Characteristics of Complete Chloroplast Genome of Grevillea robusta

Abstract

Abstract Grevillea robusta is an important plant in Proteaceae, and decoding and understanding the chloroplast genome of Grevillea robusta is of great theoretical significance and practical value to the genetic diversity and phylogenetic relationship of Proteaceae. On the basis of high-throughput sequencing data of Grevillea robusta, we assembled and annotated the sequencing results using GetOrganelle and CPGAVAS2 programs, and downloaded the chloroplast genome data of genera Macadamia, Helicia and Protea from NCBI database. The chloroplast genomes of four generas. The length of chloroplast genome of Grevillea robusta was 158,642 bp, consisting of 129 genes, including 84 protein-coding genes, 37 tRNA genes and 8 rRNA genes. 56 SSRs were obtained from Grevillea robusta, among which the single nucleotide repeats were the most (66.07%) and the six nucleotide repeats were the least (1). At the same time, 34 repeats were detected in chloroplast genome of Grevillea robusta, mainly are palindrome repeats (16). The IR region of Grevillea robusta didn’t experience a significant contraction/expansion event, whereas Protea kilimandscharica showed a dramatic contraction. Gene selection pressure analysis showed that ycf1 genes showed positive selection signals. Analysis of RNA editing sites showed that there were 148 RNA editing sites in the protein-coding genes of chloroplast genome of Grevillea robusta, and most of them are C/U editing, up to 54.73%. Phylogenetic analysis confirmed that Grevillea robusta was belongs to Proteaceae, and grouped with Helicia and Macadamia, with a support rate of 100%. The chloroplast genome of Grevillea robusta was assembled successfully, which had high similarity with the chloroplast genome of Helicia and Macadamia, and was clustered into a branch during the phylogeny of Proteaceae. The results of this study laid a foundation for understanding the systematic evolution of the Proteaceae plants, and provide rich data supported for the development of molecular biological information such as molecular marker.