Response to osmotic stress and temperature of the fungus Ustilago maydis

Abstract

Ustilago maydis is a fungal pathogen which is exposed during its life cycle to both abiotic and biotic stresses before and after the infection of maize. To cope with extreme environmental changes, microorganisms usually accumulate the disaccharide trehalose. We have investigated both the accumulation of trehalose and the activity of trehalase during the adaptation of U. maydis haploid cells to thermal, sorbitol, and NaCl stresses. Sorbitol and sodium chloride induced sustained accumulation of trehalose, while a transient increase was observed under heat stress. Sorbitol stressed cells showed higher trehalase activity compared with control cells and to those stressed by NaCl and high temperature. Addition of cycloheximide, a protein synthesis inhibitor, did not affect the trehalose accumulation during the first 15 min, but basal levels of trehalose were reached after the second period of 15 min. The proteomic analysis of the response of U. maydis to temperature, sorbitol, and salt stresses indicated a complex pattern which highlights the change of 18 proteins involved in carbohydrate and amino acid metabolism, protein folding, redox regulation, ion homeostasis, and stress response. We hypothesize that trehalose accumulation during sorbitol stress in U. maydis might be related to the adaptation of this organism during plant infection.

Integrated proteomics, genomics, metabolomics approaches reveal oxalic acid as pathogenicity factor in Tilletia indica inciting Karnal bunt disease of wheat

“…Heat shock proteins (HSPs), a highly conserved family of molecular chaperones that play a crucial role in correct folding, stabilization and post translational modification of proteins 48 . The role of some HSP 70 family proteins has been demonstrated under various abiotic stress conditions such as osmotic stress and temperature stress 49 , 50 .…”

Small heat shock proteins (HSP12, HSP20 and HSP30) play a role inUstilago maydispathogenesis

“…Although a number of studies have already been done to elucidate the mechanism of pathogenic development of the fungus (Heimel et al ., ), nothing is known about the involvement, if any, of HSPs in the virulence of the fungus. However, studies led by Holden (Holden et al ., ) and Salmeron‐Santiago (Salmeron‐Santiago et al ., ) showed differential expression of certain HSP 70 family proteins in response to different stress conditions involving heat stress and osmotic stress. Therefore in the present study we attempted to explore the status of U. maydis HSPs, and small HSPs in particular, during an event of maize infection using mating‐compatible FB1 and FB2 strains of the fungus.…”

Proteomic analysis of mycelial proteins from Magnaporthe oryzae under nitrogen starvation

“…Trehalose stores carbohydrates not only to cope with carbon starvation, but also in response to abiotic stress, such as salt and high temperature (Garg et al, 2002;Cortina and Culiáñez-Macià, 2005;Salmerón-Santiago et al, 2011). Our data showed that in response to nitrogen starvation, M. oryzae reduced the expression levels of trehalase in order to increase trehalose accumulation to enhance resistance.…”