Fine-Scale analysis of both wild and cultivated horned galls provides insight into their quality differentiation.

BACKGROUND: Galla chinensis is a traditional Chinese medicine (TCM) produced due to the interaction between the Fordinae aphids and the Rhus plant species. Horned galls with high tannin content are the most widely cultivated gall type, and Wufeng county of Hubei province in China is the center of cultivation. However, long-term artificial cultivation and domestication of horned galls to meet the increasing production demand have led to quality degradation. Understanding the reasons underlying quality degradation is urgent for horned gall production and application. The present study used a combination of metabolic, genetic, and ecological analyses to investigate the quality and genetic differentiation of the horned galls under long-term domestication as well as the potential relationships between them. RESULTS: Analysis of gallic acid content and other three phenotypic traits (fresh weight, gall size, and wall thickness) revealed quality differentiation of horned galls collected from five locations in Wufeng, in which the cultivated samples from Wang Jiaping (WJP) showed the highest degradation. Genetic differentiation between the cultivated and wild Rhus chinensis trees in WJP, and between WJP and the other populations was detected based on SSR molecular markers, however, no significant difference in genetic structure was seen for the aphid populations. Among the various ecological factors examined, temperature was identified as the primary one affecting the quality of horned galls. CONCLUSIONS: Both genetic and ecological factors caused quality differentiation of horned galls. The collection of diverse germplasm of host trees and aphids will help reduce the quality degradation of horned galls in Wufeng.

Comparative and phylogenetic analysis of complete chloroplast genomes from five Artemisia species.

Artemisia Linn. is a large genus within the family Asteraceae that includes several important medicinal plants. Because of their similar morphology and chemical composition, traditional identification methods often fail to distinguish them. Therefore, developing an effective identification method for Artemisia species is an urgent requirement. In this study, we analyzed 15 chloroplast (cp) genomes, including 12 newly sequenced genomes, from 5 Artemisia species. The cp genomes from the five Artemisia species had a typical quadripartite structure and were highly conserved across species. They had varying lengths of 151,132-151,178 bp, and their gene content and codon preferences were similar. Mutation hotspot analysis identified four highly variable regions, which can potentially be used as molecular markers to identify Artemisia species. Phylogenetic analysis showed that the five Artemisia species investigated in this study were sister branches to each other, and individuals of each species formed a monophyletic clade. This study shows that the cp genome can provide distinguishing features to help identify closely related Artemisia species and has the potential to serve as a universal super barcode for plant identification.

[Chloroplast genome structure characteristics and phylogenetic analysis of Artemisia indica].

Artemisia indica is an important medicinal plant in the Asteraceae family, but its molecular genetic information has been rarely reported. In this study, the chloroplast genome of A. indica was sequenced, assembled, and annotated by the high-throughput sequencing technology, and its sequence characteristics, repeat sequences, codon usage bias, and phylogeny were analyzed. The results showed that the length of the chloroplast genome for A. indica was 151 161 bp, which was a typical circular four-segment structure, including two inverted repeat regions(IRs), a large single-copy(LSC) region, and a small single-copy(SSC) region, with a GC content of 37.47%. A total of 132 genes were annotated, and 114 were obtained after de-duplication, including 80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Fifty long repeat sequences and 191 SSRs were detected in the chloroplast genome of A. indica, and SSRs were mainly single nucleotides. Codon usage bias analysis showed that leucine was the most frequently used amino acid(10.77%) in the chloroplast genome, and there were 30 codons with relative synonymous codon usage(RSCU)>1 and all ended with A/U. The phylogenetic tree constructed based on the chloroplast genomes of the 19 species from the Asteraceae family showed that A. indica and A. argyi were closest in the genetic relationship, and Artemisia species clustered into separate evolutionary branches. The results of this study are expected to provide a theoretical basis for the genetic diversity and resource conservation of Artemisia medicinal plants.