利用三个重组自交系群体进行 QTL 作图分析玉米穗颈长度的遗传分析。

Genetic analysis of maize shank length by QTL mapping in three recombinant inbred line populations.

机构信息

College of Biological Science and Technology, Liaoning Province Research Center of Plant Genetic Engineering Technology, Shenyang Key Laboratory of Maize Genomic Selection Breeding, Shenyang Agricultural University, Shenyang, 110866, China; Department of Plant Production and Forestry Science, University of Lleida-Agrotecnio Center, Av. Alcalde Rovira Roure, Lleida, 25198, Spain.

出版信息

Plant Sci. 2021 Feb;303:110767. doi: 10.1016/j.plantsci.2020.110767. Epub 2020 Nov 22.

DOI:10.1016/j.plantsci.2020.110767

PMID:33487352

Abstract

In maize, the shank is a unique tissue linking the stem to the ear. Shank length (SL) mainly affects the transport of photosynthetic products to the ear and the dehydration of kernels via regulated husk morphology. The limited studies on SL revealed it is a highly heritable quantitative trait controlled by significant additive and additive-dominance effects. However, the genetic basis of SL remains unclear. In this study, we analyzed three maize recombinant inbred line (RIL) populations to elucidate the molecular mechanism underlying the SL. The data indicated the SL varied among the three RIL populations and was highly heritable. Additionally, the SL was positively correlated with the husk length (HL), husk number (HN), ear length (EL), and ear weight (EW) in the BY815/K22 (BYK) and CI7/K22 (CIK) RIL populations, but was negatively correlated with the husk width (HW) in the BYK RIL population. Moreover, 10 quantitative trait loci (QTL) for SL were identified in the three RIL populations, five of which were large-effect QTL. The percentage of the total phenotypic variation explained by the QTL for SL was 13.67 %, 20.45 %, and 30.81 % in the BY815/DE3 (BYD), BYK, and CIK RIL populations, respectively. Further analyses uncovered some genetic overlap between SL and EL, SL and ear row number (ERN), SL and cob weight (CW), and SL and HN. Unlike the large-effect QTL qSL BYK-2-2, which spanned the centromere, the other four large-effect QTL were delimited to a single peak bin via bin map. Furthermore, 2, 5, 6, and 12 genes associated with SL were identified for qSL BYK-2-1, qSL CIK-2-1, qSL CIK-9-1, and qSL CIK-9-2, respectively. Five of the candidate genes for SL may contribute to the hormone metabolism and sphingolipid biosynthesis regulating cell elongation, division, differentiation, and expansion. These results may be relevant for future studies on the genetic basis of SL and for the molecular breeding of maize based on marker-assisted selection to develop new varieties with an ideal SL.

摘要

在玉米中，穗颈是连接茎和穗的独特组织。穗颈长度（SL）主要通过调节苞叶形态影响光合产物向穗部的运输和子粒脱水。对 SL 的有限研究表明，它是一个高度可遗传的数量性状，受显著的加性和加性-显性效应控制。然而，SL 的遗传基础仍不清楚。本研究通过分析三个玉米重组自交系（RIL）群体，阐明了 SL 的分子机制。结果表明，三个 RIL 群体的 SL 存在差异，且具有高度的遗传力。此外，在 BY815/K22（BYK）和 CI7/K22（CIK）RIL 群体中，SL 与苞叶长度（HL）、苞叶数量（HN）、穗长（EL）和穗重（EW）呈正相关，但在 BYK RIL 群体中与苞叶宽度（HW）呈负相关。此外，在三个 RIL 群体中鉴定到 10 个 SL 数量性状位点（QTL），其中 5 个为大效应 QTL。在 BY815/DE3（BYD）、BYK 和 CIK RIL 群体中，SL 的 QTL 解释了总表型变异的 13.67%、20.45%和 30.81%。进一步分析发现，SL 与 EL、SL 与穗行数（ERN）、SL 与穗粒重（CW）和 SL 与 HN 之间存在一些遗传重叠。与位于着丝粒的大效应 QTL qSL BYK-2-2 不同，其他四个大效应 QTL 通过 bin map 被限制在单个峰 bin 中。此外，分别为 qSL BYK-2-1、qSL CIK-2-1、qSL CIK-9-1 和 qSL CIK-9-2 鉴定到与 SL 相关的 2、5、6 和 12 个候选基因。SL 的候选基因中有 5 个可能与激素代谢和神经酰胺生物合成有关，从而调节细胞伸长、分裂、分化和扩展。这些结果可能有助于进一步研究 SL 的遗传基础，并为基于标记辅助选择的玉米分子育种提供指导，以开发具有理想 SL 的新品种。