The mitochondrial oxidation resistance protein AtOXR2 increases plant biomass and tolerance to oxidative stress

COLOMBATTI, FRANCISCO; MANSILLA, NATANAEL; GONZALEZ, DANIEL H; MENCIA, REGINA; ALEMANO, SERGIO; WELCHEN, ELINA; GARCIA, LUCILA; ANDRADE, ANDREA M

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2019 vol. 70 p. 3177 - 3195

0022-0957

In this work, we describe the existence of the OXR (OXidation Resistance) protein family in plants. Arabidopsis possesses six OXR members containing the highly conserved TLDc domain characteristic of this eukaryotic protein family, most likely originated from three ancestors already present in algae by duplications that took place at different stages of plant evolution. We characterised AtOXR2 as a mitochondrial protein able to alleviate the stress sensitivity of a yeast oxr1 mutant. AtOXR2 is induced by oxidative stress, and its increased expression confers plant tolerance to methylviologen, antimycin A and high light intensity. AtOXR2 overexpression in Arabidopsis (oeOXR2) increases ascorbate levels, enhances photosynthetic performance and increases biomass and seed production. oeOXR2 plants also show higher ABA content, changes in ABA sensitivity and modified expression of ABA- and stress-regulated genes. Contrariwise, oxr2 mutant plants look phenotypically normal but show increased sensitivity to stress-related growth conditions. We propose that, by a not fully elucidated mechanism comprising an alteration in reactive oxygen species (ROS) levels, AtOXR2 improves the photosynthetic machinery and elicits basal plant tolerance against situations that produce oxidative stress, providing beneficial characteristics for plant growth.