Biological Characteristics and Antimicrobial Activity of EndophyticStreptomycessp. TQR12-4 Isolated from EliteCitrus nobilisCultivar Ham Yen of Vietnam

Abstract

Ham Yen orange (Citrus nobilis Lour) is the highly valuable commercial fruit of Vietnam. With the blooming of fruit production and farming area, this specialty crop is facing threats from several serious diseases; therefore the search for new effective biocontrollers is required to prevent the existing excessive use of fertilizers and plant protection chemicals. Endophytic actinomycetes are of great scientific interest due to their high potential of application in agriculture and pharmaceutical research. In this work, endophytic actinomycetes were isolated from a native orange species of Northeast mountainous province Tuyen Quang. Among 49 isolates obtained, the isolate TQR12-4 strongly inhibited test pathogens Colletotrichum truncatum, Geotrichum candidum, Fusarium oxysporum, and F. udum. This isolate gave comparatively high biomass yields on different substrates, for example, carboxy methyl cellulose, starch, protein, and chitin, within a wide range of temperature from 15 to 45°C and pH from 4 to 10. Sequence analysis of 16S rDNA gene showed that TQR12-4 shared 99% similarity to Streptomyces prasinopilosus; however, it slightly differed from the latter in spore morphology and hence was named as Streptomyces sp. TQR12-4. A thermostable antifungal substance of nonpeptide nature produced by Streptomyces sp. TQR12-4 had MIC against Fusarium udum of 100 μg/mL and 400 μg/mL respective to extract fractions X 4 and X 5.

Exploring the Antimicrobial and Antitumor Potentials of Streptomyces sp. AGM12-1 Isolated from Egyptian Soil

“…The primers used for amplification of the 16S rRNA gene were 11F: 5′-TAACACATGCAAGTCGAACG-3′ (Birri et al, 2013; Hong-Thao et al, 2016) and 12R: 5′-AGGGTTGCGCTCGTTG-3′ (Stackebrandt and Charfreitag, 1990; Isik et al, 2014). PCR was carried out in 50 μl reaction volume in sterile 200 μl PCR tube.…”

Diversity and Applications of Endophytic Actinobacteria of Plants in Special and Other Ecological Niches

“…Streptomyces sp. TQR12-4, an endophyte of Citrus nobilis Lour was reported to produce thermostable antifungal compound with MIC values of 100 μg/ml and 400 μg/ml (Thao et al, 2016 ). Crude extracts of the metabolites from Microbispora sp.…”

Plant growth promotion and chilli anthracnose disease suppression ability of rhizosphere soil actinobacteria

“…Endophytic actinobacteria are reported to play an important role in the growth, physiology, and health of the host plant via their metabolic activity and mechanisms such as antibiosis, niche competition, and induction of host systemic resistance (Hong-Thao et al 2016). Among studied endophytes, Streptomyces are one particular group of interest because of their ability to produce antibiotics as well as other bioactive secondary metabolites (Yan et al 2010;Wang et al 2010;Joseph et al 2012;Ryan et al 2012;Taechowisan et al 2013).…”