Validation of the VRN-H2/VRN-H1 epistatic model in barley reveals that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity
Validation of the VRN-H2/VRN-H1 epistatic model in barley reveals that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity
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DOI：
10.1007/s00438-006-0195-8
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发表时间：
2007-03-01
影响因子：
3.1
通讯作者：
Hayes, Patrick M.
中科院分区：
文献类型：
--
作者：
Szucs, Peter;Skinner, Jeffrey S.;Hayes, Patrick M.
VRN-H1 和 VRN-H2 基因座等位基因的上位相互作用决定了大麦的春化敏感性。为了验证当前双基因座上位性的分子模型，我们将在 VRN-H1（Dicktoo）或 VRN-H2（俄勒冈沃尔夫大麦显性）或两个 VRN-H（Calicuchima-sib）基因座上携带预测的“冬季型”等位基因的纯合春化不敏感植物进行杂交，并测量了未春化 F-2 后代在长日光周期下的开花时间。我们通过确定这些位点的等位基因序列变异及其相对于生长习性的影响，评估了 Calicuchima-sib 的春季生长习性是否是双基因座上位模型的例外，或者是否在 VRN-H1 (HvBM5A) 和/或 VRN-H2 (ZCCT-H) 处包含新的“春季”等位基因。我们发现（a）在 VRN-H1 和 VRN-H2 等位基因上均具有预测“冬季型”等位基因的后代在三个 F-2 群体中的两个中表现出极其延迟的开花（即春化敏感）表型，（b）HvBM5A 内含子 1 春化关键区域侧翼的序列可能影响春化敏感性程度，（c）当 ZCCT-Ha 被保留时，保留了冬季习性。缺失，(d) ZCCT-H 基因比其他耐寒调节基因具有更高水平的等位基因多态性。我们的结果验证了解释 VRN-H2 和 VRN-H1 在长日照条件下上位相互作用的模型，证明了从春化不敏感基因型杂交中恢复春化敏感后代，表明 VRN-H1 中的内含子长度变化可能解释了春化敏感性的连续性，并提供了准确预测 VRN-H 位点“冬季型与春季型”等位基因的分子标记。
The epistatic interaction of alleles at the VRN-H1 and VRN-H2 loci determines vernalization sensitivity in barley. To validate the current molecular model for the two-locus epistasis, we crossed homozygous vernalization-insensitive plants harboring a predicted "winter type" allele at either VRN-H1 (Dicktoo) or VRN-H2 (Oregon Wolfe Barley Dominant), or at both VRN-H (Calicuchima-sib) loci and measured the flowering time of unvernalized F-2 progeny under long-day photoperiod. We assessed whether the spring growth habit of Calicuchima-sib is an exception to the two-locus epistatic model or contains novel "spring" alleles at VRN-H1 (HvBM5A) and/or VRN-H2 (ZCCT-H) by determining allele sequence variants at these loci and their effects relative to growth habit. We found that (a) progeny with predicted "winter type" alleles at both VRN-H1 and VRN-H2 alleles exhibited an extremely delayed flowering (i.e. vernalization-sensitive) phenotype in two out of the three F-2 populations, (b) sequence flanking the vernalization critical region of HvBM5A intron 1 likely influences degree of vernalization sensitivity, (c) a winter habit is retained when ZCCT-Ha has been deleted, and (d) the ZCCT-H genes have higher levels of allelic polymorphism than other winterhardiness regulatory genes. Our results validate the model explaining the epistatic interaction of VRN-H2 and VRN-H1 under long-day conditions, demonstrate recovery of vernalization-sensitive progeny from crosses of vernalization-insensitive genotypes, show that intron length variation in VRN-H1 may account for a continuum of vernalization sensitivity, and provide molecular markers that are accurate predictors of "winter vs spring type" alleles at the VRN-H loci.