Expression Profiling of Heat Shock Protein Genes as Putative Early Heat-Responsive Members in Lettuce

• Main Authors: Yeeun Kang, Suk-Woo Jang, Hee Ju Lee, Derek W. Barchenger, Seonghoe Jang
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Horticulturae
• Subjects: heat shock proteins; heat stress; lettuce; qRT-PCR; transcriptome sequencing
• Online Access: https://www.mdpi.com/2311-7524/7/9/312

High temperatures due to global warming can cause harmful effects on the productivity of lettuce, a cool-season crop. To identify lettuce <i>heat shock protein</i> (<i>HSP</i>) genes that could be involved in early responses to heat stress in plants, we compared RNA transcriptomes between lettuce plants with and without heat treatment of 37 °C for 1 h. Using transcriptome sequencing analyses, a total of 7986 differentially expressed genes (DEGs) were identified including the top five, <i>LsHSP70A</i>, <i>LsHSP70B</i>, <i>LsHSP17.3A</i>, <i>LsHSP17.9A</i> and <i>LsHSP17.9B,</i> which were the most highly differentially expressed genes. In order to investigate the temporal expression patterns of 24 lettuce <i>HSP</i> genes with a fold-change greater than 100 under heat stress, the expression levels of the genes were measured by qRT-PCR at 0, 1, 4, 8, 14, and 24 h time points after heat treatment. The 24 <i>LsHSP</i> genes were classified into three groups based on the phylogenetic analysis and/or major domains available in each protein, and we provided a potential link between the phylogenetic relationships and expression patterns of the <i>LsHSP</i> genes. Our results showed putative early heat-responsive lettuce <i>HSP</i> genes that could be possible candidates as breeding guides for the development of heat-tolerant lettuce cultivars.