Identification of differentially expressed miRNAs between male sterile and fertile floral buds in watermelon (Citrullus lanatus L.) via high-throughput sequencing.

This experiment used floral buds from watermelon genic male sterile dual-purpose lines as materials to explore the differentially expressed miRNAs (DEMs) between male fertile and sterile floral buds of watermelon. Paraffin sectioning technology was employed for a cytological analysis, and small RNA sequencing was used to explore miRNAs related to anther or pollen development. Cytological analysis indicated that the abnormal development of tapetal cells may cause microspore abortion. Small RNA sequencing identified a total of 314 miRNAs (29 known and 285 novel, which belonged to 12 and 61 miRNA families, respectively) in floral buds. Differential expression revealed 36 (5 known and 31 novel) DEMs between male fertile and sterile buds, 7 and 29 of which were up-regulated and down-regulated, respectively. Target genes analysis showed that the 36 DEMs were predicted to target 577 genes, and these targets might participate in various biological processes, such as response to metal ions, floral organ development, stamen development, anther development, pollen maturation, and programmed cell death. Moreover, pathway analysis indicated that these genes were mainly enriched in purine metabolism, starch and sucrose metabolism, RNA transport, and other pathways. In addition, the 55 miRNA-target modules, including 3 known and 16 novel miRNAs with 30 target genes, might be related to anther or pollen development in watermelon. Our findings provide important miRNA-target modules related to watermelon anther or pollen development and can lay the foundation for biological functional analysis.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-024-04084-6.