Cladosporium sphaerospermum as a new plant growth-promoting endophyte from the roots of Glycine max (L.) Merr.

Abstract

Endophytic fungi are plant symbionts that produce a variety of beneficial metabolites for plant growth and protection against herbivory and pathogens. Fourteen fungal samples were isolated from the roots of soybean cultivar Daemangkong and screened on waito-c rice for their plant growth-promoting capacity. Twelve of the fungal isolates promoted plant growth, while two inhibited it. The fungal isolate DK-1-1 induced maximum plant growth in both waito-c rice and soybean. The plant growth promotion capacity of DK-1-1 was higher than the wild type Gibberella fujikuroi. Gibberellin (GA) analysis of culture filtrate of DK-1-1 showed the presence of higher amounts of bioactive GA(3), GA(4), and GA(7) (6.62, 2.1 and 1.26 ng/mL, respectively) along with physiologically inactive GA(5), GA(15), GA(19), and GA(24). Phylogenetic analysis of 18S rDNA sequence identified the fungal isolate as a new strain of Cladosporium sphaerospermum. Gibberellin production and plant growth-promoting ability of genus Cladosporium are reported for the first time in the present study.