Identification of Chaetomium and Amesia species associated with different diseases of some herbaceous ornamentals in Ahvaz

Abstract

Introduction: Common zinnia (Zinnia elegans), canna (Canna sp.), petunia (Petunia hybrida), compacta (Dracaena Compacta), dahlia (Dahlia sp.), gazania (Gazania sp.), marigold (Tagetes sp.), rose moss (Portulaca grandiflora) and nasturtium (Tropaeolum majus) are common ornamental plants in Ahvaz. The identification of fungi associated with these plants will contribute to improving the future managment of their cultivation. Members of the genera Amesia and Chaetomium are widely distributed in soil, water, plants, animals and humans. In this study, 12 isolates from Chaetomium and Amesia genera, obtained from herbaceous ornamentals, were identified based on morphology and phylogenetic analysis. Materials and methods: During 2017-2018, 40 symptomatic plants, showing root rot, stem canker and leaf spot, were collected and their associated fungi were isolated. Among those, 12 chaetomiaceae-like isolates were obtained, which their morphological and molecular characterizations were surveyed. Mycelial biomass of the isolates, produced into potato-dextrose-broth (PDB), was collected by passing through filter paper and freeze-dried. ITS and partial regions of the 28s-D1/D2 (for 4 isolates) and tub2 (for 9 isolates) were amplified using appropriate primers and sequenced. Results: The isolates under survey were compared with known strains using BLASTn search and phylogenetic analysis beased on ITS, 28S and tub2 regions. Accordingly, the isolates under study were identified as follow: Amesia atrobrunnea, Chaetomium rectangulare, C. globosum, C. ascotrichoides and C. olivaceum. The morphological characteristics of these isolates were in accordance with the type strains of each species. Discussion and conclusion: To our knowledge, this is the first record of C. ascotrichoides in Iran and the association of C. rectangulare on compacta, C. globosum on zinnia and canna, C. ascotrichoides on petunia, C. olivaceum on common zinnia, nasturtium and marigold throughout the world.

Keywords

• chaetomiaceae
• β‐tubulin
• molecular phylogeny
• morphology
• associated fungi