Affiliation: | 1. International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China;2. Key Laboratory of Horticultural Plant Biology (MOE), Huazhong Agricultural University, Wuhan, China;3. International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China Department of Plant Cell Biology and Bioengineering, Biological Faculty, Belarusian State University, Minsk, Belarus;4. International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China Scholl of Mathematics & Big Data, Foshan University, Foshan, China |
Abstract: | Soil salinization is a major threat to global food security and the biodiversity of natural ecosystems. To adapt to salt stress, plants rely on ROS-mediated signalling networks that operate upstream of a broad array of physiological and genetic processes. A key player in ROS signalling is NADPH oxidase, a plasma-membrane-bound enzyme encoded by RBOH genes. In this study, we have conducted a comprehensive bioinformatic analysis of over 50 halophytic and glycophytic species to link the difference in the kinetics of ROS signalling between contrasting species with the abundance and/or structure of NADPH oxidases. The RBOH proteins were predicted in all the tested plant lineages except some algae species from the Rhodophyta, Chlorophyta and Streptophyta. Within the glycophytic group, the number of RBOH copies correlated negatively with salinity stress tolerance, suggesting that a reduction in the number of RBOH isoforms may be potentially related to the evolution of plant salinity tolerance. While halophytes did not develop unique protein families during evolution, they evolved additional phosphorylation target sites at the N-termini of NADPH oxidases, potentially modulating enzyme activity and allowing more control over their function, resulting in more efficient ROS signalling and adaptation to saline conditions. |