Transcriptome Analysis Revealed Plant Hormone Biosynthesis and Response Pathway Modification by Epichloëgansuensis in Achnatheruminebrians under Different Soil Moisture Availability.

Chao Xia,Michael J Christensen,Xingxu Zhang,Zhenrui Zhao,Mingzhu Kou,Rui Zhong

doi:10.3390/jof7080640

Abstract

The present study was designed to explore the effects of the endophyte Epichloë gansuensis on gene expression related to plant hormone biosynthesis and response pathways and the content of salicylic acid (SA) and jasmonic acid (JA) hormones of Achnatherum inebrians, under different moisture conditions. Through a pot experiment and transcriptome analysis, we found a total of 51 differentially expressed genes (DEGs) related to hormone biosynthesis and response pathways, including 12 auxin related genes, 8 cytokinin (CTK) related genes, 3 gibberellin (GA) related genes, 7 abscisic acid (ABA) related genes, 7 ethylene (ET) related genes, 12 JA related genes and 4 SA related genes. Furthermore, key genes of JA and SA biosynthesis and response pathways, such as LOX2S, AOS, OPR, ACX, JMT, JAZ, PAL, NPR1, TGA and PR-1, showed different degrees of upregulation or downregulation. Under 60% soil moisture content, the JA content of endophyte-free (EF) A. inebrians was significantly (p < 0.05) higher than that of endophyte-infected (EI) A. inebrians. Under 30% and 60% soil moisture content, the SA content of EF A. inebrians was significantly (p < 0.05) higher than that of EI A. inebrians. SA content of EI A. inebrians under 30% and 60% soil moisture content was significantly (p < 0.05) higher than that under 15% soil moisture content. With both EI and EF plants, the SA and JA levels, respectively, are very similar at 15% soil moisture content. This study has revealed that E. gansuensis differentially activated plant hormone synthesis and signal transduction pathways of A. inebrians plants under different soil moisture availability.

Highlights

Due to a sessile lifestyle combined with unstable environments, plants inevitably encounter various biotic and abiotic stresses, such as diseases, pests, drought, salinity, extreme temperatures and heavy metals
The following hypothesis was established: firstly, in response to different soil moisture availability changes would occur in the salicylic acid (SA) and jasmonic acid (JA) hormone content and in the expression level of genes associated with biosynthesis and response pathways of plant hormones, SA and JA, in A. inebrians plants host to E. gansuensis
differentially expressed genes (DEGs) Related to Hormone Biosynthesis and Response Based on analysis under different treatments, we found a total of 51 DEGs related to hormone biosynthesis and response pathways (Figure 2), including 12 indole-3-acetic acid (IAA) related genes, 8 CTK related genes, 3 GA related genes, 7 abscisic acid (ABA) related genes, 7 ET related genes, 12 JA related genes and 4 SA related genes

Summary

Introduction

Due to a sessile lifestyle combined with unstable environments, plants inevitably encounter various biotic and abiotic stresses, such as diseases, pests, drought, salinity, extreme temperatures and heavy metals. Among these factors, drought is one of the most dramatic stresses that affects the normal growth and development of plants and limits crop yields [1,2]. E. gansuensis [10] or E. inebrians [11] are present in nearly 100% of Achnatherum inebrians plants in the arid and semi-arid grasslands of northwest China as the presence of an Epichloë endophyte in grasses can provide protection against abiotic and biotic stresses [12]. Studies have shown that the presence of E. gansuensis can improve the tolerance of A. inebrians to diseases [14], pests [15], low temperature [16], heavy metals [17] and drought [18]

Methods

Results

Conclusion