Genome-wide characterization of GRAS gene family and their expression profiles under diverse biotic and abiotic stresses in Amorphophallus konjac.

backgroundThe GRAS gene family is a plant-specific group of genes that play critical roles in various biological processes, including plant growth and development, responses to adverse stress, light signaling, hormone signaling, and others. To elucidate the characteristics of the GRAS transcription factor family in Amorphophallus konjac (AkGRAS), we identified GRAS family members based on whole-genome data and bioinformatics methods. We further analyzed their physicochemical properties, gene structure, evolutionary relationships, regulatory networks, and stress response patterns using bioinformatics tools.

resultsA total of 57 AkGRAS genes were identified in the A. konjac genome. Most of the encoded proteins were unstable, hydrophilic proteins with molecular weights ranging from 15.78 to 90.82 kDa. Chromosomal localization analysis revealed that the 57 AkGRAS genes were unevenly distributed across 13 chromosomes. Phylogenetic analysis classified the 57 AkGRAS genes into eleven subgroups: DELLA, Os04, SHR, PAT1, HAM, SCR, SCL28, SCL4/7, LAS, LISCL, and SCL3. Six pairs of duplicated genes were identified within the AkGRAS gene family. Protein-protein functional associations analysis suggested that the top three functionally associated proteins were RGA, PAT1-2, and NSP2 in Arabidopsis thaliana. Enrichment analysis predicted the involvement of AkGRAS genes in numerous biological processes. To investigate the expression patterns of AkGRAS genes under Abscisic Acid (ABA), Jasmonic Acid (JA), Salicylic Acid (SA), Pectobacterium carotovorum subsp. carotovorum (Pcc), low temperature, drought, and Salt stresses, we analyzed RNA-seq data and performed RT-qPCR assays. Our results indicated that these genes exhibited tissue-specific expression and diverse responses to biotic and abiotic stresses. Specifically, AkGRAS07, AkGRAS09, and AkGRAS19 expression were upregulated under Pcc infection. AkGRAS19, AkGRAS34, AkGRAS38, and AkGRAS39 were upregulated in response to low-temperature stress. Additionally, AkGRAS09, AkGRAS19, AkGRAS34, and AkGRAS38 were highly induced by drought stress. Notably, AkGRAS23 and AkGRAS53 showed markedly higher expression levels under the 21-day natural drought treatment compared to other conditions. Furthermore, AkGRAS07, AkGRAS09, AkGRAS19, AkGRAS34 and AkGRAS38 were strongly upregulated under 24 h salt treatment.

conclusionsThis study identified candidate GRAS genes in A. konjac that may play crucial roles in biotic and abiotic stress responses. The findings provide a theoretical foundation for further research on the functions of AkGRAS genes and their underlying mechanisms in A. konjac stress tolerance.