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

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.

Mucilaginibacter sp. K Improves Growth and Induces Salt Tolerance in Nonhost Plants via Multilevel Mechanisms

“…Dietzia natronolimnaes STR1 potentiated salinity tolerance in wheat through upregulation of an ABA signaling cascade and modulation of expression of genes related to ion transport and antioxidant enzymes ( Bharti et al, 2016 ). Exogenous application of a functional analog of ABA alleviated salt stress in maize via enhanced root growth, increased antioxidant enzyme activity, and upregulated expression of aquaporin genes ( Geng et al, 2021 ). We previously found that strain K inoculation led to higher transcription of the ABA-dependent DR29A following salinity stress in Arabidopsis ( Fan and Smith, 2021 ), showing that strain K might prime for ABA-dependent signaling upon salt stress.…”

Research Progress on the Mechanism of Salt Tolerance in Maize: A Classic Field That Needs New Efforts

“…It achieved this by increasing the activity of antioxidant enzymes and reducing the rate of ROS generation by 16.48%. Furthermore, B2 exhibited the capacity to enhance water absorption by upregulating the expression of the aquaporin gene ZmPIP1 [ 45 ]. Chen et al (2021) demonstrated that alternative splicing is likely to mediate early responses to salt stress during maize seed germination by using RNA-seq and SWATH-MS-based quantitative proteomics [ 46 ].…”