Four Novel Mycoviruses from the Hypovirulent Botrytis cinerea SZ-2-3y Isolate from Paris polyphylla: Molecular Characterisation and Mitoviral Sequence Transboundary Entry into Plants

A hypovirulent SZ-2-3y strain isolated from diseased Paris polyphylla was identified as Botrytis cinerea. Interestingly, SZ-2-3y was coinfected with a mitovirus, two botouliviruses, and a 3074 nt fusarivirus, designated Botrytis cinerea fusarivirus 8 (BcFV8); it shares an 87.2% sequence identity with the previously identified Botrytis cinerea fusarivirus 6 (BcFV6). The full-length 2945 nt genome sequence of the mitovirus, termed Botrytis cinerea mitovirus 10 (BcMV10), shares a 54% sequence identity with Fusarium boothii mitovirus 1 (FbMV1), and clusters with fungus mitoviruses, plant mitoviruses and plant mitochondria; hence BcMV10 is a new Mitoviridae member. The full-length 2759 nt and 2812 nt genome sequences of the other two botouliviruses, named Botrytis cinerea botoulivirus 18 and 19 (BcBoV18 and 19), share a 40% amino acid sequence identity with RNA-dependent RNA polymerase protein (RdRp), and these are new members of the Botoulivirus genus of Botourmiaviridae. Horizontal transmission analysis showed that BcBoV18, BcBoV19 and BcFV8 are not related to hypovirulence, suggesting that BcMV10 may induce hypovirulence. Intriguingly, a partial BcMV10 sequence was detected in cucumber plants inoculated with SZ-2-3y mycelium or pXT1/BcMV10 agrobacterium. In conclusion, we identified a hypovirulent SZ-2-3y fungal strain from P. polyphylla, coinfected with four novel mycoviruses that could serve as potential biocontrol agents. Our findings provide evidence of cross-kingdom mycoviral sequence transmission.

Effective prediction of biosynthetic pathway genes involved in bioactive polyphyllins in Paris polyphylla

The genes in polyphyllins pathway mixed with other steroid biosynthetic genes form an extremely complex biosynthetic network in Paris polyphylla with a giant genome. The lack of genomic data and tissue specificity causes the study of the biosynthetic pathway notably difficult. Here, we report an effective method for the prediction of key genes of polyphyllin biosynthesis. Full-length transcriptome from eight different organs via hybrid sequencing of next generation sequencingand third generation sequencing platforms annotated two 2,3-oxidosqualene cyclases (OSCs), 216 cytochrome P450s (CYPs), and 199 UDP glycosyltransferases (UGTs). Combining metabolic differences, gene-weighted co-expression network analysis, and phylogenetic trees, the candidate ranges of OSC, CYP, and UGT genes were further narrowed down to 2, 15, and 24, respectively. Beside the three previously characterized CYPs, we identified the OSC involved in the synthesis of cycloartenol and the UGT (PpUGT73CR1) at the C-3 position of diosgenin and pennogenin in P. polyphylla. This study provides an idea for the investigation of gene cluster deficiency biosynthesis pathways in medicinal plants.

Paris Polyphylla Monomer PP-26 Induces Mitochondrial Pathway-Mediated Cell Apoptosis by Inhibiting the PI3K/Akt Pathway in Human Gastric Cancer Cells

Background: Paris polyphylla is a traditional Chinese medicinal herb that has been used as a haemostatic, antimicrobial and anticancer agent. Gastric cancer (GC) is a global health problem, with more than 1 million people newly diagnosed with gastric cancer worldwide each year.Methods: The MTT and colony formation assay were used to test the anti-proliferative effects of PP-26 on MGC-803 and BGC-823 cells. Flow cytometry assays, Hoechst 33258 staining assay and Caspase inhibitor Z-VAD-FMK were used to test apoptosis. JC-1 staining used to measure changes in mitochondrial membrane potential and western blot analysis were used to test apoptotic and PI3K/Akt pathway related proteins.Results: PP-26 had a dose-dependent inhibitory effect on the proliferation of MGC-803 and BGC-823 cells, but had no obvious anti-proliferative effect on normal liver LO2 cells and normal embryonic kidney HEK-293 cells. Additionally, PP-26 induced typical apoptotic morphological changes, such as nuclear pyknosis, nuclear cracking and apoptotic bodies. Moreover, PP-26 induced a decrease in mitochondrial membrane potential. And PP-26 modulated the expression of Bcl-xL, Mcl-1, Bax, caspase-9/-3 and PARP proteins and induced cell apoptosis through the mitochondrial apoptotic pathway. Next, using an irreversible general caspase inhibitor (Z-VAD-FMK), we confirmed the activation of the mitochondrial apoptotic pathway induced by PP-26. Furthermore, PP-26 inhibited the phosphorylation of Akt and GSK-3β. The inhibition of Akt protein activated the mitochondrial apoptotic pathway.Conclusion: Collectively, these results indicated that PP-26 inhibited the proliferation of MGC-803 and BGC-823 cells by inhibiting the Akt signalling pathway and activating the mitochondrial apoptotic pathway.

Two new species of Cladosporium from leaf spots of Paris polyphylla in north-western Yunnan Province, China

During the survey of pathogenic fungi on medicinal plant leaves in Yunnan Province, China, two Cladosporium-like taxa were isolated from leaf spots of Paris polyphylla. Based on morphological characteristics and phylogenetic analysis of combined ITS, TEF1-α and ACT genes, two new species were discovered. Two new species Cladosporium yunnanensis and C. paris are introduced, the detailed descriptions and illustrations are provided. Morphology of the two new species is compared with other related Cladosporium species. This study widens the host diversity of the genus Cladosporium.

Extraction and Purification of Secondary Metabolites of Paris polyphylla (Smith) Using Column Chromatography.

Paris polyphylla Smith is an erect and herbaceous plant. It has rich chemical constituents such steroidal saponins, phytosterols, flavonoids, and alkaloids that possess antimicrobial and anticancer activities. In the current investigation, we examined the effect of different solvents in the extraction yield and further purification via column chromatography. The ground powdered rhizomes of P. polyphylla was extracted with 100% hexane, 100% ethyl acetate, 70% ethanol, and 70% methanol. The extracts were filtered, evaporated using a rotary evaporator, concentrated, and measured. Subsequently, the solvent with high extraction yield was further purified using column chromatography. Ethanol produced the highest extraction yield as compared to the other solvents. About 30 fractions were eluted which was pooled into four fractions based on the Rf values and bands observed through thin layer chromatography (TLC) analysis.