Non-intrinsic ATP-binding cassette proteins ABCI19, ABCI20 and ABCI21 modulate cytokinin response at the endoplasmic reticulum in Arabidopsis thaliana
Non-intrinsic ATP-binding cassette proteins ABCI19, ABCI20 and ABCI21 modulate cytokinin response at the endoplasmic reticulum in Arabidopsis thaliana
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DOI：
10.1007/s00299-019-02503-0
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发表时间：
2020-02-03
影响因子：
6.2
通讯作者：
Lee, Youngsook
中科院分区：
文献类型：
--
作者：
Kim, Areum;Chen, Jilin;Lee, Youngsook
非内在ABC蛋白ABCI20和ABCI21在HY5调节下由光诱导，定位于ER，并改善年轻拟南芥幼苗中细胞分裂素驱动的生长抑制。植物ATP结合盒（ABC）I亚家族（ABCI）包括含有在其它ABC蛋白中发现的任何结构域的异质蛋白。已知一些ABCI在基础代谢和应激反应中起作用，但许多ABCI在功能上仍然没有特征。拟南芥的ABCI 19、ABCI 20和ABCI 21在系统发育树中聚在一起，并且被认为是转录因子伸长下胚轴5（HY5）的靶点。在这里，我们揭示了这三个ABCI参与调节细胞分裂素反应在早期幼苗发育。ABCI 19、ABCI 20和ABCI 21启动子具有HY5结合基序，并且ABCI 20和ABCI 21表达以HY5依赖性方式被光诱导。abci19 abci20 abci21三重和abci20 abci21双敲除突变体在幼苗生长迟缓测定中对细胞分裂素高度敏感，但在对照培养基或含有生长素、阿坝、GA、ACC或BR的培养基中均未显示出与野生型的表型差异。ABCI 19、ABCI 20和ABCI 21在幼苗中表达，这三种蛋白质相互作用，在内质网（ER）膜上形成一个大的蛋白复合物。这些结果表明，ABCI 19、ABCI 20和ABCI 21在幼苗期在HY5的控制下微调ER处的细胞分裂素反应。
Key message The non-intrinsic ABC proteins ABCI20 and ABCI21 are induced by light under HY5 regulation, localize to the ER, and ameliorate cytokinin-driven growth inhibition in young Arabidopsis thaliana seedlings. The plant ATP-binding cassette (ABC) I subfamily (ABCIs) comprises heterogeneous proteins containing any of the domains found in other ABC proteins. Some ABCIs are known to function in basic metabolism and stress responses, but many remain functionally uncharacterized. ABCI19, ABCI20, and ABCI21 of Arabidopsis thaliana cluster together in a phylogenetic tree, and are suggested to be targets of the transcription factor ELONGATED HYPOCOTYL 5 (HY5). Here, we reveal that these three ABCIs are involved in modulating cytokinin responses during early seedling development. The ABCI19, ABCI20 and ABCI21 promoters harbor HY5-binding motifs, and ABCI20 and ABCI21 expression was induced by light in a HY5-dependent manner. abci19 abci20 abci21 triple and abci20 abci21 double knockout mutants were hypersensitive to cytokinin in seedling growth retardation assays, but did not show phenotypic differences from the wild type in either control medium or auxin-, ABA-, GA-, ACC- or BR-containing media. ABCI19, ABCI20, and ABCI21 were expressed in young seedlings and the three proteins interacted with each other, forming a large protein complex at the endoplasmic reticulum (ER) membrane. These results suggest that ABCI19, ABCI20, and ABCI21 fine-tune the cytokinin response at the ER under the control of HY5 at the young seedling stage.