Molecular mechanisms of flowering time differentiation revealed by transcriptomic sequencing and de novo analysis in Chinese invasive populations of Ambrosia artemisiifolia

Abstract BackgroundAmbrosia artemisiifolia is a highly invasive species with a notorious reputation for its deleterious effects on both public health and agricultural systems. Previous research has demonstrated that flowering time varies latitudinally along a cline and this may have significant implications for local adaptation and the successful invasion of A. artemisiifolia in China. However, the molecular mechanisms underlying variation in flowering time in this species remains poorly understood. In this study, a common garden experiment and transcriptome analysis were performed using different populations of A. artemisiifolia that originated from diverse locations across a latitudinal gradient in China. Results Our study confirmed the presence of a latitudinal cline in the flowering time of A. artemisiifolia.Transcriptome comparisons identified substantial variation in gene expression among populations exhibiting different flowering time, with a greater abundance of differentially expressed genes (DEGs) observed between populations spanning wider latitudinal ranges. The functional annotation results revealed the involvement of light, sugar, vernalization and autonomous pathways in the modulation of flowering time variation among populations. Furthermore, a comprehensive set of DEGs encompassed various transcription factors (TFs) associated with flowering time regulation, including WRKY, AP2/ERF, bZIP, C2H2, bHLH, NAC and MYB-related TFs. Several candidate genes associated with variation in flowering time variation were identified. CO, GAI, FES1and FD function as promoters of flowering induction, while LFY, FVE, FLKand SVP act as inhibitors of flowering initiation in A. artemisiifolia. Several previously uncharacterized unigenes, involved in the regulation of flowering time in A. artemisiifolia, were also been identified. Conclusions The findings in this study suggest that the differentiation of flowering time in A. artemisiifolia is collectively influenced by numerous genes involved in the photoperiodic, vernalization, gibberellin, temperature, sugar and autonomous pathways. The elucidation of the molecular mechanisms underlying the differentiation of flowering time will significantly advance our understanding of the factors facilitating the successful invasion of A. artemisiifolia in China.