Understanding the functions of CYCLIN-Ps in Arabidopsis gynoecium development

Jamil, Iqra (2024) Understanding the functions of CYCLIN-Ps in Arabidopsis gynoecium development. Doctoral thesis, University of East Anglia.

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Abstract

Coherent organ development and symmetry formation are fundamental for plant growth and survival. The Arabidopsis gynoecium, which subsequently forms the fruit, is an ideal system to study how important regulators of organ patterning co-ordinate with plant growth regulators, such as phytohormones, to control cell division rate or orientation and regulate the symmetric patterning of a developing organ. P-type cyclins (CYCLIN-Ps) is a novel family of cyclins, recently identified in Arabidopsis thaliana, consisting of seven members. Like other cyclins, CYCLIN-Ps (CYCPs henceforth) can interact with one of the key cell cycle regulators i.e., cyclin-dependent kinase (CDKA;1), but their role in cell division cycle and organ development remains largely unstudied. Here we have shown that CYCP3s (CYCP3;1 and CYCP3;2) are negatively regulated in-vivo by SPATULA (SPT) and INDEHISCENT (IND) which are key transcription factors regulating symmetry establishment and transitions in the Arabidopsis gynoecium. These data are in line with SEM analysis of overexpression of CYCP3s showing symmetry break at the apical region (style) of gynoecium and analysis of triple mutant of spt CRISPR cycp3s showing suppression of SPT bilateralstyle (split) phenotype. Moreover, we have shown that CYCP3s are induced by exogenous cytokinin (CK) treatment in the style of the WT Arabidopsis gynoecium, which becomes ectopic in the spt mutant background; that suggests that CK activity (to regulate CYCP3s expression) is independent and antagonistic to SPT. Our findings also show that increasing cell-division rate (by exogenous CKtreatment) in mutants of cell-division orientation, i.e., ton1a, trm6,7,8 and pok1,2 enhance the breaks in radial style symmetry that corroborates our hypothesis that control of cell-division rate and orientation, particularly in the apical-medial cells of gynoecium, is fundamental to form normal radial style in gynoecium.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Kitty Laine
Date Deposited:	12 Nov 2024 13:26
Last Modified:	12 Nov 2024 13:26
URI:	https://ueaeprints.uea.ac.uk/id/eprint/97646
DOI:

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