Yang Qianying, Zhang Jie, Kojima Mikiko, Takebayashi Yumiko, Uragami Takuya, Kiba Takatoshi, Sakakibara Hitoshi, Lee Youngsook
Department of Life Sciences, POSTECH, Pohang, South Korea.
International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China.
Front Plant Sci. 2022 Jul 25;13:976267. doi: 10.3389/fpls.2022.976267. eCollection 2022.
The Arabidopsis ABC transporter ABCG11 transports lipidic precursors of surface coating polymers at the plasma membrane of epidermal cells. Mutants in exhibit severe developmental defects, suggesting that ABCG11 might also participate in phytohormone-mediated development. Here, we report that ABCG11 is involved in cytokinin-mediated development. The roots of mutant seedlings failed to respond to cytokinins and accumulated more cytokinins than wild-type roots. When grown under short-day conditions, exhibited longer roots and shorter hypocotyls compared to wild type, similar to , a knockout mutant in a cytokinin transporter. Treatment with exogenous -zeatin, which inhibits primary root elongation in the wild type, enhanced primary root elongation. It also increased the expression of cytokinin-responsive Arabidopsis response regulator () genes, and the signal of the :: reporter in roots compared to wild-type roots, suggesting that cytokinin signaling was enhanced in roots. When we treated only the roots of with -zeatin, their shoots showed lower induction than the wild type. The double mutant did not have additional root phenotypes compared to . Together, these results suggest that ABCG11 is necessary for normal cytokinin-mediated root development, likely because it contributes to cytokinin transport, either directly or indirectly.
拟南芥ABC转运蛋白ABCG11在表皮细胞质膜上运输表面涂层聚合物的脂质前体。该基因的突变体表现出严重的发育缺陷，这表明ABCG11可能也参与植物激素介导的发育过程。在此，我们报道ABCG11参与细胞分裂素介导的发育过程。突变体幼苗的根对细胞分裂素无反应，且比野生型根积累更多的细胞分裂素。在短日条件下生长时，与野生型相比，突变体表现出更长的根和更短的下胚轴，类似于细胞分裂素转运蛋白的敲除突变体。用外源反式玉米素处理（反式玉米素可抑制野生型主根伸长）可增强突变体主根伸长。与野生型根相比，它还增加了细胞分裂素响应的拟南芥反应调节因子（ARR）基因的表达，以及突变体根中ARR2::GUS报告基因的信号，这表明突变体根中的细胞分裂素信号增强。当我们仅用反式玉米素处理突变体的根时，其地上部分显示出比野生型更低的ARR诱导。与单突变体相比，双突变体没有额外的根表型。这些结果共同表明，ABCG11对于正常的细胞分裂素介导的根发育是必需的，可能是因为它直接或间接地促进了细胞分裂素的运输。
