分子标记辅助构建甜瓜CmGLK近等基因系

王晓娟 郭姚淼 张凯歌 杨路明 杨森 朱华玉

摘    要：黄绿叶色突变体是研究叶绿体发育和光合能力的重要材料，前期精细定位到一个控制叶色的CmGLK基因。为了更好地研究其功能，以黑皮甜瓜自交系HB42为轮回亲本，黄绿叶色突变体M68为供体亲本;利用与黄绿叶色共分离的cmglk-dCAPS1标记为前景选择标记，及163对在亲本间多态性好、染色体上分布相对均匀的SSR标记为背景选择标记，构建了HB42遗传背景下的cmglk近等基因系，并对其表型进行分析。结果显示，在回交两代后的入选群体平均背景回复率超过非选择条件下的理论值，BC1F1和BC2F1世代最高背景回复率单株分别为81.63%、93.98%。背景回复率最高的3个BC2F2代cmglk纯系植株的表型显示其叶色表型均为黄绿色，成熟期果实大小和含糖量与野生型相比也显著下降。

关键词：甜瓜;黄绿叶色;分子标记;近等基因系

中图分类号：S652 文献标志码：A 文章编号：1673-2871（2021）06-011-09

Molecular marker-assisted construction of CmGLK near-isogenic lines in melon

WANG Xiaojuan， GUO Yaomiao， ZHANG Kaige， YANG Luming， YANG Sen， ZHU Huayu

（College of Horticulture， Henan Agricultural University， Zhengzhou 450002， Henan， China）

Abstract： The yellow-green leaf mutants are important materials for the study of chloroplast development and photosynthetic capacity. We have fine mapped a CmGLK gene controlling the leaf color in melon. To better investigate the biological function of the CmGLK gene in melon， we constructed a near-isogenic line of the cmglk gene by molecular marker-assisted selection. In our current study， a black rind melon inbred line HB42 was used as the recurrent parent， and the yellow-green leaf mutant M68 as the donor parent which resulted from the mutation of CmGLK gene. In the marker assisted selection， the cmglk locus co-segregating marker dCAPS1 was used as foreground selection marker， and 163 SSR markers with good polymorphism and relatively distributed on 12 chromosomes of melon were selected as background selection markers to develop the near-isogenic line of cmglk gene in the HB42 background. The results showed that the average background recovery rate of the selected population was significantly higher than the theoretical value under non-selective conditions after two generations of backcrossing. Furthermore， we investigated the phenotypes of three homozygous cmglk plants with the highest recovery rate in BC2F2 generation， which showed that all of them had yellow-green leaf color phenotype and their fruit sizes and sugar content at maturity were also significantly reduced compared to the wild type HB42.

Key words： Melon; Yellow-green leaf; Molecular markers; Near-isogenic lines

甜瓜（Cucumis melo L.）為葫芦科（Cucurbitaceae）甜瓜属（Cucumis）一年生蔓生植物，含有丰富的碳水化合物以及柠檬酸等人体所需的营养物质，深受人们的喜爱[1]。目前甜瓜已在世界范围内广泛栽培，并且成为中国、伊朗、土耳其等世界甜瓜生产大国出口创汇的重要农作物之一[2]。我国是最早栽培甜瓜的国家之一，同时也是世界上甜瓜栽培面积最大、产量最高的国家[3]。作为栽培甜瓜重要的起源地之一，我国甜瓜种质资源十分丰富[4]。

近等基因系（Near-isogenic line， NIL）是指除了决定目标性状的基因不同，其他遗传背景完全相同的一组遗传材料（品系）[5]。最早由Young等[6]和Muclmore等[7]提出，它在作物的品种改良[5-8]、基因定位[9-10]、基因的功能分析和遗传互作[11-12]等方面具有重要作用。……