Reactive oxygen and nitrogen species (ROS and RNS, respectively) are messengers that carry signals to alter the redox state in order to activate plant responses and other physiological processes, such as differentiation, aging, senescence, and pathogen defense. Quite a large number of genes are involved in this signaling and lead to oxidative stress in plants. Although the role of ROS/RNS during stress conditions is well documented, a comprehensive list of genes and comparative study of these genes has not yet been completed. Accordingly, the in silico identification of oxidative stress-related genes was performed for soybeans and Arabidopsis. These genes were also studied in relation to multiple domain prediction. The presence of domains like dehydogenase and ATPase suggests that these genes are involved in various metabolic processes, as well as the transportation of ions under optimal environmental conditions. In addition to a sequence analysis, a phylogenetic analysis was also performed to identify orthologous pairs among the soybean and Arabidopsis oxidative stress-related genes based on neighbor joining. This study was also conducted with the objective of further understanding the complex molecular signaling mechanism in plants under various stress conditions.

Receptor mediated signal carriers play a critical role in regulation of plant defense and development. Rapid Alkalization Factor (RALF) is an important signaling family which has a role in plant growth and development. However, only few RALF polypeptides have been identified till date, mainly because of enormous efforts required for their isolation or identify their gene through mutational analysis. In this study, an extensive database search yield 39, 43, 34 and 23 potential RALF genes in Arabidopsis, rice, corn and soybeans, respectively. RALF genes are highly conserved across the plant species. A comprehensive analysis including the chromosomal location, gene structure, subcellular location, conserved motif, protein structure and promoter analysis was performed. RALF genes from four plants under study were divided in 7 groups based on phylogenetic analysis. In silico expression analysis of these genes, using microarray and EST data, reveled that these genes exhibit a variety of expression pattern. Furthermore, RALF genes showed distinct expression pattern under nitricoxide (NO) stress in Arabidopsis. This suggests a role of RALF genes in plant defense regulation. Our comprehensive analysis of RALF genes is a valuable resource that further elucidates the roles of RALF family members in plant growth and development. In addition, comparative genomics analyses deepen our understanding of the evolution of RALF gene family and will contribute to further genetics and genomics studies of other monocot and dicot plant species.