Genome-wide comprehensive characterization and expression analysis of TLP gene family revealed its responses to hormonal and abiotic stresses in watermelon (Citrullus lanatus)

Thaumatin-like protein (TLP) is the well-known sweetest protein which plays a crucial role in diverse devel-opmental processes and different stress conditions in plants, fungi and animals. The TLP gene family is exten-sively studied in different plant species including crop plants. Watermelon (Citrullus lanatus) is an important cucurbit crop cultivated worldwide; however, the comprehensive information about the TLP gene family is not available in watermelon. In the present study, we identified the 29 TLP genes as gene family members in watermelon using various computational methods to understand its role in different developmental processes and stress conditions. ClaTLP gene family members were not uniformly distributed on 22 chromosomes. Phylogenetic analysis revealed that the ClaTLP gene family members were grouped into 10 sub-groups. Further, gene duplication analysis showed thirteen gene duplication events which included one tandem and twelve segmental duplications. Amino acid sequence alignment has shown that ClaTLP proteins shared 16 conserved cysteine residues in their THN domain. Furthermore, cis-acting regulatory elements analysis also displayed that ClaTLP gene family members contain diverse phytohormone, various defense, and stress-responsive elements in their promoter region. The expression profile of the ClaTLP gene family revealed the differential expression of gene family members in different tissues and abiotic stresses conditions. Moreover, the expression profile of ClaTLP genes was further validated by semi-quantitative reverse transcriptase PCR. Taken together, these results indicate that ClaTLP genes might play an important role in developmental processes and diverse stress condi-tions. Therefore, the outcome of this study brings forth the valuable information for further interpret the precise role of ClaTLP gene family members in watermelon.

Automated summary

Thaumatin-like protein (TLP) is a well-known protein that plays important roles in developmental processes and stress conditions in various organisms. In this study, the TLP gene family was identified in watermelon, a significant cucurbit crop, to understand its functions. The genes were found to be unevenly distributed on chromosomes and were grouped into different sub-groups. Gene duplication events were detected, and conserved cysteine residues were identified in the protein sequences. Additionally, diverse regulatory elements were found in the promoter region. Expression analysis revealed tissue-specific and stress-responsive expression patterns. These findings suggest that the TLP genes in watermelon are involved in developmental processes and stress conditions. The results of this study provide valuable information for further investigating the precise roles of TLP genes in watermelon.