Ectopic Expression of a Pak-choi YABBY Gene, BcYAB3, Causes Leaf Curvature and Flowering Stage Delay in Arabidopsis thaliana.

Hualan Hou,Ye Lin,Xilin Hou

doi:10.3390/genes11040370

Abstract

The YABBY family are a group of seed plant-specific transcription factors, which are involved in the specification of abaxial polarity in lateral organs. In Arabidopsis thaliana, YABBY3 (YAB3) plays a critical role in regulating abaxial patterning, growth of lateral organs, and inflorescence phyllotaxy. In this study, the BcYAB3 gene was isolated from Pak-choi (Brassica rapa subsp. chinensis). The tissue-specific expression analysis indicated that the BcYAB3 gene has significantly high transcript levels in stem, leaf, and flower. We investigated the subcellular localization of BcYAB3 and found the protein to be expressed in the nucleus. In the transgenic Arabidopsis thaliana plants expressing the BcYAB3 gene, the leaves were curling downward with the plant growth, and the bolting and flowering stages were delayed. These results not only validate the function of BcYAB3 in the leaf and flower development in Arabidopsis, but also contribute to unravel the molecular regulatory mechanism of YAB3 gene in the establishment of adaxial–abaxial polarity of the lateral organs in Pak-choi.

Highlights

The leaf is a major organ of plants, responsible for photosynthesis, respiration, and transpiration.the flattening of the leaf is essential for maximizing photosynthesis
Pak-choi YABBY genes are distributed in five subclasses, and most YABBY genes from dicots are together together and separated from monocots, suggesting that that they have clustered and separated from monocots, suggesting they havefunctional functionaldifferentiation
The results demonstrated that BcYAB3 is a nuclear-localized protein

Summary

Introduction

The leaf is a major organ of plants, responsible for photosynthesis, respiration, and transpiration. The flattening of the leaf is essential for maximizing photosynthesis. Leaf shape generally depends on the development of three axes of polarity, namely the proximal–distal axis, adaxial–abaxial axis, and medial–lateral axis. The adaxial–abaxial axis serve as the basis for establishment of the medial–lateral axis and proximal–distal axis [1]. The juxtaposition of adaxial and abaxial cells is essential for normal lamina outgrowth [2]. The adaxial–abaxial polarity is established in the development of lateral organs and controlled by several transcriptional factors and small non-coding RNAs, such as the HD-Zip III family, AS1/AS2

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