Preliminary analysis of the mechanism of ethylene response factor LIERF12 regulating bulbil formation in Lilium lancifolium
To explore the effect of ethylene on bulbil formation of Lilium lancifolium,the stem segment of Lilium lancifolium was treated with different concentrations of ethephon(ETH)and ethylene signal transduction inhibitor 1-methylcyclopropene(1-MCP).The phenotypic statistics,physiological index determination and downstream gene expression analysis were carried out.The ethylene responsive factor LIERF12 that may be involved in the regulation of bulbil formation was screened by using transcriptome data of L.lancifolium bulbil formation process.Bioinformatics software was used to analyze and predict its biochemical characteristics.The expression of LIERF12 gene in different periods,different tissues,different lily varieties and different concentrations of ETH and 1-MCP treatment was detected by real-time fluorescence quantification.Finally,the role of LIERF12 in the process of bulbil formation of L.lancifolium was verified by VIGS technology.The results showed that:1)The development process of L.lancifolium bulbils was divided into four periods,which were S0,S1,S2,and S3;2)1-MCP treatment increased the glucose content in leaf axils and promoted the number of bulbils by promoting the expression of axillary bud marker gene LISTM(SHOOTMERISTEMLESS),while ETH treatment reduced the number of bulbils by inhibiting the expression of LISTM.3)The expression level of LIERF12 was higher in the period of bulbil preparation,and the expression level of LIERF12 in lily varieties with natural bulbils was significantly higher than in other lily varieties.4)ETH treatment significantly inhibited the expression of LIERF12,while 1-MCP treatment was the opposite.5)Silencing the LIERF12 gene resulted in a decrease in the expression of LISTM,which further inhibited the number of bulbils of L.lancifolium,demonstrating the positive regulatory role of LIERF12 in the process of bulbil formation.In summary,LIERF12 promotes the accumulation of glucose in leaf axils and affects the expression of the downstream axillary bud marker gene LISTM by responding to ethylene signal transduction,thereby regulating the formation of bulbils of L.lancifolium.