The Relationship between Population Structure and Aluminum Tolerance in Cultivated Sorghum uri icon

abstract

  • Background: Acid soils comprise up to 50% of the world?s arable lands and in these areas aluminum (Al) toxicity impairsroot growth, strongly limiting crop yield. Food security is thereby compromised in many developing countries located intropical and subtropical regions worldwide. In sorghum, SbMATE, an Al-activated citrate transporter, underlies the AltSB locuson chromosome 3 and confers Al tolerance via Al-activated root citrate release.Methodology: Population structure was studied in 254 sorghum accessions representative of the diversity present incultivated sorghums. Al tolerance was assessed as the degree of root growth inhibition in nutrient solution containing Al. Agenetic analysis based on markers flanking AltSB and SbMATE expression was undertaken to assess a possible role for AltSB inAl tolerant accessions. In addition, the mode of gene action was estimated concerning the Al tolerance trait. Comparisonsbetween models that include population structure were applied to assess the importance of each subpopulation to Altolerance.Conclusion/Significance: Six subpopulations were revealed featuring specific racial and geographic origins. Al tolerancewas found to be rather rare and present primarily in guinea and to lesser extent in caudatum subpopulations. AltSB wasfound to play a role in Al tolerance in most of the Al tolerant accessions. A striking variation was observed in the mode ofgene action for the Al tolerance trait, which ranged from almost complete recessivity to near complete dominance, with ahigher frequency of partially recessive sources of Al tolerance. A possible interpretation of our results concerning the originand evolution of Al tolerance in cultivated sorghum is discussed. This study demonstrates the importance of deeplyexploring the crop diversity reservoir both for a comprehensive view of the dynamics underlying the distribution andfunction of Al tolerance genes and to design efficient molecular breeding strategies aimed at enhancing Al tolerance

publication date

  • 2011
  • 2011