Metabolic profiles and morphological characteristics of leaf tips among different sweet potato(Ipomoea batatas Lam.)varieties

Sweet potato leaf tips have high nutritional value,and exploring the differences in the metabolic profiles of leaf tips among different sweet potato varieties can provide information to improve their qualities.In this study,a UPLC-Q-Exactive Orbitrap/MS-based untargeted metabolomics method was used to evaluate the metabolites in leaf tips of 32 sweet potato varieties.Three varieties with distinct overall metabolic profiles(A01,A02,and A03),two varieties with distinct profiles of phenolic acids(A20 and A18),and three varieties with distinct profiles of flavonoids(A05,A12,and A16)were identified.In addition,a total of 163 and 29 differentially expressed metabolites correlated with the color and leaf shape of sweet potato leaf tips,respectively,were identified through morphological characterization.Group comparison analysis of the phenotypic traits and a metabolite-phenotypic trait correlation analysis indicated that the color differences of sweet potato leaf tips were markedly associated with flavonoids.Also,the level of polyphenols was correlated with the leaf shape of sweet potato leaf tips,with lobed leaf types having higher levels of polyphenols than the entire leaf types.The findings on the metabolic profiles and differentially expressed metabolites associated with the morphology of sweet potato leaf tips can provide useful information for breeding sweet potato varieties with higher nutritional value.

A high-quality genome assembly of Morinda officinalis,a famous native southern herb in the Lingnan region of southern China

Morinda officinalis is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of southern China.Its dried roots(called bajitian in traditional Chinese medicine)are broadly used to treat various diseases,such as impotence and rheumatism.Here,we report a high-quality chromosome-scale genome assembly of M.officinalis using Nanopore single-molecule sequencing and Hi-C technology.The assembled genome size was 484.85Mb with a scaffold N50 of 40.97 Mb,and 90.77%of the assembled sequences were anchored on eleven pseudochromosomes.The genome includes 27,698 protein-coding genes,and most of the assemblies are repetitive sequences.Genome evolution analysis revealed that M.officinalis underwent core eudicotγgenome triplication events but no recent whole-genome duplication(WGD).Likewise,comparative genomic analysis showed no large-scale structural variation after species divergence between M.officinalis and Coffea canephora.Moreover,gene family analysis indicated that gene families associated with plant–pathogen interactions and sugar metabolism were significantly expanded in M.officinalis.Furthermore,we identified many candidate genes involved in the biosynthesis of major active components such as anthraquinones,iridoids and polysaccharides.In addition,we also found that the DHQS,GGPPS,TPS-Clin,TPS04,sacA,and UGDH gene families—which include the critical genes for active component biosynthesis—were expanded in M.officinalis.This study provides a valuable resource for understanding M.officinalis genome evolution and active component biosynthesis.This work will facilitate genetic improvement and molecular breeding of this commercially important plant.

Gap-free genome assembly and comparative analysis reveal the evolution and anthocyanin accumulation mechanism of Rhodomyrtus tomentosa

Rhodomyrtus tomentosa is an important f leshy-fruited tree and a well-known medicinal plant of the Myrtaceae family that is widely cultivated in tropical and subtropical areas of the world.However,studies on the evolution and genomic breeding of R.tomentosa were hindered by the lack of a reference genome.Here,we presented a chromosome-level gap-free T2T genome assembly of R.tomentosa using PacBio and ONT long read sequencing.We assembled the genome with size of 470.35 Mb and contig N50 of∼43.80 Mb with 11 pseudochromosomes.A total of 33382 genes and 239.31 Mb of repetitive sequences were annotated in this genome.Phylogenetic analysis elucidated the independent evolution of R.tomentosa starting from 14.37MYA and shared a recent WGD event with other Myrtaceae species.We identified four major compounds of anthocyanins and their synthetic pathways in R.tomentosa.Comparative genomic and gene expression analysis suggested the coloring and high anthocyanin accumulation in R.tomentosa tends to be determined by the activation of anthocyanin synthesis pathway.The positive selection and up-regulation of MYB transcription factors were the implicit factors in this process.The copy number increase of downstream anthocyanin transport-related OMT and GST gene were also detected in R.tomentosa.Expression analysis and pathway identification enriched the importance of starch degradation,response to stimuli,effect of hormones,and cell wall metabolism during the f leshy fruit development in Myrtaceae.Our genome assembly provided a foundation for investigating the origins and differentiation of Myrtaceae species and accelerated the genetic improvement of R.tomentosa.

一株地膜降解真菌的筛选及其降解性能分析

【目的】分离并鉴定具有聚乙烯材料降解能力的微生物菌株,探究其降解农用地膜的效能,为地膜的微生物降解途径提供支撑。【方法】以线性低密度聚乙烯粉末为唯一碳源的培养物中分离出1株具有降解聚乙烯材料能力的真菌,利用分子生物学方法结合菌株的培养性状对该菌株进行鉴定,通过观察聚乙烯粉末降解情况和测定地膜失重率,结合红外扫描、高分辨场发射扫描电子显微镜分析该菌株对农用地膜的降解效果。【结果】筛选获得1株具有农用地膜降解效果的真菌菌株PT1,经鉴定为桔青霉(Penicillium citrinum),桔青霉PT1菌株能以重均分子量(Mw)2000和400000的聚乙烯粉末作为唯一碳源生长,经红外扫描、电镜观察发现桔青霉PT1可侵蚀传统聚乙烯地膜。桔青霉PT1能快速利用聚酯类生物降解地膜生长,35 d地膜失重率达50%左右。【结论】本文筛选到具有地膜降解特性的桔青霉PT1真菌,丰富了降解聚乙烯材料的微生物类群,同时也为废弃农用地膜的处理提供了环保的处理途径。