IN SILICO GENOME WIDE SEARCH FOR KEY PUTATIVE GENES OF THE ANTIOXIDANT ENZYMES INVOLVED IN THE PHYSIOLOGICAL ELIMINATION OF ROS

Abstract

Biotic and abiotic stresses, such as wounding, heavy metals, illumination, temperature extremes, drought or salt stress, cause an increase in reactive oxygen species (ROS), which are linked with programmed cell death (PCD). Accumulation of ROS increases the activity of catalase (CAT), ascorbate peroxidase (APX) and superoxide dismutase (SOD), which take part in cell defence mechanisms against ROS. In grafted plants, vascular elements are regenerated by complex processes and the graft union can be successful or incompatible. Whereas the biological formation of incompatible and compatible grafts is similar in the early phase of development, it has been reported that oxidative stress increases at the graft union in incompatible herbaceous plants. In this work, we have performed an in silico assessment of genes involved in ROS elimination. APX, SOD and CAT were identified by BLAST searches in the peach, apple and Arabidopsis genomes. Evolutionary relationships were inferred by phylogenetic analysis of aligned amino acid sequences for each gene family, which showed that they were highly conserved among the Rosaceae family. Additionally, specific gene expression and enzymatic activity were assayed in different pear and quince tissues used for grafting studies. Work is currently ongoing to determine gene expression and activity of these antioxidant enzymes in different graft combinations at different developmental stages.