Submitted to: Plant and Soil
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/22/2007
Publication Date: 6/22/2007
Citation: Zhou, L., Bai, G., Carver, B. 2007. Identification of New Sources of Aluminum Resistance in Wheat. Plant and Soil Journal. DOI: 10.1007/s11104-007-9324-3. Interpretive Summary: Aluminum (Al) toxicity is a major constraint for wheat production in acidic soils. An Al-resistance gene from Brazilian wheat has been extensively studied, but information on Al resistance genes in other wheat varieties is lacking. In this study, we evaluated 590 wheat accessions from the USA and several other countries and identified 88 wheat accessions having at least moderate resistance to Al toxicity. Marker analysis of selected resistant accessions indicated that many of the selected Al-resistant accessions from East Asia did not have the Al-resistant marker allele of gene ALMT1, a gene that was reported to be responsible for Al resistance in Brazilian wheat. Most of the cultivars derived from Jagger and Atlas 66 from the USA have the Al-resistant marker for the ALMT1 gene, therefore, this marker can still be used to select Al resistance from Jagger or Atlas 66 and their derivatives. Potentially new sources of Al resistance different from those derived from Brazil can be used in breeding programs to increase aluminum tolerance.
Technical Abstract: Aluminum (Al) toxicity is a major constraint for wheat production in acidic soils. An Al-resistance gene on chromosome 4DL that traces to Brazilian wheat has been extensively studied, and can provide partial protection from Al damage. To identify potentially new sources of Al resistance, 590 wheat accessions, including elite wheat breeding lines from the United States and other American and European countries, landraces and commercial cultivars from East Asia, and synthetic wheat lines from CIMMYT, were screened for Al resistance by measuring relative root elongation in culture with nutrient solution containing Al, and by staining Al-stressed root tips with hematoxylin. Eighty-eight wheat accessions demonstrated at least moderate resistance to Al toxicity. Those selected lines were subjected to analysis of microsatellite markers linked to an Al-resistance quantitative trait locus (QTL) on 4DL and a gene marker for the Al-activated malate transporter (ALMT1) locus. Many of the selected Al-resistant accessions from East Asia did not have the Al-resistant marker allele of ALMT1, although they showed Al resistance similar to the US Al-resistant cultivar, Atlas 66. Most of the cultivars derived from Jagger and Atlas 66 have the Al-resistant marker allele of ALMT1, however, which can still be used as a diagnostic marker if selecting for Atlas 66- or Jagger-based Al-resistance. Cluster analysis separated the selected Al-resistant germplasms into two major clusters, labeled as Asian and American-European clusters. Potentially new sources of Al resistance different from those derived from Brazil were identified. Further investigation of Al resistance in those new sources may reveal alternative Al-resistance mechanisms in wheat.