An Ancestral Role for CONSTITUTIVE TRIPLE RESPONSE1 Proteins in Both Ethylene and Abscisic Acid Signaling1[OPEN]
A Physcomitrella patens protein regulates both ethylene and abscisic acid signaling, and this dual function was subsequently lost during evolution. Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus...
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Published in | Plant physiology (Bethesda) Vol. 169; no. 1; pp. 283 - 298 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
American Society of Plant Biologists
04.08.2015
|
Series | Focus on Ethylene |
Subjects | |
Online Access | Get full text |
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Summary: | A Physcomitrella patens protein regulates both ethylene and abscisic acid signaling, and this dual function was subsequently lost during evolution.
Land plants have evolved adaptive regulatory mechanisms enabling the survival of environmental stresses associated with terrestrial life. Here, we focus on the evolution of the regulatory CONSTITUTIVE TRIPLE RESPONSE1 (CTR1) component of the ethylene signaling pathway that modulates stress-related changes in plant growth and development. First, we compare CTR1-like proteins from a bryophyte,
Physcomitrella patens
(representative of early divergent land plants), with those of more recently diverged lycophyte and angiosperm species (including Arabidopsis [
Arabidopsis thaliana
]) and identify a monophyletic CTR1 family. The fully sequenced
P. patens
genome encodes only a single member of this family (PpCTR1L). Next, we compare the functions of PpCTR1L with that of related angiosperm proteins. We show that, like angiosperm CTR1 proteins (e.g. AtCTR1 of Arabidopsis), PpCTR1L modulates downstream ethylene signaling via direct interaction with ethylene receptors. These functions, therefore, likely predate the divergence of the bryophytes from the land-plant lineage. However, we also show that PpCTR1L unexpectedly has dual functions and additionally modulates abscisic acid (
ABA
) signaling. In contrast, while AtCTR1 lacks detectable
ABA
signaling functions, Arabidopsis has during evolution acquired another homolog that is functionally distinct from AtCTR1. In conclusion, the roles of CTR1-related proteins appear to have functionally diversified during land-plant evolution, and angiosperm CTR1-related proteins appear to have lost an ancestral
ABA
signaling function. Our study provides new insights into how molecular events such as gene duplication and functional differentiation may have contributed to the adaptive evolution of regulatory mechanisms in plants. |
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Bibliography: | www.plantphysiol.org/cgi/doi/10.1104/pp.15.00233 Present address: Leading Graduate School, Division of Life Sciences, Ochanomizu University, 2–1–1 Otsuka, Bunkyo-ku, Tokyo 112–8610, Japan. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Nicholas P. Harberd (nicholas.harberd@plants.ox.ac.uk). |
ISSN: | 0032-0889 1532-2548 |
DOI: | 10.1104/pp.15.00233 |