Publications of NIPGR Scientists

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Start date: 2020Subject: search.filters.subject.cell cycle

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    KRP3 stability controls rice plant architecture and productivity via MPK3-mediated phosphorylation
    (John Wiley & Sons, 2026) Banerjee, Gopal; Jonwal, Sarvesh; Rengasamy, Balakrishnan; Pal, Uttam; Singh, Dhanraj; Mohit, Mohit; Sinha, Alok Krishna
    Yield is a critical agronomic trait in cereal crops, shaped by factors like tiller and seed number, and seed weight. Understanding the factors governing these traits will help in improving the yield of plants. In this study, we identified an orphan gene, KRP3, belonging to cereal crops as a key regulator of rice plant architecture. Altered KRP3 protein homeostasis affected plant height, tiller number, and seed production, highlighting its role in maintaining rice plant vigor and productivity. The stability of the KRP3 protein is positively regulated by MPK3-mediated phosphorylation, as unphosphorylated KRP3 is targeted for degradation via the ubiquitin-proteasome pathway. Our findings reveal that the identified MPK3-KRP3 module operates as an S-phase checkpoint, modulating the pace of cell division in the actively dividing zones and maintaining a balance between cell division and elongation. These findings provide valuable insights for improving plant growth and grain yield in rice.
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    The small RNA biogenesis in rice is regulated by MAP kinase-mediated OsCDKD phosphorylation
    (John Wiley & Sons, 2024) Singh, Dhanraj; Verma, Neetu; Rengasamy, Balakrishnan; Banerjee, Gopal; Sinha, Alok Krishna
    CDKs are the master regulator of cell division and their activity is controlled by the regulatory subunit cyclins and phosphorylation by the CAKs. However, the role of MAP kinases in regulating plant cell cycle or CDKs have not been explored. Here, we report that the MAP kinases OsMPK3, OsMPK4, and OsMPK6 physically interact and phosphorylate OsCDKD and its regulatory subunit OsCYCH in rice. MAP kinases phosphorylate CDKD at Ser-168 and Thr-235 residues in OsCDKD. The MAP kinase-mediated phosphorylation of OsCDKD is required for its activation to control the small RNA biogenesis. The phosphodead version of OsCDKD fails to activate the C-terminal domain of RNA Polymerase II, thereby negatively impacting small RNA transcription. Further, the overexpression lines of wild-type (WT) OsCDKD and phosphomimic OsCDKD show increased root growth, plant height, tiller number, panicle number, and seed number in comparison to WT, phosphodead OsCDKD-OE, and kinase-dead OsCDKD-OE plants. In a nutshell, our study establishes a novel regulation of OsCDKD by MAPK-mediated phosphorylation in rice. The phosphorylation of OsCDKD by MAPKs imparts a positive effect on rice growth and development by regulating miRNAs transcription.
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    MAP kinases may mediate regulation of the cell cycle in rice by E2F2 phosphorylation
    (John Wiley & Sons, 2023) Singh, Dhanraj; Banerjee, Gopal; Verma, Neetu; Sinha, Alok Krishna
    E2F is the key transcription factor that determines the proliferative status of cells by regulating the G1/S phase of the cell cycle. In this study, we show that in rice (Oryza sativa), OsE2F2 is a phosphorylation target of MAP kinases. The MAP kinases OsMPK3, OsMPK4, and OsMPK6 interact with and phosphorylate OsE2F2. Next, we determined the serine and threonine residues that could play a role in the phosphorylation of OsE2F2. Subsequently, our study suggests a possible link between MAP kinase-mediated OsE2F2 phosphorylation and its impact on DNA proliferation in the roots of rice seedlings. Finally, we found positive feedback regulation of OsMPK4 by OsE2F2. Therefore, our study hints at the potential impact of MAP kinase signaling on the cell cycle of rice plants.