Zhang Lihong, Byrne Patrick F, Pilon-Smits Elizabeth A H
Biology Department, Colorado State University, Fort Collins, CO 80523, USA.
New Phytol. 2006;170(1):33-42. doi: 10.1111/j.1469-8137.2006.01635.x.
Selenium is essential for many organisms, but is toxic at higher levels. To investigate the genetic basis of selenate tolerance in Arabidopsis thaliana, quantitative trait loci (QTL) associated with selenate tolerance in accessions Landsberg erecta and Columbia were mapped using recombinant inbred lines (RILs). The selenate tolerance index (TI(D10) = root growth + 30 microm selenate/root growth control x 100%) was fourfold higher for parental line Col-4 (59%) than for parent Ler-0 (15%). Among the 96 F8 RILs, TI(D10) ranged from 11 to 75% (mean 37%). Using composite interval mapping, three QTL were found on chromosomes 1, 3 and 5, which together explained 24% of variation in TI(D10) and 32% of the phenotypic variation for the difference in root length +/- Se (RL(D10)). Highly significant epistatic interactions between the QTL and markers on chromosome 2 explained additional variation for both traits. Potential candidate genes for Se tolerance in each of the QTL regions are discussed. These results offer insight into the genetic basis of selenate tolerance, and may be useful for identification of selenate-tolerance genes.
硒对许多生物体来说是必不可少的，但在高浓度时具有毒性。为了研究拟南芥中耐硒酸盐的遗传基础，利用重组自交系（RILs）对Landsberg erecta和Columbia这两个生态型中与耐硒酸盐相关的数量性状基因座（QTL）进行了定位。硒酸盐耐受指数（TI(D10)=根生长量 + 30微摩尔硒酸盐/根生长对照×100%），亲本系Col-4（59%）是亲本Ler-0（15%）的四倍。在96个F8 RILs中，TI(D10)范围为11%至75%（平均37%）。通过复合区间作图，在第1、3和5号染色体上发现了3个QTL，它们共同解释了TI(D10)中24%的变异以及根长差异±硒（RL(D10)）中32%的表型变异。第2号染色体上的QTL与标记之间高度显著的上位性相互作用解释了这两个性状的额外变异。文中讨论了每个QTL区域中耐硒的潜在候选基因。这些结果为耐硒酸盐的遗传基础提供了见解，可能有助于鉴定耐硒酸盐基因。
