title: Isolation and expression of two polyketide synthase genes from Trichoderma harzianum 88 during mycoparasitism.
abstract: Metabolites of mycoparasitic fungal species such as Trichoderma harzianum 88 have important biological roles. In this study, two new ketoacyl synthase (KS) fragments were isolated from cultured Trichoderma harzianum 88 mycelia using degenerate primers and analysed using a phylogenetic tree. The gene fragments were determined to be present as single copies in Trichoderma harzianum 88 through southern blot analysis using digoxigenin-labelled KS gene fragments as probes. The complete sequence analysis in formation of pksT-1 (5669bp) and pksT-2 (7901bp) suggests that pksT-1 exhibited features of a non-reducing type I fungal PKS, whereas pksT-2 exhibited features of a highly reducing type I fungal PKS. Reverse transcription polymerase chain reaction indicated that the isolated genes are differentially regulated in Trichoderma harzianum 88 during challenge with three fungal plant pathogens, which suggests that they participate in the response of Trichoderma harzianum 88 to fungal plant pathogens. Furthermore, disruption of the pksT-2 encoding ketosynthase-acyltransferase domains through Agrobacterium-mediated gene transformation indicated that pksT-2 is a key factor for conidial pigmentation in Trichoderma harzianum 88.
authors.affiliation: Key Laboratory of Molecular and Cytogenetics and Genetic Breeding of Heilongjiang Province, Harbin Normal University, Harbin, PR China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yao
authors.affiliation: Research Center on Life Sciences and Environmental Sciences, Harbin University of Commerce, Harbin, PR China.
authors.forename: Chong
authors.initials: C
authors.lastname: Tan
authors.affiliation: Department of Life Science and Engineering, Harbin Institute of Technology, Harbin, PR China.
authors.forename: Jinzhu
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Life Science and Engineering, Harbin Institute of Technology, Harbin, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Key Laboratory of Molecular and Cytogenetics and Genetic Breeding of Heilongjiang Province, Harbin Normal University, Harbin, PR China.
authors.forename: Lijie
authors.initials: L
authors.lastname: Yu
authors.affiliation: Key Laboratory of Molecular and Cytogenetics and Genetic Breeding of Heilongjiang Province, Harbin Normal University, Harbin, PR China. Electronic address: qianyangcn@yeah.net.
authors.forename: Xinling
authors.initials: X
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008969:Molecular Sequence Data; D025282:Mycelium / Q000201:enzymology / Q000235:genetics; D010935:Plant Diseases / Q000382:microbiology; D048630:Polyketide Synthases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D014242:Trichoderma / Q000145:classification / Q000201:enzymology* / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D048630:Polyketide Synthases
keywords: Fungal plant pathogens; Gene disruption; Polyketide synthese; Real time quantitative PCR