The adaptive evolution of Euryale ferox to the aquatic environment through paleo‐hexaploidization

Abstract

Occupation of living space is one of the main driving forces of adaptive evolution, especially for aquatic plants whose leaves float on the water surface and thus have limited living space. Euryale ferox, from the angiosperm basal family Nymphaeaceae, develops large, rapidly expanding leaves to compete for space on the water surface. Microscopic observation found that the cell proliferation of leaves is almost completed underwater, while the cell expansion occurs rapidly after they grow above water. To explore the mechanism underlying the specific development of leaves, we performed sequences assembly and analyzed the genome and transcriptome dynamics of E. ferox. Through reconstruction of the three sub-genomes generated from the paleo-hexaploidization event in E. ferox, we revealed that one sub-genome was phylogenetically closer to Victoria cruziana, which also exhibits gigantic floating leaves. Further analysis revealed that while all three sub-genomes promoted the evolution of the specific leaf development in E. ferox, the genes from the sub-genome closer to V. cruziana contributed more to this adaptive evolution. Moreover, we found that genes involved in cell proliferation and expansion, photosynthesis, and energy transportation were overretained and showed strong expression association with the leaf development stages, such as the expression divergence of SWEET orthologs as energy uploaders and unloaders in the sink and source leaf organs of E. ferox. These findings provide novel insights into the genome evolution through polyploidization, as well as the adaptive evolution regarding the leaf development accomplished through biased gene retention and expression sub-functionalization of multi-copy genes in E. ferox.

EfABI4 Transcription Factor Is Involved in the Regulation of Starch Biosynthesis in Euryale ferox Salisb Seeds

“…The filtered sequenced sequence was compared with the reference genome E. ferox . Trinity software was used for a series of sequence assembly of high-quality sequencing data, and long and high-quality transcripts were obtained for subsequent research and analysis [ 54 ].…”

Once, twice, three times a genome – how the three sub‐genomes of a water lily control leaf development

“…AKE, ancestral karyotype of E. ferox . Figure adapted from Wu et al., 2022. [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…Analysis of these genome sequences showed that E. ferox has undergone an ancient allo-hexaploidization event that N. colorata has not. In this issue, Peng Wu and colleagues investigated this genome triplication and tried to understand how it contributed to the development of leaves in E. ferox (Wu et al, 2022). Most water lilies, including N. colorata, develop relatively small leaves; however, E. ferox develops gigantic prickly floating leaves that can grow up to 2 m in diameter, much like the leaves of the Santa Cruz waterlily (Victoria cruziana), a popular water plant in botanical gardens.…”

Molecular identification of phenylalanine ammonia lyase-encoding genes EfPALs and EfPAL2-interacting transcription factors in Euryale ferox

“…Euryale ferox, belonging to the Nymphaeaceae and genus Euryale, is a characteristic aquatic vegetable and has become recognized as a health food (Wu et al, 2022b). It has the effect of tonifying kidney, tonifying spleen (Song et al, 2011;Sun et al, 2014).…”