Agronomical, physiological and molecular evaluation reveals superior salt-tolerance in bread wheat through salt-induced priming approach

Heba ABOUSEADAA,Othman ALZAHRANI,Mohamed A. M. ATIA,Mohammed A. ALSHEHRI,Taghreed K. ABDELMONEIM,Hossam S. EL-BELTAGI,Mohamed EL-MOGY

doi:10.15835/nbha49212310

Abstract

Salt stress significantly limit wheat crop productivity worldwide. Exposure to non-lethal levels of salt stress, referred to as "salt-priming", allows plants to persist subsequent lethal conditions; the priming effect continues even after an extended salt stress-free period. This study attempted to evaluate the effectiveness of the salt-induced priming approach to cope with the toxic effects of long-term salinity stress in wheat. After 22 days of gradual salt acclamation to reach 250 mM NaCl, plants were recovered for eight days and finally shocked with 250 mM NaCl (priming+shock) for 7 days. After that, physiological parameters and gene expression of six salt-responsive genes were assessed. Additionally, 120 days after germination (at the end of the season), agronomic traits were recorded. Analysis of the agronomical traits revealed higher productivity in the salt-pretreated group (priming+shock) plants than the non-pretreated (shock only). Consistently, salt-pretreated plants maintained higher photosynthetic pigments level and decreased proline and MDA content than non-pretreated, suggesting enhanced salt tolerance. Moreover, salt-pretreated plants sustained high expressional levels of salt-responsive genes (TaNHX1, TaSOS1, TaSOS4, TaHKT1, TaHKT2, and TaAKT1) comparing with non-pretreated, indicating a vital role in ion homeostasis and conferring salt tolerance. Ultimately, this finding could facilitate novel smart approaches to improve wheat productivity under salt stress.

Highlights

Bread wheat (Triticum aestivum L.) is one of the three most widely consumed cereals worldwide
Comparative evaluation of the 13 wheat cultivars under control and salt stress conditions demonstrated that all the salt-stressed groups exhibited consistent patterns of decrease compared to the control, for the salt-pretreated group, which always takes an intermediate value between the non-pretreated group and the priming group (Figures 2A-H)
Concerning the expression levels of the Salt Overly Sensitive (SOS) pathway-related genes (TaSOS1 and TaSOS4 genes) in response to long-term treatment of salinity stress, we found that both genes showed a significant increase, especially in the salt priming group compared to the control group

Summary

Introduction

Bread wheat (Triticum aestivum L.) is one of the three most widely consumed cereals (maize, rice, and wheat) worldwide. It is grown in many countries and greatly participates in the global agricultural economy. According to FAO, wheat provides one-fifth of food calories and proteins to the world population (FAO 2011). By 2050, it is expected that wheat demand rises by 60% in the developing countries due to the expected increase in the global population (Bodirsky et al, 2015). The gap between wheat production and consumption must be filled to meet increasing future food issues (Godfray et al, 2010; Shiferaw et al, 2011). The production of wheat as well as other cereals and several other crops is limited by various abiotic and biotic constraints (Majeed et al, 2018)

Methods

Results

Discussion

Conclusion