Singh Chandan Kumar, Singh Dharmendra, Tomar Ram Sewak Singh, Karwa Sourabh, Upadhyaya K C, Pal Madan
Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, India.
Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India.
Mol Biol Rep. 2018 Dec;45(6):2103-2113. doi: 10.1007/s11033-018-4368-4. Epub 2018 Sep 14.
Development of aluminium (Al) resistant genotypes through molecular breeding is a major approach for increasing seed yield under acidic conditions. There are no available reports on mapping of Al resistance loci and molecular breeding for Al resistant varieties in lentil. The present study reports a major quantitative trait loci (QTL) for Al resistance using simple sequence repeat (SSR) markers in F and F mapping populations derived from contrasting parents. Phenotypic response to Al was measured on the bases of root re-growth (RRG), fluorescent signals (callose accumulation) and Al contents in hydroponic assay. After screening 495 SSR markers to search polymorphism between two contrasting parents, 73 polymorphic markers were used for bulk segregation analysis. Two major QTLs were identified using seven trait linked markers, one each for fluorescent signals and RRG mapped on linkage group (LG) 1 under Al stress conditions in F mapping population of cross BM-4 × L-4602. One major QTL (qAlt_fs) was localised between PLC_88 and PBA_LC_373, covering 25.9 cM with adjacent marker PLC_88 at a distance of 0.4 cM. Another major QTL (qAlt_rrg) for RRG was in the marker interval of PBA_LC_1247 and PLC_51, covering a distance of 45.7 cM with nearest marker PBA_LC_1247 at a distance of 21.2 cM. Similarly, in F families of BM-4 × L-4602 and BM-4 × L-7903, LG-1 was extended to 285.9 and 216.4 cM respectively, having four newly developed genic-SSR markers. These QTLs had a logarithm of odd (LOD) value of 140.5 and 28.8 along with phenotypic variation of 52% and 11% for fluorescent signals and RRG respectively, whereas, qAlt_rrg had LOD of 36 and phenotypic variance of 25% in F population of BM-4 × L-4602. Two major QTLs identified in the present study can be further dissected for candidate gene discovery and development of molecular markers for breeding improved varieties with high Al resistance.
通过分子育种培育耐铝基因型是在酸性条件下提高种子产量的主要途径。目前尚无关于小扁豆耐铝位点定位和耐铝品种分子育种的报道。本研究报道了在由性状差异较大的亲本衍生的F和F作图群体中，利用简单序列重复（SSR）标记鉴定出一个主要的耐铝数量性状位点（QTL）。在水培试验中，基于根再生（RRG）、荧光信号（胼胝质积累）和铝含量测定了对铝的表型反应。在筛选了495个SSR标记以寻找两个性状差异较大的亲本之间的多态性后，73个多态性标记用于群体分离分析。利用7个与性状相关的标记鉴定出两个主要的QTL，在杂交组合BM-4×L-4602的F作图群体中，铝胁迫条件下，一个用于荧光信号，一个用于RRG，各位于连锁群（LG）1上。一个主要的QTL（qAlt_fs）定位在PLC_88和PBA_LC_373之间，覆盖25.9 cM，相邻标记PLC_88距离为0.4 cM。另一个与RRG相关的主要QTL（qAlt_rrg）位于PBA_LC_1247和PLC_51的标记区间内，覆盖距离为45.7 cM，最近的标记PBA_LC_1247距离为21.2 cM。同样，在BM-4×L-4602和BM-4×L-7903的F家系中，LG-1分别扩展到285.9和216.4 cM，有4个新开发的基因SSR标记。这些QTL的对数优势（LOD）值分别为140.5和28.8，荧光信号和RRG的表型变异分别为52%和11%，而在BM-4×L-4602的F群体中，qAlt_rrg的LOD为36，表型方差为25%。本研究中鉴定出的两个主要QTL可进一步剖析，以发现候选基因并开发分子标记，用于培育高耐铝性的改良品种。
