Ouaja Maroua, Ghimire Bikash, Bahri Bochra Amina, Maher Medini, Ferjaoui Sahbi, Udupa Sripada, Hamza Sonia
Laboratory of Cereal Breeding, Institut National Agronomique de Tunisie, University of Carthage, Tunis, Tunisia.
Department of Plant Pathology, Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Griffin, GA, United States of America.
PLoS One. 2025 Feb 6;20(2):e0310390. doi: 10.1371/journal.pone.0310390. eCollection 2025.
Septoria tritici blotch (STB) is a devastating fungal disease affecting durum and bread wheat worldwide. Tunisian durum wheat landraces are reported to be valuable genetic resources for resistance to STB and should prominently be deployed in breeding programs to develop new varieties resistant to STB disease. In this study, a collection of 367 old durum and 6 modern wheat genotypes previously assessed using single Tunisian Zymoseptoria tritici isolate TUN06 during 2016 and 2017 and TM220 isolate during 2017 were phenotyped for resistance to a mixture of isolates (BULK) under field conditions. Significant correlations for disease traits using the three different inoculums were observed. Using 7638 SNP markers, fifty-one marker-trait associations (MTAs) for STB resistance were identified by genome-wide association study (GWAS) at Bonferroni correction threshold of -log10(P) > 5.184 with phenotypic variance explained (PVE) reaching up to 58%. A total of eleven QTL were identified using TUN06 isolate mean disease scoring (TUNMeanD and TUNMeanA) including threeQTL controlling resistance to both isolates TUN06 and TM220. A major QTL was identified on each of chromosomes 1B, 4B, 5A, and 7B, respectively. The QTL on 7B chromosome colocalized with Stb8 identified in bread wheat. Four QTL including the major QTL identified on chromosome 1B were considered as novel. SNP linked to the significant QTL have the potential to be used in marker-assisted selection for breeding for resistance to STB.
小麦黄斑叶枯病（STB）是一种毁灭性的真菌病害，影响着全球的硬粒小麦和面包小麦。据报道，突尼斯硬粒小麦地方品种是抗STB的宝贵遗传资源，应在育种计划中大力推广，以培育抗STB病的新品种。在本研究中，收集了367份古老的硬粒小麦和6份现代小麦基因型，这些材料在2016年和2017年曾使用突尼斯单株小麦壳针孢菌分离株TUN06进行评估，并在2017年使用TM220分离株进行评估。在田间条件下，对这些材料针对混合分离株（BULK）的抗性进行了表型分析。观察到使用三种不同接种物时病害性状之间存在显著相关性。利用7638个单核苷酸多态性（SNP）标记，通过全基因组关联研究（GWAS）在Bonferroni校正阈值-log10（P）>5.184下鉴定出51个与STB抗性相关的标记-性状关联（MTA），表型变异解释率（PVE）高达58%。使用TUN06分离株的平均病害评分（TUNMeanD和TUNMeanA）共鉴定出11个数量性状位点（QTL），其中包括3个控制对TUN06和TM220两种分离株抗性的QTL。分别在1B、4B、5A和7B染色体上各鉴定出一个主要QTL。7B染色体上的QTL与在面包小麦中鉴定出的Stb8共定位。包括在1B染色体上鉴定出的主要QTL在内的4个QTL被认为是新的。与显著QTL连锁的SNP有潜力用于抗STB育种的标记辅助选择。
