Heat-shock response of the entomopathogenic fungusBeauveria brongniartii

Abstract

The heat-shock response of five strains of the entomopathogenic fungus Beauveria brongniartii was studied using two-dimensional (2D) gel electrophoresis. The fungal cells were heat shocked at 4S°C for 1 h and the total cellular protein was subjected to 2D gel electrophoresis. Proteins were separated in the first dimension using isoelectric focusing (pH range of 3.0-10) and in the second dimension by sodium dodecyl sulphate -polyacrylamide gel electrophoresis. More than 150 polypeptides for each strain were visualized by silver staining and have been assigned individual numbers as polypeptide coordinates. Analysis of the polypeptide map obtained by 2D gels indicated three patterns; several unique heat-shock proteins (HSPs) were (i) induced, (ii) enhanced, or (iii) repressed. Some of the HSPs induced by 45°C were unique for each of the strains tested. Identification of heat-inducible protein synthesis or repression has ramificati~ns~for field survival and performance of entomopathogenic fungi. As well, the HSPs can be used as "signature proteins" for identification pruposes and this raises the possibility of using HSPs as a diagnostic tool applicable to other pest control fungi.Resume : La rCponse au choc thermique de cinq souches de Beauvaria brongniartii, un champignon entomopathogkne, a Ct C CtudiCe par Clectrophorbse en gel B deux dimensions. Les cellules fongiques ont Ct C soumises a un choc thermique B 45°C pendant 1 h et le contenu protCique cellulaire total a Ct C analysC par Clectrophorbse en gel B deux dimensions. Dans la premibre dimension, les protkines ont Ct C sCparCes selon leur point isoClectrique (pH 3,O-10) et dans la deuxibme dimension par leur migration en gel de polyacrylamide -dodCcyl sulfate de sodium. Chez chacune des souches, plus de 150 polypeptides ont pu &tre mis en evidence par coloration B l'argent et nous leur avons attribue des numCros individuels comme coordonnCes polypeptidiques. La cartographie des polypeptides obtenue des gels bi-dimensionnels a rCvClC trois profils; quelques protkines uniques de choc thermique (HSP) Ctaient (i) induites, (ii) favorisCes ou (iii) r6primCes. Certaines des HSP induites B 4S°C Ctaient uniques de chacune des souches CtudiCes. La comprChension de la synthbse ou de la rkpression des protCines inductibles par la chaleur a des implications sur la survie dans la nature et la performance des champignons entomopathogbnes. Ainsi, les HSP pourraient &tre utilisCes comme "prot6ines-signatures" pour fins d'identification et il pourrait &re possible de se servir des HSP comme outil de diagnostic applicable B d'autres champignons utilisCs dans la lutte biologique contre les insectes.Mots clis : protkines de choc thermique, rCponse au choc thermique, electrophorbse bi-dimensionnelle, champignons entomopathogbnes, Beauvaria brongniartii. [Traduit par la rCdaction]

Use of Pathogen Combinations to Overcome the Constraints of Temperature on Entomopathogenic Hyphomycetes against Grasshoppers

“…Although the optimal temperature for growth of M. flavoviride hyphae is approximately 27 to 28°C, exposures to 35 and 40°C for 2 to 8 h/day increased the rate of growth relative to 25°C. The reason for the increased rate of growth of M. flavoviride hyphae exposed to high temperatures is uncertain but recently the induction of heat shock proteins (HSPs) was observed in B. brongniartii blastospores exposed to 45°C (Xavier and Khachatourians, 1996) and the formation of HSPs in hyphae may explain the observed increase in vegetative growth. Relatively poor relationships were observed between mortality and hyphal growth or conidial germination.…”

Fungii entomopatogeni

“…Temperatura înaltă afectează direct sporularea, iar temperaturile extreme pot inhiba complet producerea de spori (Piatkowski, Krzyzewska, 2007;Mwamburi, Laing, Miller, 2015). De asemenea este cunoscut faptul că la temperaturi mai mari de 45°C se induce sinteza de proteine de șoc termic (Xavier, Khachatourians, 1996). Toleranța termică este un element cheie pentru stabilitatea și efi ciența preparatului pe bază de condii fungice în condiții de câmp (Tong, Feng, 2020).…”

A Two Dimensional Gel Electrophoresis Technique Combining a Micro‐ and a Mini‐gel System for Proteomic Analysis of Fungal Heat Shock Proteins

“…There exists a need for a rapid 2-DGE technique that could analyze limited amounts of protein samples in an initial experiment to monitor and identify proteins of interest whose expression changes as a result of environmental conditions or disease. To this end we describe a 2-DGE technique currently used in our laboratory to study the stress response of several deuteromycetous fungi which requires 2-DGE screening and analysis of total cellular proteins of several fungal species or isolates (Xavier and Khachatourians 1996;Xavier er al. 1999).…”