title: RNA-Seq-based transcriptome analysis of aflatoxigenic Aspergillus flavus in response to water activity.
abstract: Aspergillus flavus is one of the most important producers of carcinogenic aflatoxins in crops, and the effect of water activity (a(w)) on growth and aflatoxin production of A. flavus has been previously studied. Here we found the strains under 0.93 a(w) exhibited decreased conidiation and aflatoxin biosynthesis compared to that under 0.99 a(w). When RNA-Seq was used to delineate gene expression profile under different water activities, 23,320 non-redundant unigenes, with an average length of 1297 bp, were yielded. By database comparisons, 19,838 unigenes were matched well (e-value < 10⁻⁵) with known gene sequences, and another 6767 novel unigenes were obtained by comparison to the current genome annotation of A. flavus. Based on the RPKM equation, 5362 differentially expressed unigenes (with |log₂Ratio| ≥ 1) were identified between 0.99 a(w) and 0.93 a(w) treatments, including 3156 up-regulated and 2206 down-regulated unigenes, suggesting that A. flavus underwent an extensive transcriptome response during water activity variation. Furthermore, we found that the expression of 16 aflatoxin producing-related genes decreased obviously when water activity decreased, and the expression of 11 development-related genes increased after 0.99 a(w) treatment. Our data corroborate a model where water activity affects aflatoxin biosynthesis through increasing the expression of aflatoxin producing-related genes and regulating development-related genes.
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. fzhang@fafu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. joancikwok@hotmail.com.
authors.forename: Zhenni
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. zhonghong_321@yahoo.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. wangsen123jay@yahoo.com.
authors.forename: Sen
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. ywq20011@outlook.com.
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Yang
authors.affiliation: Shenzhen Key Laboratory of Bioenergy, BGI-Shenzhen, Shenzhen 518083, China. liuyongfeng@bgitechsolutions.com.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of the Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China. shwang@fafu.edu.cn.
authors.forename: Shihua
authors.initials: S
authors.lastname: Wang
mesh_terms: D000348:Aflatoxins / Q000096:biosynthesis*; D001231:Aspergillus flavus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D002274:Carcinogens, Environmental / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D013045:Species Specificity; D013312:Stress, Physiological; D013696:Temperature; D059467:Transcriptome; D055548:Vapor Pressure
chemical_list: D000348:Aflatoxins; D002274:Carcinogens, Environmental; D005656:Fungal Proteins