Chromosome-anchored QTL conferring aluminum tolerance in hexaploid oat

Aluminum (Al) toxicity is a major constraint on crop production in acid soils around the world. Hexaploid oat (Avena sativa L.) possesses significant Al tolerance making it a good candidate for production in these environments. Genetic improvement for Al tolerance in oat has traditionally been achieved through conventional plant breeding and could be enhanced by marker-assisted selection. The objectives of this study were to develop a chromosome-anchored genetic map for an oat recombinant inbred population and to identify SNP markers linked to quantitative trait loci (QTL) affecting root growth response to Al. Three QTL on chromosomes 7C-17A, 13A, and 19A conferring Al tolerance were identified using primary root regrowth of recombinant inbred lines derived from the cross between UFRGS 17 (Al tolerant) and UFRGS 930598-6 (Al sensitive). Localization of each QTL onto the sequenced rice genome revealed the genetic region on chromosome 13A might be associated with a putative malate transporter locus (LOC_Os06g15779). Studies of root apex tissue indicated that exudation of malate was increased in the Al-tolerant parent UFRGS17 and not in the sensitive parent. Based on these data, the malate transporter might be a candidate gene responsible for one of the Al tolerance QTL identified in this study.