Generation and characterization of expressed sequence tags(ESTs) from coralloid root cDNA library of Cycas debaoensis  

作　　者：Yunhua Wang Nan Li Ting Chen Yiqing Gong 

机构地区：[1]Shenzhen Key Laboratory of Southern Subtropical Plant Diversity,Fairylake Botanical Garden,Shenzhen & Chinese Academy of Sciences

出　　处：《Plant Diversity》2018年第5期245-252,共8页植物多样性（英文版）

基　　金：supported by the Grant(201522)from Shenzhen Urban Management

摘　　要：A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN （duplex-specific nuclease） normalization method combined with the SMART （Switching Mechanism At 5＇ end of the RNA Transcript） technique. The titer of the original cDNA library was about 1.5 × 10^6 cfu·mL^-1 and the average insertion size was about 1 kb with a high recombination rate （97%）. The 5011 high-quality expressed sequence tags （ESTs） were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally anno- tated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 （50.1%） unigenes were associated with 4082 Gene Ontology （GO） terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups （COG） functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase （RLK） genes were screened. Furthermore, a total of 94 simple sequence repeats （SSRs） were discovered, of which 20 loci were successfully amplified in C debaoensis. This study is the first EST analysis for the coralloid roots of C debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C debaoensis and related cycad species.A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN(duplex-specific nuclease) normalization method combined with the SMART(Switching Mechanism At 5' end of the RNA Transcript) technique.The titer of the original cDNA library was about1.5 x 10~6 cfu.mL^(-1) and the average insertion size was about 1 kb with a high recombination rate(97%).The 5011 high-quality expressed sequence tags(ESTs) were obtained from 5393 randomly picked cDNA clones.Clustering and assembly of ESTs resulted in 2984 unique sequences,consisting of 618 contigs and2366 singlets.EST sequence annotation revealed that 2333 and 1901 unigenes were functionally annotated in the NCBI non-redundant database and Swiss-Prot protein database,respectively.Functional analysis demonstrated that 1495(50.1%) unigenes were associated with 4082 Gene Ontology(GO) terms.A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups(COG) functional categories.Based on the EST dataset,22 ESTs that encoded putative receptor-like protein kinase(RLK) genes were screened.Furthermore,a total of 94 simple sequence repeats(SSRs) were discovered,of which 20 loci were successfully amplified in C.debaoensis.This study is the first EST analysis for the coralloid roots of C.debaoensis and provides a valuable genomic resource for novel gene discovery,gene expression and comparative genomics,conservation and management studies as well as applications in C.debaoensis and related cycad species.

关 键 词：Cycas debaoensis Coralloid root cDNA library Expressed sequence tags Symbiosis and defense SSRS 

分 类 号：Q94-4[生物学—植物学] X171[环境科学与工程—环境科学]