Genome-Wide Investigation and Expression Analysis of the Catalase Gene Family in Oat Plants (Avena sativa L.).

Through the degradation of reactive oxygen species (ROS), different antioxidant enzymes, such as catalase (CAT), defend organisms against oxidative stress. These enzymes are crucial to numerous biological functions, like plant development and defense against several biotic and abiotic stresses. However, despite the major economic importance of Avena sativa around the globe, little is known about the CAT gene's structure and organization in this crop. Thus, a genome-wide investigation of the CAT gene family in oat plants has been carried out to characterize the potential roles of those genes under different stressors. Bioinformatic approaches were used in this study to predict the AvCAT gene's structure, secondary and tertiary protein structures, physicochemical properties, phylogenetic tree, and expression profiling under diverse developmental and biological conditions. A local Saudi oat variety (AlShinen) was used in this work. Here, ten AvCAT genes that belong to three groups (Groups I-III) were identified. All identified CATs harbor the two conserved domains (pfam00199 and pfam06628), a heme-binding domain, and a catalase activity motif. Moreover, identified AvCAT proteins were located in different compartments in the cell, such as the peroxisome, mitochondrion, and cytoplasm. By analyzing their promoters, different cis-elements were identified as being related to plant development, maturation, and response to different environmental stresses. Gene expression analysis revealed that three different AvCAT genes belonging to three different subgroups showed noticeable modifications in response to various stresses, such as mannitol, salt, and ABA. As far as we know, this is the first report describing the genome-wide analysis of the oat catalase gene family, and these data will help further study the roles of catalase genes during stress responses, leading to crop improvement.

Identification of a putative kinase interacting domain in the durum wheat catalase 1 (TdCAT1) protein.

Catalases are crucial antioxidant enzymes that regulate plants responses to different biotic and abiotic stresses. It has been previously shown that the activities of durum wheat catalase proteins (TdCAT1) were stimulated in the presence of divalent cations Mn2+, Mg2+, Fe2+, Zn2+, and Ca2+. In addition, TdCAT1s can interact with calmodulins in calcium-independent manner, and this interaction stimulates its catalytic activity in a calcium-dependent manner. Moreover, this activity is further enhanced by Mn2+ cations. The current study showed that wheat catalase presents different phosphorylation targets. Besides, we demonstrated that catalase is able to interact with Mitogen Activated Proteins kinases via a conserved domain. This interaction activates wheat catalase independently of its phosphorylation status but is more promoted by Mn2+, Fe2+ and Ca2+ divalent cations. Interestingly, we have demonstrated that durum wheat catalase activity is differentially regulated by Mitogen Activated Proteins kinases and Calmodulins in the presence of calcium. Moreover, the V0 of the reaction increase gradually following the increasing quantities of Mn2+ divalent cations. Such results have never been described before and suggest i) complex regulatory mechanisms exerted on wheat catalase, ii) divalent cations (Mn2+; Mg2+; Ca2+ and Fe2+) act as key cofactors in these regulatory mechanisms.