Aspergillus niger causes black mould disease on Piarom dates, the most economically valuable export date cultivar in southern Iran

Abstract

In 2021, we observed symptoms of black mould disease on dates cv. Piarom, the most economically valuable export date cultivar in Hormozgan province, southern Iran. This study aimed to evaluate the disease incidence, identify the aetiological agent, and fulfill the pathogenicity on Piarom dates in this area. Aspergillus isolates were permanently obtained from the symptomatic dates on PDA, which were identified as Aspergillus niger based on morphological characteristics, as well as partial sequence data from the internal transcribed spacer region (ITS1-5.8S-ITS2) and Beta Tubulin (benA) gene. A phylogeny inferred using individual sequence data from ITS and benA sequences placed our isolates together with the other A. niger strains in the GenBank. The pathogenicity assays using symptom-free Piarom dates revealed the association of A. niger with the disease. Reisolation from the inoculated fruits yielded the isolates of A. niger, proving Koch's postulates. This is the first report of A. niger causing black mould disease on Piarom dates in Iran.