AHMAD DAHAM RAJAB AL-SAMARRAI*, ABDUL-HAMID M. HAMOODY AND OMAR RAHEEM KHALAF AL-OBAIDI
Department of Biology, College of Education, University of Samarra, Iraq
*(e-mail : ahmed.dahham@uosamarra.edu.iq; Mobile : 00964 78221 08830)
(Received : February 10, 2022; Accepted : March 9, 2022)
ABSTRACT
The problem of damaging building wall paint with biological components is a widespread economic problem,
so the study was conducted to determine some of the most important fungi that cause damage to
building wall paint. A group of isolates of fungal colonies growing on the painted walls surfaces of some
neighbourhoods in Samarra city, Salah-al-Din, Iraq were taken. Isolation techniques and phenotypic
diagnosis were used for the purpose of preliminary identification of the isolates that were taken from
the walls of painted buildings, which showed the presence of the fungus Aspergillus niger and Alternaria
alternata. Genetic indicators and molecular diagnosis were used to confirm the genera that were isolated
using a number of genes, which are the ITS1, ITS4 genes. As a general diagnostic gene for the fungal
genera, two specialized diagnostic genes were also used, namely, the lipase gene for the diagnosis of A.
niger and the b-tubulin gene for the diagnosis of A. alternata. Molecular diagnostics results revealed that
the appearance of a 500 bp band of both fungi in relation to the ITS1, ITS4 gene primers, and the
appearance of a 184 bp band of the primers of the b-tubulin gene for the detection of the genus A.
alternata. As for the primers of the lipase gene, it did not indicate the presence of any genetic bundle,
which meant that there was no genetic match.
Key words : Paint, Alternaria alternata, Aspergillus niger, PCR