Alternaria Species Associated with Strawberry Cultivars in the Almaty Region of Kazakhstan: Diversity,Multilocus Characterization and Pathogenicity

Alternaria species are important fungal pathogens of strawberry, while information on their occurrence and genetic diversity in Kazakhstan remains limited. This study aimed to characterize Alternaria isolates associated with symptomatic strawberry plants in the Almaty Region,to describe their recovery patterns among the examined cultivars and plant organs, and to assess the pathogenicity of representative isolates. Seventy plants representing nine strawberry cultivars were collected from four commercial farms. Fungal isolates were characterized based on cultural and morphological features and multilocus sequence analysis of the ITS, GAPDH, and TEF1 regions, followed by maximum-likelihood phylogenetic analysis. Alternaria spp. were detected in 14 of 70 plants (20.0%), from which 19 isolates were obtained and molecularly characterized. Of these, 14 isolates (73.7%) were assigned to A. alternata, whereas five (26.3%) were assigned to A. tenuissima. The isolates were recovered from leaves, berries, stems, and roots and were detected in five of the nine cultivars examined. Multilocus phylogenetic analysis supported the placement of the A. alternata isolates within the A. alternata species complex, whereas the A. tenuissima-assigned isolates did not form a single exclusive lineage. A preliminary pathogenicity assay using two representative isolates showed that both were capable of inducing necrotic lesions and other disease symptoms on strawberry plants under controlled conditions; however, the limited number of isolates tested restricts inference to the broader recovered population.These findings provide new data on Alternaria associated with strawberry in the Almaty Region of Kazakhstan and highlight the value of multilocus approaches for their accurate characterization.