Molecular identification of fungal pathogens associated with date palm root diseases in the United Arab Emirates

Date palm is the most widely cultivated crop in the United Arab Emirates (UAE). This study identified the main fungal root pathogens of date palms in the UAE. Isolations were established from 84 root samples and the recovered fungal isolates were identified using morphology and sequences of the internal transcribed spacer region of the ribosomal RNA gene (ITS rRNA) or the translation elongation factor gene (TEF1). The study revealed association of 10 fungal species with date palm roots, with Fusarium solani (82%), Lasiodiplodia hormozganensis (57%), Ceratocystis radicicola (7%) and L. theobromae (7%) being the most common. A pathogenicity test revealed that C. radicicola is the most aggressive, followed by L. hormozganensis and L. theobromae. These fungi resulted in rotting and development of necrosis on the roots as well as the development of wilt symptoms on 12-month old date palm seedlings. To our knowledge, this study is the first report of association of C. radicicola with date palm root diseases in the UAE. It also appears to report for the first time three new fungal species in the UAE, Fusarium keratoplasticum, Cochliobolus hawaiiensis and Cephaliophora tropica.