A Streptomyces morookaensis strain promotes plant growth and suppresses Fusarium wilt of banana

Fusarium wilt of banana, caused by Fusarium oxysporum f. sp. cubense (Foc), tropical race 4 (TR4), is one of the most devastating diseases, thus control of this disease is an urgent need in banana production. Streptomyces morookaensis strain Sm4-1986 significantly inhibited mycelial growth and spore germination of pathogen Foc-TR4. Chrome Azurol S assay showed that the strain Sm4-1986 is able to produce siderophores, and spectrometric scan confirmed that the siderophores produced belong to carboxylate-type. Addition of FeCl 3 eliminated the antagonism between the strain Sm4-1986 and Foc-TR4. Inoculation of banana plantlets with strain Sm4-1986 promotes plant growth, which may be mainly due to the production of indole-3-acetic acid (IAA). Application of strain Sm4-1986 to banana plantlets significantly reduced disease severity index and disease incidence of Fusarium wilt. These findings suggest that the Streptomyces morookaensis strain Sm4-1986 could be explored for uses such as biocontrol agents or biofertilizers in banana plantation.