Occurrence and pathogenicity of Enterobacter sp. causing sprout decay and seedling stunting of upland cotton (Gossypium hirsutum L.)

摘要

A new sprout decay and seedling stunting disease of unknown aetiology in upland cotton (Gossypium hirsutum L.) affecting nearly 5%-10% of young seedlings was noticed in vertisols of central Vidarbha (Maharashtra state, India) in July of 2017. The bacterium was consistently isolated from diseased seedlings and identified with a polyphasic method of characterization, including morphological, physiological, biochemical and 16S rRNA gene sequence analysis. The bacterium strain CICR-MGMG1 was isolated from diseased plants identified as Enterobacter sp. Inoculation of healthy cotton seed with an axenic culture of strain CICR-MGMG1 isolated from diseased young seedling reproduced disease symptoms of yellowing, stunting and deformed growth similar to the symptoms reported from infected field condition. The strain CICR-MGMG1 was consistently isolated from both diseased seedlings and stunted plants. Thus, the pathogenicity test of Koch's postulates was confirmed with the bacterium Enterobacter sp. strain CICR-MGMG1 as the causal organism of sprout decay and seedling stunting. To the best of our knowledge, this is the first record of Enterobacter sp. causing sprouts decay and seedling stunting of cotton.