Genome-wide association study (GWAS) reveals genetic loci of lead (Pb) tolerance during seedling establishment in rapeseed (Brassica napus L.)

Abstract

Background Lead (Pb) pollution in soil has become one of the major environmental threats to plant growth and human health. Safe utilization of Pb contaminated soil by phytoremediation require Pb tolerant rapeseed ( Brassica napus L.) accessions. However, breeding of new B. napus cultivars tolerance to Pb stress has been restricted by limited knowledge on molecular mechanisms involved in Pb tolerance. This work was carried out to identify genetic loci related to Pb tolerance during seedling establishment in rapeseed. Results Pb tolerance, which was assessed by quantifying radicle length (RL) under 0 or 100 mg/L Pb stress condition, shown an extensive variation in 472 worldwide-collected rapeseed accessions. Based on the criterion of relative RL>80%, six Pb tolerant genotypes were selected. Four quantitative trait loci (QTL) associated with Pb tolerance were identified by Genome-wide association study. The expression level of nine promising candidate genes, including GSTUs , BCATs , UBP13 , TBR and HIPP01 , located in these four QTL regions, were significantly higher or induced by Pb in Pb tolerant accessions in comparison to Pb sensitive accessions. Conclusion To our knowledge, this is the first study on Pb tolerant germplasms and genomic loci in B. napus . The findings can provide valuable genetic resources for the breeding of Pb tolerant B. napus cultivar and understanding of Pb tolerance mechanism in Brassica species.

Unlocking the genetic control of spring wheat kernel traits under normal and heavy metals stress conditions

“…The initial step in the safe exploitation of Pb and Sn polluted soil will be the development of new cultivars with tolerance to Pb and Sn toxicity (Grant et al 2008;Ali et al 2013;Gupta et al 2013;Zhang et al 2020). This can be achieved through screen wheat germplasm under both stresses.…”