title: Transcriptional analysis of the conidiation pattern shift of the entomopathogenic fungus Metarhizium acridum in response to different nutrients.
abstract: Most fungi, including entomopathogenic fungi, have two different conidiation patterns, normal and microcycle conidiation, under different culture conditions, eg, in media containing different nutrients. However, the mechanisms underlying the conidiation pattern shift are poorly understood.
  
  
  
  In this study, Metarhizium acridum undergoing microcycle conidiation on sucrose yeast extract agar (SYA) medium shifted to normal conidiation when the medium was supplemented with sucrose, nitrate, or phosphate. By linking changes in nutrients with the conidiation pattern shift and transcriptional changes, we obtained conidiation pattern shift libraries by Solexa/Illumina deep-sequencing technology. A comparative analysis demonstrated that the expression of 137 genes was up-regulated during the shift to normal conidiation, while the expression of 436 genes was up-regulated at the microcycle conidiation stage. A comparison of subtractive libraries revealed that 83, 216, and 168 genes were related to sucrose-induced, nitrate-induced, and phosphate-induced conidiation pattern shifts, respectively. The expression of 217 genes whose expression was specific to microcycle conidiation was further analyzed by the gene expression profiling via multigene concatemers method using mRNA isolated from M. acridum grown on SYA and the four normal conidiation media. The expression of 142 genes was confirmed to be up-regulated on standard SYA medium. Of these 142 genes, 101 encode hypothetical proteins or proteins of unknown function, and only 41 genes encode proteins with putative functions. Of these 41 genes, 18 are related to cell growth, 10 are related to cell proliferation, three are related to the cell cycle, three are related to cell differentiation, two are related to cell wall synthesis, two are related to cell division, and seven have other functions. These results indicate that the conidiation pattern shift in M. acridum mainly results from changes in cell growth and proliferation.
  
  
  
  The results indicate that M. acridum shifts conidiation pattern from microcycle conidiation to normal conidiation when there is increased sucrose, nitrate, or phosphate in the medium during microcycle conidiation. The regulation of conidiation patterning is a complex process involving the cell cycle and metabolism of M. acridum. This study provides essential information about the molecular mechanism of the induction of the conidiation pattern shift by single nutrients.
authors: Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 400045, People's Republic of China.|Chongqing Engineering Research Center for Fungal Insecticide, Chongqing University, Chongqing, 400045, People's Republic of China.|Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400045, People's Republic of China.
authors: Zhenglong
authors: Z
authors: Wang
authors: Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 400045, People's Republic of China.|Chongqing Engineering Research Center for Fungal Insecticide, Chongqing University, Chongqing, 400045, People's Republic of China.|Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400045, People's Republic of China.
authors: Kai
authors: K
authors: Jin
authors: Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, 400045, People's Republic of China. yuxianxia@cqu.edu.cn.|Chongqing Engineering Research Center for Fungal Insecticide, Chongqing University, Chongqing, 400045, People's Republic of China. yuxianxia@cqu.edu.cn.|Key Laboratory of Gene Function and Regulation Technologies under Chongqing Municipal Education Commission, Chongqing University, Chongqing, 400045, People's Republic of China. yuxianxia@cqu.edu.cn.
authors: Yuxian
authors: Y
authors: Xia
mesh_terms: D019295:Computational Biology / Q000379:methods; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D063990:Gene Ontology; D053858:Metabolic Networks and Pathways; D052981:Metarhizium / Q000502:physiology*; D009747:Nutritional Physiological Phenomena / Q000235:genetics*; D059467:Transcriptome
keywords: Conidiation pattern shift; Metarhizium acridum; Normal and microcycle conidia; Pathway analysis