Abstract Detail

Biochemistry, metabolism, carbon flux

Lapointe, Line [1], Dong, Yanwen [2], Munne-Bosch, Sergi [3], Gérant, Dominique [4].

Growth temperature influences the metabolite and phytohormone profile in leaves as they age and enter senescence.

Leaf senescence can be induced either by an abiotic stress, by environmental cues such as a photoperiod or in response to a change in plant carbon and/or nutrient needs. For example, leaf senescence can be induced by a reduction in sink demand once sink growth is completed. The signalling pathway that induces leaf senescence has only been partially uncovered, and it appears to vary depending on the driving cause of senescence (stress, phenology or sink limitation). Until recently, metabolites and phytohormones involved in the induction of senescence were investigated mostly on a one to one basis. New technologies such as metabolomic allow us to investigate the potential role of a much larger pool of metabolites in the induction of leaf senescence. We characterized leaf metabolite and phytohormone profiles in Erythronium americanum, a spring ephemeral, in which leaf senescence has been shown to be induced by a reduction in sink demand. Different growth temperatures were used to modulate sink demand and the timing of senescence. The leaf metabolite profile, which included over 80 different metabolites and 7 phytohormones, presents clear changes with leaf phenology, according to PCA analyses. A first group of metabolites is associated with leaf unrolling, a second group with fully developed leaves and a third group with leaf senescence. This last group includes plants that were harvested a few days before the first visual sign of leaf senescence, strongly suggesting that some of these metabolites are involved in the induction of leaf senescence. Only three metabolites associated with the senescent stage are common to all three growth temperatures: sorbose, abscisic acid, and tocopherol. At low temperatures, the leaf appears to accumulate many different sugars as senescence approaches. These include trehalose, isomaltose, melezitose and mannitol. At warmer temperatures, other sugars and some polyols become more abundant as senescence approaches: fructose, arabitol, sorbitol and mannitol, whereas glycerol decreases. Furthermore, more phytohormones appear to be involved in the induction of senescence at higher temperatures. To the best of our knowledge, some of these metabolites have not been reported to be associated with leaf senescence in other species. Further investigation is needed to determine which metabolites are modulated in response to a sink limitation and those that might be specific to this group of plants. These studies will most likely unravel new signalling pathways that can induce leaf senescence under specific conditions.

1 - Universite Laval, Dept De Biologie, Pavillon Vachon, Québec, QC, G1V 0A6, Canada
2 - Université Laval, Département de biologie / Centre d'étude de la forêt, 1045, avenue de la Médecine, Pavillon Vachon, Bureau 3047-E, Québec, QC, G1V 0A6, Canada
3 - Universitat de Barcelona, Departament de Biologia Vegetal, , Barcelona, Spain
4 - Université de Lorraine, UMR1137 INRA, Écologie et Écophysiologie Forestières (EEF), Nancy, France

Keywords:
Metabolomics
spring ephemerals
source–sink relationship
low temperature
senescence.

Presentation Type: Oral Paper:Papers for Topics
Session: 27
Location: Hall A/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 8:00 AM
Number: 27001
Abstract ID:1026
Candidate for Awards:None