A peptidogalactomannan isolated from Cladosporium herbarum induces defense-related genes in BY-2 tobacco cells

Bianca Braz Mattos; Caroline Montebianco; Elisson Romanel; Tatiane da Franca Silva; Renato Barroso Bernabé; Fernanda Simas-Tosin; Lauro M Souza; Guilherme L Sassaki; Maite F S Vaslin; Eliana Barreto-Bergter

doi:10.1016/j.plaphy.2018.02.023

A peptidogalactomannan isolated from Cladosporium herbarum induces defense-related genes in BY-2 tobacco cells

Plant Physiol Biochem. 2018 May:126:206-216. doi: 10.1016/j.plaphy.2018.02.023. Epub 2018 Mar 2.

Affiliations

¹ Laboratório de Química Biológica de Microorganismos, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941599, Rio de Janeiro, Brazil.
² Laboratório de Química Biológica de Microorganismos, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941599, Rio de Janeiro, Brazil; Laboratório de Virologia Molecular Vegetal, Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941590, Rio de Janeiro, Brazil.
³ Laboratório de Virologia Molecular Vegetal, Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941590, Rio de Janeiro, Brazil.
⁴ Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná (UFPR), Curitiba, Paraná, Brazil.
⁵ Laboratório de Virologia Molecular Vegetal, Departamento de Virologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941590, Rio de Janeiro, Brazil. Electronic address: maite@micro.ufrj.br.
⁶ Laboratório de Química Biológica de Microorganismos, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), Av. Carlos Chagas Filho, 373, CCS 21941599, Rio de Janeiro, Brazil. Electronic address: eliana.bergter@micro.ufrj.br.

PMID: 29525444
DOI: 10.1016/j.plaphy.2018.02.023

Abstract

Cladosporium herbarum is a plant pathogen associated with passion fruit scab and mild diseases in pea and soybean. In this study, a peptidogalactomannan (pGM) of C. herbarum mycelium was isolated and structurally characterized, and its role in plant-fungus interactions was evaluated. C. herbarum pGM is composed of carbohydrates (76%) and contains mannose, galactose and glucose as its main monosaccharides (molar ratio, 52:36:12). Methylation and ¹³C-nuclear magnetic resonance (¹³C-NMR) spectroscopy analysis have shown the presence of a main chain containing (1 → 6)-linked α-D-Manp residues, and β-D-Galf residues are present as (1 → 5)-interlinked side chains. β-Galactofuranose containing similar structures were characterized by our group in A. fumigatus, A. versicolor, A. flavus and C. resinae. Tobacco BY-2 cells were used as a model system to address the question of the role of C. herbarum pGM in cell viability and induction of the expression of plant defense-related genes. Native and partially acid hydrolyzed pGMs (lacking galactofuranosyl side-chain residues) were incubated with BY-2 cell suspensions at different concentrations. Cell viability drastically decreased after exposure to more than 400 μg ml^-1 pGM; however no cell viability effect was observed after exposure to a partially acid hydrolyzed pGM. BY-2 cell contact with pGM strongly induce the expression of plant defense-related genes, such as phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX), as well as the pathogen-related PR-1a, PR-2 and PR-3 genes, suggesting that pGM activates defense responses in tobacco cells. Interestingly, contact with partially hydrolyzed pGM also induced defense-related gene expression at earlier times than native pGM. These results show that the side chains of the (1 → 5)-linked β-D-galactofuranosyl units from pGM play an important role in the first line fungus-plant interactions mediating plant responses against C. herbarum. In addition, it was observed that pGM and/or C. herbarum conidia are able to induced HR when in contact with tobacco leaves and in vitro plantlets roots, producing necrotic lesions and peroxidase and NO burst, respectively.

Keywords: Cladosporium herbarum; Glycoprotein; Peptidogalactomannan; Plant defense-related genes.

MeSH terms

Cladosporium*
Gene Expression Regulation, Developmental*
Gene Expression Regulation, Plant*
Nicotiana* / cytology
Nicotiana* / enzymology
Nicotiana* / microbiology
Plant Cells / metabolism
Plant Diseases / microbiology*
Plant Leaves* / cytology
Plant Leaves* / enzymology
Plant Leaves* / microbiology
Plant Roots* / cytology
Plant Roots* / enzymology
Plant Roots* / microbiology