A novel repressor-activator-competitor module comprising C2H2 zinc finger and NAC transcription factors regulates rice grain development

Jaiswal, P.; Priyadarshini, R.; Yadav, A.; V, A. P.; Mahto, A.; Mathew, I.; Das, U.; Qasim, F.; Vichitra, A.; Panwar, A.; Verma, A.; Tyagi, A. K.; Agarwal, P.

doi:10.1101/2024.07.15.603577

bioRxiv · 10.1101/2024.07.15.603577

A novel repressor-activator-competitor module comprising C2H2 zinc finger and NAC transcription factors regulates rice grain development

Jaiswal, P.·Priyadarshini, R.·Yadav, A.·V, A. P.·Mahto, A.·Mathew, I.·Das, U.·Qasim, F.·Vichitra, A.·Panwar, A.·Verma, A.·Tyagi, A. K.·Agarwal, P.

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Abstract

Grain size and quality are crucial agronomic traits. We have characterized a seed-preferential C2H2 zinc finger transcriptional repressor, ZOS1-15. Its overexpression, knock-down and knock-out plants indicated a negative control over grain size due to altered cell expansion. ZOS1-15 homodimerized and directly interacted with co-repressor TOPLESS and histone deacetylases to form a repression complex. ZOS1-15 also interacted with Mediator subunit MED14_1 and a seed-preferential transcriptional activator, ONAC024, with three alternatively spliced isoforms. The ectopic expression of ONAC024 negatively affected plant growth and development. Seed-preferential overexpression and knock-down plants showed ONAC024 as a positive regulator of grain length due to increased cell proliferation and expansion. CRES-T generated transgenic rice plants indicated a functional divergence amongst ONAC024 isoforms. Tandem interactions were observed between ONAC024-ONAC023-ONAC026-ONAC020. ZOS1-15 and ONAC024 functioned antagonistically to regulate grain amylose and SSP accumulation while ONAC023 affected only amylose. ZOS1-15 and ONAC024 directly regulated the expression of two SSP encoding genes. Binding of ONAC024 was competed by ONAC025-MADS29 complex. The seed-preferential overexpression of SS1/ ONAC025 resulted in decreased grain size and amylose content, but higher yield. This study proposes a repressor-activator-competitor module, wherein ZOS1-15, ONAC024, ONAC023, ONAC025 along with their interactors synergistically and antagonistically regulate multiple aspects of rice grain development.

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Jaiswal, P., Priyadarshini, R., Yadav, A., V, A. P., Mahto, A., Mathew, I., Das, U., Qasim, F., Vichitra, A., Panwar, A., Verma, A., Tyagi, A. K., Agarwal, P.. 2024-07-17. A novel repressor-activator-competitor module comprising C2H2 zinc finger and NAC transcription factors regulates rice grain development. https://doi.org/10.1101/2024.07.15.603577

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