Genome-Wide Identification of GRAS Gene Family in Cunninghamia lanceolata and Expression Pattern Analysis of ClDELLA Protein Under Abiotic Stresses

Abstract

The Chinese fir (Cunninghamia lanceolata) is a significant species utilized in afforestation efforts in southern China. It is distinguished by its rapid growth and adaptability to diverse environmental conditions. The GRAS gene family comprises a group of plant-specific transcription factors that play a pivotal role in plant growth and development, response to adversity, and hormone regulatory networks. However, the exploration of the GRAS family in gymnosperm Chinese fir has not yet begun. In this study, a total of 43 GRAS genes were identified in the whole genome of Chinese fir, and a phylogenetic analysis classified them into nine distinct subfamilies. Gene structure analysis revealed that the majority of ClGRAS genes lacked introns. It is notable that among these proteins, both ClGAI and ClGRA possess distinctive DELLA structural domains. Cis-acting element analysis revealed that nearly all ClGRAS genes contained light-responsive elements, while hormone-responsive elements, environmental-responsive elements (low-temperature- or defense-responsive elements), and meristem-organization-related elements were also identified. Based on transcriptome data and RT-qPCR expression patterns, we analyzed the expression of ClGAI and ClRGA genes across different developmental stages, hormones, and three abiotic stresses. Subcellular localization analysis demonstrated that ClGAI and ClRGA were localized to the nucleus. Transcriptional activation assays showed that both genes have self-activating activity. In conclusion, the results of this study indicate that the ClGRAS gene family is involved in the response of Chinese fir to environmental stress. Further research on the ClDELLA genes provides valuable information for exploring the potential regulatory network of DELLA proteins in Chinese fir.