列指标较野生型均显著降低。eed1颖果严重皱缩,且胚乳呈粉质。利用扫描电镜观察发现,与中花11相比, eed1胚乳中淀粉粒排列疏松,多以单一、分散的淀粉粒存在,且呈近似球形。eed1胚胎结构异常,部分颖果未见有胚胎分化的痕迹。qRT-PCR发现, eed1胚乳中参与淀粉和贮藏蛋白合成的大部分基因表达下调。利用eed1与籼稻南京6号杂交得到的F2分离群体进行基因定位分析,将EED1定位于9号染色体长臂672kb的范围内,包含114个开放读码框。本研究为进一步解析EED1基因调控水稻胚胎和胚乳发育的机制奠定了基础。

Phenotypic and genetic analyses of a rice mutant eed1 with defected embryo and endosperm development

A stably inherited embryo and endosperm defective mutant,named embryo and endosperm defective 1(eed1),was obtained from the mutant population of rice Zhonghua 11,generated by ethylmethane sulfonate(EMS).The 1000-grain weight,grain length,grain width,grain thickness,germination rate,total starch,amylose,and storage protein contents in eed1 mature caryopses were significantly decreased compared with wild type.In eed1,the caryopses were shrunken and the endosperm was opaque.Scanning electron microscopy observation revealed that starch granules in eed1 endosperm cells were loosely packed,in single,disperse and spherical forms.The embryo of eed1 was abnormal,and some caryopses showed no sign of embryonic differentiation.Most genes involved in biosynthesis of starch and storage protein were down-regulated in eed1 endosperm by qRT-PCR.EED1 was mapped in an interval of 672 kb on chromosome 9 using a F2 population derived from a cross between eed1 and Nanjing 6.The region contained 114 open reading frames.This study lays a foundation for further studying EED1 gene in regulating development of rice embryo and endosperm.