Comparative analysis of the chloroplast genomes of a novel albino tea “Huabai 1” and the traditional albino tea “Huangjinya”

Abstract

The chloroplast genomes of albino tea variety “Huangjinya” and the newly discovered albino tea resource were analyzed comparatively, and DNA barcodes were used to construct phylogenetic trees between albino tea and other plants in theaceae, aiming to reveal the differences in the albino mechanism between the novel albino tea resource “Huabai 1” and the albino tea variety “Huangjinya” and to clarify the genetic evolutionary relationship between the novel albino tea resource “Huabai 1” and other plants in theaceae from the perspective of chloroplast genome. Studies result have shown that the chloroplast genome size of “Huangjinya” and “Huabai 1” is 158,916 bp, 157,028 bp, respectively, LSC (large single-copy),SSC (small single-copy) and IR (inverted repeat) are 86,654 bp, 86,590 bp,18,277 bp, 16,463 bp, and 27,900 bp, 26,081 bp, respectively for “Huangjinya” and “Huabai 1”, with a total of 113 genes annotated were obtained in the chloroplast genome of both albino tea, these include 84 protein coding genes, 24 tRNA genes and 5 rRNA genes. GC content of chloroplast genome of “Huabai 1” was 37.3%, slightly higher than that of “Huangjinya” (37.22%). The gene composition, classification and codon preference (preferred to use codons ending in A/U) of chloroplast genome in “Huabai 1” were basically the same as that in “Huangjinya”, but the main difference was the length of ycf1 fragment in IR region, the length of “Huabai 1” ycf1 fragment was only 987 bp, while that of “Huangjinya” was 2889 bp. The construction of phylogenetic tree was based on the four DNA barcodes (matK, rbcL, trnH-psbA, and ycf1), and the results showed that ycf1, with the most taxonomic levels, was most suitable for the identification of tea varieties and the interpretation of the evolution of genetic relationships among varieties. Ycf1 cluster showed that the relationship between “Huangjinya” and "Longjing 43″ was closer, and that of “Huabai 1” and "Fuding Dabai" was closer. It is speculated that the two tea varieties “Huangjinya” and "Huabai1″ may come from different ancestors, and thus led their quite different albino mechanism. This research will provide the basis for the revealing the albino molecular mechanism and phylogenetic development of the novel albino tea resource “Huabai 1”.