title: Factors affecting distribution and abundance of Aspergillus section Nigri in vineyard soils from grapevine growing regions of Argentina.
abstract: BACKGROUND
  Aspergillus species belonging to section Nigri are the main fungi responsible for ochratoxin (OTA) contamination in grapes and wine. These species live as saprophytes in the superficial layer of the vineyard soil. We evaluated the biodiversity of potentially ochratoxigenic strains of Aspergillus section Nigri isolated from vineyard soils from different grapevine growing regions of Argentina. The isolates were characterized by classical and molecular methods. A multiple correspondence analysis was performed to identify the overall correlation of the Aspergillus group distribution with environmental conditions, geographical characteristics and vineyard practices.
  
  
  RESULTS
  Aspergillus niger aggregate was the prevalent group (71%) and A. carbonarius made up only 2%. Species discrimination by species-specific primers showed that in A. niger aggregate 89% were A. tubingensis; 97% of the uniseriate were A. japonicus/A. aculeatus. Isolates belonging to these groups were unable to produce OTA. Our results clearly demonstrate a strong association between presence of A. carbonarius, high average temperatures and drip irrigation. Precipitation levels appear as a secondary factor, and altitude, vineyard age, predominant species, grape variety or total fungal count showed no association with A. carbonarius.
  
  
  CONCLUSIONS
  We demonstrated a low prevalence of ochratoxigenic species in vineyard soil from the grape-growing regions of Argentina.
authors.affiliation: Department of Microbiology and Immunology, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Córdoba, Argentina.
authors.forename: Mauricio G
authors.initials: MG
authors.lastname: Barberis
authors.forename: Guillermo
authors.initials: G
authors.lastname: Giaj Merlera
authors.forename: Maria M
authors.initials: MM
authors.lastname: Reynoso
authors.forename: Sofia N
authors.initials: SN
authors.lastname: Chulze
authors.forename: Adriana M
authors.initials: AM
authors.lastname: Torres
mesh_terms: D000383:Agriculture / Q000379:methods*; D001118:Argentina; D001230:Aspergillus / Q000145:classification / Q000302:isolation & purification*; D012988:Soil Microbiology; D027843:Vitis
keywords: Aspergillus section Nigri distribution; multiple correspondence analysis; ochratoxin; vineyard soil