Sacred lotus (Nelumbo nucifera or lotus) is an important aquatic plant in horticulture and ecosystems. As a foundation for exploring genomic variation and evolution among different germplasms, we re‐sequenced 19 individuals from three cultivated temperate lotus subgroups (rhizome, seed and flower lotus), one wild temperate lotus subgroup (wild lotus), one tropical lotus group (Thai lotus) and an outgroup (Nelumbo lutea). Through genetic diversity and polymorphism analysis by non‐missing SNP sites widely distributed in the whole genome, we confirmed that wild and Thai lotus exhibited greater differentiation with a higher genomic diversity compared to cultivated lotus. Rhizome lotus had the lowest genomic diversity and a closer relationship to wild lotus, whereas the genomes of seed and flower lotus were admixed. Genes in energy metabolism process and plant immunity evolved rapidly in lotus, reflecting local adaptation. We established that candidate genes in genomic regions with significant differentiation associated with temperate and tropical lotus divergence always exhibited highly divergent expression pattern. Together, this study comprehensive and credible interpretates important patterns of genetic diversity and relationships, gene evolution, and genomic signature from ecotypic differentiation of sacred lotus.

Monocots are one of the most diverse groups of flowering plants, and tracing the evolution of their ancestral genome into modern species is essential for understanding their evolutionary success. Here, we report a high-quality assembly of the Acorus tatarinowii genome, a species that diverged early from all the other monocots. Genome-wide comparisons with a range of representative monocots characterized Acorus as a slowly evolved genome with one whole-genome duplication. Our inference of the ancestral monocot karyotypes provides new insights into the chromosomal evolutionary history assigned to modern species and reveals the probable molecular functions and processes related to the early adaptation of monocots to wetland or aquatic habitats (that is, low levels of inorganic phosphate, parallel leaf venation and ephemeral primary roots). The evolution of ancestral gene order in monocots is constrained by gene structural and functional features. The newly obtained Acorus genome offers crucial evidence for delineating the origin and diversification of monocots, including grasses.

Sacred lotus (Nelumbo nucifera, or lotus) is one of the most widely grown aquatic plant species with important uses, such as in water gardening and in vegetable and herbal medicine. A public genomic database of lotus would facilitate studies of lotus and other aquatic plant species. Here, we constructed an integrative database: the Nelumbo Genome Database (NGD, http://nelumbo.biocloud.net). This database is a collection of the most updated lotus genome assembly and contains information on both gene expression in different tissues and coexpression networks. In the NGD, we also integrated genetic variants and key traits from our 62 newly sequenced lotus cultivars and 26 previously reported cultivars, which are valuable for lotus germplasm studies. As applications including BLAST, BLAT, Primer, Annotation Search, Variant and Trait Search are deployed, users can perform sequence analyses and gene searches via the NGD. Overall, the valuable genomic resources provided in the NGD will facilitate future studies on population genetics and molecular breeding of lotus.

Flower morphology, a phenomenon regulated by a complex network, is one of the vital ornamental features in Nelumbo nucifera. Stamen petaloid is very prevalent in lotus flowers. However, the mechanism underlying this phenomenon is still obscure. Here, the comparative transcriptomic analysis was performed among petal, stamen petaloid and stamen through RNA-seq. Using pairwise comparison analysis, a large number of genes involved in hormonal signal transduction pathways and transcription factors, especially the MADS-box genes, were identified as candidate genes for stamen petaloid in lotus. Taken together, these results provide an insight into the molecular networks underlying lotus floral organ development and stamen petaloid.

The accurate placement of an ancient whole-genome duplication (WGD) in relation to the lineage divergence is important. Here, we re-investigated the Aquilegia coerulea WGD and found it is more likely lineage-specific rather than shared by all eudicots.