Characterization of a respiratory burst oxidase homolog from Gracilariopsis lemaneiformis (Rhodophyta) during stress and phytohormone treatments

Abstract

Abstract Plant respiratory burst oxidase homologs (rbohs), a source of reactive oxygen species (ROS), play a central role in the response to biotic and abiotic stresses in plants. Here, an rboh gene from the seaweed Gracilariopsis lemaneiformis (Glrboh) was characterized and analyzed in terms of its structure and changes in its expression profile in response to high salinity, high temperature and phytohormone treatments. The results show that high salinity and high temperature mostly induced Glrboh expression at the mRNA, protein and enzyme activity levels within 3–6 h, and the levels decreased thereafter, but there was an almost continuous decline in Glrboh mRNA during the 24 h following exposure to high temperature. Under heat stress, abscisic acid (ABA) dramatically enhanced the levels of Glrboh mRNA at 3 h and increased Glrboh protein expression and enzyme activity throughout most of the 24-h period. However, salicylic acid (SA) and methyl jasmonate (MJ) had only slight and varied effects on Glrboh expression. These results indicate that Glrboh is involved in heat and salt stress responses and that the phytohormone ABA is more closely related to ROS production in this alga than SA and MJ.