Identification of Alternaria alternata as a Causal Agent for Leaf Blight in Syringa Species

Abstract

While many isolates of Alternaria alternata are common saprophytes on trees and shrubs, this study clearly demonstrated that A. alternata is a primary pathogen in lilac (Syringa sp.), causing a leaf-blight that affects different Syringa species. Isolates of Alternaria sp. were collected from leaf blight samples of lilacs in the field. The internal transcribed spacer (ITS) region and morphological characterization were used to identify lilac blight pathogen. Based on 100% ITS nucleotide sequence identities to the Alternaria genus in the GenBank and morphological features, these isolates were identified as A. alternata. Disease symptoms were reproduced in lilac plants inoculated with A. alternata mycelial plugs and sprayed with a fungus-free culture filtrate, indicating that pathogenesis in lilac involves secondary metabolites or toxins. Diagnostic primers were developed to detect Alternaria sp. and A. alternata in lilac leaf blight based on ITS region and four known genes associated with pathogenesis in A. alternata: mixed-linked glucanase precursor, endopolygalacturonase, hsp70, and histone genes. The results from our study indicated A. alternata is a primary pathogen in lilac leaf blight, and these diagnostic primers can be used as a tool for the fast detection of A. alternata associated with lilac leaf blight.

Genetic Analysis and Pathogenic Characterization of Alternaria tenuissima Induced Fruit Rot of Bitter Gourd

“…The ribosomal genes and their ITS regions have been extensively used for distinguishing and naming of the species (Yang et al 2020), along with the study of genetic diversity (Ghosh et al 2019;Turzhanova et al 2020), phylogenetic relationship (Ozkilinc et al 2018;Liu et al 2019;Tao et al 2019), and taxonomic studies (Mahmoudi et al 2017;Poursafar et al 2018). In fungi, ITS region is used in species identification and phylogenetic studies of closely related species (Mmbaga et al 2011). Since there is a higher degree of variation in ITS gene sequence, it has been extensively applied in molecular taxonomy to discriminate at species levels or sometimes even within species (Al Ghafri et al 2019).…”

Population genetic analysis reveals cryptic sex in the phytopathogenic fungus Alternaria alternata

“…Both Alternaria alternata and A. solani can cause early blight on potatoes in the world 26 30 31 32 33 . A. alternata produces densely turfy colonies in dark grey to black brown color on PDA plates.…”

A PCR ITS-RFLP method for identifying fungal contamination of date palm (Phoenix dactylifera L.) tissue cultures

“…The ITS sequencing was a rapid and reliable method to identify different species of date palm fungal contamination; many published reports have proved the effectiveness and reliability of ITS products as a tool of fungal discrimination including the species of Aspergillus, Alternaria and Penicillium (Henry et al, 2000;Konstantinova et al, 2002;Martinez-Culebras and Ramon, 2007;Diguta et al, 2011;Mmbaga et al, 2011;Pashley et al, 2012). The digestion with restriction endonucleases EcoRI and SmaI following the ITS amplification, indicated that both restriction endonucleases were sufficient to recognize the fungal contaminants (Aspergillus, Alternaria and Penicillium) of date palm tissue culture at species level.…”

“…Most of the isolated fungi belonged to the B Type pattern, with an exception of species A. calvatus which belonged to the C Type pattern with three fragments after digestion with SmaI. The ITS-RFLP procedure is widely used as a rapid and reliable technique for fungal identification, especially for the close taxa within the genera of fungi such as Aspergillus, Alternaria and Penicillium (Martinez-Culebras and Ramon, 2007;Diguta et al, 2011;Mmbaga et al, 2011).…”