NOL‐mediated functional stay‐green traits in perennial ryegrass (Lolium perenne L.) involving multifaceted molecular factors and metabolic pathways regulating leaf senescence. (15th May 2021)

• Record Type: Journal Article
• Authors: Yu, Guohui; Xie, Zheni; Zhang, Jing; Lei, Shanshan; Lin, Wenjing; Xu, Bin; Huang, Bingru
• Is Part Of: Plant journal. Volume 106:Number 5(2021)
• Page Start: 1219
• Page End: 1232
• Publication Date: 2021-05-15
• Subjects: ryegrass -- NYC1‐LIKE (NOL) -- chlorophyll -- senescence -- stay‐green -- transcriptome -- photosynthesis; Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.15204
• Languages: English
• ISSNs: 0960-7412

Abstract

SUMMARY: Loss of chlorophyll (Chl) is a hallmark of leaf senescence, which may be regulated by Chl catabolic genes, including NON‐YELLOW COLORING 1 ( NYC1 ) ‐like ( NOL ). The objective of this study was to determine molecular factors and metabolic pathways underlying NOL regulation of leaf senescence in perennial grass species. LpNOL was cloned from perennial ryegrass ( Lolium perenne L.) and found to be highly expressed in senescent leaves. Transient overexpression of LpNOL accelerated leaf senescence and Chl b degradation in Nicotiana benthamiana . LpNOL RNA interference ( NOLi ) in perennial ryegrass not only significantly blocked Chl degradation in senescent leaves, but also delayed initiation and progression of leaf senescence. This study found that NOL, in addition to functioning as a Chl b reductase, could enact the functional stay‐green phenotype in perennial grass species, as manifested by increased photosynthetic activities in NOLi plants. Comparative transcriptomic analysis revealed that NOL‐mediated functional stay‐green in perennial ryegrass was mainly achieved through the modulation of Chl catabolism, light harvesting for photosynthesis, photorespiration, cytochrome respiration, carbohydrate catabolism, oxidative detoxification, and abscisic acid biosynthesis and signaling pathways. Significance Statement: Chlorophyll (Chl) degradation is a hallmark of leaf senescence. Here, we demonstrated that blocking a Chl catabolic gene, LpNOL, in perennial ryegrass results in functional stay‐green associated with metabolic modulation of Chl metabolism, light harvesting, photorespiration, cytochrome respiration, carbohydrate catabolism, oxidative detoxification, and abscisic acid biosynthesis and signaling to maintain the ability of photosynthesis and reactive oxygen species clearance, and metabolic energy supply, while inhibiting sugar accumulation.