The impact of photoperiod insensitive Ppd-1a mutations on the photoperiod pathway across the three genomes of hexaploid wheat (Triticum aestivum)
The impact of photoperiod insensitive Ppd-1a mutations on the photoperiod pathway across the three genomes of hexaploid wheat (Triticum aestivum)
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DOI：
10.1111/j.1365-313x.2012.04971.x
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发表时间：
2012-07-01
期刊：
影响因子：
7.2
通讯作者：
Laurie, David A.
中科院分区：
文献类型：
--
作者：
Shaw, Lindsay M.;Turner, Adrian S.;Laurie, David A.
开花时间是小麦在驯化过程中被广泛改变的一个性状，使其在不同的环境中具有高产能力，为研究适应机制提供了丰富的变异来源。六倍体小麦的祖先是一种长日照植物，但许多环境需要具有光周期不敏感（PI）的品种，可以在短时间内开花。PI是由A、B或D基因组上的Ppd-1基因突变引起的，个体突变赋予了不同程度的早期性。人们对其基础知之甚少。利用共同的遗传背景，利用基因组特异性表达分析研究了a、B和D基因组PI突变对生物钟和光周期通路基因的影响。Ppd-1 PI突变不影响时钟或即时时钟输出，但影响TaCO1和TaFT1，随着TaFT1表达增加，TaCO1表达减少。因此，虽然Ppd-1与拟南芥生物钟的PRR基因有关，但Ppd-1通过另一种途径影响开花，最可能的途径是上调TaFT1，并通过反馈效应降低TaCO1的表达。生物钟和光周期通路中的单个基因主要在一个基因组中表达，并且Ppd-1的作用没有基因组特异性。在2个或3个基因组上组合PI突变的品系，其早熟性增强，TaFT1诱导水平较高，但诱导时间不早，表明Ppd-1突变、TaFT1表达与开花之间存在直接的定量关系。
Flowering time is a trait that has been extensively altered during wheat domestication, enabling it to be highly productive in diverse environments and providing a rich source of variation for studying adaptation mechanisms. Hexaploid wheat is ancestrally a long-day plant, but many environments require varieties with photoperiod insensitivity (PI) that can flower in short days. PI results from mutations in the Ppd-1 gene on the A, B or D genomes, with individual mutations conferring different degrees of earliness. The basis of this is poorly understood. Using a common genetic background, the effects of A, B and D genome PI mutations on genes of the circadian clock and photoperiod pathway were studied using genome-specific expression assays. Ppd-1 PI mutations did not affect the clock or immediate clock outputs, but affected TaCO1 and TaFT1, with a reduction in TaCO1 expression as TaFT1 expression increased. Therefore, although Ppd-1 is related to PRR genes of the Arabidopsis circadian clock, Ppd-1 affects flowering by an alternative route, most likely by upregulating TaFT1 with a feedback effect that reduces TaCO1 expression. Individual genes in the circadian clock and photoperiod pathway were predominantly expressed from one genome, and there was no genome specificity in Ppd-1 action. Lines combining PI mutations on two or three genomes had enhanced earliness with higher levels, but not earlier induction, of TaFT1, showing that there is a direct quantitative relationship between Ppd-1 mutations, TaFT1 expression and flowering.