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Research article - Peer-reviewed, 2021

GIGANTEA influences leaf senescence in trees in two different ways

Fataftah, Nazeer; Bag, Pushan; Andre, Domenique; Lihavainen, Jenna; Zhang, Bo; Ingvarsson, Par K.; Nilsson, Ove; Jansson, Stefan

Abstract

GIGANTEA (GI) genes have a central role in plant development and influence several processes. Hybrid aspen T89 (Populus tremula x tremuloides) trees with low GI expression engineered through RNAi show severely compromised growth. To study the effect of reduced GI expression on leaf traits with special emphasis on leaf senescence, we grafted GI-RNAi scions onto wild-type rootstocks and successfully restored growth of the scions. The RNAi line had a distorted leaf shape and reduced photosynthesis, probably caused by modulation of phloem or stomatal function, increased starch accumulation, a higher carbon-to-nitrogen ratio, and reduced capacity to withstand moderate light stress. GI-RNAi also induced senescence under long day (LD) and moderate light conditions. Furthermore, the GI-RNAi lines were affected in their capacity to respond to "autumn environmental cues" inducing senescence, a type of leaf senescence that has physiological and biochemical characteristics that differ from those of senescence induced directly by stress under LD conditions. Overexpression of GI delayed senescence under simulated autumn conditions. The two different effects on leaf senescence under LD or simulated autumn conditions were not affected by the expression of FLOWERING LOCUS T. GI expression regulated leaf senescence locally-the phenotype followed the genotype of the branch, independent of its position on the tree-and trees with modified gene expression were affected in a similar way when grown in the field as under controlled conditions. Taken together, GI plays a central role in sensing environmental changes during autumn and determining the appropriate timing for leaf senescence in Populus.

Published in

Plant Physiology
2021, volume: 187, number: 4, pages: 2435-2450
Publisher: OXFORD UNIV PRESS INC

Authors' information

Fataftah, Nazeer
Umea University
Bag, Pushan
Umea University
André, Domenique
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Lihavainen, Jenna
Umea University
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Swedish University of Agricultural Sciences, Department of Plant Biology
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Jansson, Stefan
Umea University

UKÄ Subject classification

Genetics

Publication Identifiers

DOI: https://doi.org/10.1093/plphys/kiab439

URI (permanent link to this page)

https://res.slu.se/id/publ/115190