title: Effect of heat shock treatment on stress tolerance and biocontrol efficacy of Metschnikowia fructicola.
abstract: The effect of high temperature and oxidative stress on the cell viability of the yeast antagonist, Metschnikowia fructicola was determined. A mild heat shock (HS) pretreatment (30 min at 40 °C) improved the tolerance of M. fructicola to subsequent high temperature (45 °C, 20-30 min) and oxidative stress (0.4 mol L⁻¹ hydrogen peroxide, 20-60 min). HS-treated yeast cells showed less accumulation of reactive oxygen species (ROS) than nontreated cells in response to both stresses. Additionally, HS-treated yeast exhibited significantly greater (P<0.0001) biocontrol activity against Penicillium expansum and a significantly faster (P<0.0001) growth rate in wounds of apple fruits stored at 25 °C compared with the performance of untreated yeast cells. Transcription of a trehalose-6-phosphate synthase gene (TPS1) was upregulated in response to HS and trehalose content also increased. Results indicate that the higher levels of trehalose induced by the HS may contribute to an improvement in ROS scavenging, stress tolerance, population growth in apple wounds and biocontrol activity of M. fructicola.
authors.affiliation: US Department of Agriculture-Agricultural Research Service (USDA-ARS), Kearneysville, WV 25430, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Liu
authors.forename: Michael
authors.initials: M
authors.lastname: Wisniewski
authors.forename: Samir
authors.initials: S
authors.lastname: Droby
authors.forename: Shiping
authors.initials: S
authors.lastname: Tian
authors.forename: Vera
authors.initials: V
authors.lastname: Hershkovitz
authors.forename: Thomas
authors.initials: T
authors.lastname: Tworkoski
mesh_terms: D000898:Antibiosis; D001483:Base Sequence; D005638:Fruit / Q000382:microbiology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D027845:Malus / Q000382:microbiology; D055163:Metschnikowia / Q000235:genetics / Q000502:physiology*; D050296:Microbial Viability; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010407:Penicillium / Q000472:pathogenicity / Q000502:physiology; D010935:Plant Diseases / Q000517:prevention & control; D017382:Reactive Oxygen Species / Q000032:analysis; D014199:Trehalose / Q000096:biosynthesis
chemical_list: D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D014199:Trehalose; D006861:Hydrogen Peroxide; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase