Regulatory Mechanism of ABA and ABI3 on Vegetative Development in the Moss Physcomitrella patens.

Mengkai Zhao,Qilong Li,Xiaoqin Wang,Fang Bao,Zhenhua Chen,Yikun He,Qiang Lv

doi:10.3390/ijms19092728

Abstract

The moss Physcomitrella patens is a model system for studying plant developmental processes. ABSCISIC ACID INSENSITIVE3 (ABI3), a transcription factor of the ABA signaling pathway, plays an important role in plant growth and development in vascular plant. To understand the regulatory mechanism of ABA and PpABI3 on vegetative development in Physcomitrella patens, we applied physiological, cellular, and RNA-seq analyses in wild type (WT) plants and ∆abi3 mutants. During ABA treatment, the growth of gametophytes was inhibited to a lesser extent ∆abi3 plants compared with WT plants. Microscopic observation indicated that the differentiation of caulonemata from chloronemata was accelerated in ∆abi3 plants when compared with WT plants, with or without 10 μM of ABA treatment. Under normal conditions, auxin concentration in ∆abi3 plants was markedly higher than that in WT plants. The auxin induced later differentiation of caulonemata from chloronemata, and the phenotype of ∆abi3 plants was similar to that of WT plants treated with exogenous indole-3-acetic acid (IAA). RNA-seq analysis showed that the PpABI3-regulated genes overlapped with genes regulated by the ABA treatment, and about 78% of auxin-related genes regulated by the ABA treatment overlapped with those regulated by PpABI3. These results suggested that ABA affected vegetative development partly through PpABI3 regulation in P. patens; PpABI3 is a negative regulator of vegetative development in P. patens, and the vegetative development regulation by ABA and PpABI3 might occur by regulating the expression of auxin-related genes. PpABI3 might be associated with cross-talk between ABA and auxin in P. patens.

Highlights

Abscisic acid (ABA) is a well-known phytohormone that regulates seed dormancy and germination, stomatal closure, and response to environmental stress
ABA and PpABI3 could regulate the vegetative development of the moss P. patens
ABA regulated vegetative development partly through PpABI3, and other regulators might be involved in regulating vegetative development in the moss P. patens

Summary

Introduction

Abscisic acid (ABA) is a well-known phytohormone that regulates seed dormancy and germination, stomatal closure, and response to environmental stress. ABA regulates numerous aspects of plant growth and development. The role of ABA in regulating the floral transition has been reported. Increase in ABA can induce overexpression of the ABA-insensitive genes ABI4 and ABI5, which may delay floral transition, suggesting that ABA inhibits flowering [3,4]. Several ABA signaling components have been indicated to regulate root growth and root system architecture. The ABA receptor PYL9 (PYRABACTIN RESISTANCE-LIKE PROTEIN 9), together with PYL8, is responsible for the recovery of lateral roots from ABA inhibition [7]. The gene products ABI1, ABI2, ABI3, ABI4, ABI5, and ABI8, important regulators of the ABA signal transduction pathway, are involved in regulating root development [8,9,10,11]

Methods

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Discussion

Conclusion