Shuangxi Fan’s research while affiliated with Xinjiang Agricultural University and other places

Lettuce is susceptible to high-temperature stress during cultivation, leading to bolting and affecting yield. Plant-specific transcription factors, known as GRAS proteins, play a crucial role in regulating plant growth, development, and abiotic stress responses. In this study, the entire lettuce LsGRAS gene family was identified. The results show that 59 LsGRAS genes are unevenly distributed across the nine chromosomes. Additionally, all LsGRAS proteins showed 100% nuclear localization based on the predicted subcellular localization and were phylogenetically classified into nine conserved subfamilies. To investigate the expression profiles of these genes in lettuce, we analyzed the transcription levels of all 59 LsGRAS genes in the publicly available RNA-seq data under the high-temperature treatment conducted in the presence of exogenous melatonin. The findings indicate that the transcript levels of the LsGRAS13 gene were higher on days 6, 9, 15, 18, and 27 under the high-temperature (35/30 °C) treatment with melatonin than on the same treatment days without melatonin. The functional studies demonstrate that silencing LsGRAS13 accelerated bolting in lettuce. Furthermore, the paraffin sectioning results showed that flower bud differentiation in LsGRAS13-silenced plants occurred significantly faster than in control plants. In this study, the LsGRAS genes were annotated and analyzed, and the expression pattern of the LsGRAS gene following melatonin treatment under high-temperature conditions was explored. This exploration provides valuable information and identifies candidate genes associated with the response mechanism of lettuce plants high-temperature stress.

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.