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籽粒灌浆是水稻(Oryza sativa)生长发育过程中极为重要的阶段,涉及复杂的遗传调控网络和环境互作,直接关系到水稻产量和品质的形成.本研究通过甲基磺酸乙酯(EMS)诱变籼稻品种宜香1B,筛选到一个能稳定遗传的籽粒灌浆延长突变体gef1(grain extended filling 1).与野生型相比,该突变体灌浆速率下降,灌浆延长约30 d,且籽粒变大,结实率下降.相关生理指标测定表明,突变体gef1在整个灌浆过程中光合同化物供应正常,但同化物的分配与转化效率较低.对突变体gef1组织细胞学观察发现,穗轴与茎秆部位的大维管束数量减少,表明同化物的运输效率降低是影响灌浆速率的原因之一;颖壳内表皮细胞纵向伸长且数量增多,推测籽粒大小的改变与细胞的数量及形状有关.基因表达分析表明,gef1影响籽粒中糖代谢相关酶的表达;遗传分析表明,该突变表型受单隐性核基因控制,利用图位克隆法将gef1基因定位于水稻第3染色体短臂标记InDel3-1与InDel3-2之间198 kb的范围内,在该区域内尚未有与水稻籽粒灌浆相关基因的报道.
Grain filling is an extremely important stage in the growth and development of rice (Oryza sativa), involving complex genetic regulation networks and environmental interactions, and is directly related to the formation of rice yield and quality.In this study, methyl ethyl methanesulfonate (EMS) The mutant strain gef1 (grain extended filling 1) was screened from the indica variety Yixiang 1B, and its grain filling rate was decreased compared with the wild type, and the grain filling prolonged for about 30 days. Large, seed setting rate decreased.Related physiological index measurements showed that the mutant gef1 photosynthetic compounds supply normal during the whole filling process, but the assimilation of the distribution and transformation efficiency is low.Observed on the mutant gef1 histological cytology cob and The number of large vascular bundles in the stalk decreased, indicating that the reduction of the transport efficiency of the assimilates was one of the reasons that affected the filling rate. The epidermal cells in the shell of the glume grew longitudinally and increased in number, suggesting that the change of the grain size was related to the number and shape of the cells .Gene expression analysis indicated that gef1 affected the expression of enzymes related to glucose metabolism in the grain. Genetic analysis showed that the phenotype was controlled by a recessive nuclear gene, The gef1 gene located within the range of 198 kb between markers InDel3-1 short arm of chromosome 3 and InDel3-2 rice, not been reported in the region with grains - filling related genes.