WITHDRAWN: Transcriptome and targeted metabolome reveal the regulation network of Lilium davidii var. unicolor during dormancy release

Abstract

Background：Regulation and control of bulb dormancy are critical for ensuring annual production and high-level cultivation of lily. Application of low temperatures is the most effective method for breaking lily bulb dormancy, but the molecular regulatory mechanism underlying this response is unclear. Results：Herein, targeted metabolome and transcriptome analyses were performed with buds of Lilium davidii var. unicolor bulbs stored for 0, 50 and 100 days at 4°C. Dormancy release mainly depended on the accumulation of GA4 and GA7, which are synthesized by the "non13-hydroxylation" pathway, rather than GA3, and ABA was degraded in the process. The contents of nonbioactive GA9, GA15 and GA24, the precursors of GA4 synthesis, increased with bulb dormancy release. Altogether, 113,252 unique transcripts were de novo assembled through high-throughput transcriptome sequences, and 639 genes were continuously differentially expressed. Enrichment analysis showed that the carbohydrate metabolism and hormone metabolism pathways play major roles in dormancy release. Energy sources during carbohydrate metabolism mainly depend on glycolysis and the PPP pathway rather than on the TCA cycle. Association analysis of the transcriptome and target metabolome showed that genes related to ABA, GA, starch and sucrose metabolism and some TF families, such as MYB, WRKY, NAC and TCP, involved in dormancy release were highly correlated with the target metabolome. Coexpression analysis further confirmed that ABI5, PYL8, PYL4 and PP2C, vital ABA signaling elements, regulated GA3ox and GA20ox in the GA4 biosynthesis pathway. The TFs WRKY32, WRKY71, MYB, DAM14, NAC8, ICE1, bHLH93 and TCP15 also participated in the ABA/GA4 regulatory network, and ICE1 may be the key factor linking temperature signals and hormone metabolism. Conclusions：These results will help to reveal the bulb dormancy molecular mechanism and to develop new strategies for high-quality bulb production.