An ABA Functional Analogue B2 Enhanced Salt Tolerance by Inducing the Root Elongation and Reducing Peroxidation Damage in Maize Seedlings.

Shiying Geng,Liusheng Duan,Yumei Zhang,Zhaohu Li,Zhaobin Ren,Lijun Liang,Yuyi Zhou

doi:10.3390/ijms222312986

Abstract

Salt stress negatively affects maize growth and yield. Application of plant growth regulator is an effective way to improve crop salt tolerance, therefore reducing yield loss by salt stress. Here, we used a novel plant growth regulator B2, which is a functional analogue of ABA. With the aim to determine whether B2 alleviates salt stress on maize, we studied its function under hydroponic conditions. When the second leaf was fully developed, it was pretreated with 100 µM ABA, 0.01 µM B2, 0.1 µM B2, and 1 µM B2, independently. After 5 days treatment, NaCl was added into the nutrient solution for salt stress. Our results showed that B2 could enhance salt tolerance in maize, especially when the concentration was 1.0 µMol·L−1. Exogenous application of B2 significantly enhanced root growth, and the root/shoot ratio increased by 7.6% after 6 days treatment under salt stress. Compared with control, the ABA level also decreased by 31% after 6 days, which might have resulted in the root development. What is more, B2 maintained higher photosynthetic capacity in maize leaves under salt stress conditions and increased the activity of antioxidant enzymes and decreased the generation rate of reactive oxygen species by 16.48%. On the other hand, B2 can enhance its water absorption ability by increasing the expression of aquaporin genes ZmPIP1-1 and ZmPIP1-5. In conclusion, the novel plant growth regulator B2 can effectively improve the salt tolerance in maize.

Highlights

Salinity is a major threat in the modern agriculture, inhibiting growth and reducing yield, leading to economic loss for the farming organization and the country [1,2]
After the maize seeds were treated with 100 μM Abscisic acid (ABA), the germination rate was significantly reduced by 59.1% under normal conditions but was significantly increased under salt stress conditions
This study investigated the effects of ABA functional analogue B2 on growth, photosynthesis, antioxidant enzyme activity, reactive oxygen species, and related genes of maize seedlings under salt stress

Summary

Introduction

Salinity is a major threat in the modern agriculture, inhibiting growth and reducing yield, leading to economic loss for the farming organization and the country [1,2]. High salt concentrations have adverse effects on plant metabolic processes, including nutritional imbalance, oxidative stress, water stress, membrane disturbance, and ionic toxicity [3,4,5,6]. When plants are exposed to salt stress, specific signals are generated to initiate their response to salt stress, improving their tolerance to salt stress [7,8]. In order to solve the problem of salinity, people have found many methods including improving the physical and chemical properties of land, cultivating new crop varieties that are salt-tolerant, and using plant hormones or plant growth regulators. Abscisic acid (ABA), a plant stress hormone, can amplify primary signal and stimulate other signaling networks [12,13]. ABA can regulate the response of root growth to phosphorus starvation in barley, and this effect is related to the concentration of cytokinin and auxin [14]

Methods

Results

Conclusion