Jadhav Kashmiri Prakash, Saykhedkar Gajanan R, Tamilarasi Pandiampalayam Marappan, Devasree Subramani, Ranjani Rajagopalan Veera, Sarankumar Chandran, Bharathi Pukalenthy, Karthikeyan Adhimoolam, Arulselvi Soosai, Vijayagowri Esvaran, Ganesan Kalipatty Nalliappan, Paranidharan Vaikuntavasan, Nair Sudha K, Babu Raman, Ramalingam Jegadeesan, Raveendran Muthurajan, Senthil Natesan
Department of Plant Biotechnology, Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India.
Asian Regional Maize Program, International Maize and Wheat Improvement Center (CIMMYT), ICRISAT Campus, Patancheru, India.
Front Genet. 2022 Jul 20;13:890133. doi: 10.3389/fgene.2022.890133. eCollection 2022.
Sorghum downy mildew (SDM), caused by the biotrophic fungi threatens maize production worldwide, including India. To identify quantitative trait loci (QTL) associated with resistance to SDM, we used a recombinant inbred line (RIL) population derived from a cross between resistant inbred line UMI936 (w) and susceptible inbred line UMI79. The RIL population was phenotyped for SDM resistance in three environments [E1-field (Coimbatore), E2-greenhouse (Coimbatore), and E3-field (Mandya)] and also utilized to construct the genetic linkage map by genotyping by sequencing (GBS) approach. The map comprises 1516 SNP markers in 10 linkage groups (LGs) with a total length of 6924.7 cM and an average marker distance of 4.57 cM. The QTL analysis with the phenotype and marker data detected nine QTL on chromosome 1, 2, 3, 5, 6, and 7 across three environments. Of these, QTL namely , , and were notable due to their high phenotypic variance. from chromosome 3 was detected in more than one environment (E1 and E2), explaining the 10.3% and 13.1% phenotypic variance. Three QTL, , and from chromosomes 1, 5, and 6 were identified in either E1 or E3, explaining 15.2%-18% phenotypic variance. Moreover, genome mining on three QTL (, , and ) reveals the putative candidate genes related to SDM resistance. The information generated in this study will be helpful for map-based cloning and marker-assisted selection in maize breeding programs.
高粱霜霉病（SDM）由活体营养型真菌引起，威胁着包括印度在内的全球玉米生产。为了鉴定与高粱霜霉病抗性相关的数量性状位点（QTL），我们使用了一个重组自交系（RIL）群体，该群体源自抗性自交系UMI936（w）和感病自交系UMI79之间的杂交。对RIL群体在三种环境下[E1-田间（哥印拜陀）、E2-温室（哥印拜陀）和E3-田间（曼迪亚）]进行了高粱霜霉病抗性表型分析，并通过测序基因分型（GBS）方法构建了遗传连锁图谱。该图谱由10个连锁群（LG）中的1516个单核苷酸多态性（SNP）标记组成，全长6924.7厘摩（cM），平均标记距离为4.57厘摩。利用表型和标记数据进行的QTL分析在三个环境中检测到了位于第1、2、3、5、6和7号染色体上的9个QTL。其中，QTL即 、 和 因其高表型变异而值得关注。来自第3号染色体的 在不止一个环境（E1和E2）中被检测到，解释了10.3%和13.1%的表型变异。来自第1、5和6号染色体的三个QTL，即 、 和 在E1或E3中被鉴定出来，解释了15.2%-18%的表型变异。此外，对三个QTL（ 、 和 ）的基因组挖掘揭示了与高粱霜霉病抗性相关的推定候选基因。本研究产生的信息将有助于玉米育种计划中的基于图谱的克隆和标记辅助选择。
