Phylogenetic Analysis of Alternaria species Associated with Citrus Black Rot in Iran

Abstract

Citrus black rot caused by Alternaria spp. is significant post harvest problem in Iran. The causal agent of black rot was originally identified as A. citri by Ellis and Pierce. The genus Alternaria circumscribes considerable morphological diversity and citrus black rot may be caused by more than one morphospecies in addition to A. citri. Morphological identification of small-spored Alternaria spp. is difficult. Phylogenetic analysis was performed on 7 small-spored Alternaria isolates from black rotted citrus fruit in Iran using sequence data from an anonymous locus, OPA10-2. Samples were collected from navel oranges in Mazandaran province in the north of Iran. All isolates caused black rot in a fruit inoculation assay with Navel and Valencia oranges and significant differences were observed between cultivars and among isolates. No association was found between morphological classification and phylogenetic clade. We identified A. tenuissima (ALT 6) as the causal agents of citrus black rot. Two isolates (ALT8 and ALT9) grouped together, separately from other clades in most parsimonious trees. It suggested that both of them belong to different species. This is the first report of molecular characterization of citrus-associated Alternaria species in Iran and A. tenuissima is reported as the causal agent of citrus black rot in Iran for the first time. Rang et al. [12] studied morphologically the isolates of black

Withdrawn: Spectral pattern study of citrus black rot caused by Alternaria alternata and selecting optimal wavelengths for decay detection

“…The rot spreads slowly and the disease is not controlled by pre‐ and postharvest fungicides (Timmer et al., 2003 ). It affects mainly navel oranges, but it can infect all citrus fruits when appropriate condition is prepared (Mojerlou, 2012 ).…”

“…The rot spreads slowly and the disease is not controlled by pre-and postharvest fungicides . It affects mainly navel oranges, but it can infect all citrus fruits when appropriate condition is prepared (Mojerlou, 2012).Infected fruits ripen well before maturity and some of them fall off before harvest. The optimum conditions for Alternaria infections are temperatures from 23 to 27°C, but still, it can grow…”

Morphological and Molecular Characterization of Alternaria sect. Ulocladioides/Ulocladium Isolated from Citrus Fruits in Upper Egypt

“…Bukar et al [35] who reported that different spoilage types were observed when the healthy oranges were reinoculated with the pure isolates of the pathogens. Mojerlou and Safaie [53] claimed that all Alternaria isolates caused black rot to Navel and Valencia oranges cultivars and significant differences were observed between cultivars and among isolates. Nemsa et al [54] studies the pathogenicity of nine isolates of Alternaria against Fortune mandarin.…”

Etiology and management of citrus Melanose disease in Pakistan: A review

“…Brown spot of citrus, black rot of citrus and stem-end rot are well-known citrus diseases. Among these diseases, black rot caused by Alternaria citri produces brown to black spots on fruit (Mojerlou and Safaie, 2012). Several species of Colletotricum are known to cause important diseases of citrus; the most important disease caused by this pathogen is citrus anthracnose, and the characteristic symptom is the withering of twigs and lesions on fruits and leaves (Guarnaccia et al, 2017).…”