A chromosome‐level genome of Syringa oblata provides new insights into chromosome formation in Oleaceae and evolutionary history of lilacs

Abstract

Lilacs (Syringa L.), a group of well-known ornamental and aromatic woody plants, have long been used for gardening, essential oils and medicine purposes in East Asia and Europe. The lack of knowledge about the complete genome of Syringa not only hampers effort to better understand its evolutionary history, but also prevents genome-based functional gene mining that can help in the variety improvement and medicine development. Here, a chromosome-level genome of Syringa oblata is presented, which has a size of 1.12 Gb including 53 944 protein coding genes. Synteny analysis revealed that a recent duplication event and parallel evolution of two subgenomes formed the current karyotype. Evolutionary analysis, transcriptomics and metabolic profiling showed that segment and tandem duplications contributed to scent formation in the woody aromatic species. Moreover, phylogenetic analysis indicated that S. oblata shared a common ancestor with Osmanthus fragrans and Olea europaea approximately 27.61 million years ago (Mya). Biogeographic reconstruction based on a resequenced data set of 26 species suggested that Syringa originated in the northern part of East Asia during the Miocene (approximately 14.73 Mya) and that the five Syringa groups initially formed before the Late Miocene (approximately 9.97 Mya). Furthermore, multidirectional dispersals accompanied by gene introgression among Syringa species from Northern China during the Miocene were detected by biogeographic reconstruction. Taken together, the results showed that complex gene introgression, which occurred during speciation history, greatly contributed to Syringa diversity.

Reticulate evolution of the tertiary relict Osmanthus

“…For example, Forsythia originated in eastern China 16.6 Ma ago, then dispersed westward during the Late Miocene eventually reaching Europe (Ha et al., 2018); Syringa originated in northeastern China about 14.73 Ma ago. Five main groups of the genus were formed about 9.97 Ma ago and spread in several directions including toward Japan, Central Asia, and Europe (Wang, Lu, et al., 2022). Considering the fruit type of the Oleaceae i.e.…”

Syringa oblata genome provides new insights into molecular mechanism of flower color differences among individuals and biosynthesis of its flower volatiles

“…Depending on the structure, plant floral volatiles can be divided into three main groups: terpenoids, phenylpropanoids/benzenoids and fatty acids ( Muhlemann et al., 2014 ), and previous studies indicated that terpenes were the main components of S. oblata volatiles ( Li et al., 2006 ; Gegen et al., 2022 ; Wang et al., 2022 ). Lilac aldehyde and lilac alcohol were the main volatiles of the S. oblata flowers found in our study which were oxygenated derivatives of the monoterpenoid linalool ( Kreck et al., 2003 ; Boachon et al., 2015 ).…”

“…S. oblata has a strong floral fragrance, and previous studies have revealed that the main volatiles of its flowers are terpenoids such as lilac aldehyde, lilac alcohol, α-pinene, sabinene and β-pinene ( Li et al., 2006 ; Gegen et al., 2022 ; Wang et al., 2022 ), while terpene synthase (TPS) is the pivotal gene family for the biosynthesis of plant terpenes ( Chen et al., 2011 ). Plant secondary metabolites usually require post-modification processes to produce biologically active metabolites ( Li et al, 2009 ) and many S. oblata flower volatiles undergo post-modification processes, such as lilac aldehyde and lilac alcohol, which are oxygenated derivatives of linalool formed through the catalysis of cytochrome P450 ( Raguso, 2016 ).…”

The Ethanol Extract of Syringa oblata Heartwood, a Mongolian Folk Medicine Containing Major Lignans, Exerts Analgesic and Sedative Effects on Mice

“…It's native to Southwest China and widely distributed in Southwest China, North China, and the middle latitudes of Eurasia and North America. [1] Besides its high ornamental value, SO has been used in both traditional Chinese medicine (TCM) and Mongolian folk medicine (MFM). According to the theory of Chinese medicine, the medicinal parts of SO include the leaves, buds, flowers, branches, and bark, which have been used to treat hepatitis, intestinal disorders, and diarrhea, whereas the heartwood of SO is used as an MFM for its efficacy of clearing heat and inhibiting the partial prosperity of "Khii" in the theory of traditional Mongolian medicine.…”

“…(SO), also known as lilac, is a well‐known deciduous shrub belonging to the Oleaceae family. It's native to Southwest China and widely distributed in Southwest China, North China, and the middle latitudes of Eurasia and North America [1] . Besides its high ornamental value, SO has been used in both traditional Chinese medicine (TCM) and Mongolian folk medicine (MFM).…”