ABA Is Involved in Regulation of Cold Stress Response in Bermudagrass.

Xuebing Huang,Liang Chen,Zhengrong Hu,Ao Liu,Haiyan Shi,Jinmin Fu,Erick Amombo

doi:10.3389/fpls.2017.01613

Abstract

As a representative warm-season grass, Bermudagrass [Cynodon dactylon (L). Pers.] is widely used in turf systems. However, low temperature remarkably limits its growth and distribution. ABA is a crucial phytohormone that has been reported to regulate much important physiological and biochemical processes in plants under abiotic stress. Therefore, the objective of this study was to figure out the effects of ABA on the cold-sensitive (S) and cold-resistant (R) Bermudagrass genotypes response to cold stress. In this study, the plants were treated with 100 μM ABA solution and exposed to 4°C temperature. After 7 days of cold treatment, the electrolyte leakage (EL), malonaldehyde (MDA) and H2O2 content were significantly increased in both genotypes compared with control condition, and these values were higher in R genotype than those of S genotype, respectively. By contrast, exogenous ABA application decreased the electrolyte leakage (EL), MDA and H2O2 content in both genotypes compared with those plants without ABA treatment under cold treatment condition. In addition, exogenous ABA application increased the levels of chlorophyll a fluorescence transient curve for both genotypes, and it was higher in R genotype than that of S genotype. Analysis of photosynthetic fluorescence parameters revealed that ABA treatment improved the performance of photosystem II under cold condition, particularly for the R genotype. Moreover, cold stress significantly increased δ13C values for both genotypes, while it was alleviated by exogenous ABA. Additionally, exogenous ABA application altered the expression of ABA- or cold related genes, including ABF1, CBF1, and LEA. In summary, exogenous ABA application enhanced cold resistance of both genotypes by maintaining cell membrane stability, improving the process of photosystem II, increasing carbon isotopic fractionation under cold stress, and more prominently in R genotype compared with S genotype.

Highlights

Bermudagrass [Cynodondactylon (L) Pers.] is widely used in golf courses, sports fields and lawns globally (Fan et al, 2014)
These findings indicated that ABA treatment improved Bermudagrass tolerance to cold stress, especially in cold- resistant Bermudagrass
To investigate whether the exogenous ABA played a positive role in maintaining cell membrane stability of Bermudagrass species under cold stress, MDA content and electrolyte leakage (EL) levels were determined

Summary

Introduction

Bermudagrass [Cynodondactylon (L) Pers.] is widely used in golf courses, sports fields and lawns globally (Fan et al, 2014). As a representative warm-season grass, its optimal growth temperature ranges from 26◦C to 35◦C (Fan et al, 2014). When two Bermudagrass [Cynodon dactylon (L.) Pers. Dactylon] cultivars, Riviera (cold tolerant) and Princess-77 (cold sensitive) were exposed to cold acclimation at 8/4◦C (day/night), relative EL values were remarkably increased, resulting in the damage to cell membrane. Previous results showed that H2O2 content increased in plants tissues after low temperature treatment (Fadzillah et al, 1996; O’Kane et al, 1996). To protect themselves from cold-induced damage, plants have evolved multiple mechanisms to enhance their cold tolerance, which include alterations of membrane fluidity, metabolism homeostasis, enzyme activity and the C-repeat-Binding Factor/DRE-Binding Factor (CBF/DREB) pathway (Thomashow, 1999; Zhu et al, 2004; Chinnusamy et al, 2010; Knight and Knight, 2012)

Objectives

Methods

Results

Discussion

Conclusion