Transcriptome Analysis of Sponge Gourd (Luffa cylindrica) Reveals Candidate Genes Associated with Fruit Size

Abstract

Sponge gourd belongs to the Cucurbitaceae family and Luffa genus. It is an economically valuable vegetable crop with medicinal properties. The fruit size of sponge gourd presents distinct diversity; however, the molecular insights of fruit size regulation remain uncharacterized. Therefore, two sponge gourd materials with distinct fruit sizes were selected for a comparative transcriptome analysis. A total of 1390 genes were detected as differentially expressed between long sponge gourd (LSG) and short sponge gourd (SSG) samples, with 885 downregulated and 505 upregulated in SSG compared with LSG. KEGG pathway enrichment analysis revealed that the MAPK signaling pathway, biosynthesis of secondary metabolites, and plant hormone signal transduction were significantly enriched. The DEGs involved in the cell cycle and cell division, plant hormone metabolism, and MAPK signal transduction were crucial for sponge gourd fruit size regulation. Additionally, the transcription factor families of ERF, NAC, bHLH, MYB, WRKY, and MADS-box were associated with fruit size regulation. The qRT-PCR validation for selected DEGs were generally consistent with the RNA-Seq results. These results obtained the candidate genes and pathways associated with fruit size and lay the foundation for revealing the molecular mechanisms of fruit size regulation in sponge gourd.