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International Journal of Current Microbiology and Applied Sciences (IJCMAS)
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National Academy of Agricultural Sciences (NAAS)
NAAS Score: *5.38 (2020)
[Effective from January 1, 2020]
For more details click here

ICV 2018: 95.39
Index Copernicus ICI Journals Master List 2018 - IJCMAS--ICV 2018: 95.39
For more details click here

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Original Research Articles

PRINT ISSN : 2319-7692
Online ISSN : 2319-7706
Issues : 12 per year
Publisher : Excellent Publishers
Email : editorijcmas@gmail.com / submit@ijcmas.com
Editor-in-chief: Dr.M.Prakash
Index Copernicus ICV 2018: 95.39
NAAS RATING 2020: 5.38

Int.J.Curr.Microbiol.App.Sci.2018.7(2): 663-670
DOI: https://doi.org/10.20546/ijcmas.2018.702.082


Symptomatology and Molecular Characterization of Fungi Associated with Sigatoka Leaf Spot Disease of Banana in Kerala
Milsha George1*, K. Anita Cherian1, S. Beena1 and P.M. Namitha2
1Department of Plant Pathology, College of Horticulture, Vellanikkara, Thrissur, Kerala, India
2Department of Plant Pathology, Banana Research Station, Kannara, Thrissur, Kerala, India
*Corresponding author
Abstract:

Sigatoka leaf spot disease of banana is spreading at a faster rate causing a serious threat to banana cultivation in Kerala, the southern most state of Indian peninsula which enjoys a humid tropical climate. A survey was conducted under different agro-climatic zones prevailing in the state to study and document the symptomatology and etiology of the pathogen inciting Sigatoka leaf spot disease of banana occurring in the state of Kerala. The disease was noticed in most of the commercially grown varieties of banana viz., Nendran (AAB), Grandnaine (AAA), Njalipoovan (AB) and Robusta (AAA) throughout the year, but become more severe with the onset of rains. The symptoms initially appeared as small light green to yellow dashes on the lower surface of the leaf which was visible only when the leaves was held against sunlight. This later changed into faint brown visible streaks. During the next stage, these streaks turned rusty brown on the adaxial surface of the leaves, which then developed into oval or elliptical brown spots with greyish centre surrounded by definite dark brown border with black pin head like fruiting bodies embedded in it. Upon heavy infection, the spots coalesced leading to complete necrosis of the leaves thereby destroying the functional green tissues of the leaves. This resulted in drastic reduction in the photosynthetic area causing an impact in yield reduction. The disease also resulted in premature ripening of the fruits affecting the fruit quality. The microscopic observations of these necrotic lesions revealed the presence of flask shaped telomorphic fruiting bodies called perithecia bearing asci and ascospores. The presence of the pathogen wasfurther confirmed by amplification of the ITS- rDNA region of the fungus using ITS 1 and ITS 4 primers which yielded amplicons of size ranging from 540- 580 bp. The amplicons were further sequenced and blasted in NCBI which showed 97 - 100% sequence homology to Mycosphaerella emusae. Hence, the pathogen inciting Sigatoka leaf spot diseases on banana in Kerala was identified and confirmed as Mycosphaerella emusae.


Keywords: Sigatoka leaf spot complex, Perithecia, ascospores, ITS – rDNA, Amplicons, Mycosphaerella emusae
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How to cite this article:

Milsha George, K. Anita Cherian, S. Beena and Namitha, P.M. 2018. Symptomatology and Molecular Characterization of Fungi Associated with Sigatoka Leaf Spot Disease of Banana in Kerala.Int.J.Curr.Microbiol.App.Sci. 7(2): 663-670. doi: https://doi.org/10.20546/ijcmas.2018.702.082