Submitted to: Science in China
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/6/2007
Publication Date: 5/1/2007
Citation: Guo, P., Bai, G., Ronghua, L., Carver, B., Baum, M. 2007. Molecular characterization of Atlas 66 derived wheat near-isogenic lines contrasting in Aluminum (Al) tolerance. Science in China. Interpretive Summary: Aluminum (Al) toxicity is the major limiting factor for wheat production in acidic soils. Use of Al resistant cultivars is the most cost-effective solution to solve the problem. DNA markers linked to the gene that controls Al resistance in wheat can make selection of Al-resistance genes more accurate and efficient. To identify DNA markers linked to Al-tolerance genes in wheat, two type of DNA marker called Amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) were used to tag the Al resistance gene in Al-resistant cultivar Atlas 66. Near isogenic lines (NILs) differing in Al resistance were developed by transferring Al-resistance genes from Atlas 66 into two sensitive cultivars, Century and Chisholm. We found that nine markers were linked to Al tolerance in the Chisholm-derived NILs, and seven were associated with Al tolerance in the Century-derived NILs. Three markers associated with Al tolerance were located on wheat chromosome 4D. These common markers across two backgrounds may be the major DNA markers for Al tolerance in Atlas 66 and could be used for marker-assisted breeding for Al tolerance in wheat. The result also suggested that Atlas 66 may carry more than one gene for Al tolerance.
Technical Abstract: Aluminum (Al) toxicity is the major limiting factors for wheat growth in acidic soils. Genetic improvement of Al tolerance is one of the most cost-effective solutions to improve wheat productivity. The objective of this study was to identify DNA markers associated with the Al-tolerance in wheat using Amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) in Al-sensitive recurrent cultivars Chisholm and Century, their Al-tolerance and sensitive near isogenic lines (NILs), and Atlas 66, donor of Al tolerance. A total of 200 AFLP and 88 SSR primer combinations were screened and 12 markers (11 AFLPs and one SSR) were associated with Al-tolerance in NILs of at least one recurrent background. Among them, nine were linked to Al tolerance in the Chisholm-derived NILs, seven were associated with Al tolerance in the Century-derived NILs, and three AFLPs derived from the primer combinations of pAG/mGCAG, pCAG/mAGC and pGTG/mGCG, and one SSR, Xwmc331 on chromosome 4D, associated with Al tolerance in NILs both recurrent parental backgrounds. These common markers across two background may be the major marker loci associated with Al tolerance in Atlas 66 and could be useful for marker-assisted breeding for Al tolerance in wheat. In addition, evaluation of Al tolerance among different genotypes using hematoxylin stain and relative root growth revealed that Atlas 66 was more tolerant to Al stress than the NILs, therefore, suggested that the Al-tolerant NILs may not carry all Al-tolerance loci from Atlas 66 and Al tolerance in Atlas 66 is more likely multi-genic.