摘要： 利用实验室收集的优良种质资源籼稻亲本B91及B233分析影响粒质量的关键表型性状，挖掘粒质量相关的遗传位点与候选基因，进一步了解多基因调控粒型性状的遗传基础，以期在种质资源改良中加以应用。以2个籼稻亲本B91和B233及杂交繁育的F₂群体为研究材料，对B91和B233籽粒颖壳和胚乳进行扫描电镜观察，测定两亲本灌浆速率；对B91和B233构建的F₂分离群体进行QTL-seq分析，通过注释基因表达位置以及预测功能进一步筛选出粒质量候选基因。结果表明，根据籽粒颖壳和胚乳扫描电镜观察，B233与B91粒长、粒宽、粒厚的差异是由细胞大小和细胞数量共同决定的，且与B91相比B233籽粒饱满度较差。通过灌浆参数的比较，B233起始生长势，活跃灌浆时间，最大灌浆速率等指标均大于B91。QTL-seq分析共得到了430 762个有效SNP位点，发现了位于6条染色体上共8个QTL。主要关注正阈值区内的5个QTL，对正阈值区QTL位点内△（SNP-index）>0.7的SNP位点进行了筛选，选出在基因中非同义突变及剪接位点上的SNP突变23个基因，同时挑选出Indel突变基因共11个。根据NCBI网站对注释基因的转录表达分析及基因功能预测筛选出6个可能为调控粒质量性状的候选基因，其中基因Os04g0617600、Os04g0619600编码蛋白起到蛋白激酶或转录调节因子作用，Os04g0624600、Os04g0631000调控碳水化合物的合成与分解，Os04g0653100调控生物大分子的运输，同时也是花粉壁细胞的重要组成成分，Os02g0611450可能调控生物大分子的合成和细胞周期。综上，水稻粒长、粒宽、粒厚及饱满度均直接影响水稻籽粒质量，通过扫描电镜观察，灌浆速率调查从细胞水平和生理水平解释粒质量差异。通过QTL-seq结合注释基因转录表达分析及功能预测等手段可以更高效的筛选出粒质量的候选基因。水稻粒质量可能受到蛋白磷酸化、转录调节相关基因的影响。

关键词: 水稻, 粒质量基因, QTL-seq, 数量性状基因座, SNP-index

Abstract: Using the elite germplasm resources collected by the laboratory, B91 and B233 were used to analyze the key phenotypic traits affecting grain weight, and the genetic sites and candidate genes involved in grain weight correlation were explored to further understand the genetic basis of multi-gene regulation of grain traits, for applying it in the improvement of germplasm resources. Two indica parents B91 and B233 and the crossbreeding F₂ population were used as research materials. The scanning morphological observations of B91 and B233 grain hulls and endosperm were carried out to determine the parenteral filling rate. QTL-seq analysis was performed using the F₂ segregating population constructed by B91 and B233, and the grain weight candidate gene was further screened by annotating gene expression position and predictive function. The results showed that according to scanning electron microscopy of grain hulls and endosperm, the difference between B233 and B91 grain length, grain width and grain thickness was determined by cell size and cell number, and the grain fullness of B233 was worse than B91. Through the comparison of grouting parameters, the initial growth potential of B233, active grouting time, maximum grouting rate and other indicators were all greater than B91. A total of 430 762 effective SNP locis were obtained from QTL-seq analysis and a total of 8 QTLs were found on 6 chromosomes. This study mainly focused on the five QTLs in the positive threshold region, and screened SNP sites with △(SNP-index)>0.7 in the QTL sites of the positive threshold region. In the positive threshold region, 23 SNP mutations genes and 11 Indel mutation genes were selected, and six candidate genes for regulating grain weight traits were screened based on the NCBI website for transcriptional expression analysis and gene function prediction of the annotated genes. In the six candidate genes, the gene Os04g0617600, Os04g0619600 encoded protein acts as a protein kinase or transcriptional regulator; Os04g0624600, Os04g0631000 regulated the synthesis and decomposition of carbohydrates; Os04g0653100 regulated the transport of biological macromolecules and was also an important component of pollen wall cells; Os02g0611450 might regulate the synthesis and cell cycle of biological macromolecules. Comprehensively, rice grain length, grain width, grain thickness and fullness directly affected the grain weight of rice. By scanning electron microscopy, the filling rate investigation explained the difference in grain weight from the cell level and physiological level. Through QTL-seq combined with annotation gene transcriptional expression analysis and functional prediction, the candidate genes of grain weight could be screened more efficiently. Rice grain weight may be affected by protein phosphorylation and transcriptional regulation-related genes.

Key words: Rice, Grain weight gene, QTL-seq, Quantitative trait loci, SNP-index

中图分类号: 

• S511.4+2