Fine mapping and identification of candidate genes for a QTL affecting Meloidogyne incognita reproduction in Upland cotton.
Fine mapping and identification of candidate genes for a QTL affecting Meloidogyne incognita reproduction in Upland cotton.
复制标题
DOI：
10.1186/s12864-016-2954-1
复制
发表时间：
2016-08-08
期刊：
影响因子：
4.4
通讯作者：
Chee PW
中科院分区：
文献类型：
--
作者：
Kumar P;He Y;Singh R;Davis RF;Guo H;Paterson AH;Peterson DG;Shen X;Nichols RL;Chee PW
南方根结线虫（Meloidogyne incognita；RKN）是陆地棉（Gossypium hirsutum L.）最重要的经济害虫之一。宿主植物抗性，即植物抑制线虫繁殖的能力，是针对这种地下害虫提供保护的最经济、实用且对环境无害的方法。抗性品系 Auburn 623RNR 和由其衍生的许多优良育种品系仍然是根结线虫 (RKN) 抗性的最重要来源。先前的遗传分析已鉴定出两个上位相互作用的 RKN 抗性 QTL，qMi-C11 和 qMi-C14，分别影响瘿形成和 RKN 繁殖。我们开发了仅针对 qMi-C14 基因座进行分离的遗传群体，并评估了该 QTL 在缺乏 qMi-C11 基因座的情况下对 RKN 抗性的遗传影响。 qMi-C14 基因座的 LOD 得分为 12，占产蛋总表型变异的 24.5%。除了与瘿形成不显着相关外，该位点对 RKN 繁殖的主效应比我们之前的研究中发现的要低，这进一步支持了 qMi-C11 在奥本 623RNR 来源中赋予 RKN 抗性的上位性证据。通过添加 16 个新开发的标记，对基因座 qMi-C14 进行了精细定位。通过使用 G. raimondii 的参考基因组序列，我们在新定义的 2.3 Mb 区域（两侧有两个 SSR 标记）中鉴定了 20 个编码抗病蛋白同源物的候选基因。对 RKN 抗性和易感性陆地棉种质的重新测序显示，候选基因中仅四个编码区存在非同义突变，因此这四个基因受到高度关注。我们的作图结果验证了 qMi-C14 抗性位点的效果，将 QTL 限制在更小的区域，并鉴定了紧密连锁的 SSR 标记，以提高标记辅助选择的效率。确定的候选基因需要功能研究，这将有助于识别和表征针对根结线虫的实际 qMi-C14 防御基因。本文的在线版本 (doi:10.1186/s12864-016-2954-1) 包含补充材料，可供授权用户使用。
The southern root-knot nematode (Meloidogyne incognita; RKN) is one of the most important economic pests of Upland cotton (Gossypium hirsutum L.). Host plant resistance, the ability of a plant to suppress nematode reproduction, is the most economical, practical, and environmentally sound method to provide protection against this subterranean pest. The resistant line Auburn 623RNR and a number of elite breeding lines derived from it remain the most important source of root-knot nematode (RKN) resistance. Prior genetic analysis has identified two epistatically interacting RKN resistance QTLs, qMi-C11 and qMi-C14, affecting gall formation and RKN reproduction, respectively. We developed a genetic population segregating only for the qMi-C14 locus and evaluated the genetic effects of this QTL on RKN resistance in the absence of the qMi-C11 locus. The qMi-C14 locus had a LOD score of 12 and accounted for 24.5 % of total phenotypic variation for egg production. In addition to not being significantly associated with gall formation, this locus had a lower main effect on RKN reproduction than found in our previous study, which lends further support to evidence of epistasis with qMi-C11 in imparting RKN resistance in the Auburn 623RNR source. The locus qMi-C14 was fine-mapped with the addition of 16 newly developed markers. By using the reference genome sequence of G. raimondii, we identified 20 candidate genes encoding disease resistance protein homologs in the newly defined 2.3 Mb region flanked by two SSR markers. Resequencing of an RKN resistant and susceptible G. hirsutum germplasm revealed non-synonymous mutations in only four of the coding regions of candidate genes, and these four genes are consequently of high interest. Our mapping results validated the effects of the qMi-C14 resistance locus, delimiting the QTL to a smaller region, and identified tightly linked SSR markers to improve the efficiency of marker-assisted selection. The candidate genes identified warrant functional studies that will help in identifying and characterizing the actual qMi-C14 defense gene(s) against root-knot nematodes. The online version of this article (doi:10.1186/s12864-016-2954-1) contains supplementary material, which is available to authorized users.