Corrigendum: Comparative plastome analyses and evolutionary relationships of 25 East Asian species within the medicinal plant genus Scrophularia (Scrophulariaceae)

Xia Wang ¹ Lei Guo ¹ Lulu Ding ^1* Leopoldo Medina ^2* Ruihong Wang ^1* Pan Li ^3*

• ¹ Zhejiang Sci-Tech University, Hangzhou, China
• ² Real Jard´ın Bota´ nico, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
• ³ Laboratory of Systematic and Evolutionary Botany and Biodiversity, College of Life Sciences, Zhejiang University, Hangzhou, Jiangsu Province, China

Scrophularia L., a species-rich and complicated genus of Scrophulariaceae, comprises nearly 300 species across the Northern temperate zone (Hong et al., 1998; Wang, 2015). Southern Europe and the Mediterranean are the main center of Scrophularia diversity (Hong, 1983), while East Asia is the secondary center with a total of 42 documented species, 36 of which are recorded in China (Li et al., 1999; Wang, 2015). Many species of this genus possess high therapeutic properties and are extensively employed as herbal medications to treat fever, constipation, rheumatism, and inflammatory affections (Huang, 2018; Lee et al., 2021; Cui, 2023). It is notable that Scrophularia plants possess bioactive iridoids, such as harpagide and harpagoside, which are found in most species of this genus (Li et al., 1999; de Santos Galíndez et al., 2002; Pasdaran and Hamedi, 2017). Scrophularia ningpoensis Hemsl., which has a wider distribution in China and was officially listed in the Chinese Pharmacopoeia as the sole medicinal source of Scrophulariae Radix (SR, also called “Xuan Shen”), has been used over two thousand years (Chinese Pharmacopoeia Commission, 2020; Lee et al., 2021). While the remaining species in China tend to exhibit distinct regional characteristics (Supplementary Table 1) and are usually utilized as local folk remedies or ethnic medicines, such as S. spicata Franch., S. fargesii Franch., S. henryi Hemsl. and S. moellendorffii Maxim (Li et al., 1999). S. incisa Weinm. is a traditional Mongolian medicine, and its entire plant is used for treating measles and rash diseases (Editorial Board of the Chinese Materia Medica, 2003). S. dentata Royle ex Benth. is employed as an ethnic medicine known as “Alpine Tibetan herb” for the treatment of exanthema and fever (Zhang et al., 2013; Ni et al., 2016). S. buergeriana Miq., S. kakudensis Franch. and S. yoshimurae T. Yamaz., as the common substitution and adulterants of SR, have been employed in Korea and in Taiwan Province for over 20 years (Sagare et al., 2001; Nam et al., 2020; Manivannan et al., 2021; Guo et al., 2023b). However, due to restricted wild distribution and indiscriminate harvesting and exploitation, wild strains of S. ningpoensis are facing a diminishing genetic diversity (Wang and Wang, 2007; Zhao, 2008; Chen, 2014). Furthermore, S. ningpoensis is well-known as one of the “Zhe Ba Wei” (eight traditional Chinese medicines from Zhejiang Province), and it is grown in many other provinces across China by introduction breeding (Chen, 2011). Due to the decreasing cultivation area of authentic S.ningpoensis in Zhejiang (He et al., 2020), extensive cultivation in other provinces has intensified market competition (Zhang et al., 2022a). The intensification of market competition has led to an increase in artificial cultivation. However, owing to intensive artificial selection (Chen, 2011) and the unsustainable practices adopted by farmers, like long-term asexual reproduction, the genetic diversity of cultivated varieties and the quality of medicinal materials continue to decline (Yang, 2011). Therefore, it is crucial to clarify the species relationship of Scrophularia in East Asia and develop its medicinal resources reasonably. Efficient universal molecular markers are also essential to promote contemporary breeding projects in order to explore and conserve the germplasm of this medicinally and economically significant genus. Despite the considerable medicinal worth of Scrophularia rhizomes, differentiating among species presents a challenge because of their analogous therapeutic properties and physical characteristics (Guo et al., 2023b). To understand species’ genetic background, since the 1990s, a multitude of approaches have been applied to explore the origin, genetic diversity and evolutionary relationships of Scrophularia (Ortega Olivencia and Devesa Alcaraz, 1993), including pollination system (Navarro-Pérez et al., 2013), plastid DNA datasets (e.g. trnL-trnF, psbA-trnH, trnQ-rps16 and trnS-trnG), and nuclear ribosomal DNA sequences (nuclear ITS) (Attar et al., 2011; Scheunert and Heubl, 2011; Navarro-Pérez et al., 2013; Scheunert and Heubl, 2014; 2017). Among these efforts, the most extensive sampling of phylogenetic relationships within the Scrophularia genus to date has been constructed using sequences from the nuclear ITS region and two plastid DNA regions, encompassing 147 species worldwide, but only 13 East Asian species included (Scheunert and Heubl, 2017). In addition, several subclades and infrageneric relationships had weak support, especially within the East-Asian lineage of S. sect. Scrophularia. Considering this, further investigation of East Asian Scrophularia using more comprehensive genomic information, including the plastome, would be of great interest and significance for advancing our understanding in this field. East Asia is a natural plant floristic region and one of the most diverse and complex regions in terms of plant biodiversity worldwide (Boufford and Ōba, 1998; Li et al., 2015). Once a vital ice age refuge, it’s now seen as a hub for angiosperm diversification and possesses one of the world’s oldest and most complete series of plant diversity evolution (Li, 2008). East Asiatic Floristic Kingdom reflects the evolutionary history and interrelationships of species, revealing the impact of environmental and ecological interactions (Deng, 2015), from the uplift of Qinghai-Tibetan Plateau (An and Harrison, 2000; Liu et al., 2006) to monsoonal climates (Azani et al., 2019). Therefore, East Asia is a critical region for the origin and evolution of angiosperms worldwide, as well as an important area and natural laboratory for studying distribution processes. Most of China is part of the East Asiatic Floristic Kingdom (Chen et al., 2022b), a young biome from the Early Miocene (Tang and Li, 1996; Milne and Abbott, 2002; Yang et al., 2023), rich in both relict plants (Milne and Abbott, 2002) and young species. Investigating the inter-species relationships within East Asian Scrophularia could provide theoretical support for applications such as molecular plant breeding and the analysis of medicinal components, while also offering a useful perspective on the evolution of East Asian Scrophularia species.