Complete Chloroplast Genome of a Montane PlantSpathoglottis aureaLindl.: Comparative Analyses and Phylogenetic Relationships among members of Tribe Collabieae

Abstract

AbstractThe yellow–floweredSpathoglottis aurea(tribe Collabieae; family Orchidaceae) is native to the mountainous areas of Peninsular Malaysia. The species is well known as an ornamental plant and for its role in artificial hybrid breeding. There is an interesting evolutionary relationship betweenS. aureaand the geographically isolatedS. microchilinafrom Borneo that has encouraged further study of theS. aureapopulations, but the genomic resource forS. aureahas not yet been reported. The present study reports the first work to characterize a chloroplast genome among theSpathoglottisgenus. The complete chloroplast (cp) genome ofS. aureawas assembled from a sequence generated by the Illumina platform and analysed in comparison with other Collabieae species available in the GenBank database. The cp genome ofS. aureais 157,957 base pairs (bp) in length with guanine-cytosine (GC) content of 37.3%. The genome possessed a typical quadripartite chloroplast genome structure with large single-copy (LSC) (86,888 bp), small single-copy (SSC) (18,125 bp) and inverted repeat (IR) (26,472 bp) sequences. A total of 134 genes were annotated, with 88 protein coding genes (PCGs), 38 transfer RNA (tRNA) genes and eight ribosomal RNA (rRNA) genes. Overall, 80 simple sequence repeats (SSR) or microsatellites were identified. Comparative analysis with other Collabieae species revealed high conservation in the cp genome arrangements with minimal difference in genome lengths. However, several mutational hotspots were also detected, with high potential to be developed as genetic markers for phylogenetic analysis. Characterization of theS. aureacp genome revealed its conserved nature without gene loss or rearrangements when compared to other species of the Collabieae tribe. Phylogenetic analysis of Collabieae species also revealed thatS. aureahas a distant evolutionary relationship to other members of the Collabieae species, despite the presence of problematic genera such asPhaiusandCephalantheropsis.