MOLECULAR CHARACTERIZATION AND PATHOGENICITY TEST ON CITRUS FRUITS BY GREEN MOLD AND BLUE MOLD

Abstract

Citrus fruits are essential for preventing various health conditions, including diabetes, neurological diseases, and cancer. Among the postharvest diseases affecting citrus fruits, Penicillium digitatum and Penicillium italicum are particularly significant. This study aimed to characterize Penicillium spp. isolated from three citrus varieties: orange (Citrus sinensis), small orange, and Malta. Pathogenicity tests confirmed that these Penicillium isolates were capable of infecting the tested citrus fruits. For molecular characterization, PCR amplification of the D1/D2 domain of 26S rDNA was performed using universal primers, which target the conserved regions of the nucleotide sequence. The PCR products were inserted into the pGEM-T Easy vector and transformed into E. coli Dh5α. The presence of the D1/D2 domain was verified by endonuclease digestion with EcoR1. Sequencing was conducted using the T7 promoter primer, and the resulting DNA sequences were analyzed with the DNAMAN analysis system. Sequence analysis revealed that the D1/D2 region of 26S rDNA from the orange isolate showed 99% similarity with Penicillium sp., while the D1/D2 region from the small orange isolate had 99.84% similarity with P. digitatum strain CBS 112082. The D1/D2 region from the Malta isolate showed 100% similarity with P. digitatum. Multiple sequence alignments among the three Penicillium isolates revealed a 98.81% identity. This study highlights the use of molecular techniques for understanding the pathogenicity of Penicillium spp. in citrus fruits.