Baisakh Niranjan, Da Silva Eduardo A, Pradhan Anjan K, Rajasekaran Kanniah
School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, United States.
Department of Agriculture, Federal University of Lavras, Lavras, Brazil.
Front Plant Sci. 2023 Jul 18;14:1214907. doi: 10.3389/fpls.2023.1214907. eCollection 2023.
Aflatoxin (AF) contamination, caused by , compromises the food safety and marketability of commodities, such as maize, cotton, peanuts, and tree nuts. Multigenic inheritance of AF resistance impedes conventional introgression of resistance traits into high-yielding commercial maize varieties. Several AF resistance-associated quantitative trait loci (QTLs) and markers have been reported from multiple biparental mapping and genome-wide association studies (GWAS) in maize. However, QTLs with large confidence intervals (CI) explaining inconsistent phenotypic variance limit their use in marker-assisted selection. Meta-analysis of published QTLs can identify significant meta-QTLs (MQTLs) with a narrower CI for reliable identification of genes and linked markers for AF resistance. Using 276 out of 356 reported QTLs controlling resistance to infection and AF contamination in maize, we identified 58 MQTLs on all 10 chromosomes with a 66.5% reduction in the average CI. Similarly, a meta-analysis of maize genes differentially expressed in response to (a)biotic stresses from the to-date published literature identified 591 genes putatively responding to only infection, of which 14 were significantly differentially expressed (-1.0 ≤ Log2Fc ≥ 1.0; ≤ 0.05). Eight MQTLs were validated by their colocalization with 14 resistance-associated SNPs identified from GWAS in maize. A total of 15 genes were physically close between the MQTL intervals and SNPs. Assessment of 12 MQTL-linked SSR markers identified three markers that could discriminate 14 and eight cultivars with resistance and susceptible responses, respectively. A comprehensive meta-analysis of QTLs and differentially expressed genes led to the identification of genes and makers for their potential application in marker-assisted breeding of -resistant maize varieties.
由[未提及具体原因]引起的黄曲霉毒素（AF）污染，会损害玉米、棉花、花生和坚果等商品的食品安全和市场适销性。AF抗性的多基因遗传阻碍了抗性性状向高产商业玉米品种的传统导入。在玉米的多个双亲图谱绘制和全基因组关联研究（GWAS）中，已经报道了几个与AF抗性相关的数量性状基因座（QTL）和标记。然而，置信区间（CI）较大且解释的表型变异不一致的QTL限制了它们在标记辅助选择中的应用。对已发表的QTL进行荟萃分析，可以识别出CI更窄的显著元QTL（MQTL），以便可靠地鉴定AF抗性基因和连锁标记。利用报道的356个控制玉米对[未提及具体感染]感染和AF污染抗性的QTL中的276个，我们在所有10条染色体上鉴定出58个MQTL，平均CI降低了66.5%。同样，对迄今为止已发表文献中响应（非）生物胁迫而差异表达的玉米基因进行荟萃分析，鉴定出591个仅对[未提及具体感染]感染有推定响应的基因，其中14个基因差异显著表达（-1.0≤Log2Fc≥1.0；P≤0.05）。通过与从玉米GWAS中鉴定出的14个抗性相关单核苷酸多态性（SNP）共定位，验证了8个MQTL。在MQTL区间和SNP之间共有15个基因在物理上紧密相邻。对12个与MQTL连锁的简单序列重复（SSR）标记进行评估，鉴定出3个标记，它们分别可以区分14个抗性品种和8个感病品种。对QTL和差异表达基因进行全面的荟萃分析，从而鉴定出基因和标记，以便它们在抗[未提及具体感染]玉米品种的标记辅助育种中潜在应用。
