Genome-wide analysis of Respiratory burst oxidase homolog (Rboh) genes inAquilariaspecies and its association with agarwood formation

Abstract

AbstractRespiratory burst oxidase homolog (Rboh), generate reactive oxygen species (ROS) to maintain normal growth and pathogen induced defence responses in plants. InAquilariaplants, wounding and fungal invasion results in the biosynthesis of secondary metabolites as a defence response which with due course develop into agarwood. During pathogen invasion,Aquilariatree accumulate ROS species through the action of Rboh enzymes. Although in agarwood formation role of Rboh gene family has been implicated, an comprehensives study onRbohgene family and information of its role during agarwood formation in missing. In this study, sevenRbohgenes were identified from the genomes of twoAquilariaspecies viz.,Aquilaria agallochaandAquilaria sinensisand phylogenetically classified into five groups.Stress response, hormone regulation, and development related regulatory elements were identified in the promoter regions. The protein sequences comprised of four conserved domains, an EF-hand domain, and a transmembrane region which they probably utilise for MAPK signaling, plant-pathogen interaction and plant hormone signal transduction pathways. Expression analyses revealed that among the seven members,AaRbohAandAaRhobCwere involved in generation of ROS species, and also probably play role in agarwood formation. These findings provide valuable information regarding the Rboh members ofA. agallochawhich can be further used for functional analyses for in-depth understanding of ROS mediated signalling and regulation of agarwood formation.Graphical abstract