| C.aromatica Salisbury,C.kwangsiensis S.G.Lee & C.F.Liang,C.longa L.,C.phaeocaulis Val.,C.wenyujin Y.H.Chen & C.Ling is commonly used in Dai medicine which was included in the " Pharmacopoeia of the People’s Republic of China" in 2020,and has an incredibly high medicinal and economic value.However,the morphological characteristics of Curcuma are very similar,and the medicinal parts are mainly rhizomes.It is challenging to accurately identify the medicinal materials of closely related species within the genus or even between different genera.In particular,the Curcuma of Chinese Dai medicines,which have similar appearances,overlapping medicinal materials and plant names,similar efficacy,confusion,and intersection of basic plants,etc.,which affect the identification and cultivation of medicinal materials.In view of the above situation,in this study,8 Curcuma plants from different sources(3 Curcuma longa,1 Curcuma phaeocauli,3 Curcuma aromatica,and 1 Curcuma sichuanensis)were used in this study.Based on the Illumina high-throughput sequencing platform,Get-Organelle software assembled the 8Curcuma chloroplast genomes,combined with 33 Curcuma chloroplast genomes downloaded from Genbank,yielded a total of 41 Curcuma chloroplast genomes(including17 species).The basic information of the chloroplast genome of the Curcuma genus was counted by Geneious software.The specific research results of the study are as follows:(1)Based on the comparison of specimens,it was determined that the differences in flower and leaf morphology and internal color characteristics of the rhizome of Curcuma can be used as distinguishing characteristics to distinguish some plants of the genus Curcuma.For example,those with wider leaves and yellow rhizome inside are C.aromatica.The leaves are glabrous,and the inflorescences are pulled out from the top leaf sheath;the orange-yellow ones inside the rhizomes are C.phaeocaulis.The plant blooms in spring and the inflorescences are extracted from the rhizomes alone;there is a purple band in the center of the leaves;the yellow ones inside the rhizomes are Curcuma phaeocaulis.The leaves are green,and those with hairs on both sides are Curcuma sichuanensis.However,morphological identification is not applicable to all Curcuma plants,and the rhizomes that have been used in Chinese herbal medicines cannot be effectively distinguished.(2)Through the comparative analysis of the chloroplast genomes of 8 samples of Curcuma phaeocaulis,Curcuma longa,Curcuma aromatica,and Curcuma sichuanensis,and the chloroplast genomes of 33 samples(17 species)of the genus Curcuma downloaded from NCBI,it was found that they were all typical four Split structure,the genome sequence length is 159,423～163,539 bp,the GC content ranges from 36.2～36.3,and the coding genes are 125～133;Curcuma phaeocaulis,Curcuma longa,Curcuma aromatica,and Curcuma sichuanensis all contain 133 genes,including 38 t RNAs,8 r RNA,and 87protein-coding genes,and there are 31-33 high-frequency codons,most of which end with A/T,indicating that the codons in the chloroplast genome of Curcuma are biased towards the A/T ending pattern;In the detected species of Curcuma chloroplast genomes,the number of detected SSRs ranged from 97 to 128,and single nucleotide A/T was the majority,the genome sequence had Rich AT content.(3)Comparative analysis showed that the intraspecific sequences of Curcuma were highly conserved,and the interspecific comparative analysis screened rps16-trn Q,trn Q-psb K,atp F-atp H,pet N-psb M,pet A-psb J,ndh F-rpl32,rpl32-trn L,and ndh A can be used as a hypervariable region of a potential identification marker;based on 53 individuals of Zingiberaceae,we verified the identification efficiency of 8 hypervariable regions,and the results showed that the 8 fragments and the traditional DNA barcode fragments rbc L and psb K-psb Ihad lower identification efficiency in Curcuma species.(4)The phylogenetic tree constructed with the whole chloroplast genome as a super barcode shows that the Curcuma genus is not monophyletic.However,the Chinese herbal medicines of Curcuma,Curcuma phaeocaulis,Curcuma kwangsiensis,Curcuma longa,Curcuma aromatica,and Curcuma sichuanensis form a single lineage.Separate branches,suggesting that these medicinal turmeric plants are very closely related.In general,the complete chloroplast genome contains many variation and information sites.In phylogenetic analysis,the whole chloroplast genome can be used as a "super barcode" to precisely identify the interspecies relationship of Curcuma. |
