Lavaud Clément, Lesné Angélique, Leprévost Théo, Pilet-Nayel Marie-Laure
IGEPP, INRAE, Institut Agro, Univ Rennes, 35653, Le Rheu, France.
Theor Appl Genet. 2024 Feb 9;137(2):47. doi: 10.1007/s00122-024-04548-6.
QTL mapping and recombinant screening confirmed the major effect of QTL Ae-Ps4.5 on pea resistance to pathotype III of Aphanomyces euteiches and fine-mapped the QTL to a 3.06-Mb interval. Aphanomyces root rot, caused by Aphanomyces euteiches, is the most important disease of pea (Pisum sativum L.) worldwide. The development of pea-resistant varieties is a major challenge to control the disease. Previous linkage studies identified seven main resistance quantitative trait loci (QTL), including the QTL Ae-Ps4.5 associated with partial resistance in US nurseries infested by the pea pathotype III of A. euteiches. This study aimed to confirm the major effect of Ae-Ps4.5 on A. euteiches pathotype III, refine its interval, and identify candidate genes underlying the QTL. QTL mapping on an updated genetic map from the Puget × 90-2079 pea recombinant inbred line population identified Ae-Ps4.5 in a 0.8-cM confidence interval with a high effect (R = 89%) for resistance to the Ae109 reference strain of A. euteiches (pathotype III) under controlled conditions. However, the QTL mapping did not detect Ae-Ps4.5 for resistance to the RB84 reference strain of A. euteiches (pathotype I). Screening 224-pea BC5F2 plant progeny derived from three near-isogenic lines (NILs) carrying the 90-2079 allele at Ae-Ps4.5 in the Puget genetic background with 26 SNP markers identified 15 NILs showing recombination in the QTL interval. Phenotyping of the recombinant lines for resistance to the Ae109 strain of A. euteiches reduced the QTL to a physical interval of 3.06 Mb, containing 50 putative annotated genes on the Caméor pea genome V1a among which three candidate genes highlighted. This study provides closely linked SNP markers and putative candidate genes to accelerate pea breeding for resistant varieties to Aphanomyces root rot.
数量性状基因座（QTL）定位和重组筛选证实了QTL Ae-Ps4.5对豌豆抗豌豆根腐病菌（Aphanomyces euteiches）III型致病型的主要作用，并将该QTL精细定位到一个3.06兆碱基的区间。由豌豆根腐病菌引起的根腐病是全球范围内豌豆（Pisum sativum L.）最重要的病害。培育抗豌豆品种是控制该病的一项重大挑战。先前的连锁研究确定了七个主要的抗性数量性状基因座（QTL），包括与美国苗圃中受豌豆根腐病菌III型致病型侵染的部分抗性相关的QTL Ae-Ps4.5。本研究旨在证实Ae-Ps4.5对豌豆根腐病菌III型致病型的主要作用，缩小其区间，并鉴定该QTL潜在的候选基因。在来自Puget×90-2079豌豆重组自交系群体的更新遗传图谱上进行QTL定位，在0.8厘摩的置信区间内鉴定出Ae-Ps4.5，在可控条件下对豌豆根腐病菌Ae109参考菌株（III型致病型）具有高抗性效应（R = 89%）。然而，QTL定位未检测到Ae-Ps4.5对豌豆根腐病菌RB84参考菌株（I型致病型）的抗性。用26个单核苷酸多态性（SNP）标记对来自三个近等基因系（NIL）、在Puget遗传背景下Ae-Ps4.5携带90-2079等位基因的224株豌豆BC5F2植株后代进行筛选，鉴定出15个在QTL区间发生重组的NIL。对重组系对豌豆根腐病菌Ae109菌株的抗性进行表型分析，将该QTL缩小到3.06兆碱基的物理区间，在Caméor豌豆基因组V1a上包含50个推定注释基因，其中突出了三个候选基因。本研究提供了紧密连锁的SNP标记和推定的候选基因，以加速抗豌豆根腐病品种的豌豆育种。
