Polygonatum kingianum Coll.et Hemsl is a kind of perennial herb, whose rhizome bud will get into endo-dormancy stage when it extends to 3～6 mm. Here, we found that rhizome buds chilling-treated at 3～6.5 ℃ for at least 30 days began to grow and chilling-treatment for 90 days would release buds’ endo-dormancy completely. The following chilling-treatment would induce the rhizome bud enter into eco-dormancy. Transmission electron microscopy showed that obvious changes occurred in the bud cell wall and plasmodesmata between endo- and eco-dormant buds. HPLC-MS analysis showed reduced ABA/GA3 and IAA level but increased tZR level from endo- to non-dormancy transition. To explore rhizome bud dormancy transition mechanism, transcriptomes of endo-, eco- and non-dormant buds were analyzed. A total of 95462 differentially expressed genes were discovered. Clustering and principal component analysis confirmed different physiological status of these three kinds of bud samples. Abundance changes of transcripts associated with IAA, ZR, GA, ABA, BR, JA, ethylene, SA, cell wall loosening factors and plasmodesmata were analyzed during bud dormancy transition in P. kingianum, furthermore, gene co-expression of these genes identified NIT4 and TSA1, two genes related to IAA synthesis, as hub genes of the network, in addition, strong interactions within plant hormones or between hormones and cell wall-related factors were discovered. Therefore, during bud dormancy transition induced by temperature, we hypothesis a regulating model where IAA, through two genes TSA1 and NIT4, regulates other plant hormones involving synthesis, signaling transduction or transport, and then, genes related to cell wall could be regulated.
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