Plastid Phylogenomic Data Offers Novel Insights Into the Taxonomic Status of the Trichosanthes kirilowii Complex (Cucurbitaceae) in South Korea.

Inkyu Park,Byeong Cheol Moon,Sungyu Yang,Sungwook Chae,Jun-Ho Song

doi:10.3389/fpls.2021.559511

Inkyu Park, Byeong Cheol Moon + Show 3 more

Open Access

https://doi.org/10.3389/fpls.2021.559511

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Abstract

Trichosanthes is a genus in Cucurbitaceae comprising 90–100 species. Trichosanthes species are valuable as herbaceous medicinal ingredients. The fruits, seeds, and roots of species such as T. kirilowii and T. rosthornii are used in Korean traditional herbal medicines. T. rosthornii is only found in China, whereas in South Korea two varieties, T. kirilowii var. kirilowii and T. kirilowii var. japonica, are distributed. T. kirilowii var. kirilowii and T. kirilowii var. japonica have different fruit and leaf shapes but are recognized as belonging to the same species. Furthermore, although its members have herbal medicine applications, genomic information of the genus is still limited. The broad goals of this study were (i) to evaluate the taxonomy of Trichosanthes using plastid phylogenomic data and (ii) provide molecular markers specific for T. kirilowii var. kirilowii and T. kirilowii var. japonica, as these have differences in their pharmacological effectiveness and thus should not be confused and adulterated. Comparison of five Trichosanthes plastid genomes revealed locally divergent regions, mainly within intergenic spacer regions (trnT-UGU–trnL-UAA: marker name Tri, rrn4.5–rrn5: TRr, trnE-UUC–trnT-GGU: TRtt). Using these three markers as DNA-barcodes for important herbal medicine species in Trichosanthes, the identity of Trichosanthes material in commercial medicinal products in South Korea could be successfully determined. Phylogenetic analysis of the five Trichosanthes species revealed that the species are clustered within tribe Sicyoeae. T. kirilowii var. kirilowii and T. rosthornii formed a clade with T. kirilowii var. japonica as their sister group. As T. kirilowii in its current circumscription is paraphyletic and as the two varieties can be readily distinguished morphologically (e.g., in leaf shape), T. kirilowii var. japonica should be treated (again) as an independent species, T. japonica.

Highlights

Trichosanthes L. is a large genus of the tribe Sicyoeae Schrad. (Cucurbitaceae Juss.) comprising 90– 100 species
Fresh T. kirilowii var. kirilowii and T. kirilowii var. japonica leaves were collected from five natural habitats in South Korea (Supplementary Figure 1), and one T. rosthornii individual was collected from its natural habitat in China (Supplementary Table 1)
In the case of the fruit, pepos were globose to oblong in T. kirilowii var. kirilowii (Figure 1E), and oblong to ellipsoidal in T. kirilowii var. japonica (Figure 1F)

Summary

Introduction

Trichosanthes L. is a large genus of the tribe Sicyoeae Schrad. (Cucurbitaceae Juss.) comprising 90– 100 species (de Wilde and Duyfjes, 2010; de Boer and Thulin, 2012). (Cucurbitaceae Juss.) comprising 90– 100 species (de Wilde and Duyfjes, 2010; de Boer and Thulin, 2012). The members of the genus are diecious, rarely monecious, perennial climbing herbs, characterized by unlobed or palmately lobed, rarely compound leaves with branched tendrils, a usually distinct fimbriate corolla, and ovoid to Comparative Analysis of Trichosanthes Chloroplast Genomes globose or elongated fusiform pepos (Huang et al, 2011; de Boer and Thulin, 2012). The center of diversity for the genus is Southeast Asia, and its range is India to East Asia and southeast Australia (de Wilde and Duyfjes, 2010; Huang et al, 2011; de Boer and Thulin, 2012). South Korea hosts two varieties of a Trichosanthes species: T. kirilowii var. Japonica is distinguished from T. kirilowii var. The two T. kirilowii varieties are distinguished based on leaf shape as well as seed color (Ohba, 1999)

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