"Learning from data: Big lessons from a small plant"

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Monday 17 September 2018, 11:00 - 12:30


The molecular function of proteins that lack sequence similarity to known proteins is difficult to predict using most bioinformatics tools. To discover novel transcriptional regulators from these unpredictable proteins, we developed a feature-based pipeline and identified 43 putative transcriptional regulator families in Arabidopsis thaliana. Phenotypic analysis of available mutant lines in the putative regulators identified a gene involved in organ size determination (CHIQUITA1 (CHIQ1)). Adult plants lacking CHIQ1 have smaller organs with fewer and smaller cells. Cell cycle marker studies indicated that cell proliferation ends prematurely in chiq1-1 leaves; and most chiq1-1 pavement cells do not enter endoreduplication after exiting the mitotic cell cycle. These results suggest that cell division exit is affected in chiq1-1 leaves. Contrarily and counter-intuitively, studies on leaves in the proliferating phase indicated that chiq1-1 proliferating leaves are bigger with cells dividing ~1.7x faster than wild type. Consistently, a transcriptome analysis in seedlings showed that positive regulators of growth are up regulated and ribosomal proteins are down regulated in chiq1-1. All these data together suggest that accelerated early growth in chiq1-1 might trigger a feedback mechanism that results in smaller adult plants, supporting a tight balance between growth and size in plants. The discovery of CHIQ1 suggests that our prediction pipeline might reveal new genes that are relevant for plant development and adaptation.


Location Jozef Schell Seminar Room
Contact Dr Seung Yon (Sue) Rhee
Carnegie Institution for Science
Department of Plant Biology