Transcriptomic profiling of tall fescue in response to heat stress and improved thermotolerance by melatonin and 24-epibrassinolide

Mohammad Nur Alam,Qingfeng Wang,Hong Luo,Yang Liu,Li Yang,Md Rabiul Islam,Zhulong Chan,Pingfang Yang,Lihua Zhang

doi:10.1186/s12864-018-4588-y

Abstract

BackgroundTall fescue is a widely used cool season turfgrass and relatively sensitive to high temperature. Chemical compounds like melatonin (MT) and 24-epibrassinolide (EBL) have been reported to improve plant heat stress tolerance effectively.ResultsIn this study, we reported that MT and EBL pretreated tall fescue seedlings showed decreased reactive oxygen species (ROS), electrolyte leakage (EL) and malondialdehide (MDA), but increased chlorophyll (Chl), total protein and antioxidant enzyme activities under heat stress condition, resulting in improved plant growth. Transcriptomic profiling analysis showed that 4311 and 8395 unigenes were significantly changed after 2 h and 12 h of heat treatments, respectively. Among them, genes involved in heat stress responses, DNA, RNA and protein degradation, redox, energy metabolisms, and hormone metabolism pathways were highly induced after heat stress. Genes including FaHSFA3, FaAWPM and FaCYTC2 were significantly upregulated by both MT and EBL treatments, indicating that these genes might function as the putative target genes of MT and EBL.ConclusionsThese findings indicated that heat stress caused extensively transcriptomic reprogramming of tall fescue and exogenous application of MT and EBL effectively improved thermotolerance in tall fescue.

Highlights

Tall fescue is a widely used cool season turfgrass and relatively sensitive to high temperature
In response to heat stress, various molecular pathways and relevant physiological processes were modulated in plants, resulting in increase of misfolding proteins which were bound to HSP70/90 and released HSFA1s to activate downstream heat stress responsive genes [2,3,4,5]
Effects of exogenous MT and EBL on plant growth under heat stress As a cool season turfgrass, tall fescue is relatively susceptible to high temperature

Summary

Introduction

Tall fescue is a widely used cool season turfgrass and relatively sensitive to high temperature. Chemical compounds like melatonin (MT) and 24-epibrassinolide (EBL) have been reported to improve plant heat stress tolerance effectively. Heat stress has become the major limiting factor for inhibition of plant growth and development and is causing severe reduction of crop yield worldwide [1]. Melatonin (N-acetyl-5-methoxytryptamine) was discovered by McCord and Allen [8] in bovine pineal gland and found to act as a neurohormone contributing to many physiological events in animals [9,10,11]. Melatonin was considered exclusively as an animal hormone till a couple of decades ago when two independent groups simultaneous had discovered melatonin in edible plants [12, 13]. Melatonin existed among the plant species from the lowest ng kg-1 to maximum mg kg-1 as dry weight [14].

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Conclusion