Molecular and pathogenic variability of multilocus isolates of Alternaria lini Dey cause Alternaria blight in linseed (Linum usitatissimum L.)

Abstract

The pathogen of Alternaria blight of linseed was isolated from infected leaf, buds and seeds collected from eleven locations of India and the isolates were designated as Nj, Kr, Ji, Fd, Rr, Hr, Pr, Ri, Nr, Plr and Ra. All the isolates showed variability in term of colony colour, conidial shape, size, septation and growth behavior at different pH, temperature and media. Three out of 11 isolates show grey (Nj, Kr, Fd), 6 grayish black (Ji, Rr, Ra, Ri, Nr, Hr) and two black (Plr, Pr) colour with circular colony pattern. Conidial size of all isolates ranged from 20.32 to 28.25µm length with 3.76 to 7.55µm width. Nj isolate have maximum conidial size whereas, Fd isolate have minimum size. The conidia also showed dark brown (Nj, Kr, Plr), and light brown colour. Three out of eleven isolates shown obclevate shape (Nj, Rr and Pr), three flask shaped (Kr, Ji and Plr) and rest of the isolates (Fd, Hr, Ri, Nr, Ra) were oval in shape. Transverse septation were ranged from 7-2 and longitudinal from 4-1 septaion with 7 transverse septa were found in conidia of Plr isolate. Similarly, maximum with four longitudinal septa were recorded in Plr isolate. Pathogenic behavior of the isolates revealed that Nj isolates is more pathogenic indicating maximum disease severity as compare to other. Profiling of soluble protein of multilocus isolates showed that number of protein bands varies from 9-14 with 14 maximum number of bands was found in Nj, Hr and Nr isolates, whereas, the minimum with 09 bands were found Fd and Ri isolates indicating variability exist among the isolates.