Comparative Genomics of the Balsaminaceae Sister Genera Hydrocera triflora and Impatiens pinfanensis.

Zhi-Zhong Li,Andrew W Gichira,Josphat K Saina,Jin-Ming Chen,Qing-Feng Wang,Cornelius M Kyalo

doi:10.3390/ijms19010319

Abstract

The family Balsaminaceae, which consists of the economically important genus Impatiens and the monotypic genus Hydrocera, lacks a reported or published complete chloroplast genome sequence. Therefore, chloroplast genome sequences of the two sister genera are significant to give insight into the phylogenetic position and understanding the evolution of the Balsaminaceae family among the Ericales. In this study, complete chloroplast (cp) genomes of Impatiens pinfanensis and Hydrocera triflora were characterized and assembled using a high-throughput sequencing method. The complete cp genomes were found to possess the typical quadripartite structure of land plants chloroplast genomes with double-stranded molecules of 154,189 bp (Impatiens pinfanensis) and 152,238 bp (Hydrocera triflora) in length. A total of 115 unique genes were identified in both genomes, of which 80 are protein-coding genes, 31 are distinct transfer RNA (tRNA) and four distinct ribosomal RNA (rRNA). Thirty codons, of which 29 had A/T ending codons, revealed relative synonymous codon usage values of >1, whereas those with G/C ending codons displayed values of <1. The simple sequence repeats comprise mostly the mononucleotide repeats A/T in all examined cp genomes. Phylogenetic analysis based on 51 common protein-coding genes indicated that the Balsaminaceae family formed a lineage with Ebenaceae together with all the other Ericales.

Highlights

The family Balsaminaceae of the order Ericales contains only two genera, Impatiens Linnaeus (1753:937) and Hydrocera Wight and Arnott (1834:140) and are predominantly perennial and annual herbs [1]
The complete chloroplast genomes of I. pinfanensis and H. triflora share the common feature of possessing a typical quadripartite structure composed of a pair of inverted repeats (IRs) separating a large single copy (LSC) and a small single copy (SSC), similar to other angiosperm cp genomes [23]
Not all the simple sequence repeats (SSRs) types were identified in all the species, Penta and hexanucleotide repeats were not found in I. pinfanensis, Diospyros lotus, and Pouteria campechiana, while only hexanucleotides were not identified in Ardisia polysticta and Barringtonia fusicarpa (Table 4)

Summary

Introduction

The family Balsaminaceae of the order Ericales contains only two genera, Impatiens Linnaeus (1753:937) and Hydrocera Wight and Arnott (1834:140) and are predominantly perennial and annual herbs [1]. One of the largest genera in angiosperms, consists of over 1000 species [3,4,5,6] primarily distributed in the Old World tropics, subtropics and temperate regions, and in Europe, and central and North America [5,7]. The geographical regions, including south-east Asia, the eastern Himalayas, tropical Africa, Madagascar, southern India and Sri Lanka occupied by Impatiens, have been identified as diversity hotspots [7,8]. Numerous new species have been recorded within these regions each year [9,10,11,12,13,14]

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