A Novel Sweetpotato Transcription Factor Gene IbMYB116 Enhances Drought Tolerance in Transgenic Arabidopsis.

Yuanyuan Zhou,Ning Zhao,Zihao Wei,Shihan Xing,Qingchang Liu,Hong Zhu,Shaozhen He,Hong Zhai

doi:10.3389/fpls.2019.01025

Abstract

Several members of the MYB transcription factor family have been found to regulate growth, developmental processes, metabolism, and biotic and abiotic stress responses in plants. However, the role of MYB116 in plants is still unclear. In this study, a MYB transcription factor gene IbMYB116 was cloned and characterized from the sweetpotato [Ipomoea batatas (L.) Lam.] line Xushu55-2, a line that is considered to be drought resistant. We show here that IbMYB116 is a nuclear protein and that it possesses a transactivation domain at the C terminus. This gene exhibited a high expression level in the leaf tissues of Xushu55-2 and was strongly induced by PEG6000 and methyl-jasmonate (MeJA). The IbMYB116-overexpressing Arabidopsis plants showed significantly enhanced drought tolerance, increased MeJA content, and a decreased H2O2 level under drought stress. The overexpression of IbMYB116 in Arabidopsis systematically upregulated jasmonic acid (JA) biosynthesis genes and activated the JA signaling pathway as well as reactive oxygen species (ROS)-scavenging system genes under drought stress conditions. The overall results suggest that the IbMYB116 gene might enhance drought tolerance by activating a ROS-scavenging system through the JA signaling pathway in transgenic Arabidopsis. These findings reveal, for the first time, the crucial role of IbMYB116 in the drought tolerance of plants.

Highlights

Drought seriously affects the productivity of agricultural crops in the world (Yang et al, 2010; Boyer et al, 2013)
Our results showed that overexpression of IbMYB116 in Arabidopsis systematically upregulated the jasmonic acid (JA) biosynthesis genes, including AtLOX, AtAOS, AtAOC, AtOPR, AtOPCL, AtCOX3, AtfadA, and AtACAA1, and the MeJA content increased under drought stress conditions (Figures 7, 8)
AtCOI1 and AtJAZ were downregulated, and AtMYC2 was upregulated in the transgenic Arabidopsis plants under drought stress conditions (Figure 8). These findings suggest that IbMYB116 enhances drought tolerance through the JA signaling pathway in transgenic Arabidopsis (Figure 9)

Summary

Introduction

Drought seriously affects the productivity of agricultural crops in the world (Yang et al, 2010; Boyer et al, 2013). Jasmonic acid (JA), abscisic acid (ABA), salicylic acid (SA), and ethylene (ETH) play important roles in plant growth and development as well as protective responses against biotic and. Jasmonates (JAs), including JA, methyl-jasmonate (MeJA), and JA-isoleucine (JA-Ile), are important regulators of plant responses to environmental stresses, such as drought, salt, and ozone exposure (Overmyer et al, 2000; Turner et al, 2002; Lorenzo et al, 2003; Rojo et al, 2003; Wasternack et al, 2006; Dhakarey et al, 2017; Zhang et al, 2017). The JA signaling pathway plays a critical role in regulating the response to drought stress in plants (Liu et al, 2015; Ahmad et al, 2016)

Methods

Results

Discussion

Conclusion