Molecular characterization molecular characterization of fungal pathogens associated with citrus withertip/dieback from major citrus growing areas of Punjab, Pakistan

Abstract

Citrus withertip/dieback is an emerging threat to the citrus production which results into yield losses including death of the plants. Characteristic symptoms are leaf chlorosis, drooping of the leaves, dieback spreading towards main stem and black pustules on the dead twigs. The current study was designed for molecular characterization of casual organism associated with citrus withertip/dieback. Samples were collected from four main citrus growing district (Sargodha, Kot Momin, Bhalwal and Faisalabad) of Punjab, Pakistan. It was found that different species of Colletotrichum were associated with citrus withertip/dieback on morphological basis. Pathogenicity test were performed following Koch's postulates to confirm the association of fungal species with citrus dieback. To characterize the pathogens, Whole genome of seven Pakistani isolates were sequenced, submitted to NCBI and have given accession numbers. Multi-gene phylogenetic and Average Nucleotide identity (ANI) analysis revealed that two different species of Colletotrichum; C. gloeosporioides and C. siamense were responsible for Citrus withertip/dieback in Punjab, Pakistan.