Coordinating the morphogenesis-differentiation balance by tweaking the cytokinin-gibberellin equilibrium.

Alon Israeli,Maya Bar,Iris Daphne Zelnik,Noa Sela,Alisdair R Fernie,Yogev Burko,Naomi Ori,Takayuki Tohge,Sharona Shleizer-Burko,Mohammad R Hajirezaei

doi:10.1371/journal.pgen.1009537

Abstract

Morphogenesis and differentiation are important stages in organ development and shape determination. However, how they are balanced and tuned during development is not fully understood. In the compound leaved tomato, an extended morphogenesis phase allows for the initiation of leaflets, resulting in the compound form. Maintaining a prolonged morphogenetic phase in early stages of compound-leaf development in tomato is dependent on delayed activity of several factors that promote differentiation, including the CIN-TCP transcription factor (TF) LA, the MYB TF CLAU and the plant hormone Gibberellin (GA), as well as on the morphogenesis-promoting activity of the plant hormone cytokinin (CK). Here, we investigated the genetic regulation of the morphogenesis-differentiation balance by studying the relationship between LA, CLAU, TKN2, CK and GA. Our genetic and molecular examination suggest that LA is expressed earlier and more broadly than CLAU and determines the developmental context of CLAU activity. Genetic interaction analysis indicates that LA and CLAU likely promote differentiation in parallel genetic pathways. These pathways converge downstream on tuning the balance between CK and GA. Comprehensive transcriptomic analyses support the genetic data and provide insights into the broader molecular basis of differentiation and morphogenesis processes in plants.

Highlights

Morphogenesis, originating from the Greek words morphe/shape and genesis/formation, is a fascinating biological process that has attracted human eyes since ancient times [1,2]
We investigate the relationship between the transcription factors LA, CLAU and TKN2, and the plant hormones GA and CK, in the regulation of the morphogenesis-differentiation balance
We show that LA and CLAU effect essentially similar outcomes in tomato leaf development via likely partially parallel genetic pathways

Summary

Introduction

Morphogenesis, originating from the Greek words morphe/shape and genesis/formation, is a fascinating biological process that has attracted human eyes since ancient times [1,2]. Plants provide an excellent model system to investigate the shaping of an organism during the adult life cycle [7,8]. Lateral organs produced by the plant throughout its life cycle. Morphogenesis and differentiation are important stages in leaf development, and the spatial and temporal balance between these processes influences leaf size and shape [10,13,14]. The length of the morphogenetic window is a key determinant of final leaf shape. Tomato leaf development is an attractive system to investigate the contribution of the morphogenesis-differentiation balance to organ shaping

Methods

Results

Discussion

Conclusion