Transcriptomic Analysis of Dark-Induced Senescence in Bermudagrass (Cynodon dactylon).

Jibiao Fan,Liwen Cao,Haiyan Shi,Yanhong Lou,Liang Chen

doi:10.3390/plants8120614

Abstract

Leaf senescence induced by prolonged light deficiency is inevitable whenever turfgrass is cultivated in forests, and this negatively influences the survival and aesthetic quality of the turfgrass. However, the mechanism underlying dark-induced senescence in turfgrass remained obscure. In this study, RNA sequencing was performed to analyze how genes were regulated in response to dark-induced leaf senescence in bermudagrass. A total of 159,207 unigenes were obtained with a mean length of 948 bp. The differential expression analysis showed that a total of 59,062 genes, including 52,382 up-regulated genes and 6680 down-regulated genes were found to be differentially expressed between control leaves and senescent leaves induced by darkness. Subsequent bioinformatics analysis showed that these differentially expressed genes (DEGs) were mainly related to plant hormone (ethylene, abscisic acid, jasmonic acid, auxin, cytokinin, gibberellin, and brassinosteroid) signal transduction, N-glycan biosynthesis, and protein processing in the endoplasmic reticulum. In addition, transcription factors, such as WRKY, NAC, HSF, and bHLH families were also responsive to dark-induced leaf senescence in bermudagrass. Finally, qRT-PCR analysis of six randomly selected DEGs validated the accuracy of sequencing results. Taken together, our results provide basic information of how genes respond to darkness, and contribute to the understanding of comprehensive mechanisms of dark-induced leaf senescence in turfgrass.

Highlights

Cultivating turfgrass in forests has become a necessity of developing forestry economy and constructing gardens and landscapes
After 7 d of dark treatment (DT), leaf senescence initiated from the bottom, and severely yellowing leaves were observed in the bottom leaves (Figure 1a,b)
Chlorophyll contents (Figure 1c) and PSII max-photo efficiencies (Fv/Fm) (Figure 1d) of the bottom leaves both declined after 7 d of dark treatment

Summary

Introduction

Cultivating turfgrass in forests has become a necessity of developing forestry economy and constructing gardens and landscapes. Light deprivation caused by the forests exerts many negative effects on the turfgrass. When turfgrass is exposed to light-deficiency conditions, a series of morphological changes happen, including an increase in shoot elongation, leaf length, and leaf area [1,2,3]. Leaf senescence will be induced by prolonged and severe light deficiency. Leaf senescence is a critical concern for turfgrass because it negatively influences plant growth and development, and the aesthetic turf quality. It is important to investigate the mechanisms underlying dark-induced leaf senescence in order to develop ways to delay leaf senescence and improve turf quality under environments of light deficiency

Objectives

Methods

Results

Conclusion