title: Expression of plant ferredoxin-like protein (PFLP) enhances tolerance to heat stress in Arabidopsis thaliana.
abstract: Under adverse environments, plants produce reactive oxygen species (ROS), which can trigger cell death when their accumulation surpasses the antioxidant capacity of ROS scavenging systems. These systems function in chloroplasts mainly through the ascorbate-mediated water-water cycle, in which ascorbate is photoreduced by ferredoxin in the photosynthetic system. Our previous study showed that the fraction of the reduced form of ascorbate was increased in ferredoxin-transgenic Arabidopsis (CPF) plants which overexpressed plant ferredoxin-like protein (PFLP) in their chloroplasts. Thus, we hypothesized that expression of PFLP could alter the tolerance of plants to abiotic stresses through increasing reduced form of ascorbate. In this study, we found that two CPF lines exhibited lower mortality rates at five days, following two days of heat treatment. Compared to non-transgenic wild type (Col-0) plants, CPF plants exhibited decreased H2O2 content, MDA accumulation, and ion leakage after heat treatment. To confirm the efficacy of ferredoxin against heat stress in chloroplasts, we evaluated two RNA interference (RNAi) lines on two endogenous ferredoxin isoforms, Atfd1 or Atfd2, of Arabidopsis plants. Both lines not only decreased their amounts of ascorbate, but also exhibited adverse reactions following heat treatment. Based on these results, we conclude that expression of PFLP in chloroplasts can confer tolerance to heat stress. This tolerance might be associated with the increasing of ascorbate in plants.
authors.affiliation: Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: yhlin@mail.npust.edu.tw.
authors.forename: Yi-Hsien
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Taoyuan, Taiwan.
authors.forename: Li-Fen
authors.initials: LF
authors.lastname: Huang
authors.affiliation: Laboratory of Regulation of Biological Reactions, Institute for Protein Research, Osaka University, Osaka, Japan.
authors.forename: Tashiharu
authors.initials: T
authors.lastname: Hase
authors.affiliation: Department of Life Science, National Taitung University, Taitung, Taiwan.
authors.forename: Hsiang-En
authors.initials: HE
authors.lastname: Huang
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Teng-Yung
authors.initials: TY
authors.lastname: Feng
mesh_terms: D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology*; D001205:Ascorbic Acid / Q000378:metabolism; D018533:Biomass; D005288:Ferredoxins / Q000378:metabolism*; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000378:metabolism; D007477:Ions; D008315:Malondialdehyde / Q000378:metabolism; D010641:Phenotype; D030821:Plants, Genetically Modified; D034622:RNA Interference; D013312:Stress, Physiological
chemical_list: D005288:Ferredoxins; D007477:Ions; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D001205:Ascorbic Acid