Ectopic Expression of Mulberry G-Proteins Alters Drought and Salt Stress Tolerance in Tobacco.

Changying Liu,Yazhen Xu,Boning Cao,Aichun Zhao,Dingpei Long,Yang Feng,Zhonghuai Xiang

doi:10.3390/ijms20010089

Changying Liu, Yazhen Xu + Show 5 more

Open Access

https://doi.org/10.3390/ijms20010089

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Abstract

Heterotrimeric guanine-nucleotide-binding proteins (G-proteins) play key roles in responses to various abiotic stress responses and tolerance in plants. However, the detailed mechanisms behind these roles remain unclear. Mulberry (Morus alba L.) can adapt to adverse abiotic stress conditions; however, little is known regarding the associated molecular mechanisms. In this study, mulberry G-protein genes, MaGα, MaGβ, MaGγ1, and MaGγ2, were independently transformed into tobacco, and the transgenic plants were used for resistance identification experiments. The ectopic expression of MaGα in tobacco decreased the tolerance to drought and salt stresses, while the overexpression of MaGβ, MaGγ1, and MaGγ2 increased the tolerance. Further analysis showed that mulberry G-proteins may regulate drought and salt tolerances by modulating reactive oxygen species’ detoxification. This study revealed the roles of each mulberry G-protein subunit in abiotic stress tolerance and advances our knowledge of the molecular mechanisms underlying G-proteins’ regulation of plant abiotic stress tolerance.

Highlights

Abiotic stresses, such as drought, heat, cold, nutritional deficiency, soil salinity, and heavy metal exposure, limit plant growth, development, and reproduction [1]
Signal recognition and transduction play key roles in plant abiotic stress responses, and stress signal sensors, secondary messengers, receptor-like protein kinases, the Ca2+-signal pathway, abscisic acid (ABA) signal transduction, the salt overly sensitive (SOS) signal pathway, mitogen-activated protein kinase (MAPK) cascades, the reactive oxygen species (ROS)-related signal pathway, and transcription factors participate in this process [4,5,6,7,8,9,10,11]
To evaluate the roles of mulberry G-proteins-encoding genes in plant tolerances to drought and salt stresses, the full-length sequences were independently cloned into the pLGNL expression vector under the control of the CaMV35S promoter and transformed into wild type (WT) tobacco plants (Figure 1A)

Summary

Introduction

Abiotic stresses, such as drought, heat, cold, nutritional deficiency, soil salinity, and heavy metal exposure, limit plant growth, development, and reproduction [1]. To adapt to these abiotic stress conditions, plants change their physiological and biochemical processes [2,3]. Little is known about the molecular mechanisms involved in the plant G-protein-mediated signal pathway regulation of abiotic stress responses. Mulberry can adapt well to adverse abiotic stresses, such as drought, flooding, water logging, high salinity, and metal exposure, but little is known regarding the molecular mechanisms involved in such processes [25]. Our results suggest a proposed pathway for G-proteins in plant tolerance to drought and salt stresses and provide a basis for further characterizations of the functions of G-proteins in abiotic stress responses and tolerances

Determination of Transgenic Tobacco Plants

Plasmid Construction and Plant Transformation

Stress Tolerance Analysis of Transgenic Plants

Quantitative Real-Time PCR

Statistical Analyses