title: A PKS I gene-based screening approach for the discovery of a new polyketide from Penicillium citrinum Salicorn 46.
abstract: Salicorn 46, an endophytic fungus isolated from Salicornia herbacea Torr., was identified as Penicillium citrinum based on its internal transcribed spacer and ribosomal large-subunit DNA sequences using a type I polyketide synthase (PKS I) gene screening approach. A new polyketide, penicitriketo (1), and seven known compounds, including ergone (2), (3β,5α,8α,22E)-5,8-epidioxyergosta-6,9,22-trien-3-ol (3), (3β,5α,8α,22E)-5,8-epidioxyergosta-6,22-dien-3-ol (4), stigmasta-7,22-diene-3β,5α,6α-triol (5), 3β,5α-dihydroxy-(22E,24R)-ergosta-7,22-dien-6β-yl oleate (6), N b-acetyltryptamine (7), and 2-(1-oxo-2-hydroxyethyl) furan (8), were isolated from the culture of Salicorn 46, and their chemical structures were elucidated by spectroscopic analysis. Antioxidant experiments revealed that compound 1 possessed moderate DPPH radical scavenging activity with an IC50 value of 85.33 ± 1.61 μM. Antimicrobial assays revealed that compound 2 exhibited broad-spectrum antimicrobial activity against Candida albicans, Clostridium perfringens, Mycobacterium smegmatis, and Mycobacterium phlei with minimal inhibitory concentration (MIC) values of 25.5, 25.5, 18.5, and 51.0 μM, respectively. Compound 3 displayed potent antimicrobial activities against C. perfringens and Micrococcus tetragenus with a MIC value of 23.5 μM. Compounds 5 and 6 showed high levels of selectivity toward Bacillus subtilis and M. phlei with MIC values of 22.5 and 14.4 μM, respectively. The results of this study highlight the use of PCR-based techniques for the screening of new polyketides from endophytic fungi containing PKS I genes.
authors.affiliation: Key Laboratory of Food Processing and Quality Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Tianxing
authors.initials: T
authors.lastname: Liu
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Xin
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects; D002175:Candida / Q000187:drug effects; D016000:Cluster Analysis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D060026:Endophytes / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D005820:Genetic Testing; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010407:Penicillium / Q000145:classification / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D048630:Polyketide Synthases / Q000235:genetics* / Q000378:metabolism*; D061065:Polyketides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000235:genetics; D017422:Sequence Analysis, DNA; D013057:Spectrum Analysis
chemical_list: D000890:Anti-Infective Agents; D004271:DNA, Fungal; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer; D061065:Polyketides; D012335:RNA, Ribosomal; C065096:RNA, ribosomal, 26S; D048630:Polyketide Synthases