Karsai I, Szucs P, Mészáros K, Filichkina T, Hayes P M, Skinner J S, Láng L, Bedo Z
Hungarian Academy of Sciences, Agricultural Research Institute, 2462, Martonvásár, Hungary.
Theor Appl Genet. 2005 May;110(8):1458-66. doi: 10.1007/s00122-005-1979-7. Epub 2005 Apr 16.
With the aim of dissecting the genetic determinants of flowering time, vernalization response, and photoperiod sensitivity, we mapped the candidate genes for Vrn-H2 and Vrn-H1 in a facultative x winter barley mapping population and determined their relationships with flowering time and vernalization via QTL analysis. The Vrn-H2 candidate ZCCT-H genes were completely missing from the facultative parent and present in the winter barley parent. This gene was the major determinant of flowering time under long photoperiods in controlled environment experiments, irrespective of vernalization, and under spring-sown field experiments. It was the sole determinant of vernalization response, but the effect of the deletion was modulated by photoperiods when the vernalization requirement was fulfilled. There was no effect under short photoperiods. The Vrn-H1 candidate gene (HvBM5A) was mapped based on a microsatellite polymorphism we identified in the promoter of this gene. Otherwise, the HvBM5A alleles for the two parents were identical. Therefore, the significant flowering time QTL effect associated with this locus suggests tight linkage rather than pleiotropy. This QTL effect was smaller in magnitude than those associated with the Vrn-H2 locus and was significant in two-way interactions with Vrn-H2. The Vrn-H1 locus had no effect on vernalization response. Our results support the Vrn-H2/Vrn-H1 repressor/structural gene model for vernalization response in barley and suggest that photoperiod may also affect the Vrn genes or tightly linked loci.
为了解析开花时间、春化反应和光周期敏感性的遗传决定因素，我们在一个兼性×冬大麦作图群体中定位了Vrn-H2和Vrn-H1的候选基因，并通过QTL分析确定了它们与开花时间和春化的关系。兼性亲本中完全缺失Vrn-H2候选ZCCT-H基因，而冬大麦亲本中存在该基因。在控制环境实验中，无论春化与否，以及在春播田间实验中，该基因都是长光周期下开花时间的主要决定因素。它是春化反应的唯一决定因素，但当满足春化需求时，缺失的影响会受到光周期的调节。在短光周期下没有影响。Vrn-H1候选基因（HvBM5A）是基于我们在该基因启动子中鉴定的微卫星多态性进行定位的。否则，两个亲本的HvBM5A等位基因是相同的。因此，与该位点相关的显著开花时间QTL效应表明存在紧密连锁而非多效性。该QTL效应的大小比与Vrn-H2位点相关的效应小，并且在与Vrn-H2的双向互作中显著。Vrn-H1位点对春化反应没有影响。我们的结果支持大麦春化反应的Vrn-H2/Vrn-H1抑制子/结构基因模型，并表明光周期也可能影响Vrn基因或紧密连锁的位点。
