Relative quantification of phenolic compounds in exocarp-mesocarp and endocarp of sumac (Toxicodendron vernicifluum) combined with transcriptome analysis provides insights into glycosylation of flavonoids and biflavonoid biosynthesis.

The pericarp of fruit can be differentiated into endocarp, mesocarp, and exocarp. To explore the differences in gene expression and metabolites in different tissues of the pericarp, the fruits of sumac (Toxicodendron vernicifluum) were separated into endocarp and mesocarp-exocarp. The metabolites and transcriptome of exocarp-mesocarp and endocarp of Toxicodendron vernicifluum were analyzed by HPLC-QTOF-MS/MS and RNA sequencing, respectively. A total of 52 phenolic compounds were identified, including 3 phenylpropane derivatives, 10 urushiol compounds and 39 flavonoids. The exocarp-mesocarp contained more urushiol compounds and flavonoid glycosides while the endocarp contained more biflavonoids, such as rhusflavone and dihydromorelloflavone. The characteristic component of endocarp was rhusflavone and the characteristic component of exocarp-mesocarp was urushiol (triene). Most of the genes involved in flavonoid synthesis pathway were upregulated in endocarp compared with exocarp-mesocarp and positively correlated with the content of flavonoids. The candidate genes related to the synthesis of components of flavonoid glycosides and biflavonoids were screened. Metabolomic and transcriptomic analyses provide new insights into the synthesis and distribution of flavonoid glycosides and biflavonoids in the fruits of Toxicodendron vernicifluum.

Complete Chloroplast Genome Sequence of Chinese Lacquer Tree (Toxicodendron vernicifluum, Anacardiaceae) and Its Phylogenetic Significance.

Chinese lacquer tree (Toxicodendron vernicifluum) is an important commercial arbor species widely cultivated in East Asia for producing highly durable lacquer. Here, we sequenced and analyzed the complete chloroplast (cp) genome of T. vernicifluum and reconstructed the phylogeny of Sapindales based on 52 cp genomes of six families. The plastome of T. vernicifluum is 159,571 bp in length, including a pair of inverted repeats (IRs) of 26,511 bp, separated by a large single-copy (LSC) region of 87,475 bp and a small single-copy (SSC) region of 19,074 bp. A total of 126 genes were identified, of which 81 are protein-coding genes, 37 are transfer RNA genes, and eight are ribosomal RNA genes. Forty-nine mononucleotide microsatellites, one dinucleotide microsatellite, two complex microsatellites, and 49 long repeats were determined. Structural differences such as inversion variation in LSC and gene loss in IR were detected across cp genomes of the six genera in Anacardiaceae. Phylogenetic analyses revealed that the genus Toxicodendron is closely related to Pistacia and Rhus. The phylogenetic relationships of the six families in Sapindales were well resolved. Overall, this study providing complete cp genome resources will be beneficial for determining potential molecular markers and evolutionary patterns of T. vernicifluum and its closely related species.

The complete genome sequence of Toxicodendron radicans, Eastern Poison Ivy.

Eastern Poison Ivy ( Toxicodendron radicans, Anacardiaceae) is well known in Eastern North America for causing contact dermatitis, an itchy and painful rash in most people who come in contact with it.  We present the whole genome sequence and annotation of this species. A total of 96,255,779 paired-ends reads consisting of 28.9 G bases were obtained by sequencing one leaf from a wild-collected plant.  The reads were assembled by a de novo method followed by alignment to related species. Annotation was performed via GenMark-ES. The raw and assembled data is publicly available via GenBank: Sequence Read Archive ( SRR10325927) and Assembly ( GCA_009867345).

[De novo Assembly and Analysis of Sumac (Toxicodendron vernicifluum (Stokes) F.A. Barkley) Transcriptomes Provides Insights into the Biosynthesis of Urushiol].

Sumac is universally known for its abundance of raw lacquer. Toxicodendron vernicifluum (Stokes) F.A. Barkley is one of the widely distributed native sumac cultivars. To accelerate sumac breeding for more prolific, high-quality, and robust cultivars, it is essential to explore its lacquer metabolism. However, transcriptomic and genomic data available for sumac are still limited. In this study, we generated the transcriptomic profiles of triploid Toxicodendron vernicifluum CV. Dahongpao (Dahongpao) and diploid T. vernicifluum and Toxicodendron vernicifluum CV. Huoyanzi (Huoyanzi), with 87856 unigenes. About 53% of these unigenes were annotated using Nr, Swiss-Prot, Kyoto Encyclopedia of Genes and Genomes (KEGG), Cluster of Orthologous Groups (COG) and Gene Ontology (GO). We identified nine differentially expressed candidate genes associated with type III polyketide synthase formation, which is the first step in urushiol biosynthesis. Additionally, a number of simple sequence repeats (EST-SSRs) were identified in T. vernicifluum for further molecular marker-assisted breeding. This study is the first report of Toxicodendron species transcriptome.

The origin of wild populations of Toxicodendron succedaneum on mainland Japan revealed by genetic variation in chloroplast and nuclear DNA.

Toxicodendron succedaneum: (L.) Kuntze is a tree cultivated for the production of sumac wax, which is extracted from the mesocarp. There are several hypotheses regarding the origin of T. succedaneum on mainland Japan. In this study, the geographical distribution of genetic variation in 13 wild populations on Honshu, Shikoku, Kyushu, and Ryukyu Islands, Japan was investigated and compared with that of individuals from continental Asia. Seven chloroplast DNA haplotypes of T. succedaneum were observed in Japan and could be divided into three lineages based on relatedness between haplotypes. One of these lineages was also observed in continental Asia, and the others were genetically distant from the haplotypes that originated on the continent, with one considered to have originated on the Ryukyu Islands, and the other on mainland Japan. The genetic diversity of both chloroplast and nuclear DNA was lower in populations from Ryukyu Islands than in populations from mainland Japan. Bayesian clustering based on nuclear genotypes showed a clear difference between the groups from Ryukyu Islands and mainland Japan. Based on approximate Bayesian computation analysis of polymorphic data for both genomes, it was inferred that wild populations of T. succedaneum on mainland Japan consist of both lineages with natural distribution on mainland Japan and those introduced from Ryukyu Islands and continental Asia.

Characterization of 42 microsatellite markers from poison ivy, Toxicodendron radicans (Anacardiaceae).

Poison ivy, Toxicodendron radicans, and poison oaks, T. diversilobum and T. pubescens, are perennial woody species of the Anacardiaceae and are poisonous, containing strong allergens named urushiols that cause allergic contact dermatitis. Poison ivy is a species distributed from North America to East Asia, while T. diversilobum and T. pubescens are distributed in western and eastern North America, respectively. Phylogreography and population structure of these species remain unclear. Here, we developed microsatellite markers, via constructing a magnetic enriched microsatellite library, from poison ivy. We designed 51 primer pairs, 42 of which successfully yielded products that were subsequently tested for polymorphism in poison oak, and three subspecies of poison ivy. Among the 42 loci, 38 are polymorphic, while 4 are monomorphic. The number of alleles and the expected heterozygosity ranged from 1 to 12 and from 0.10 to 0.87, respectively, in poison ivy, while varied from 2 to 8 and, from 0.26 to 0.83, respectively in poison oak. Genetic analysis revealed distinct differentiation between poison ivy and poison oak, whereas slight genetic differentiation was detected among three subspecies of poison ivy. These highly polymorphic microsatellite fingerprints enable biologists to explore the population genetics, phylogeography, and speciation in Toxicodendron.

[Genetic evaluation of Toxicodendron vernicifluum cultivars using amplified fragment length polymorphism markers].

Accurate identification of Toxicodendron vernicifluum varieties and understanding their genetic relationships are essential for the improved varieties selection. In this study, Amplified fragment length polymorphism (AFLP) markers was used to evaluate the genetic resources of nine Toxicodendron vernicifluum cultivars from Shaanxi. Eight pairs of AFLP primers with Mse I fluorescent labeled were screened from EcoR I /Mse I primer combinations. Different pair of primers differs widely to detect genetic polymorphism of Toxicodendron vernicifluum. The polymorphic bands detected by each pair of primers ranged from 242 to 622 with average value of 350.88. Eight pairs of AFLP primers produced 4463 bands in total. Among them, 2807 bands (62.64%) were polymorphic. genetic similarity coefficient (SC) among all cultivars varied from 0.673 to 0.833, which further verified that only a little genetic diversity existed among the cultivars. It was the first time that AFLP technique was applied to identify Toxicodendron vernicifluum cultivars. The study suggested that AFLP technique is a useful tool for individual identification of Toxicodendron vernicifluum cultivars and could be applied to the Toxicodendron vernicifluum' fingerprinting work in China.