PHENOTYPIC AND MOLECULAR VARIABILITYAMONG ALTERNARIA SOLANI CAUSING POTATOEARLY BLIGHT IN GUJARAT, INDIA
29 / 18
Authors
-
DR. JAINA PATEL
ASSISTANT RESEARCH SCIENTIST, BIOLOGICAL CONTROL RESEARCH LABORATORY, ICAR UNIT-9, ANAND AGRICULTURAL UNIVERSITY, ANAND
Keywords:
Potato, Early blight, Alternaria solani, Variability, RAPDAbstract
Early blight, caused by Alternaria solani, is an important foliar disease of potato and
can cause substantial yield losses. This study assessed phenotypic and molecular variability among
thirty-six A. solani isolates collected from major potato-growing regions of Gujarat, India. Thirty-six
Alternaria isolates obtained from six major potato-growing districts of Gujarat exhibited substantial
cultural, morphological and molecular variability. Conidial dimensions varied from 12.5–89.4 √
4.6–30.5 μm on potato dextrose agar and from 12.1–82.4 √ 4.1–27.7 μm on Richard’s agar. ITS1/ITS4
amplification and sequencing of representative isolate As1 produced an amplicon of approximately 540
bp and showed 98–99% similarity with A. solani sequences in Gen Bank, supporting its identification.
RAPD analysis of all 36 isolates using five informative primers generated 30 scorable loci, of which
28 were polymorphic (93.3%). UPGMA analysis resolved the isolates into two major clusters. AMOVA
attributed 20% of molecular variation to differences between the two geographic populations and
80% to variation within populations. The results demonstrate substantial phenotypic and RAPD-based
genetic variability in the Gujarat isolate collection and provide baseline information relevant to
pathogen surveillance, resistance breeding and early-blight management.
Downloads
References
Abdel-Hamid MAM, Khalil MA, Abbas MS, Abd-El-
Moneim ML and Soliman AS. (2023) Biological
control and molecular differences among some
isolates of Alternaria solani, the causative agent
of early blight in potatoes. Egyptian Journal of
Chemistry 66(9): 421–438. https://doi.org/10.21608/
ejchem.2023.179624.7289
Adhikari TB, Ingram T, Halterman D and Louws FJ.
(2020) Gene genealogies reveal high nucleotide
diversity and admixture haplotypes within three
Alternaria species associated with tomato and
potato. Phytopathology 110(8): 1449–1464. https://
doi.org/10.1094/PHYTO-12-19-0487-R
Adhikari TB, Muzhinji N, Halterman D and Louws FJ.
(2021) Genetic diversity and population structure
of Alternaria species from tomato and potato in
North Carolina and Wisconsin. Scientific Reports
11: 17024. https://doi.org/10.1038/s41598-021-
95486-6
Blair MW, Panaud O and McCouch SR. (1999) Intersimple
sequence repeat (ISSR) amplification for
analysis of microsatellite motif frequency and
fingerprinting in rice (Oryza sativa L.). Theoretical
and Applied Genetics 98: 780–792.
Ellis MB. (1971) Dematiaceous Hyphomycetes.
Commonwealth Mycological Institute, Kew, Surrey,
England.
Haware MP. (1968) Assessment of yield losses due to
early blight of potato. Jawaharlal Nehru Krishi Vishwa
Vidyalaya Research Journal 2: 67–68.
Ivanovic Z, Blagojevic J, Jovanovic G, Ivanovic B and
Zezelj D. (2022) New insight in the occurrence
of early blight disease on potato reveals high
distribution of Alternaria solani and Alternaria
protenta in Serbia. Frontiers in Microbiology 13: 856898.
https://doi.org/10.3389/fmicb.2022.856898
Blair M W, Panaud O and McCouch S R (1999) Inter
simple sequence repeat (ISSR) amplification for
analysis of microsatellite motif frequency and
fingerprinting in rice (Oryza sativa L.). Theoretical
and Applied Genetics 98: 780-792
Ellis M B (1971) Demataceous Hyphomycetes.
Commonwealth Mycological Institute, Kew, Surrey,
England
Haware M P (1968) Assessment of yield losses due to
early blight of potato. Jawaharlal Nehru Krishi Vishwa
Vidyalaya Research 2: 67-68
Ivanović Ž, Blagojević J, Jovanović G, Ivanović B, Zezelj
D (2022) New insight in the occurrence of early
blight disease on potato reveals high distribution
of Alternaria solani and Alternaria protenta in
Serbia. Frontiers in Microbiology 13:856898.
https://doi.org/10.3389/fmicb.2022.856898
Kaur, T., Yadav, A. N., Sharma, S., & Singh, N. (2020)
Diversity of fungal isolates associated with early
blight disease of tomato from mid-Himalayan
region of India. Archives of Phytopathology and Plant
Protection, 53 (14), 612-624.
Marak, T. R., Ambesh, B. S., & Das, S. (2014) Cultural,
morphological and biochemical variations of
Alternaria solani causing diseases on solanaceous
crops. The Bioscan, 9 (3), 1295-1300.
Mugao LG, Muturi PW, Gichimu BM and Kamiri
AK (2021) Morphological and molecular
characterization of Alternaria solani and Phytophthora
infestans isolates from tomato farms in Kenya.
Plant Pathology Journal 20: 29–40. https://doi.
org/10.3923/ppj.2021.29.40
Nilsson RH, Ryberg M, Abarenkov K, Sjökvist E
and Kristiansson E (2009) The ITS region as a
target for characterization of fungal communities
using emerging sequencing technologies. FEMS
Microbiology Letters 296: 97–101. https://doi.
org/10.1111/j.1574-6968.2009.01618.x
Nuwamanya AM, Runo S and Mwangi M (2022)
Morphological and molecular characterization
of Alternaria solani isolates causing tomato early
blight in Kenya. Journal of Plant Pathology Research
3: 70–80. https://doi.org/10.36959/394/628
Pachori A, Sharma O, Sasode R and Sharma RN (2016)
Collection of different isolates of Alternaria solani
in Bhind, Morena and Gwalior districts of Madhya
Pradesh. International Journal of Applied Research 2:
217–219.
Rohlf FJ (1993) NTSYS-pc: Numerical Taxonomy and
Multivariate Analysis System, version 1.80. Applied
Biostatistics Inc., Setauket, New York, USA.
Rotem J (1994) The Genus Alternaria: Biology, Epidemiology
and Pathogenicity. APS Press, St Paul, Minnesota,
USA, 326 pp.
Rouse DI (1985) Some approaches to prediction of potato
early dying disease severity. American Potato Journal
62: 187–193.
Schmey T, Tominello-Ramirez CS, Brune C and Stam
R. (2024). Alternaria diseases on potato and tomato.
Variability among Alternaria solani
Potato J 53 (1): January - June, 2026 33
Molecular Plant Pathology 25(3): e13435. https://doi.
org/10.1111/mpp.13435
Schoch CL, Seifert KA, Huhndorf S, Robert V, Spouge
JL, Levesque CA, Chen W and Fungal Barcoding
Consortium. (2012). Nuclear ribosomal internal
transcribed spacer region as a universal DNA
barcode marker for fungi. Proceedings of the National
Academy of Sciences of the United States of America
109(16): 6241–6246. https://doi.org/10.1073/
pnas.1117018109
Van der Waals JE, Korsten L and Aveling TAS. (2001).
A review of early blight of potato. African Plant
Protection 7(2): 91–102.
White TJ, Bruns T, Lee S and Taylor JW. (1990).
Amplification and direct sequencing of fungal
ribosomal RNA genes for phylogenetics. In: PCR
Protocols: A Guide to Methods and Applications
(Innis MA, Gelfand DH, Sninsky JJ and White
TJ, eds), pp. 315–322. Academic Press, San Diego,
California, USA.
Yadav R and Pathak SP. (2011). Variability among
Alternaria solani isolates causing early blight of
potato. Plant Archives 11(2): 953–956.
Downloads
Published
Issue
Section
License
Copyright (c) 2026 Potato Journal
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
The copyright of the articles published in Potato Journal is vested with the Indian Council of Agricultural Research, which reserves the right to enter into any agreement with any organization in India or abroad, for reprography, photocopying, storage and dissemination of information. The Council has no objection to using the material, provided the information is not being utilized for commercial purposes and wherever the information is being used, proper credit is given to ICAR.
How to Cite
