Effect of Streptomyces xantholiticus on Rice Blast Disease Reduction and Enzyme Activity

The rice blast infection triggered by Pyricularia oryzae Cav. is a grave issue restraining rice yields globally. Biological regulation has been seen as an encouraging option to such chemical fungicides. The biological control proficiency of 24 isolates of Streptomyces against P. oryzae (KT693184.1) has been examined. Analysis of defense enzymes such as polyphenol, peroxidase (PO), and total protein and phenol content was performed. The Streptomyces isolate that was determined to have maximum effectiveness was determined to be Streptomyces xantholiticus. The sequence was sent to the NCBI vide accession number MW029942. The S. xantholiticus isolate inhibited P. oryzae 92% using dual culture tests. The greenhouse experiments showed that the disease gravity in rice plants with S. xantholiticus isolate was considerably lower compared to plants sans the treatment. The S. xantholiticus isolate was analyzed for its effects concerning the activity of polyphenol and Po enzymes as well as the total protein content present in rice leaves under greenhouse conditions in both presence and absence of P. oryzae. It was found that rice species treated with the S. xantholiticus isolate had enhanced resistance to the rice blast pathogen along with increasing activity levels of the polyphenol and PO enzymes. There was a direct impact on pathogen growth along with the defense response triggered in the plants as a result of the treatment.

Evaluation of a Potential Antibacterial, Produced by Streptomyces Cinereoruber Sp. Isolated from Chlika lake

Streptomyces, isolated from marine and estuarine habitat have been widely recognized as a potential source of antifungal, anti-tumour, anti-bacterial compounds. In the present study, the antimicrobial agent production potential of a Streptomyces cinereoruber sp was evaluated. The selective isolation of the strain was carried out on starch casein agar. The primary screening of the Streptomyces isolate was done by cross streak method against pathogenic test strains Escherichia.coli MTCC 82, Staphylococcus aureus MTCC 96, Bacillus cereus IP406 and Salmonella typhi MTCC 734 and Micrococcus leuteus and the antimicrobial property against Micrococcus leuteus was confirmed. The secondary screening was carried out by using the culture supernatant against the test strain by agar well diffusion method. The growth and antimicrobial production ability of the strain against Micrococcus leuteus was studied. The antimicrobial agent production was also observed till pH 11 and NaCl concentration 3% (w/v). The partially purified compound showed a peak similar to streptomycin in HPLC. The culture condition for the production of the compound was optimised.

Biological Control of Fusarium Crown and Root Rot of Wheat by Streptomyces Isolates – It’s Complicated

The predominant causal agents of Fusarium crown and root rot (FCR) of wheat, along with Fusarium pseudograminearum, are F. graminearum and F. culmorum. Members of the Gram-positive bacterial genus Streptomyces have been shown to inhibit isolates of the genus Fusarium, and Fusarium spp. isolates are also able to inhibit Streptomyces isolates in vitro. However, little is known about these complex antagonistic interactions and the potential for inhibitory Streptomyces to reduce FCR of wheat. The aim of this study was to analyze whether inhibitory Streptomyces isolates affect FCR of wheat and reduce root and stem base colonization by Fusarium culmorum. We enriched sterilized potting soil with spore suspensions of two Streptomyces isolates, inoculated the soil with F. culmorum-colonized wheat straw, and planted pre-germinated wheat seedlings. At 4 weeks, F. culmorum-inoculated plants had significant FCR symptoms on roots and showed reduced fresh weight of roots and above-ground plant biomass compared with the non-inoculated controls. Enrichment of soil with an inhibitory Streptomyces isolate reduced F. culmorum DNA in roots and stem bases by 75% compared with inoculation with F. culmorum alone. Interestingly, co-inoculation of F. culmorum with a non-inhibitory Streptomyces isolate led to the highest levels F. culmorum DNA in stem base tissue and greatest Streptomyces densities (CFU per g of soil) in the rhizosphere. In vitro assays revealed that F. culmorum showed a strong inhibitory activity against the pathogen-inhibitory Streptomyces isolate but not against the non-inhibitory isolate. In vitro tests with a larger set of 17 Streptomyces and five Fusarium spp. isolates revealed that there was little variation among Fusarium spp. isolates in capacities to inhibit the collection of Streptomyces isolates. In contrast, the sensitivity to inhibition by pathogenic Fusarium spp. isolates varied widely among Streptomyces isolates. The results of this study suggest the potential of Streptomyces isolates for biocontrol of FCR of wheat, while highlighting the specificity of Streptomyces−Fusarium interactions. Broader understanding of the variation in susceptibility within Fusarium spp. populations to Streptomyces inhibition and vice versa are needed to advance the potential for successful biological control.

Identification of a Novel Salt-Tolerant Streptomyces Isolate with Bio-Fertilizing Property

<p><em>A 65 local Streptomyces isolates were tested for their salt tolerance ability. Four of them were found to grow on 6% salt concentration medium. These were selected as candidates for bio-fertilizing use. Only one of them named Streptomyces NS-38 was found to pose such trait by enhancing accelerated seed germination of different types of plants on salt and normal media. Result showed that incubation of seeds with this bacterium extract for 15 hours before implantation increased the number of germinating seeds and yield significantly.</em></p>

Legonaridin, a new member of linaridin RiPP from a Ghanaian Streptomyces isolate

In this paper we describe the identification of a new linaridin RiPP, legonaridin, from the new soil bacterium Streptomyces sp. CT34.