Phylogenetic Diversity, Pathogenic Variability and Tenuazonic Acid Production of Small‐Spored
                    Alternaria
                    Species Associated With Citrus Black Rot in Upper Egypt

Youssuf A. Gherbawy; Helal F. Al‐Harthi; Hanan Alomari; Thanaa A. Maghraby; Karima E. Abdel Fattah; Pet Ioan; Mohamed A. Hussein

doi:10.1111/jph.70296

journal article Mar 01, 2026

Phylogenetic Diversity, Pathogenic Variability and Tenuazonic Acid Production of Small‐Spored Alternaria Species Associated With Citrus Black Rot in Upper Egypt

Youssuf A. Gherbawy

Helal F. Al‐Harthi Hanan Alomari Thanaa A. Maghraby Karima E. Abdel Fattah Pet Ioan Mohamed A. Hussein

Journal of Phytopathology Vol. 174 No. 2 · Wiley

View at Publisher Save 10.1111/jph.70296

Abstract

ABSTRACT

Alternaria
species is the main causative agent for black rot of citrus. 157 isolates were recovered from 150 rotten citrus samples in Upper Egypt. In this study, 150 rotten citrus samples yielded 157 fungal isolates, predominantly

Alternaria alternata

(150 isolates) and, to a lesser extent,

A. arborescens

(7 isolates) species complex. Identification was achieved through both morphological assessment and molecular techniques using the
Alt a1
gene. The virulence of these isolates was evaluated exclusively on orange fruits (cv. Washington Navel) to allow direct comparison among strains from different citrus hosts. All

A.
alternata‐like

isolates induced black rot, though disease severity varied considerably, with the average lesion diameter (ALD) ranging from 20.0 to 40.5 mm while
Alternaria arborescens‐like
isolates exhibited minimal variation (ALD 30.0–31.5 mm). Statistical analyses indicated no significant difference in disease severity between the two species (
p
= 0.824), suggesting that pathogenicity is more closely associated with specific isolates rather than their species classification. Further analysis using high‐performance liquid chromatography (HPLC) revealed that 88.8% of

A. alternata

and 71.5% of

A. arborescens

lineages produced tenuazonic acid, with the highest level (31.02 μg/mL) detected in

A. arborescens

SVUAar152. These results provide a deeper understanding of the diversity and toxigenic capacities of
Alternaria
species linked to citrus black rot in Egypt, while highlighting the need for future multi‐locus studies to definitively resolve species boundaries within these complex lineages.

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References

52

[1]

10.3390/genes14051115

[2]

10.3389/fmicb.2024.1273076

[3]

10.1016/j.postharvbio.2025.114041

[4]

10.1016/j.ijfoodmicro.2014.11.029

[5]

10.1128/aem.51.6.1235-1238.1986

[6]

Baiyewu R. A. "Survey of the Postharvest Diseases and Aflatoxin Contamination of Marketed Pawpaw Fruit ( Carica papaya L.) in Southwestern Nigeria" African Journal of Agricultural Research (2007)

[7]

Bottalico A. (1998)

[8]

10.1016/j.funbio.2022.02.003

[9]

10.1017/s0953756201005317

[10]

10.1080/07060661.2022.2061605

[11]

10.36253/phyto-14559

[12]

10.1016/j.foodchem.2024.140060

[13]

10.1111/jph.12752

[14]

10.9734/ajbgmb/2020/v5i430138

[15]

10.1016/j.pmpp.2023.101998

[16]

UFBoot2: Improving the Ultrafast Bootstrap Approximation

Diep Thi Hoang, Olga Chernomor, Arndt von Haeseler et al.

Molecular Biology and Evolution 10.1093/molbev/msx281

[17]

10.1016/j.fgb.2004.10.009

[18]

Kiasat N. "Identification and Genetic Diversity of Alternaria Species Recovered From the Air of Ahvaz City, the Southwestern Part of Iran" International Journal of Molecular Epidemiology and Genetics (2022)

[19]

Lawrence D. P. "The Sections of Alternaria: Complexes Lookalikes and Many New Sections" Studies in Mycology (2013)

[20]

10.4315/0362-028x-64.4.567

[21]

Li Y. "Morphological and Phylogenetic Analyses Reveal Two New Alternaria Species (Pleosporales, Pleosporaceae) From Cucurbitaceae Plants in China" MycoKeys (2024)

[22]

10.3920/wmj2009.1145

[23]

10.1038/s41598-017-09138-9

[24]

10.3389/fpls.2023.1202738

[25]

10.1093/nar/20.22.6115

[26]

IQ-TREE: A Fast and Effective Stochastic Algorithm for Estimating Maximum-Likelihood Phylogenies

Lam-Tung Nguyen, Heiko A. Schmidt, Arndt von Haeseler et al.

Molecular Biology and Evolution 10.1093/molbev/msu300

[27]

10.1016/j.ijfoodmicro.2018.01.003

[28]

10.3920/wmj2008.x013

[29]

10.1016/j.ijfoodmicro.2007.07.055

[30]

10.1016/j.ijfoodmicro.2025.111272

[31]

10.1094/phyto-95-0512

[32]

10.1094/phyto.2002.92.7.794

[33]

10.1080/15572536.2005.11833002

[34]

10.1289/ehp.730487

[35]

10.1080/15572536.2004.11833024

[36]

10.1017/s0953756200003002

[37]

10.3390/plants11091168

[38]

10.1007/s00204-024-03743-0

[39]

10.9734/bpi/ctas/v1/13548d

[40]

10.1021/bi00905a039

[41]

10.1016/s0031-9422(00)88860-3

[42]

MEGA6: Molecular Evolutionary Genetics Analysis Version 6.0

Koichiro Tamura, Glen Stecher, Daniel Peterson et al.

Molecular Biology and Evolution 10.1093/molbev/mst197

[43]

Alternaria spp.: from general saprophyte to specific parasite

Bart P. H. J. Thomma

Molecular Plant Pathology 10.1046/j.1364-3703.2003.00173.x

[44]

Timmer L. W. "Alternaria Diseases of Citrus‐Novel Pathosystems" Phytopathologia Mediterranea (2003)

[45]

Visconti A. "Tenuazonic Acid in Blackmold Tomatoes: Occurrence, Production by Associated Alternaria Species, and Phytotoxic Properties" Phytopathologia Mediterranea (1987)

[46]

Visconti A. (1994)

[47]

Wang M. "Genomics, Evolutionary History, and Diagnostics of the Alternaria alternata Species Group Including Apple and Asian Pear Pathotypes" Frontiers in Microbiology (2020)

[48]

10.3390/jof9100992

[49]

10.3114/sim0015

[50]

10.1016/j.simyco.2015.07.001

Showing 50 of 52 references

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Published: Mar 01, 2026
Vol/Issue: 174(2)
License: View

Authors

Y

Youssuf A. Gherbawy

Botany and Microbiology Department, Faculty of Science Qena University Qena Egypt; Applied and Environmental Microbiology Center Qena University Qena Egypt

H

Helal F. Al‐Harthi

Biology Department, Turabah University College Taif University Taif Saudi Arabia

H

Hanan Alomari

Department of Biological Sciences, Faculty of Science University of Jeddah Jeddah Saudi Arabia

T

Thanaa A. Maghraby

Botany and Microbiology Department, Faculty of Science Qena University Qena Egypt

K

Karima E. Abdel Fattah

Botany and Microbiology Department, Faculty of Science Qena University Qena Egypt

P

Pet Ioan

Biotechnology Dep., Faculty of Bioengineering and Animal Resources University of Life Sciences “King Mihai I” From Timisoara Timisoara Romania

M

Mohamed A. Hussein

Botany and Microbiology Department, Faculty of Science Qena University Qena Egypt; Applied and Environmental Microbiology Center Qena University Qena Egypt

Cite This Article

Youssuf A. Gherbawy, Helal F. Al‐Harthi, Hanan Alomari, et al. (2026). Phylogenetic Diversity, Pathogenic Variability and Tenuazonic Acid Production of Small‐Spored Alternaria Species Associated With Citrus Black Rot in Upper Egypt. Journal of Phytopathology, 174(2). https://doi.org/10.1111/jph.70296

Phylogenetic Diversity, Pathogenic Variability and Tenuazonic Acid Production of Small‐Spored Alternaria Species Associated With Citrus Black Rot in Upper Egypt

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