Maize Grain Extract Enriched with Polyamines Alleviates Drought Stress in Triticum aestivum through Up-Regulation of the Ascorbate–Glutathione Cycle, Glyoxalase System, and Polyamine Gene Expression

Hesham F Alharby,Hassan S Al-Zahrani,Khalid R Hakeem,Hameed Alsamadany,Mostafa M Rady,Yahya M Alzahrani

doi:10.3390/agronomy11050949

Hesham F Alharby, Hassan S Al-Zahrani + Show 4 more

Open Access

https://doi.org/10.3390/agronomy11050949

Copy DOI

Abstract

The potential protective role of priming wheat seeds with maize green extract (MGE) against the stress effects of drought was studied. Pretreatment using MGE, MGE enriched with polyamines (MGEPA), and drought treatments (irrigation deficit of 30% (severe drought) or 60% (moderate drought) versus 90% relative water content of soil as a control) were applied in a factorial completely randomized design. Under moderate drought, pretreatment with MGEPA outperformed MGE and control, while severely stressed plants died even with pretreatments. Both extracts enhanced normal plant growth and yield and mitigated the deleterious effect of moderately stressed plants. Application of both extracts markedly increased photosynthetic efficiency, membrane stability, relative water content, and accumulation of antioxidants, osmoprotectants, trans- and cis-zeatin, polyamines, and their gene expressions, while levels of superoxide (O2•−) and hydrogen peroxide (H2O2), lipid peroxidation, and electrolyte leakage were decreased. Enzymatic antioxidants and glyoxalase system activities were improved in moderately stressed plants and were further improved with pretreatment with both extracts, thus protecting plants from oxidative damage by up-regulation of the ascorbate–glutathione cycle. Glycine betaine, soluble sugars, and proline levels were greatly increased in pretreated plants, thus maintaining membrane stability and photosynthetic efficiency. The interaction between drought and pretreatment using MGEPA was significant in growing wheat plants in dry environments with 60% relative water content of soil.

Highlights

Drought, one of the major types of environmental abiotic stresses, restricts plant performance throughout its life cycle
Under Ir90% or Ir60%, seed soaking in 2% maize green extract (MGE) or MGE enriched with polyamines (MGEPA) significantly increased plant growth, yield, leaf pigments, and photosynthetic efficiency compared to the corresponding controls
Drought stress led to a severe decrease in wheat plant growth and yield due to stress negative effects such as decreased chlorophyll content, photosynthetic efficiency, water content, and gas exchange, in addition to PAs gene expression, and increased membrane lipid peroxidation and electrolyte leakage due to increased oxidative stress

Summary

Introduction

One of the major types of environmental abiotic stresses, restricts plant performance throughout its life cycle. It limits the productivity of agricultural crops, mostly in dry areas (e.g., semi-arid and arid regions), including Egypt and Saudi Arabia, causing an increasing problem over time due to the ongoing climate change. To mitigate the oxidative stress damage, complex ROS-scavenging antioxidant system (enzymes (SOD, POD, CAT, etc.) and low-molecular mass compounds (GSH, AsA, carotenoids, phenols, etc.)) are developed/adopted in plants [11]. POD acts as a scavenger of H2O2 and CAT eliminates the H2O2 in mitochondria and micro-bodies [12], helping mitigate the adverse effects of oxidative stress

Methods

Results

Discussion

Conclusion