A Streptomyces sp. strain: isolation, identification, and potential as a biocontrol agent against soilborne diseases of tomato plants

In this study, we isolated an actinomycete strain, FJAT-31547, from the rhizosphere soil of a healthy tomato plant in a serious soilborne diseased field. The strain FJAT-31547 exhibited broad-spectrum antifungal and antibacterial activities against 6 species of phytopathogenic fungi and 7 species of phytopathogenic bacteria, especially Fusarium oxysporum and Ralstonia solanacearum. Based on morphological and physiological characteristics and 99.64% of 16S rRNA gene sequence similarity with Streptomyces diastaticus subsp. ardesiacus, the strain was identified as a member of the genus Streptomyces. Thirteen chemical compounds with a high match degree (more than 90%) were identified in the crude extracts of Streptomyces sp. by gas chromatography-mass spectrometry (GC-MS) analysis, and n-hexadecanoic acid was the major constituent. The crude extract of strain FJAT-31547 exhibited the minmum inhibitory concentration (MIC) against F. oxysporum and R. solanacearum with 6.250 µg mL-1 and 3.125 µg mL-1, respectively. Pot experiments showed that after preinoculation with the strain FJAT-31547, the disease incidence of tomato plants was reduced by 80.59% for Fusarium wilt and 76.92% for bacterial wilt. Moreover, the strain FJAT-31547 had a growth promoting effect on tomato plants, increasing root length, plant height and stem diameter by 16.62%, 15.01% and 21.13%, respectively. Together, the Strptomyces sp. strain FJAT-31547 could be used as BCA against tomato Fusarium wilt and bacter...
Source: Biological Control - Category: Biology Source Type: research