We present the 1.06 Gb sequenced genome of Gastrodia elata, an obligate mycoheterotrophic plant, which contains 18,969 protein-coding genes. Many genes conserved in other plant species have been deleted from the G. elata genome, including most of those for photosynthesis. Additional evidence of the influence of genome plasticity in the adaptation of this mycoheterotrophic lifestyle is evident in the large number of gene families that are expanded in G. elata, including glycoside hydrolases and urease that likely facilitate the digestion of hyphae are expanded, as are genes associated with strigolactone signaling, and ATPases that may contribute to the atypical energy metabolism. We also find that the plastid genome of G. elata is markedly smaller than that of green plant species while its mitochondrial genome is one of the largest observed to date. Our report establishes a foundation for studying adaptation to a mycoheterotrophic lifestyle.

Many species of Corydalis (Papaveraceae) have been used as medicinal plants in East Asia, and the most well-known species are Corydalis yanhusuo and C. decumbens in the Pharmacopoeia of China. However, authentication of these species remains problematic because of their high morphological variation. Here, we selected 14 closely related species and five genomic regions (chloroplast: matK, trnG, rbcL, psbA-trnH; nuclear: ITS) to explore the utility of DNA barcoding for authenticating these herbs. In addition, the Poisson tree process (PTP) and automatic barcode gap discovery (ABGD) were also used and compared with DNA barcoding. Our results showed that the ITS region was not suitable for molecular analysis because of its heterogeneous nature in Corydalis. In contrast, matK was an ideal region for species identification because all species could be resolved when matK was used along with the other three chloroplast regions. We found that at least five traditional identified species were lumped into one genetic species by ABGD and PTP methods; thus, highlighting the overestimation of species diversity using the morphological approach. In conclusion, our first attempt of molecular analysis of Corydalis herbs presented here successfully resolved the identification of medicinal species and encouraged their taxonomic re-assessment.

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Growth rings were used to determine the root age of medicinal Paeonia lactiflora from four producing areas, and their corresponding paeoniflorin content were measured based on the identification of ages. Different P. lactiflora root samples of different ages were collected from the four major growing areas in China: Bozhou, Anhui Province; Pan'an, Zhejiang Province; Zhongjiang, Sichuan Province; and Heze, Shandong Province. The relationship between the number of growth rings and age was analyzed using hand sections and paraffin sections. The paeoniflorin content in the roots of different P. lactiflora cultivars from different growing areas was measured using high-performance liquid chromatography (HPLC). The growth rings in the P. lactiflora roots were consistent with the age of the plant from Heze, Zhongjiang, Pan'an, whereas that for the P. lactiflora from Bozhou was one less than the age of the plant. The HPLC results show that the paeoniflorin content was highest in P. lactiflora 'Baihuachuanshaoyao,' followed by 'Baihuahangshaoyao,' 'Honghuachuanshaoyao,' and 'Honghuahangshaoyao,' 'Bozhoushaoyao' had the lowest levels of paeoniflorin. With increasing age, the paeoniflorin in the roots of the different P.lactiflora cultivars slowly declined or remained the same. In summary, the age of the roots of P. lactiflora from different growing areas can be determined using growth rings. The paeoniflorin content in the roots of P. lactiflora is correlated with cultivar and it was slowly declined with increasing age.