Publications of NIPGR Scientists

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Author: search.filters.author.Banerjee, GopalSubject: search.filters.subject.rice

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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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    Transcriptional regulation of rice HSP101 promoter: Mitogen-activated protein kinase-mediated HSFA6a phosphorylation affects its stability and transactivation
    (John Wiley & Sons, 2022) Singh, Garima; Banerjee, Gopal; Sarkar, Neelam K.; Sinha, Alok Krishna; Grover, Anil
    Heat shock proteins (HSPs) and heat stress factors (HSFs) control the plant heat stress response to a large extent. HSP101 plays a decisive role in development of plant heat tolerance. We have previously shown that rice (Oryza sativa) cells contain 25 HSFs and among these, HSFA6a most predominantly binds to the HSP101 promoter and controls its transcript expression. This study shows that mitogen-activated protein kinases (MAPKs), specifically MPK3, MPK4, and MPK6 phosphorylate HSFA6a. HSFA6a showed physical interaction with MPK3/MPK4, specifically in the nucleus and this interaction involved the C-terminal end of HSFA6a. Four serine residues at positions Ser136, Ser141, Ser264, and Ser356 of HSFA6a are the putative sites of MAPK phosphorylation: we generated phospho-mutant of HSFA6a by changing the serine residues to alanine either individually or all four together. The Hsp101 promoter binding potential of Ser136 mutant was enhanced while it declined for the other three phospho-mutant HSFA6a forms. HSFA6a mutant lacking all the above four Ser residues exhibited reduced DNA binding and transactivation potential. We implicate the role of phosphorylation in the regulation of HSFA6a activity.