Comparative transcriptome analysis of fertile and sterile buds from a genetically male sterile line of Chinese cabbage

In this study, we compared the transcriptome profiles of fertile versus sterile buds of a stably inherited genic male sterile AB line of Chinese cabbage using the Illumina high-throughput sequencing platform. Based on the analysis of gene expression levels, we detected 1013 differentially expressed genes (DEGs), including 907 that were upregulated and 106 that were downregulated in fertile buds. In addition, 481 genes were specifically differentially expressed. Among these, some DEGs were previously shown to play important roles in pollen and anther development, including AMS, MS2, ms35/myb26, and so on. We also performed gene ontology (GO) analysis to reveal the main biological functions of the DEGs. Only 19 GO terms were significantly enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was performed to uncover significantly enriched metabolic pathways and signal transduction pathways involving the DEGs, revealing five significantly enriched KEGG pathways that are pentose and glucuronate interconversions; alanine, aspartate, and glutamate metabolism; cysteine and methionine metabolism; ascorbate and aldarate metabolism; and starch and sucrose metabolism. These results could potentially explain the difference between fertile and sterile buds. Finally, we analyzed the expression patterns of 31 DEGs using qRT-PCR, which verified the reliability of the transcriptome sequencing results. Analysis of the transcriptome data provides valuable information for in-depth analysis of the molecular mechanism underlying pollen development, and it lays the foundation for clarifying the functions of these crucial genes and elucidating the sterility mechanism in Chinese cabbage.