利用Solanum pennellii LA716渐渗系群体对番茄苗期耐盐QTLs进行定位及QTL效应的初步分析

Identification and Effect Analysis of QTLs Conferring Salt Tolerance at Seedling Stage Using Solanum pennellii LA716 Introgression Lines in Tomato

【目的】利用盐敏感的栽培种番茄(Solanum lycopersicum)M82与耐盐的野生种潘那利番茄(Solanum pennellii)LA716构建的渐渗系群体,对苗期耐盐QTLs进行定位,并初步分析QTL遗传效应和互作效应。【方法】将4片真叶幼苗移栽到1/2浓度的Hoagland营养液中,按一定浓度逐日增加盐,至终盐浓度700mmol·L-1NaCl+70mmol·L-1CaCl2后,按照0—10级调查耐盐级数,并利用Dunnett测验进行方差分析。【结果】定位了分布在2、6、7、8、10等5条染色体上的7个影响番茄苗期耐盐性的QTLs(Stq2a、Stq2b、Stq6a、Stq7a、Stq7b、Stq8和Stq10),这些QTLs均来自耐盐野生种S.pennellii LA716。在盐胁迫条件下,它们较M82的成活百分率提高18.9%—83.8%,包含在IL6-4与IL6-3的1个QTL(Stq6b)有待于进一步试验验证。QTL遗传效应分析初步表明,除Stq6b外,其余QTL均表现明显的显性效应。QTL互作呈现典型的小于加性的效应,但来自第7条染色体上的2个QTL互作却表现消减效应。【结论】首次定位了来自野生番茄LA716分布在5条染色体上7个耐盐位点,QTL呈现明显的显性效应,互作呈现小于加性效应,为进一步精细定位、克隆及番茄耐盐育种奠定了良好的基础。

[ Objective] The introgression line population, which was developed from a salt-sensitive parent S. lycopersicum M82 and a salt-tolerance wild species S. pennellii LA716, was employed in this paper to identify QTLs conferring salt tolerance at the seedling stage. Meanwhile the primary genetic effect and interaction of some QTLs were also analyzed. [Method] Seedlings with four fully developed true leaves were transferred into hydroponic tanks containing 50 L of half-strength modified Hoagland solution. The same amount of salts was added every day to achieve a final concentration of 700 mmol.L^-1NaCl ＋ 70 mmol.L^-1 CaCl2. After the final salt concentration was reached, the plants were evaluated using a scale of 0 to 10. Dunnett test was used for ANOVA analysis. [Result] Seven unambiguous QTLs （Stq2a, Stq2b, Stq6a, Stq7a, Stq7b, Stq8 and Stq10） located respectively on chromosome 2, 6, 7, 8 and 10 were identified, which were responsible for controlling salt tolerance at seedling stage and derived from wild relative S. pennellii LA716. The survival percentage increased by 18.9%-83.8% as compared to the control M82 under this salt stress. QTL possibly involved in IL6-4 and IL6-3 needed to be confirmed in the further experiments. Genetic analysis of some QTLs showed a significant dominant effect with the exception of Stq6b. The interaction of QTLs presented a typically less-than-additive but two QTLs located on chromosome 7 gave a reduced effect. [ Conclusion ] This is the first report to identify QTLs conferring salt tolerance from wild species S. pennellii LA716 at the seedling stage. These identified QTLs would provide a sound base for tomato breeding with salt tolerance.