Low-temperature and daylength cues are integrated to regulate FLOWERING LOCUS T in barley
Low-temperature and daylength cues are integrated to regulate FLOWERING LOCUS T in barley
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DOI：
10.1104/pp.108.116418
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发表时间：
2008-05-01
期刊：
影响因子：
7.4
通讯作者：
Trevaskis, Ben
中科院分区：
文献类型：
--
作者：
Hemming, Megan N.;Peacock, W. James;Trevaskis, Ben
在分离 H. vulgare VERNALIZATION1 (HvVRN1)、HvVRN2 和 PHOTOPERIOD1 (PPD-H1) 的双单倍体大麦 (Hordeum vulgare) 群体中检查了开花时间基因之间的相互作用。 HvVRN2 的缺失等位基因与快速花序起始和早期开花相关，但仅限于具有 PPD-H1 活跃等位基因的品系。在这些品系中，花启动子 FLOWERING LOCUS T (HvFT1) 在没有春化的情况下以高水平表达，并且这先于 HvVRN1 的诱导。具有 HvVRN2 缺失等位基因和失活 ppd-H1 等位基因的品系没有经历快速花序起始并且开花较晚。这些数据表明 HvVRN2 抵消 PPD-H1 以防止春化前开花。无论 HvVRN2 或 PPD-H1 基因型如何，以高基础水平表达的 HvVRN1 等位基因 (HvVRN1-1) 与快速花序起始相关。在具有 HvVRN1-1 等位基因的品系中，HvFT1 在没有春化的情况下表达，并且 HvFT1 转录物水平在具有活性 PPD-H1 等位基因的品系中最高；这与花序起始后顶端的快速发育相关。因此，HvVRN1 的表达促进花序起始并上调 HvFT1。对春化后不同遗传背景中HvVRN1表达的分析表明，HvVRN2、HvFT1和PPD-H1不太可能在HvVRN1的低温诱导中发挥作用。在春化反应大麦中，HvFT1 不是单独由低温诱导的，而是可以由长时间低温处理后的长日照诱导。我们得出的结论是，低温和日照开花响应途径被整合以控制大麦中 HvFT1 的表达，并且这可能是通过调节 HvVRN2 活性来实现的。
Interactions between flowering time genes were examined in a doubled haploid barley (Hordeum vulgare) population segregating for H. vulgare VERNALIZATION1 (HvVRN1), HvVRN2, and PHOTOPERIOD1 (PPD-H1). A deletion allele of HvVRN2 was associated with rapid inflorescence initiation and early flowering, but only in lines with an active allele of PPD-H1. In these lines, the floral promoter FLOWERING LOCUS T (HvFT1) was expressed at high levels without vernalization, and this preceded induction of HvVRN1. Lines with the deletion allele of HvVRN2 and the inactive ppd-H1 allele did not undergo rapid inflorescence initiation and were late flowering. These data suggest that HvVRN2 counteracts PPD-H1 to prevent flowering prior to vernalization. An allele of HvVRN1 that is expressed at high basal levels (HvVRN1-1) was associated with rapid inflorescence initiation regardless of HvVRN2 or PPD-H1 genotype. HvFT1 was expressed without vernalization in lines with the HvVRN1-1 allele and HvFT1 transcript levels were highest in lines with the active PPD-H1 allele; this correlated with rapid apex development postinflorescence initiation. Thus, expression of HvVRN1 promotes inflorescence initiation and up-regulates HvFT1. Analysis of HvVRN1 expression in different genetic backgrounds postvernalization showed that HvVRN2, HvFT1, and PPD-H1 are unlikely to play a role in low-temperature induction of HvVRN1. In a vernalization responsive barley, HvFT1 is not induced by low temperatures alone, but can be induced by long days following prolonged low-temperature treatment. We conclude that low-temperature and daylength flowering-response pathways are integrated to control expression of HvFT1 in barley, and that this might occur through regulation of HvVRN2 activity.