Identity and Pathogenicity of Fungi Associated with Crown and Root Rot of Dryland Winter Wheat in Azerbaijan

Abstract

A comprehensive survey was performed to assess fungal populations associated with crown and root rot of wheat throughout the main wheat-growing areas of Azerbaijan. Samples were taken from 76 fields; 630 fungal strains were isolated, identified, and evaluated for pathogenicity. The identification was conducted with morphological and molecular tools such as species-specific PCR and DNA sequencing of the internal transcribed spacer (ITS) and <i>translation elongation factor 1</i>-α (<i>EF1</i>-α) loci. The fungus found in the greatest number of fields (44) was <i>Fusarium culmorum</i> with 192 isolates, followed by <i>F. acuminatum</i>. Other <i>Fusarium</i> spp. isolates were identified: <i>F. equiseti, F. pseudograminearum, F. graminearum</i>, <i>F. incarnatum</i>, <i>F. avenaceum</i>, <i>F. hostae</i>, <i>F. oxysporum</i>, <i>F. proliferatum</i>, <i>F. algeriense</i>, and <i>F. brachygibbosum</i>. <i>Bipolaris sorokiniana</i>, <i>Curvularia spicifera</i>, <i>Exserohilum pedicellatum</i>, <i>Nigrospora oryzae</i>, and <i>Rhizoctonia</i> spp. isolates were also identified, associated with underground parts of wheat. Phylogenetic analyses based on ITS and <i>EF1</i>-α sequences of the isolates showed that the isolates belonging to the same species were clearly separated in the dendrogram. Pathogenicity assays revealed that <i>F. culmorum</i>, <i>F. pseudograminearum</i>, and <i>F. graminearum</i> were most aggressive; <i>F. avenaceum</i>, <i>F. hostae</i>, <i>F. algeriense</i>, <i>B. sorokiniana</i>, <i>C. spicifera</i>, and <i>R. solani</i> isolates were moderately aggressive; <i>C. inaequalis</i>, <i>E. pedicellatum</i>, and <i>N. oryzae</i> were weakly aggressive; and others were nonpathogenic. The result of this study exhibited the existence of a wide range of species associated with crown and root rot of wheat in Azerbaijan. Additionally, this is the first report of <i>F. hostae</i>, <i>F. algeriense</i>, <i>C. spicifera</i>, <i>C. inaequalis</i>, and <i>N. oryzae</i> as pathogens on wheat in Azerbaijan. Azerbaijan is the second country after Algeria in which <i>F. algeriense</i> was detected.