Mechanistic Association of Quantitative Trait Locus with Malate Secretion in Lentil (Lens culinaris Medikus) Seedlings under Aluminium Stress

Aluminium (Al) toxicity acts as a major delimiting factor in the productivity of many crops including lentil. To alleviate its effect, plants have evolved with Al exclusion and inclusion mechanisms. The former involves the exudation of organic acid to restrict the entry of Al3+ to the root cells while latter involves detoxification of entered Al3+ by organic acids. Al-induced secretion of organic acids from roots is a well-documented mechanism that chelates and neutralizes Al3+ toxicity. In this study, F-6 recombinant inbred lines (RILs) derived from a cross between L-7903 (Al-resistant) and BM-4 (Al-sensitive) were phenotyped to assess variation in secretion levels of malate and was combined with genotypic data obtained from 10 Al-resistance linked simple sequence repeat (SSRs) markers. A major quantitative trait loci (QTL) was mapped for malate (qAlt_ma) secretion with a logarithm of odd (LOD) value of 7.7 and phenotypic variation of 60.2%.Validated SSRs associated with this major QTL will be useful in marker assisted selection programmes for improving Al resistance in lentil.

Automated summary

The study identified the mechanism of organic acid secretion in lentil to alleviate aluminum toxicity, and genetic data was used to evaluate the variation in this secretion mechanism. A major quantitative trait loci (QTL) associated with malate secretion was mapped, and validated SSRs linked with this QTL will be useful in future breeding programs for improving aluminum resistance in lentil.