Molecular Plant
Abstract
Plant hormone cytokinin signals through histidine-aspartic acid (H-D) phosphorelay to regulate plant growth and development. Whilst it’s well-known that the phosphorelay involves histidine kinases, histidine phosphotransfer proteins (HPs) and responsive regulators (RRs), how this process is regulated by external components remains unknown. Here we demonstrate that PPKL1 (Protein Phosphatase with Kelch-Like domains), known as a signaling component of steroid hormone brassinosteroid, is actually a cryptic inhibitor of cytokinin phosphorelay in rice (Oryza sativaL.). Mutation at a specific amino acid D364 of PPKL1 activates cytokinin response, thus enlarges grain size in a semi-dominant mutant nameds48. Overexpression of PPKL1 containing D364, either with the deletion of the phosphatase domain or not, rescues thes48mutant phenotype. PPKL1 interacts with OsAHP2, one of authentic HPs, and D364 resides in a region resembling the receiver domain of RRs. Accordingly, PPKL1 can utilize D364 to suppress OsAHP2-to-RR phosphorelay, whereas mutation of D364 abolishes the effect. This function is independent of the phosphatase domain that should be required for brassinosteroid signaling. Importantly, editing of the D364-residential region produces a diversity of semi-dominant mutations associated with variously increased grain sizes. Screening of them enables the identification of two genotypes conferring significantly improved grain yield. We therefore uncover a noncanonical cytokinin signaling suppressor and a robust tool for seed rational design.
| 论文编号: | DOI:10.1016/j.molp.2021.09.010 |
| 论文题目: | A Cryptic Inhibitor of Cytokinin Phosphorelay Controls Rice Grain Size |
| 英文论文题目: | A Cryptic Inhibitor of Cytokinin Phosphorelay Controls Rice Grain Size |
| 第一作者: | DapuLiu, HeZhao, YunhuaXiao, GuoxiaZhang, ShouyunCao, WenchaoYin, YangwenQian, YanhaiYin, JinsongZhang, ShouyiChen, ChengcaiChu, HongningTong |
| 英文第一作者: | DapuLiu, HeZhao, YunhuaXiao, GuoxiaZhang, ShouyunCao, WenchaoYin, YangwenQian, YanhaiYin, JinsongZhang, ShouyiChen, ChengcaiChu, HongningTong |
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| 发表年度: | 2021-09-27 |
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| 摘要: | Plant hormone cytokinin signals through histidine-aspartic acid (H-D) phosphorelay to regulate plant growth and development. Whilst it’s well-known that the phosphorelay involves histidine kinases, histidine phosphotransfer proteins (HPs) and responsive regulators (RRs), how this process is regulated by external components remains unknown. Here we demonstrate that PPKL1 (Protein Phosphatase with Kelch-Like domains), known as a signaling component of steroid hormone brassinosteroid, is actually a cryptic inhibitor of cytokinin phosphorelay in rice (Oryza sativaL.). Mutation at a specific amino acid D364 of PPKL1 activates cytokinin response, thus enlarges grain size in a semi-dominant mutant nameds48. Overexpression of PPKL1 containing D364, either with the deletion of the phosphatase domain or not, rescues thes48mutant phenotype. PPKL1 interacts with OsAHP2, one of authentic HPs, and D364 resides in a region resembling the receiver domain of RRs. Accordingly, PPKL1 can utilize D364 to suppress OsAHP2-to-RR phosphorelay, whereas mutation of D364 abolishes the effect. This function is independent of the phosphatase domain that should be required for brassinosteroid signaling. Importantly, editing of the D364-residential region produces a diversity of semi-dominant mutations associated with variously increased grain sizes. Screening of them enables the identification of two genotypes conferring significantly improved grain yield. We therefore uncover a noncanonical cytokinin signaling suppressor and a robust tool for seed rational design. |
| 英文摘要: | Plant hormone cytokinin signals through histidine-aspartic acid (H-D) phosphorelay to regulate plant growth and development. Whilst it’s well-known that the phosphorelay involves histidine kinases, histidine phosphotransfer proteins (HPs) and responsive regulators (RRs), how this process is regulated by external components remains unknown. Here we demonstrate that PPKL1 (Protein Phosphatase with Kelch-Like domains), known as a signaling component of steroid hormone brassinosteroid, is actually a cryptic inhibitor of cytokinin phosphorelay in rice (Oryza sativaL.). Mutation at a specific amino acid D364 of PPKL1 activates cytokinin response, thus enlarges grain size in a semi-dominant mutant nameds48. Overexpression of PPKL1 containing D364, either with the deletion of the phosphatase domain or not, rescues thes48mutant phenotype. PPKL1 interacts with OsAHP2, one of authentic HPs, and D364 resides in a region resembling the receiver domain of RRs. Accordingly, PPKL1 can utilize D364 to suppress OsAHP2-to-RR phosphorelay, whereas mutation of D364 abolishes the effect. This function is independent of the phosphatase domain that should be required for brassinosteroid signaling. Importantly, editing of the D364-residential region produces a diversity of semi-dominant mutations associated with variously increased grain sizes. Screening of them enables the identification of two genotypes conferring significantly improved grain yield. We therefore uncover a noncanonical cytokinin signaling suppressor and a robust tool for seed rational design. |
| 刊物名称: | Molecular Plant |
| 英文刊物名称: | Molecular Plant |
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| 其它备注: | DapuLiu, HeZhao, YunhuaXiao, GuoxiaZhang, ShouyunCao, WenchaoYin, YangwenQian, YanhaiYin, JinsongZhang, ShouyiChen, ChengcaiChu, HongningTong. A Cryptic Inhibitor of Cytokinin Phosphorelay Controls Rice Grain Size. Molecular Plant. DOI:10.1016/j.molp.2021.09.010 |
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