title: Proteomic analysis of responsive stem proteins of resistant and susceptible cashew plants after Lasiodiplodia theobromae infection.
abstract: Gummosis is an aggressive disease caused by the necrotrophic fungus Lasiodiplodia theobromae (Pat.) Griffon & Maubl that threatens commercial cashew orchads in Brazil. To study the molecular mechanisms involved in the cashew response to L. theobromae, a proteomic analysis of stems from the commercial cashew clone BRS 226 (resistant) was conducted at early times post-artificial infection. In addition, changes in the stem proteome profiles of gummosis resistant and susceptible cashew plants grown under field condition and naturally exposed to pathogen were also compared. After two-dimensional gel electrophoresis (2D-PAGE), 73 proteins showed statistically significant differences in spot abundance. Of these, 31 spots were identified in BRS 226 stems compared with mock-inoculated controls and 32 in stems collected from field-grown resistant and susceptible cashew plants. L. theobromae-responsive proteins were mainly involved in energy metabolism pathways, stress and defense, cell signaling and protein metabolism indicating modulation of various cellular functions upon fungal infection. As stress-inducing factors seem to be important for susceptibility to disease, the change in the abundance relative these proteins may possibly indicate an attempt to maintain cellular homeostasis, as resistance determinant factor, related with a possible role in the regulation of oxidative burst. These findings provide the first information about the cellular mechanisms acting in the Anacardium occidentale genotypes associated with the pathophysiological state of infection with L. theobromae.
  
  
  CONCLUSIONS
  Gummosis caused by Lasiodiplodia theobromae, a necrotrophic fungus, is the major disease of cashew plants in the semi-arid conditions of northeastern Brazil. Although various studies were carried out on this pathosystem, there is no information available on the molecular mechanisms of plant defense related to the incompatible interaction of cashew with L. theobromae. Therefore, this original study comprises a differential proteomic analysis of cashew stems from: (i) resistant dwarf clone BRS 226 mock-inoculated (control) and artificially inoculated with L. theobromae; and (ii) cashew plants bearing resistant and susceptible traits to gummosis, originated from open pollination of BRS 226 in a commercial orchard with high disease incidence. The contribution of the reprogrammed proteins to molecular events triggered in cashew plants challenged by L. theobromae has a great relevance in the identification of the host candidate proteins linked to biological pathways that respond to L. theobromae infection. Furthermore this study may contribute to improve breeding programs aimed at selecting resistant/tolerant cashew clones toward this pathogen.
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceara, Brazil.
authors.forename: Aline K A L
authors.initials: AK
authors.lastname: Cipriano
authors.affiliation: School of Pharmacy, The University of Fortaleza (UNIFOR), Ceara, Brazil.
authors.forename: Darcy M F
authors.initials: DM
authors.lastname: Gondim
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceara, Brazil.
authors.forename: Ilka M
authors.initials: IM
authors.lastname: Vasconcelos
authors.affiliation: Department of Animal Science, Federal University of Ceara, Brazil.
authors.forename: Jorge A M
authors.initials: JA
authors.lastname: Martins
authors.affiliation: Department of Animal Science, Federal University of Ceara, Brazil.
authors.forename: Arlindo A
authors.initials: AA
authors.lastname: Moura
authors.affiliation: School of Pharmacy, The University of Fortaleza (UNIFOR), Ceara, Brazil.
authors.forename: Frederico B
authors.initials: FB
authors.lastname: Moreno
authors.affiliation: School of Pharmacy, The University of Fortaleza (UNIFOR), Ceara, Brazil.
authors.forename: Ana C O
authors.initials: AC
authors.lastname: Monteiro-Moreira
authors.affiliation: Brazilian Agricultural Research Corporation, Tropical Agroindustry Research Center (EMBRAPA), Brazil.
authors.forename: Jose G M
authors.initials: JG
authors.lastname: Melo
authors.affiliation: Brazilian Agricultural Research Corporation, Tropical Agroindustry Research Center (EMBRAPA), Brazil.
authors.forename: Jose E
authors.initials: JE
authors.lastname: Cardoso
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceara, Brazil.
authors.forename: Ana Luiza S
authors.initials: AL
authors.lastname: Paiva
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Ceara, Brazil. Electronic address: jtaolive@ufc.br.
authors.forename: Jose T A
authors.initials: JT
authors.lastname: Oliveira
mesh_terms: D031021:Anacardium / Q000378:metabolism* / Q000382:microbiology; D001203:Ascomycota; D060467:Disease Resistance / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000096:biosynthesis*; D040901:Proteomics
chemical_list: D010940:Plant Proteins
keywords: Anacardium occidentale; Defense; Gummosis; Lasiodiplodia theobromae; Proteomics