查看更多>>摘要：Rice(Oryza sativa)provides＞20％of the consumed calories in the human diet.However,rice is also a lead-ing source of dietary cadmium(Cd)that seriously threatens human health.Deciphering the genetic network that underlies the grain-Cd accumulation will benefit the development of low-Cd rice and mitigate the ef-fects of Cd accumulation in the rice grain.In this study,we identified a QTL gene,OsCS1,which is allelic to OsMTP11 and encodes a protein sequestering Cd in the leaf during vegetative growth and preventing Cd from being translocated to the grain after heading in rice.OsCS1 is predominantly expressed in leaf vascular parenchyma cells,where it binds to a vacuole-sorting receptor protein OsVSR2 and is translo-cated intracellularly from the trans-Golgi network to pre-vacuolar compartments and then to the vacuole.In this trafficking process,OsCS1 actively transports Cd into the endomembrane system and sequesters it in the vacuoles.There are natural variations in the promoter of OsCS1 between the indica and japonica rice subspecies.Duplication of a G-box-like motif in the promoter region of the superior allele of OsCS1 from indica rice enhances the binding of the transcription factor OsIRO2 to the OsCS1 promoter,thereby pro-moting OsCS1 expression.Introgression of this allele into commercial rice varieties could significantly lower grain-Cd levels compared to the inferior allele present in japonica rice.Collectively,our findings offer new insights into the genetic control of leaf-to-grain Cd translocation and provide a novel gene and its su-perior allele for the genetic improvement of low-Cd variety in rice.
查看更多>>摘要：Bioactive compounds play an increasingly prominent role in breeding functional and nutritive fruit crops such as citrus.However,the genomic and metabolic bases for the selection and differentiation underly-ing bioactive compound variations in citrus remain poorly understood.In this study,we constructed a species-level variation atlas of genomes and metabolomes using 299 citrus accessions.A total of 19 829 significant SNPs were targeted to 653 annotated metabolites,among which multiple significant signals were identified for secondary metabolites,especially flavonoids.Significant differential accumu-lation of bioactive compounds in the phenylpropane pathway,mainly flavonoids and coumarins,was un-veiled across ancestral citrus species during differentiation,which is likely associated with the divergent haplotype distribution and/or expression profiles of relevant genes,including p-coumaroyl coenzyme A 2'-hydroxylases,flavone synthases,cytochrome P450 enzymes,prenyltransferases,and uridine diphos-phate glycosyltransferases.Moreover,we systematically evaluated the beneficial bioactivities such as the antioxidant and anticancer capacities of 219 citrus varieties,and identified robust associations be-tween distinct bioactivities and specific metabolites.Collectively,these findings provide citrus breeding options for enrichment of beneficial flavonoids and avoidance of potential risk of coumarins.Our study will accelerate the application of genomic and metabolic engineering strategies in developing modern healthy citrus cultivars.
查看更多>>摘要：The pursuit of complete telomere-to-telomere(T2T)genome assembly in plants,challenged by genomic complexity,has been advanced by Oxford Nanopore Technologies(ONT),which offers ultra-long,real-time sequencing.Despite its promise,sequencing length and gap filling remain significant challenges.This study optimized DNA extraction and library preparation,achieving DNA lengths exceeding 485 kb;average N50 read lengths of 80.57 kb,reaching up to 440 kb;and maximum reads of 5.83 Mb.Importantly,we demonstrated that combining ultra-long sequencing and adaptive sampling can effectively fill gaps dur-ing assembly,evidenced by successfully filling the remaining gaps of a near-complete Arabidopsis genome assembly and resolving the sequence of an unknown telomeric region in watermelon genome.Collectively,our strategies improve the feasibility of complete T2T genomic assemblies across various plant species,enhancing genome-based research in diverse fields.
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维普