Morpho-molecular and Pathogenic Variability of Wilt of Lentil from Indo-Gangetic Plains of India

Abstract

Background: Fusarium wilt in lentil (Lens culinaris L.) infected by Fusarium oxysporum is considered as one of the major biotic factors for low productivity in lentil. The present study was conducted to determine nine Fusarium isolates (W1-W8 and W10) which were isolated from different lentil growing fields of West Bengal, India and were characterized for their physio-morphological, biochemical and molecular traits in vitro. Methods: Nine Fusarium infected lentil plant samples were collected from 9 different places of West Bengal. Pathogen was isolated from lentil samples using PDA media followed by cultural, morphological, pathogenic and molecular variability studies for all the isolates of Fusarium. Type of pigmentation, sporulation, conidia size of each isolate was recorded by observing culture plate after complete growth of the mycelium. Pathogenicity test were done to check the aggressiveness of all the 9 isolates of Fusarium in three varieties of lentil (Maitri, HUL-57 and BM-6). The isolated fungal DNA was amplified with specific primer pair, Forward primer ITS 1 and Reverse primer ITS 4. Result: Morphological assessment of 9 isolates showed distinct identification characters and variability. The mycelia of all the isolates were septate, profusely branched with differential pigmentation, texture and margin.All the Fusarium isolates produced micro-and macro-conidia in pure culture within seven days after inoculation and showed different morphological characters in pathogenicity test, variety Maitri showed better germination (100% in W2, W4, W6, W7, W8 and W10) and less disease severity against most of the strains (75% in W1) as compared to other two varieties against and hence variety Maitri taken into consideration for greenhouse and field trials. Furthermore, identification of molecular variability was performed by sequence analysis of rDNA-ITS region of each isolate and sequencing of rDNA-ITS region supported the morphological study and confirmed the associated fungi at species level.