Chromosome-scale genome assembly provides insights into the evolution and flavor synthesis of passion fruit (Passiflora edulis Sims)

Passion fruit(Passiflora edulis Sims)is an economically valuable fruit that is cultivated in tropical and subtropical regions of the world.Here,we report an~1341.7Mb chromosome-scale genome assembly of passion fruit,with 98.91%(~1327.18Mb)of the assembly assigned to nine pseudochromosomes.The genome includes 23,171 protein-coding genes,and most of the assembled sequences are repetitive sequences,with long-terminal repeats(LTRs)being the most abundant.Phylogenetic analysis revealed that passion fruit diverged after Brassicaceae and before Euphorbiaceae.Ks analysis showed that two whole-genome duplication events occurred in passion fruit at 65 MYA and 12 MYA,which may have contributed to its large genome size.An integrated analysis of genomic,transcriptomic,and metabolomic data showed that‘alpha-linolenic acid metabolism’,‘metabolic pathways’,and‘secondary metabolic pathways’were the main pathways involved in the synthesis of important volatile organic compounds(VOCs)in passion fruit,and this analysis identified some candidate genes,including GDP-fucose Transporter 1-like,Tetratricopeptide repeat protein 33,protein NETWORKED 4B isoform X1,and Golgin Subfamily A member 6-like protein 22.In addition,we identified 13 important gene families in fatty acid pathways and eight important gene families in terpene pathways.Gene family analysis showed that the ACX,ADH,ALDH,and HPL gene families,especially ACX13/14/15/20,ADH13/26/33,ALDH1/4/21,and HPL4/6,were the key genes for ester synthesis,while the TPS gene family,especially PeTPS2/3/4/24,was the key gene family for terpene synthesis.This work provides insights into genome evolution and flavor trait biology and offers valuable resources for the improved cultivation of passion fruit.

Genomics approaches to unlock the high yield potential of cassava,a tropical model plant

Cassava,a tropical food,feed and biofuel crop,has great capacity for biomass accumulation and an extraordinary efficiency in water use and mineral nutrition,which makes it highly suitable as a model plant for tropical crops.However,the understanding of the metabolism and genomics of this important crop is limited.The recent breakthroughs in the genomics of cassava,including whole-genome sequencing and transcriptome analysis,as well as advances in the biology of photosynthesis,starch biosynthesis,adaptation to drought and high temperature,and resistance to virus and bacterial diseases,are reviewed here.Many of the new developments have come from comparative analyses between a wild ancestor and existing cultivars.Finally,the current challenges and future potential of cassava as a model plant are discussed.