Rucheng Baimaocha (Camellia sinensis var. pubilimba Chang) is one of the four tea plants native to Hunan Province, China. Previous studies have shown that Rucheng Baimaocha is different from other three local population resources in Hunan in evolutionary status, and has distinctive characteristics in botanical characteristics, biochemical components and tea making quality. However, there are few studies on the differences of secondary metabolites of Rucheng Baimaocha germplasm resources. Using UPLC-MS/MS analysis technology, taking Anhua population (AHQT, C. sinensis var. sinensis), Chengbu Dongcha [CBDC, C. sinensis var. assamica (Masters) Kitamura], and Jianghua Kucha [JHKC, C. sinensis var. assamica (Masters) Kitamura] of typical local tea resources in Hunan as controls, the significantly different metabolites in Rucheng Baimaocha were screened and clustered by K-means analysis and differential metabolite enrichment pathway analysis. Compared with the control, 189, 180 and 162 significantly different metabolites were screened in Rucheng Baimaotea, the most species were flavonoids (69, 51 and 60 respectively), followed by phenolic acids (31, 40 and 25 respectively), and the least were lignans and coumarins (5, 4 and 4 respectively). Compared with the other three populations, Rucheng Baimaotea increased the content of 15 metabolites. The content of flavonoids and phenolic acids increased the most in Rucheng Baimaocha, and the highest increase was pinocembrin, followed by 1,2,3,6-tetra-o-galloyl-d-glucose. The differential metabolites were analyzed by K-means clustering. The metabolites with the same change trend in the four groups could be divided into nine categories. Among the four populations, there were 32 metabolites with the same change trend and the highest content in Rucheng Baimaotea, mainly flavonoids and tannins. The results of KEGG pathway enrichment of differential metabolites showed that the differential metabolites of Rucheng Baimaotea were mainly enriched in flavonoid biosynthesis pathway, flavonoid and flavonol biosynthesis pathway, phenylpropane biosynthesis pathway and so on. In addition to the differential metabolites reported in some tea, some differential metabolites less concerned in tea research were detected, such as pinocembrin, ellagic acid, kaempferol, etc. The substances would provide an important reference for the excavation and breeding of characteristic tea germplasm resources of Rucheng white tea in the later stage.

The elucidation of cucurbitacin biosynthesis pathway is essential for heterologous production due to its significant anticancer activity. The biosynthesis of cucurbitacin starts from cucurbitadienol (Cuol) catalyzed by cucurbitadienol synthase (CBS) of the oxysqualene cyclase (OSCs) family to form 2,3-oxysqualene which subsequently catalyzed by cytochrome P450 (CYP) and other enzymes for oxidative modification to produce various cucurbitacins. In this study, an efficient transient expression system mediated by Agrobacterium tumefaciens was established. The CBS gene (HcOSC6) from Hemsleya chinensis and truncated 3-hydroxy-3-methyl-glutaryl coenzyme A reductase gene (tHMGR) from Avena strigose were continuously optimized in the tobacco co-expression system to increase Cuol yield from 2.832 mg/g (DW) to 9.48 mg/g (DW) in Nicotiana benthamiana leaves. Meanwhile, HcCYP87D20 of H. chinensis was also co-infiltrated into tobacco leaves to obtain 11-carbonyl-20β-hydroxy-cucurbitol. This study would provide a theoretical basis for efficient heterologous production of cucurbitacin.

Pteris minor is one of the rare pteridophytes in the coastal zone. Because its morphology is similar to that of P. fauriei, it has been wrongly identified as P. fauriei for a long time and lacks attention. In fact, there are obvious differences between them in habitat, plant morphology, spore morphology and chromosome ploidy. Therefore, P. minor was upgraded from a variety of P. fauriei to a species. In order to clarify the distribution area and survival status of P. minor, ArcGIS 10.7 software was used to construct the geographical distribution information maps of different geographical ranges of P. minor, by sorting out the previous collection records and research results, combined with the findings of the authors' field investigation, and its protection value was evaluated according to the standard of IUCN 3.1. The results show that: (1) In terms of the world geographical distribution pattern, P. minor is mainly distributed in Asia; In terms of the geographical distribution pattern in Asia, it is mainly distributed in China, Japan and Philippines; In terms of the geographical distribution pattern of China, it is mainly distributed in Zhejiang, Fujian, Macao, Hong Kong and Taiwan; In terms of the geographical distribution pattern of Japan, it is mainly distributed in the Ryukyu Islands; In terms of the geographical distribution pattern of Philippines, it is mainly distributed in the northern islands. (2) According to the IUCN 3.1 standard, the protection level of P. minor is temporarily set as near threatened (NT). According to the current data, the distribution range of P. minor is narrow, and its habitat is vulnerable to human activities, but it lacks protection for a long time. Therefore, corresponding protection suggestions were put forward finally.