Genome-wide identification of the rubber tree superoxide dismutase ( SOD ) gene family and analysis of its expression under abiotic stress.

We identified nine genes in the rubber tree genome, including five , two , and two . Phylogenetic relationship analysis classified the SOD proteins from the rubber tree and other related species into three subfamilies. The results of gene structure and conserved motif analysis illustrated that most genes have similar exon-intron numbers and conserved motifs in the same evolutionary branch. Five hormone-related, four stress-related, and light-responsive elements were detected in the promoters. were expressed in different tissues, gradually increased with leaf development, and were abundantly expressed in mature leaves. and was significantly upregulated under low and high temperatures, and salt stress, except for , by heat. Furthermore, most genes were significantly upregulated by drought, except . These findings imply that these genes may play vital roles in rubber tree stress resistance. Our results provide a basis for further studies on the functions of genes in rubber trees and stress response mechanisms.