Screening and modes of action of antagonistic bacteria to control the fungal pathogen Phaeomoniella chlamydospora involved in grapevine trunk diseases.
The antagonistic activity of 46 bacterial strains isolated from Bordeaux vineyards were evaluated against Phaeomoniella chlamydospora, a major grapevine pathogen involved in Esca. The reduction of the necrosis length of stem cuttings ranged between 31.4% and 38.7% for the 8 most efficient strains. Two in planta trials allowed the selection of the two best strains, Bacillus pumilus (S32) and Paenibacillus sp. (S19). Their efficacy was not dependent on application method; co-inoculation, prevention in the wood and soil inoculation were tested. The involvement of antibiosis by the secretion of diffusible and/or volatile compounds in the antagonistic capacity of these two strains was assessed in vitro. Volatile compounds secreted by B. pumilus (S32) and Paenibacillus sp. (S19) were identified by gas chromatography/mass spectroscopy (GC/MS). The volatile compounds 1-octen-3-ol and 2,5-dimethyl pyrazine were obtained commercially and tested, and they showed strong antifungal activity against P. chlamydospora, which suggested that these compounds may play an important role in the bacterial antagonistic activity in planta. Furthermore, the expression of 10 major grapevine defense genes was quantified by real-time polymerase chain reaction, which demonstrated that the two strains significantly affected the grapevine transcripts four days after their application on the plants. High expression levels of different genes associated with P. chlamydospora infection in B. pumilus pre-treated plants suggests that this strain induces systemic resistance in grapevine. For the first time, we demonstrated the ability of two bacterial strains, B. pumilus and Paenibacillus sp., isolated from grapevine wood, to control P. chlamydospora via direct and/or indirect mechanisms.
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France; Tichreen University, Faculty of Science, Biology Department, P.O. Box 2231, Latakia, Syrian Arab Republic. Electronic address: haidarrana@gmail.com.
Rana
R
Haidar
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Jean
J
Roudet
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Olivier
O
Bonnard
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Marie Cécile
MC
Dufour
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Marie France
MF
Corio-Costet
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Mathieu
M
Fert
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Thomas
T
Gautier
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Alain
A
Deschamps
SAVE, INRA, Institut National de Recherche Agronomique, Bordeaux Sciences Agro, ISVV, 33882 Villenave d'Ornon, France.
Marc
M
Fermaud
D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism / Q000494:pharmacology; D001203:Ascomycota / Q000187:drug effects / Q000502:physiology*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D008826:Microbial Sensitivity Tests; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D027843:Vitis / Q000382:microbiology*; D055549:Volatile Organic Compounds / Q000378:metabolism / Q000494:pharmacology
D000935:Antifungal Agents; D055549:Volatile Organic Compounds
Antibiosis; Biocontrol; Grapevine trunk diseases; Induction of resistance; VOCs; Vitis vinifera