Transcriptome Analysis of Lilium Siberian Induced by Melatonin and LoERF96 Gene Cloning

Purpose To study the molecular regulatory mechanism of the germination stage of Lilium Siberian, and to screen the potential ethylene response factor (ERF) that responds to melatonin to promote the germination of Lilium Siberian.

Methods Transcriptome sequencing analysis was performed on the samples of Lilium Siberian bulblets under melatonin treatment during the critical period, and the differentially expressed genes were functionally annotated, screening the potential ERF genes that respond to melatonin to promote the germination of lily bulblets. The screened key gene LoERF96 was cloned and bioinformatically analyzed, and the expression of LoERF96 gene was quantified by RT-qPCR in four different growth and development periods of small bulbs.

Results According to the transcriptome data, 780 differential expressed genes were obtained, including 392 up-regulated genes and 388 down-regulated genes. The results of GO enrichment analysis showed that: the biological processes of enriched differential genes included metabolic processes, cellular processes, biological regulation, stimulus response, signaling, reproductive process, and so on. KEGG metabolic pathway analysis showed that: the metabolic pathways of the differential genes included plant hormone signal transduction, plant MAPK signaling pathway, phenylpropanoid biosynthesis, starch and sucrose metabolism, photosynthesis, carbon metabolism, protein processing in endoplasmic reticulum, and so on. The LoERF96 gene was obtained by homologous cloning, the full-length sequence of the gene was 435 bp, encoding 144 amino acids, with one AP2 conserved structural domain, the relative molecular weight of the protein was about 16.32 ku, and the theoretical isoelectric point was 4.94; it was a hydrophilic protein with no transmembrane structure, and the subcellular localization was predicted to be in nucleus. RT-qPCR results showed that: in the four different growth and development periods of lily, the relative expression level of LoERF96 gene showed a general trend of first increase and then decrease.

Conclusion The expression of ethylene response factor LoERF96 in Lilium Siberian is regulated by melatonin, which provides a theoretical basis and reference for exploring the biological functions of the lily AP2/ERF transcription factor during the germination phase.