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Summary: Cananga odorata is known as a natural perfume tree of the Annonaceae family in Magnoliales. However, its phylogenetic position and the molecular mechanisms involved in the biosynthesis of the floral volatile organic compounds (VOCs) remain unclear.Here, by combining a variety of sequencing platforms, we present a telomere‐to‐telomere (T2T) genome of C. odorata with 735.83 Mb, which represents the highest integrity and assembly quality of genome in magnoliid plants reported to date. Phylogenetic analysis based on multiple datasets and approaches showed that C. odorata, as a member of magnoliids, is sister to eudicots, after their divergence from monocots.Metabolomic of VOCs in the essential oil and flowers scent showed that sesquiterpenes, especially β‐caryophyllene, were the major compounds. Two CoTPS21 homologues derived from tandem duplication events were highly expressed during flower development and were identified as the key sesquiterpene synthases for the production of β‐caryophyllene. In addition, CoSPL3 and CoSPL9 were considered as potential transcription factors for activating the expression of CoTPS21 homologues.Our results shed light on the molecular mechanisms underlying the biosynthesis of the unique floral fragrance in C. odorata and provide new insights into the phylogenetic position of magnoliids. [ABSTRACT FROM AUTHOR]

In flowering plants, sexual reproductive success depends on the production of viable pollen grains. However, the mechanisms by which QUA QUINE STARCH (QQS) regulates pollen development and how transcriptional activators facilitate the transcription of QQS in this process remain poorly understood. Here, we demonstrate that INDUCER OF CBF EXPRESSION 1 (ICE1), a basic helix–loop–helix (bHLH) transcription factor, acts as a key transcriptional activator and positively regulates QQS expression to increase pollen germination and viability in Arabidopsis thaliana by interacting with INDETERMINATE DOMAIN14 (IDD14). In our genetic and biochemical experiments, overexpression of ICE1 greatly promoted both the activation of QQS and high pollen viability mediated by QQS. IDD14 additively enhanced ICE1 function by promoting the binding of ICE1 to the QQS promoter. In addition, mutation of ICE1 significantly repressed QQS expression; the impaired function of QQS and the abnormal anther dehiscence jointly affected pollen development of the ice1‐2 mutant. Our results also showed that the enhancement of pollen activity by ICE1 depends on QQS. Furthermore, QQS interacted with CUT1, the key enzyme for long‐chain lipid biosynthesis. This interaction both promoted CUT1 activity and regulated pollen lipid metabolism, ultimately determining pollen hydration and fertility. Our results not only provide new insights into the key function of QQS in promoting pollen development by regulating pollen lipid metabolism, but also elucidate the mechanism that facilitates the transcription of QQS in this vital developmental process. [ABSTRACT FROM AUTHOR]