The Genetic Variation Of Tea Plant [Camellia Sinensis(L.)O.ktze.] In Response To Aluminum And Candidate Genes Related To Its Al Accumulation Systems In Hubei Province

Aluminum(Al)toxicity is a major limiting factor for plant growth and crop production in acid soils.Tea plant(Camellia sinensis L.O.Kuntze)originates from Southwest of China and prefers to acid soil for the climate of subtropical and temperate habitat.The optimum pH for tea plant ranges between 4.5 and 5.5,and its Al content is several times more than other plants without showing symptoms of Al toxicity,which indicates that tea plant has envolves a special mechanism of Al accumulation,therefore,it is very important to elucidate the mechanism of Al accumulation of tea plants for breeding crops with acid and Al resistance,improving the crop yield and promoting sustainable development of agriculture.The genetic variations of Al accumulation and root growth in response to different Al concentrations were determined among 37 different tea varieties,and the transcriptome datasets of tea plants(cv.Jiaming 1)are described,and the amino acid sequence variation was analyzed among different tea varieties in this study,the results were as follows:1.In this study,the hydroponics system was used with a gradient Al concentration of0,0.2 and 0.4 mM across 37 genotypes tea plants for 4 months.The genetic variation of Al concentration and root growth were determined.White newly absorbing roots were observed in four genotypes of tea plants,cv.Fuyun 6,cv.Longjing 43,cv.Qianmei 701 and cv.Jinguanyin,There were 24 and 28 genotypes yield white absorbing roots in response to 0.2 mM and 0.4 mM Al respectively.It indicates that Al promotes the growth of tea plant root system within a suitable range of Al.There were 25 genotypes of tea plants presenting higher Al concentration in young buds exposed to 0.4 m M Al compare with that of 0 m M Al.The results demonstrated that significant genetic variations were existed in the tea plant germplasm.2.To identify the candidate genes involved in the Al accumulation in tea plant,tea plant(cv.Jiaming)following a gradient Al-level(0 mM,0.2 mM,1.0 mM)was assessed to further reveal candidate genes involved by RNA-Seq.Transcriptome sequencing obtained a total of 70.18 GB raw data and 213699 unigenes were de novo assembled totally.A large number of the differentially expressed genes related totranscription factors,membrane transporters for ion and organic acid,oxidative stress pathway,polysaccharide and cell wall metabolism,energy and primary metabolism,organic anions and enzymes metabolism involved in the tricarboxylic acid(TCA)cycle,signal and hormones were identified,these genes are ideal candidates involved in the Al accumulation.3.Genetic variation of CsSTOP1,a homolog encoding a Cys2-His2 zinc-finger transcription factor and regulating the transcription of multiple genes critical for Al tolerance in Arabidopsis,were conducted across 49 tea plant varieties.Sixty-three single nucleotide polymorphism sites were identified.The variation comprised 33 nonsynonymous loci,which lead to the changes of the amino acid sequence,and 30 synonymous loci.A 3-AAs deletion was observed in five genotypes(cv.Yunnandifangqunti,cv.Yunnandayezhong,cv.Yunkang 27,cv.Yunchapurui,cv Mengkudaye).It is interesting that the five cultivars are all belong to the assamica [C.sinensis var.Assamica(Masters)Kitamura].Furthermore,we will investigate whether the9bp-indel variation harbor the function of Al tolerance by in planta complementation assays in Arabidopsis.