Involvement of rose aquaporin RhPIP1;1 in ethylene-regulated petal expansion through interaction with RhPIP2;1
Involvement of rose aquaporin RhPIP1;1 in ethylene-regulated petal expansion through interaction with RhPIP2;1
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DOI：
10.1007/s11103-013-0084-6
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发表时间：
2013-10-01
影响因子：
5.1
通讯作者：
Gao, Junping
中科院分区：
文献类型：
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作者：
Chen, Wen;Yin, Xia;Gao, Junping
水通道蛋白(Aquaporins，AQP)是一种多功能的膜通道，可以促进水分在植物细胞膜上的运输。在植物水通道蛋白中，质膜内源蛋白(PIPs)在植物生长发育中起着关键作用，它们分别属于两个系统发育类群(PIP1和PIP2)。我们以前的工作表明，RhPIP2；1是PIP2的成员，参与了乙烯调节的玫瑰花瓣细胞扩张。然而，PIP1是否也在花瓣扩张中发挥作用仍不清楚。在这里，我们从ROSE微阵列数据库中对乙烯反应的18个PIP组装转录本中鉴定了一个PIP1亚家族成员RhPIP1；1。经乙烯处理后，RhPIP1；1的表达迅速显著下调。RhETRs沉默也明显降低了RhPIP1；1在玫瑰花瓣中的表达。在拟南芥中，RhPIP1；1启动子的活性被乙烯抑制。RhPIP1；1主要定位于内质网和质膜。我们证明，与对照相比，沉默RhPIP1；1显著地抑制了花瓣的扩张，降低了花瓣大小和细胞面积，并减少了鲜重。RhPIP1；1在非洲爪哇卵母细胞中的表达表明，RhPIP1；1在水分转运方面没有活性，而与功能基因RhPIP2；1共表达则导致质膜透性显著增加。酵母生长、β-半乳糖苷酶活性、双分子荧光互补和共定位实验证明了RhPIP1；1和RhPIP2之间存在相互作用；1.我们认为RhPIP1；1在乙烯调节的花瓣细胞扩张中发挥重要作用，至少部分是通过与RhPIP2的相互作用实现的。
Aquaporins (AQPs) are multifunctional membrane channels and facilitate the transport of water across plant cell membranes. Among the plant AQPs, plasma membrane intrinsic proteins (PIPs), which cluster in two phylogenetic groups (PIP1 and PIP2), play a key role in plant growth. Our previous work has indicated that RhPIP2;1, a member of PIP2, is involved in ethylene-regulated cell expansion of rose petals. However, whether PIP1s also play a role in petal expansion is still unclear. Here, we identified RhPIP1;1, a PIP1 subfamily member, from 18 PIPs assemble transcripts in rose microarray database responsive to ethylene. RhPIP1;1 was rapidly and significantly down-regulated by ethylene treatment. RhETRs-silencing also clearly decreased the expression of RhPIP1;1 in rose petals. The activity of the RhPIP1;1 promoter was repressed by ethylene in rosettes and roots of Arabidopsis. RhPIP1;1 is mainly localized on endoplasmic reticulum and plasma membrane. We demonstrated that RhPIP1;1-silencing significantly inhibited the expansion of petals with decreased petal size and cell area, as well as reduced fresh weight when compared to controls. Expression of RhPIP1;1 in Xenopus oocytes indicated that RhPIP1;1 was inactive in terms of water transport, while coexpression of RhPIP1;1 with the functional RhPIP2;1 led to a significant increase in plasma membrane permeability. Yeast growth, beta-Galactosidase activity, bimolecular fluorescence complementation, and colocalization assay proved existence of the interaction between RhPIP1;1 and RhPIP2;1. We argue that RhPIP1;1 plays an important role in ethylene-regulated petal cell expansion, at least partially through the interaction with RhPIP2;1.