ZmACY-1 Antagonistically Regulates Growth and Stress Responses in Nicotiana benthamiana.

Dongbin Chen,Meiai Zhao,Xiyun Song,Jun Li,Xinmei Guo,Yuhe Pei,Fuchao Jiao,Junhua Li,Qianqian Wang

doi:10.3389/fpls.2021.593001

Abstract

Aminoacylase-1 is a zinc-binding enzyme that is important in urea cycling, ammonia scavenging, and oxidative stress responses in animals. Aminoacylase-1 (ACY-1) has been reported to play a role in resistance to pathogen infection in the model plant Nicotiana benthamiana. However, little is known about its function in plant growth and abiotic stress responses. In this study, we cloned and analyzed expression patterns of ZmACY-1 in Zea mays under different conditions. We also functionally characterized ZmACY-1 in N. benthamiana. We found that ZmACY-1 is expressed specifically in mature shoots compared with other tissues. ZmACY-1 is repressed by salt, drought, jasmonic acid, and salicylic acid, but is induced by abscisic acid and ethylene, indicating a potential role in stress responses and plant growth. The overexpression of ZmACY-1 in N. benthamiana promoted growth rate by promoting growth-related genes, such as NbEXPA1 and NbEIN2. At the same time, the overexpression of ZmACY-1 in N. benthamiana reduced tolerance to drought and salt stress. With drought and salt stress, the activity of protective enzymes, such as peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) from micrococcus lysodeikticus was lower; while the content of malondialdehyde (MDA) and relative electrolytic leakage was higher in ZmACY-1 overexpression lines than that in wild-type lines. The results indicate that ZmACY-1 plays an important role in the balance of plant growth and defense and can be used to assist plant breeding under abiotic stress conditions.

Highlights

Water limitation, normally caused by drought and salt stress, is one of the most important factors affecting plant growth (Koevoets et al, 2016)
The root length, leaf area, plant height, stem diameter, shoot fresh weight, and root fresh weight of the transgenic lines all overmatched those of the wild type (Figures 3E–L), which indicates that overexpression of ZmACY-1 promotes growth of N. benthamiana
Aminoacylase-1 is a dimer zinc-binding enzyme that can catalyze the hydrolysis of acylated L-amino acids into L-amino acids and acyl groups, and is considered to play a role in the catabolism and recovery of acylated amino acids

Summary

INTRODUCTION

Normally caused by drought and salt stress, is one of the most important factors affecting plant growth (Koevoets et al, 2016). Amino acid metabolism, such as glutathione, arginine, and proline, have been reported to play important roles in stress responses. We found an important role of ZmACY-1 in plant growth and stress resistance. Since ACY-1 has an important role in response to Phytophthora infestans, we tested the expression of ZmACY-1 with different stress treatments in order to explore whether ZmACY-1 is affected by abiotic stress or hormone regulation. We found that 150 mM NaCl (Figure 2B), 20% PEG6000 (Figure 2C), jasmonic acid (Figure 2F), and salicylic acid (Figure 2G) decreased the expression of ZmACY-1, while ABA (Figure 2D) and ethylene (Figure 2E) increased the expression of ZmACY-1 This suggested that ZmACY-1 may be involved in defense responses to drought stress, salt stress, and various plant hormones

RESULTS

DISCUSSION

EXPERIMENTAL PROCEDURES

DATA AVAILABILITY STATEMENT