Superoxide serves as a putative signal molecule for plant cell division: overexpression of CaRLK1 promotes the plant cell cycle via accumulation of O₂⁻ and decrease in H₂O₂

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• 作者：Dong Ju Lee ; Hyun Jun Choi ; Mid-Eum Moon ; Youn-Tae Chi ; Kon-Young Ji and Doil Choi
• 刊名：Physiologia Plantarum
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：159
• 期：2
• 页码：228-243
• 全文大小：594K
• ISSN：1399-3054

文摘

Reactive oxygen species (ROS) exert both positive and negative effects on plant growth and development and therefore receive a great deal of attention in current research. A hot pepper, Capsicum annuum receptor-like kinase 1 (CaRLK1) was ectopically expressed in Nicotiana tabacum BY-2 cell and Nicotiana benthamiana plants. This ectopic expression of CaRLK1 enhanced cell division and proliferation in both heterologous systems. Apparently, CaRLK1 is involved in controlling the cell cycle, possibly by inducing expressions of cyclin B1, cyclin D3, cyclin-dependent protein kinase 3, condensin complex subunit 2 and anaphase-promoting complex subunit 11 genes. CaRLK1 overexpression also increased transcript accumulation of NADPH oxidase genes, generation of O₂⁻ and catalase (CAT) activity/protein levels. In parallel, it decreased cellular H₂O₂ levels and cell size. Treatment with Tiron or diphenyleneiodonium (DPI) both decreased the cell division rate and O₂⁻ concentrations, but increased cellular H₂O₂ levels. Tobacco BY-2 cells overexpressing CaRLK1 were more sensitive to amino-1,2,4-triazole (3-AT), a CAT inhibitor, than control cells, suggesting that the increased H₂O₂ levels may not function as a signal for cell division and proliferation. Overexpression of CaRLK1 stimulated progression of the cell cycle from G₀/G₁ phase into the S phase. It is concluded that the CaRLK1 protein plays a pivotal role in controlling the level of O₂⁻ as signaling molecule which promotes cell division, concomitant with a reduction in H₂O₂ by the induction of CAT activity/protein.