Purple-leaf tea plants,as anthocyanin-rich cultivars,are valuable materials for manufacturing teas with unique colors or flavors.In this study,a new purple-leaf cultivar“Zixin”(“ZX”)was examined,and its biochemical variation and mechanism of leaf color change were elucidated.The metabolomes of leaves of“ZX”at completely purple,intermediately purple,and completely green stages were analyzed using ultra-performance liquid chromatography quadrupole time of flight mass spectrometry(UPLC-QTOF-MS).Metabolites in the flavonoid biosynthetic pathway remained at high levels in purple leaves,whereas intermediates of porphyrin and chlorophyll metabolism and carotenoid biosynthesis exhibited high levels in green leaves.In addition,fatty acid metabolism was more active in purple leaves,and steroids maintained higher levels in green leaves.Saponin,alcohol,organic acid,and terpenoid-related metabolites also changed significantly during the leaf color change process.Furthermore,the substance changes between“ZX”and“Zijuan”(a thoroughly studied purple-leaf cultivar)were also compared.The leaf color change in“Zijuan”was mainly caused by a decrease in flavonoids/anthocyanins.However,a decrease in flavonoids/anthocyanins,an enhancement of porphyrin,chlorophyll metabolism,carotenoid biosynthesis,and steroids,and a decrease in fatty acids synergistically caused the leaf color change in“ZX”.These findings will facilitate comprehensive research on the regulatory mechanisms of leaf color change in purple-leaf tea cultivars.
Pineapple(Ananas comosus[L.]Merr.)is the third most important tropical fruit in the world after banana and mango.As a crop with vegetative propagation,genetic redundancy is a major challenge for efficient genebank management and in breeding.Using expressed sequence tag and nucleotide sequences from public databases,we developed 213 single nucleotide polymorphism(SNP)markers and validated 96 SNPs by genotyping the United States Department of Agriculture-Agricultural Research Service pineapple germplasm collection,maintained in Hilo,Hawaii.The validation resulted in designation of a set of 57 polymorphic SNP markers that revealed a high rate of duplicates in this pineapple collection.Twenty-four groups of duplicates were detected,encompassing 130 of the total 170 A cosmos accessions.The results show that somatic mutation has been the main source of intra-cultivar variations in pineapple.Multivariate clustering and a model-based population stratification suggest that the modern pineapple cultivars are comprised of progenies that are derived from different wild Ananas botanical varieties.Parentage analysis further revealed that both A.comosus var.bracteatus and A.comosus var.ananassoides are likely progenitors of pineapple cultivars.However,the traditional classification of cultivated pineapple into horticultural groups(e.g.‘Cayenne’,‘Spanish’,‘Queen’)was not well supported by the present study.These SNP markers provide robust and universally comparable DNA fingerprints;thus,they can serve as an efficient genotyping tool to assist pineapple germplasm management,propagation of planting material,and pineapple cultivar protection.The high rate of genetic redundancy detected in this pineapple collection suggests the potential impact of applying this technology on other clonally propagated perennial crops.
Lin ZhouTracie MatsumotoHua-Wei TanLyndel W MeinhardtSue MischkeBoyi WangDapeng Zhang
Apart from water,tea is the world’s most widely consumed beverage.Tea is produced in more than 50 countries with an annual production of approximately 4.7 million tons.The market segment for specialty tea has been expanding rapidly owing to increased demand,resulting in higher revenues and profits for tea growers and the industry.Accurate varietal identification is critically important to ensure traceability and authentication of premium tea products,which in turn contribute to on-farm conservation of tea genetic diversity.Using a set of single nucleotide polymorphism(SNP)markers developed from the expressed sequence tag(EST)database of Camilla senensis,we genotyped deoxyribonucleic acid(DNA)samples extracted from a diverse group of tea varieties,including both fresh and processed commercial loose-leaf teas.The validation led to the designation of 60 SNPs that unambiguously identified all 40 tested tea varieties with high statistical rigor(p<0.0001).Varietal authenticity and genetic relationships among the analyzed cultivars were further characterized by ordination and Bayesian clustering analysis.These SNP markers,in combination with a high-throughput genotyping protocol,effectively established and verified specific DNA fingerprints for all tested tea varieties.This method provides a powerful tool for variety authentication and quality control for the tea industry.It is also highly useful for the management of tea genetic resources and breeding,where accurate and efficient genotype identification is essential.
Wan-Ping FangLyndel W MeinhardtHua-Wei TanLin ZhouSue MischkeDapeng Zhang
Tea[Camellia sinensis(L.)O.Kuntze]is an important economic crop,and drought is the most important abiotic stress affecting yield and quality.Abscisic acid(ABA)is an important phytohormone responsible for activating drought resistance.Increased understanding of ABA effects on tea plant under drought stress is essential to develop drought-tolerant tea genotypes,along with crop management practices that can mitigate drought stress.The objective of the present investigation is evaluation of effects of exogenous ABA on the leaf proteome in tea plant exposed to drought stress.Leaf protein patterns of tea plants under simulated drought stress[(polyethylene glycol(PEG)-treated]and exogenous ABA treatment were analyzed in a time-course experiment using two-dimensional electrophoresis(2-DE),followed by matrix-assisted laser desorption/ionization time-of-flight(MALDI-TOF)mass spectrometry(MS).Among the 72 protein spots identified by MALDI-TOF MS,16 proteins were downregulated and two were upregulated by exogenous ABA.The upregulated proteins have roles in glycolysis and photosystem II stabilization.Twenty-one protein spots were responsive to drought stress and most participate in carbohydrate and nitrogen metabolism,control of reactive oxygen species(ROS),defense,signaling or nucleic acid metabolism.The combined treatments of exogenous ABA and drought showed upregulation of 10 protein spots at 12 h and upregulation of 11 proteins at 72 h after initiation of drought stress.The results support the importance of the role that ABA plays in the tea plant during drought stress,by improving protein transport,carbon metabolism and expression of resistance proteins.
Lin ZhouHui XuSue MischkeLyndel W MeinhardtDapeng ZhangXujun ZhuXinghui LiWanping Fang
