Expression of Two α-Type Expansins from Ammopiptanthus nanus in Arabidopsis thaliana Enhance Tolerance to Cold and Drought Stresses.

Yanping Liu,Ling Zhang,Li Zhang,Longqing Chen,Wenfang Hao,Yi Liu

doi:10.3390/ijms20215255

Abstract

Expansins, cell-wall loosening proteins, play an important role in plant growth and development and abiotic stress tolerance. Ammopiptanthus nanus (A. nanus) is an important plant to study to understand stress resistance in forestry. In our previous study, two α-type expansins from A. nanus were cloned and named AnEXPA1 and AnEXPA2. In this study, we found that they responded to different abiotic stress and hormone signals. It suggests that they may play different roles in response to abiotic stress. Their promoters show some of the same element responses to abiotic stress and hormones, but some special elements were identified between the expansins that could be essential for their expression. In order to further testify the reliability of the above results, we conducted an analysis of β-glucuronidase (GUS) dyeing. The analysis showed that AnEXPA1 was only induced by cold stress, whereas AnEXPA2 responded to hormone induction. AnEXPA1 and AnEXPA2 transgenic Arabidopsis plants showed better tolerance to cold and drought stresses. Moreover, the ability to scavenge reactive oxygen species (ROS) was significantly improved in the transgenic plants, and expansin activity was enhanced. These results suggested that AnEXPA1 and AnEXPA2 play an important role in the response to abiotic stress. Our research contributes to a better understanding of the regulatory network of expansins and may benefit agricultural production.

Highlights

Abiotic stresses, which are major limiting factors in agriculture, include conditions such as drought, salinity, high or low temperatures, light, deficient or excess nutrients, heavy metals, and pollutants
The abscisic acid (ABA) treatment did not affect AnEXPA1 expression (Figure 4E). These results suggested that AnEXPA1 expression was positively correlated with indole-acetic acid (IAA) and Naphthaleneacetic acid (NAA), negatively correlated with GA3, ET, and methyl jasmonate (MeJA), and not correlated with ABA
Expansins are involved in many physiological and biochemical processes, in the construction of cell walls. They play an important role in plant growth and development as well as tolerance to abiotic stress, either alone or through interactions with other expansins

Summary

Introduction

Abiotic stresses, which are major limiting factors in agriculture, include conditions such as drought, salinity, high or low temperatures, light, deficient or excess nutrients, heavy metals, and pollutants. All of these factors, working individually or together, can endanger plants by negatively affecting their growth, development, and productivity [1]. The key problem in plant growth is the extension of cell regulation under various stresses [2]. Proteins in plant cell walls play a major role in the regulation of cell wall extension [3]

Methods

Results

Conclusion