Annotated genome sequences of the carnivorous plant Roridula gorgonias and a non-carnivorous relative, Clethra arborea

Molecular Phylogenomics Reveals the Deep Evolutionary History of Carnivory across Land Plants

Plastid molecular phylogenies that broadly sampled angiosperm lineages imply that carnivorous plants evolved at least 11 times independently in 13 families and 6 orders. Within and between these clades, the different prey capture strategies involving flypaper and pitfall structures arose in parallel with the subsequent evolution of snap traps and suction bladders. Attempts to discern the deep ontological history of carnivorous structures using multigene phylogenies have provided a plastid-level picture of sister relationships at the family level. Here, we present a molecular phylogeny of the angiosperms based on nuclear target sequence capture data (Angiosperms-353 probe set), assembled by the Kew Plant Trees of Life initiative, which aims to complete the tree of life for plants. This phylogeny encompasses all carnivorous and protocarnivorous families, although certain genera such as Philcoxia (Plantaginaceae) are excluded. This study offers a novel nuclear gene-based overview of relationships within and between carnivorous families and genera. Consistent with previous broadly sampled studies, we found that most carnivorous families are not affiliated with any single family. Instead, they emerge as sister groups to large clades comprising multiple non-carnivorous families. Additionally, we explore recent genomic studies across various carnivorous clades that examine the evolution of the carnivorous syndrome in relation to whole-genome duplication, subgenome dominance, small-scale gene duplication, and convergent evolution. Furthermore, we discuss insights into genome size evolution through the lens of carnivorous plant genomes.

Draft genome and transcriptome of Nepenthes mirabilis, a carnivorous plant in China

OBJECTIVES

Nepenthes belongs to the monotypic family Nepenthaceae, one of the largest carnivorous plant families. Nepenthes species show impressive adaptive radiation and suffer from being overexploited in nature. Nepenthes mirabilis is the most widely distributed species and the only Nepenthes species that is naturally distributed within China. Herein, we reported the genome and transcriptome assemblies of N. mirabilis. The assemblies will be useful resources for comparative genomics, to understand the adaptation and conservation of carnivorous species.

DATA DESCRIPTION

This work produced ~ 139.5 Gb N. mirabilis whole genome sequencing reads using leaf tissues, and ~ 21.7 Gb and ~ 27.9 Gb of raw RNA-seq reads for its leaves and flowers, respectively. Transcriptome assembly obtained 339,802 transcripts, in which 79,758 open reading frames (ORFs) were identified. Function analysis indicated that these ORFs were mainly associated with proteolysis and DNA integration. The assembled genome was 691,409,685 bp with 159,555 contigs/scaffolds and an N50 of 10,307 bp. The BUSCO assessment of the assembled genome and transcriptome indicated 91.1% and 93.7% completeness, respectively. A total of 42,961 genes were predicted in the genome identified, coding for 45,461 proteins. The predicted genes were annotated using multiple databases, facilitating future functional analyses of them. This is the first genome report on the Nepenthaceae family.

The Chromosome-Level Genome of Miracle Fruit (Synsepalum dulcificum) Provides New Insights Into the Evolution and Function of Miraculin

Miracle fruit (Synsepalum dulcificum) is a rare valuable tropical plant famous for a miraculous sweetening glycoprotein, miraculin, which can modify sour flavors to sweet flavors tasted by humans. Here, we present a chromosome-level high-quality genome of S. dulcificum with an assembly genome size of ∼550 Mb, contig N50 of ∼14.14 Mb, and 37,911 annotated protein-coding genes. Phylogenetic analysis revealed that S. dulcificum was most closely related to Camellia sinensis and Diospyros oleifera, and that S. dulcificum diverged from the Diospyros genus ∼75.8 million years ago (MYA), and that C. sinensis diverged from Synsepalum ∼63.5 MYA. Ks assessment and collinearity analysis with S. dulcificum and other species suggested that a whole-genome duplication (WGD) event occurred in S. dulcificum and that there was good collinearity between S. dulcificum and Vitis vinifera. On the other hand, transcriptome and metabolism analysis with six tissues containing three developmental stages of fleshes and seeds of miracle fruit revealed that Gene Ontology (GO) terms and metabolic pathways of "cellular response to chitin," "plant-pathogen interaction," and "plant hormone signal transduction" were significantly enriched during fruit development. Interestingly, the expression of miraculin (Chr10G0299340) progressively increased from vegetative organs to reproductive organs and reached an incredible level in mature fruit flesh, with an fragments per kilobase of transcript per million (FPKM) value of ∼113,515, which was the most highly expressed gene among all detected genes. Combining the unique signal peptide and the presence of the histidine-30 residue together composed the main potential factors impacting miraculin's unique properties in S. dulcificum. Furthermore, integrated analysis of weighted gene coexpression network analysis (WGCNA), enrichment and metabolite correlation suggested that miraculin plays potential roles in regulating plant growth, seed germination and maturation, resisting pathogen infection, and environmental pressure. In summary, valuable genomic, transcriptomic, and metabolic resources provided in this study will promote the utilization of S. dulcificum and in-depth research on species in the Sapotaceae family.