African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5211

Full Length Research Paper

Morphological, cultural, pathogenic and molecular studies of Alternaria brassicae infecting cauliflower and mustard in India

Manika Sharma1, Swati Deep1, Dinesh Singh Bhati1, P. Chowdappa2, R. Selvamani and Pratibha Sharma1*
1Plant Pathology, Indian Agricultural Research Institute, New Delhi, India. 2Plant Pathology, Indian Institute of Horticultural Research, Bangalore, India.
Email: [email protected], [email protected]

  •  Published: 25 June 2013


Dark leaf spot (Alternaria brassicae) is one of the important diseases in crucifers causing serious yield and quality loss in production due to the seed borne nature of the pathogen. Variation in morphology and cultural characteristics among 32 representative Indian geographical isolates of Alternaria brassicae, the causal agent of Alternaria blight of cauliflower (Vegetable) rapeseed-mustard (Oil seed), was studied. All the isolates showed high level of variability in vitro in respect of conidial length, width, and number of septa. Conidia of Uttar Pradesh isolate (CaAbU4) were smallest in size with lowest number of septa. Substantial variation was found in mycelial growth, sporulation among these isolates in different nutrient media. All the isolates did not grow and sporulate abundantly on the same nutrient medium. However, Potato Dextrose Agar, Cauliflower (Host) Agar medium and Carrot Potato Agar were good for all the cultures. Variation in mycelial growth, sporulation was also observed. Cluster analysis of data on cultural variability among thirty two A. brassicae isolates found a close relationship among isolates of both origins viz, from Cauliflower and mustard. Isolates from Uttar Pradesh, Delhi, Haryana and West Bengal were found to be more similar to each other whereas the Rajasthan isolates along with Tamil Nadu and Kerala isolate were distantly related to others. All the isolates were pathogenic in nature but not directly related to the cultural and the morphological characteristics. These isolates were further molecularly characterized by using internal transcribed spacer region where all the isolates were found 56% similar to each other and 99% similar to the A. brassicae isolates present in NCBI database.


Key words: Dark leaf spotAlternaria brassicae, morphology, cultural variability,pathogenicity, ITS analysis.