Whole-genome identification of GRAS family and their potential roles in high-temperature stress of lettuce

Abstract

Abstract Lettuce is one of the most popular leafy vegetables in the world, but it is prone to high-temperature stress in the cultivation process leading to bolting, which affects the yield. The plant-specific transcription factors, GRAS proteins, play an important role which regulates plant growth development and abiotic stress. However, there is no comprehensive study of the GRAS gene family in lettuce. In this study, the complete LsGRAS genome was identified its expression was analyzed. The results showed that the 59 LsGRAS genes were classified phylogenetically divided into 4 conserved subfamilies and distributed unevenly on 9 chromosomes, with 50% physically adjacent to at least one another and 100% localized on the nucleus. Chromosome localization and gene structure analysis suggested that duplication events and a large number presence of intronless genes might be the reason why the LsGRAS gene family expands massively. Combined with gene annotation and interaction network analysis, the expression pattern of the LsGRAS gene under high-temperature treatment was analyzed, revealing the potential different functions of the LsGRAS gene under high-temperature stress. In conclusion, this study provides valuable information and candidate genes for improving the ability of lettuce to tolerate high-temperature stress.