Adaptive strategy of allohexaploid wheat to long-term salinity stress

Nadeem Bhanbhro,Huiying Lu,Binbin Xiao,Huan Wang,Lei Han,Chunwu Yang

doi:10.1186/s12870-020-02423-2

Nadeem Bhanbhro, Huiying Lu + Show 4 more

Open Access

https://doi.org/10.1186/s12870-020-02423-2

Copy DOI

Abstract

BackgroundMost studies of crop salinity tolerance are conducted under short-term stress condition within one growth stage. Understanding of the mechanisms of crop response to long-term salinity stress (LSS) is valuable for achieving the improvement of crop salinity tolerance. In the current study, we exposed allohexaploid wheat seeds to LSS conditions from germination stage to young seedling stage for 30 days. To elucidate the adaptive strategy of allohexaploid wheat to LSS, we analyzed chloroplast ultrastructure, leaf anatomy, transcriptomic profiling and concentrations of plant hormones and organic compatible solutes, comparing stressed and control plants.ResultsTranscriptomic profiling and biochemical analysis showed that energy partitioning between general metabolism maintenance and stress response may be crucial for survival of allohexaploid wheat under LSS. Under LSS, wheat appeared to shift energy from general maintenance to stress response through stimulating the abscisic acid (ABA) pathway and suppressing gibberellin and jasmonic acid pathways in the leaf. We further distinguished the expression status of the A, B, and D homeologs of any gene triad, and also surveyed the effects of LSS on homeolog expression bias for salinity-tolerant triads. We found that LSS had similar effects on expression of the three homeologs for most salinity-tolerant triads. However, in some of these triads, LSS induced different effects on the expression of the three homeologs.ConclusionsThe shift of the energy from general maintenance to stress response may be important for wheat LSS tolerance. LSS influences homeolog expression bias of salinity-tolerant triads.

Highlights

Most studies of crop salinity tolerance are conducted under short-term stress condition within one growth stage
Anatomy and solutes We compared the anatomy of leaves and the ultrastructure of chloroplasts in salt-stressed and control wheat
We found that the thylakoids in chloroplasts of stressed plants had a higher packing density than those of control plants, with more and larger starch grains in control plants than in stressed plants (Fig. 1)

Summary

Introduction

Most studies of crop salinity tolerance are conducted under short-term stress condition within one growth stage. Understanding of the mechanisms of crop response to long-term salinity stress (LSS) is valuable for achieving the improvement of crop salinity tolerance. To elucidate the adaptive strategy of allohexaploid wheat to LSS, we analyzed chloroplast ultrastructure, leaf anatomy, transcriptomic profiling and concentrations of plant hormones and organic compatible solutes, comparing stressed and control plants. Most investigations of crop salinity tolerance are conducted in a greenhouse under short-term stress condition within a single growth stage. An understanding of the mechanisms of crop response to long-term salinity stress (LSS) is helpful for crop salinity tolerance improvement. The aims of the research were to describe the physiological response of allohexaploid wheat plants to LSS across the germination and seedling stages, to identify the key response genes of the wheat plants under LSS, to demonstrate how LSS affected the expression patterns of homeologs, and to elucidate gene expression and physiological adaptation strategies to LSS

Objectives

Methods

Results

Discussion

Conclusion