Characterization and genetic diversity of Curvularia lunata isolates associated with sorghum grains mold in Egypt.

Sorghum bicolor, an important crop in arid and semi-arid areas, faces significant biotic stressors,
particularly grain mold caused by fungal infections. Curvularia lunata emerged as a prominent pathogen
in sorghum leaf spot and grain mold, significantly impacting grain quality and yield. This study aimed to
isolate and characterize C. lunata strains from sorghum grain obtained from Egyptian markets. Ten
isolates were found, and tests on sorghum cultivar Giza 15 showed a wide range of virulence, with
disease ratings ranging from 22.67% to 66.68%. Morphological identification and phylogenetic
investigation verified the isolates' identity as C. lunata, with RAPD-analysis revealing the genetic
differences between isolates. Phylogenetic analysis divided the isolates into two major groups, with
considerable genetic similarity within each group. However, some isolates revealed significant genetic
divergence. The RAPD profiling revealed 38 DNA fragments, 93.05% of which were polymorphic,
showing that the isolates studied had a high level of genetic diversity. This diversity demonstrates the
pathogen's adaptability, which may be connected to pathogenic potential in various conditions. The
findings provide critical insights for breeding resistant sorghum varieties and underscore the need for
comprehensive management strategies to mitigate grain mold's impact on sorghum production.