Proteomic Analysis Reveals Suppression of Bark Chitinases and Proteinase Inhibitors in Citrus Plants Affected by the Citrus Sudden Death Disease

• Published in: Phytopathology Vol. 98; no. 10; pp. 1084 - 1092
• Main Authors: Cantú, M.D, Mariano, A.G, Palma, M.S, Carrilho, E, Wulff, N.A
• Format: Journal Article
• Language: English
• Published: St. Paul, MN American Phytopathological Society 01.10.2008
• Subjects: amino acid sequences; bark; Biological and medical sciences; Brazil; chitinase; Chitinases - antagonists & inhibitors; Citrus; Citrus - genetics; Citrus - virology; Citrus sinensis; Electrophoresis, Gel, Two-Dimensional; Fundamental and applied biological sciences. Psychology; gel electrophoresis; host-pathogen relationships; oranges; Phytopathology. Animal pests. Plant and forest protection; Plant Bark - genetics; Plant Bark - virology; Plant Diseases - genetics; Plant Diseases - virology; plant diseases and disorders; plant pathogens; Plant Proteins - genetics; Plant Proteins - isolation & purification; Plant Stems - genetics; Plant Stems - virology; Protease Inhibitors - analysis; proteinase inhibitors; Proteome; proteomics; random amplified polymorphic DNA technique; rootstock-scion relationships; rootstocks; sequence analysis; Tymoviridae - genetics; Tymoviridae - pathogenicity; Brazil; Chitinase; Plant pathology; Serine endopeptidases; Microbiology; Plant pathogen; Enzyme; Citrus fruit; Suppression; Rutaceae; Pathogenesis related protein; Glycosylases; Citrus; Peptidases; Plant; Regulation(control); Trypsin; Dicotyledones; Glycosidases; Angiospermae; Proteomics; Hydrolases; Graft; Spermatophyta; Two dimensional electrophoresis
• ISSN: 0031-949X; 1943-7684
• DOI: 10.1094/phyto-98-10-1084

Citrus sudden death (CSD) is a disease of unknown etiology that greatly affects sweet oranges grafted on Rangpur lime rootstock, the most important rootstock in Brazilian citriculture. We performed a proteomic analysis to generate information related to this plant pathogen interaction. Protein profiles from healthy, CSD-affected and CSD-tolerant stem barks, were generated using two-dimensional gel electrophoresis. The protein spots were well distributed over a pI range of 3.26 to 9.97 and a molecular weight (MW) range from 7.1 to 120 kDa. The patterns of expressed proteins on 2-DE gels made it possible to distinguish healthy barks from CSD-affected barks. Protein spots with MW around 30 kDa and pI values ranging from 4.5 to 5.2 were down-regulated in the CSD-affected root-stock bark. This set of protein spots was identified as chitinases. Another set of proteins, ranging in pI from 6.1 to 9.6 with an MW of about 20 kDa, were also suppressed in CSD-affected rootstock bark; these were identified as miraculin-like proteins, potential trypsin inhibitors. Down-regulation of chitinases and proteinase inhibitors in CSD-affected plants is relevant since chitinases are well-known pathogenesis-related protein, and their activity against plant pathogens is largely accepted.