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.

In order to determine the quality of soil fertility of bamboo species in coastal sandy land and guide the construction and management of bamboo shelter forest in coastal sandy land, the difference of soil physical and chemical properties of different bamboo forests in coastal sandy land and evaluate the soil quality were studied. Eight bamboo species in coastal sandy land were selected from Chishan State-owned Farm in Dongshan County, Fujian Province. The physical and chemical properties of the 0-20 cm soil layer of each bamboo species were determined. One-way ANOVA analysis was conducted to test the significance of each index, and principal component analysis weighted comprehensive index method and fuzzy mathematics were used to comprehensively evaluate the soil fertility quality of different bamboo species. Soil moisture content, soil density, capillary porosity, non-capillary porosity and total soil porosity of Oligostachyum lubricum were significantly different from those of other bamboo forest (P<0.05). The average pH of soil ranged from 5.01 to 7.36, and there was no significant difference in the pH of other bamboo forests except the neutral soil pH of Bambusa oldhamii (P>0.05). The average soil organic from 4.43-11.06 g/kg, Pseudosasa amabilis var. convexa was significantly lower than that of other bamboo forests. The average range of soil total potassium and available potassium was 4.59-79.33 g/kg and 0.78-43.11 mg/kg. The average range of soil total nitrogen and total phosphorus was 0.47-2.42 g/kg and 0.09-0.37 g/kg, and soil electrical conductivity, total availability and quick availability of N, P, K. had significant differences among different bamboo forests (P<0.05). The order of soil fertility quality index order of the eight bamboo species was P. japonica>O. lubricum>Phyllostachys nidularia f. farcata>B. oldhamii>Dendrocalamus minor var. amoenus>B. tuldoides 'Swollenintrnode'>B. eutuldoides var. viridi-vittata>P. amabilis var. convexa. The physical and chemical properties and total soil quality of bamboo shelterbelt in coastal sandy land were significantly affected by the types of bamboo stands. P. japonica could effectively improve soil quality, but the effect of P. amabilis var. convexa. on soil improvement was not obvious. Bamboo species and planting methods should be selected rationally for the construction and management of bamboo shelterbelt in coastal sandy land.