Genome-Wide Identification and Expression Analysis of the -Related Sequence Family in Cassava.

The -related sequences () are plant-specific transcription factors that have been quantitatively characterized during plant growth, regeneration, and stress responses. However, the genome-wide discovery of family genes and their involvement in abiotic stress-related activities in cassava have not been documented. A genome-wide search strategy was used to identify eight family members of the gene family in cassava ( Crantz). Based on their evolutionary linkages, all genes featured homologous RING-like zinc finger and IXGH domains. Genetic architecture and conserved motif analysis validated the categorization of genes into four groups. Eight pairs of segmental duplications were detected, resulting in an increase in the number of genes. Orthologous studies of genes among cassava and three different plant species (, , and ) provided important insights into the probable history of the gene family. The functionality of genes was elucidated through the prediction of protein-protein interaction networks and -acting domains. RNA-seq data demonstrated tissue/organ expression selectivity and preference of the genes. Furthermore, qRT-PCR investigation of gene expression after exposure to salicylic acid (SA) and methyl jasmonate (MeJA) hormone treatments, as well as salt (NaCl) and osmotic (polyethylene glycol, PEG) stresses, showed their stress-responsive patterns. This genome-wide characterization and identification of the evolutionary relationships and expression profiles of the cassava family genes will be helpful for further research into this gene family and its function in stress response. It may also assist future agricultural efforts to increase the stress tolerance of cassava.