Influences of sea water on the ethylene-biosynthesis, senescence-associated gene expressions, and antioxidant characteristics of Arabidopsis plants

Kuan-Hung Lin,Chih-Ming Chiang,Wei-Jun Xie,Meng-Yuan Huang,Yi-Sheng Chen,Hui-Chung Wu,Hsin-Hung Lin,Shwu-Fen Pan

doi:10.15835/nbha49112205

Abstract

We evaluated the physiological and antioxidant characteristics of Arabidopsis thaliana (At) plants grown in different sea water (SW) products containing trace elements, namely RO3, 300K, and 340K, at various dilutions. The synthetic water (namely 300K-Test), a mixture of the main ions of SW including 143.08 mg L-1 Mg2+, 5.74 mg L-1 Na+, 170 mg L-1 K+, and 33.5 mg L-1 Ca2+ with equal concentrations to those in 300K SW without trace elements, was also used to culture At plants and study the influences that the major ions had on regulating ethylene production. The ethylene-biosynthesis (ACS7 and ACO2) and senescence-associated (NAP, SAG113, and WRKY6) gene expressions in SW- and ionic-treated At plants in response to transcriptional signaling pathways of ethylene response mechanisms were also investigated. Our results show that down-regulation of the ACS7 gene in 300K-treated plants significantly reduced the ethylene content but remarkably increased chlorophyll, total phenol, and DPPH radical scavenging accumulations and strengthened the salt tolerance of 300K-treated plants. The expression of the ACS7 gene of At plants under 300K, Ca2+, Mg2+, and Na+ treatments was correlated with decreases in NAP, SAG113, and WRKY6 gene expressions. The application of Ca2+ increased total phenol content and reduced the accumulation of superoxide, which in combination decreases plant aging brought on by ethylene. However, K+ treatment inhibited SGA113 gene expression, resulting in reducing ACS7 gene expression and ethylene content. The characterization and functional analysis of these genes should facilitate our understanding of ethylene response mechanisms in plants.

Highlights

Sea water (SW) contains abundant essential minerals (i.e. Mg2+, Na+, K+, and Ca2+), along with minute amounts of many trace elements, and has attracted attention in accordance with a rise of the consciousness of health from the standpoint of preventive medicine (Nakagawa et al, 2000).Studies have shown that SW exerts diverse biological activity, such as regulating the immune system and antioxidant activity in rats (Jung and Joo, 2006)
With the 2% mineral controlled sea water treatment the plants increased 14% of fruit yield compared to the control
The significantly higher diphenyl- 2-picrylhydrazyl (DPPH) radical scavenging effect (41.2%) and total Chl content (0.58 mg/g FW) in tested leaves were observed with 300K compared to the control (40.4% and 0.48 mg/g FW, respectively), whereas no remarkable differences in DPPH radical scavenging effects and total Chl content were detected among RO3, 340K, and controls (Figures 2B,C).These results demonstrate that only 300K treatment could increase antioxidant content and scavenge DPPH radicals, and suggests that the major ions contained in 300K SW may enhance the synthesis and accumulation of Chl

Summary

Introduction

Sea water (SW) contains abundant essential minerals (i.e. Mg2+, Na+, K+, and Ca2+), along with minute amounts of many trace elements, and has attracted attention in accordance with a rise of the consciousness of health from the standpoint of preventive medicine (Nakagawa et al, 2000).Studies have shown that SW exerts diverse biological activity, such as regulating the immune system and antioxidant activity in rats (Jung and Joo, 2006) It has therapeutic effects on lipid metabolism and IgA production (Kang et al, 2015; Shiraishi et al, 2017) and has been applied in the food, cosmetic, health, and medical fields (Nani et al, 2016; Higgins et al, 2019). Caparrotta et al (2019) showed that the use of SW treatments in hydroponic spinach cultivation has positive effects on growth parameters

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