Role of endophyte chaetomium globosum lk4 in growth of capsicum annuum by producion of gibberellins and indole acetic acid

Endophytic fungi represent a trove of unexplored natural source of plant hormones like gibberellins (GAs) and indoleacetic acid (IAA). In present study, we isolated eight endophytes from the roots of drought stressed pepper (Capsicum annuum L.) plants. To assess phytohormones secreting potential, culture filtrates (CF) of endophytes were screened on GAs biosynthesis mutant Waito-C rice. Endophyte CAC-1G significantly promoted the shoot growth, chlorophyll content and biomass of Waito-C rice seedlings as compared with CF of Fusarium fujikuroi and distilled water. CAC-1G was identified as strain of Chaetomium globosum LK4 by sequencing internal transcribed spacer regions and phylogenetic analysis of similar sequences. The CF analysis of C. globosum showed the presence of GAs (GA₁ 0.67±0.13 ng/ml; GA₄ 21.8±1.2 ng/ml; GA₉ 0.51±0.11 ng/ml; GA₁₂13.4±0.41 ng/ml; GA₂₀ 1.11±0.2 ng/ml) and IAA (16.71+1.42 μg/ml). The CF of C. globosum had higher GA₄, GA₁₂ and GA₂₀ than the CF of F. fujikuroi. The CF containing propagules of C. globosum was applied to the host-pepper plants. The results revealed significantly higher shoot growth, chlorophyll content, plant biomass and leaf area as compared to fungal-free medium and water applied plants. The present results of C. globosum can be reciprocated for improved plant growth and yield at field levels.