Journal of Integrative Agriculture ›› 2024, Vol. 23 ›› Issue (4): 1118-1133.DOI: 10.1016/j.jia.2023.05.004

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qSTA2-2,一个新的有助于玉米种子淀粉的合成的QTL

  

  • 收稿日期:2023-02-17 修回日期:2023-03-24 出版日期:2024-04-20 发布日期:2024-03-29

qSTA2-2, a novel QTL that contributes to seed starch synthesis in Zea mays L.

Minghao Cai1, Xuhui Li1, 2, Zhi Liang1, Jie Wang1, Delin Li1, 3, Zhipeng Yuan1, Riliang Gu1, Jianhua Wang1#, Li Li1#   

  1. 1 State Key Laboratory of Maize Bio-breeding/Key Laboratory of Crop Heterosis Utilization, Ministry of Education/Beijing Innovation Center for Crop Seed Technology/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China

    2 Institute of Nanfan & Seed Industry, Guangdong Academy of Science, Guangzhou 510316, China

    3 Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China

  • Received:2023-02-17 Revised:2023-03-24 Online:2024-04-20 Published:2024-03-29
  • About author:#Correspondence Li Li, E-mail: lili2016@cau.edu.cn; Jianhua Wang, E-mail: wangjh63@cau.edu.cn
  • Supported by:
    This work was supported by grants from the STI 2030-Major Projects, China (2022ZD040190101, 2022ZD040190502), the National Natural Science Foundation of China (32072130, 32272162 and 31701437), the Project of Sanya Yazhou Bay Science and Technology City, China (SCKJ-JYRC-2023-64), the 2115 Talent Development Program of China Agricultural University, and the China Agriculture Research System (CARS-02-13).

摘要:

种子贮藏物质是种子发育过程中积累的物质,也是种子萌发、建苗所必需的物质。在这里,我们使用了由改良的220I220,低淀粉小种子)和PH4CV(高淀粉大种子)构建的F2:3群体以及X178(高淀粉)和其改进的基因渗入系I178(低淀粉)构建的RIL群体,以确定控制种子储存材料的基因。我们总共鉴定了12个同淀粉、蛋白质和油的QTLs,这解释了3.44-10.79% 的表型变异。其中,F2:3群体中鉴定的qSTA2-1RIL群体中鉴定的qSTA2-27.314-9.554Mb的区间部分重叠,解释了3.44-10.21% 的淀粉含量,因此选择进一步研究。qSTA2-2与每一代I220/PH4CV回交,最后精细定位缩小到199.7Kb的区间内,包含14ORFsI220/PH4CV(BC5F2)的NILs材料发育种子的转录组学分析表明,在20DAP时,种子中仅表达11ORFs,其中5个在NILI220上调表达6个下调表达NILI220NILPH4CV之间的DEGs被富集在淀粉代谢中富集、激素信号转导和糖胺聚糖降解途径中。对于5在NILI220下调表达ORFs其中编码乙醛脱氢酶的ORF4(Zm00001d002260)可能是qSTA2-2的候选基因。进一步分析验证表明,qSTA2-2位点的突变导致除淀粉和激素外,也造成了ABA积累、胚/胚乳比的功能障碍。

Abstract:

The seed storage materials accumulate during seed development, and are essential for seed germination and seedling establishment.  Here we employed two bi-parental populations of an F2:3 population developed from a cross of improved 220 (I220, small seeds with low starch) and PH4CV (large seeds with high starch), as well as recombinant-inbred lines (RILs) of X178 (high starch) and its improved introgression line I178 (low starch), to identify the genes that control seed storage materials.  We identified a total of 12 QTLs for starch, protein and oil, which explained 3.44–10.79% of the phenotypic variances.  Among them, qSTA2-1 identified in F2:3 and qSTA2-2 identified in the RILs partially overlapped at an interval of 7.314–9.554 Mb, and they explained 3.44–10.21% of the starch content variation, so they were selected for further study.  Fine mapping of qSTA2-2 with the backcrossed populations of I220/PH4CV in each generation narrowed it down to a 199.7 kb interval that contains 14 open reading frames (ORFs).  Transcriptomic analysis of developing seeds from the near-isogenic lines (NILs) of I220/PH4CV (BC5F2) showed that only 11 ORFs were expressed in 20 days after pollination (DAP) seeds.  Five of them were upregulated and six of them were downregulated in NILI220, and the differentially expressed genes (DEGs) between NILI220 and NILPH4CV were enriched in starch metabolism, hormone signal transduction and glycosaminoglycan degradation.  Of the eleven NILI220 differential expressed ORFs, ORF4 (Zm00001d002260) and ORF5 (Zm00001d002261) carry 75% protein sequence similarity, both encodes an glycolate oxidase, were the possible candidates of qSTA2-2.  Further analysis and validation indicated that mutation of the qSTA2-2 locus resulted in the dysfunction of ABA accumulation, the embryo/endosperm ratio and the starch and hormone levels.

Key words: QTL mapping ,  seed starch ,  transcriptomic analysis ,  hormone