OsFTIP1-Mediated Regulation of Florigen Transport in Rice Is Negatively Regulated by the Ubiquitin-Like Domain Kinase OsUbDKγ4
OsFTIP1-Mediated Regulation of Florigen Transport in Rice Is Negatively Regulated by the Ubiquitin-Like Domain Kinase OsUbDKγ4
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DOI：
10.1105/tpc.16.00728
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发表时间：
2017-03-01
期刊：
影响因子：
11.6
通讯作者：
Yu, Hao
中科院分区：
文献类型：
--
作者：
Song, Shiyong;Chen, Ying;Yu, Hao
开花时间是决定作物种子生产和适应性的关键农艺性状。在开花植物中，光周期控制这一过程是由称为成花素的长距离移动的信号介导的，成花素部分由拟南芥中的FLOWERLOCUS T（FT）及其在其他植物物种中的直向同源物编码。尽管在理解双子叶植物模式拟南芥中FT运输方面取得了进展，但在农业中提供大部分生物量的单子叶植物中成花素运输的机制尚不清楚。在这里，我们表明，水稻FT-相互作用蛋白1（OsFTIP 1），多个C2结构域和跨膜区蛋白（MCTP）和拟南芥FTIP 1的最接近的直系同源物的家庭成员，是需要出口的水稻FLOWRESLOCUS T1（RFT 1）从伴随细胞的筛分元件。这影响了RFT 1向茎尖分生组织的移动及其对长日照下水稻开花时间的调节。我们进一步揭示了一个泛素样结构域激酶γ 4，OsUbDK γ 4，与OsFTIP 1相互作用，并通过26 S蛋白酶体调节其在叶片中的降解，这反过来又影响RFT 1运输到茎顶端分生组织。因此，OsUbDK γ 4对OsFTIP 1在叶片中丰度的动态调节是OsFTIP 1在水稻中介导RFT 1运输的作用的组成部分，并为FTIP 1样MCTP在有花植物中介导成花素运输中的保守作用提供了关键证据。
Flowering time is a critical agronomic trait that determines successful seed production and adaptation of crop plants. Photoperiodic control of this process in flowering plants is mediated by the long-distance mobile signal called florigen partly encoded by FLOWERING LOCUS T (FT) in Arabidopsis thaliana and its orthologs in other plant species. Despite the progress in understanding FT transport in the dicot model Arabidopsis, the mechanisms of florigen transport in monocots, which provide most of the biomass in agriculture, are unknown. Here, we show that rice FT-INTERACTING PROTEIN1 (OsFTIP1), a member of the family of multiple C2 domain and transmembrane region proteins (MCTPs) and the closest ortholog of Arabidopsis FTIP1, is required for export of RICE FLOWERING LOCUS T 1 (RFT1) from companion cells to sieve elements. This affects RFT1 movement to the shoot apical meristem and its regulation of rice flowering time under long days. We further reveal that a ubiquitin-like domain kinase gamma 4, OsUbDK gamma 4, interacts with OsFTIP1 and modulates its degradation in leaves through the 26S proteasome, which in turn affects RFT1 transport to the shoot apical meristem. Thus, dynamic modulation of OsFTIP1 abundance in leaves by a negative regulator OsUbDK gamma 4 is integral to the role of OsFTIP1 in mediating RFT1 transport in rice and provides key evidence for a conserved role of FTIP1-like MCTPs in mediating florigen transport in flowering plants.