Xanthomonas oryzae pv. oryzae (Xoo), a causal agent of bacterial leaf blight (BLB), is one of the most important pathogens of rice. The effectiveness of ten Streptomyces spp. isolates in suppressing Xoo disease was assessed in planta and in vitro. In planta experiments were carried out in a greenhouse and arranged in a randomized completely block design (RCBD) with three replications. Twenty treatments were tested which included plants inoculated with both Streptomyces spp. and Xoo, and plants inoculated with only Streptomyces spp. Plants inoculated with Xoo and sprayed with a chemical bactericide, and plants inoculated with only Xoo served as positive controls, whereas plants not inoculated with either Streptomyces spp. or Xoo were used as negative controls. The results showed that the effect of endophytic Streptomyces spp. on BLB disease expressed as area under disease progress curve (AUDPC) was not significantly different to that on control plants (P > 0.05). However, plants inoculated with endophytic Streptomyces spp. were significantly taller and produced higher tiller number than control plants (P < 0.05). Streptomyces spp. isolate AB131-1 gave the highest plant height. In vitro studies on biocontrol mechanisms of selected Streptomyces spp. isolates showed that isolate LBR02 gave the highest inhibition activity on Xoo growth, followed by AB131-1 and AB131-2. Two isolates (AB131-1 and LBR02) were able to produce chitinase, phosphatase, and siderophore which included biocontrol characteristics. Morphological and colonization studies under SEM and light microscopy confirmed that the three isolates were endophytic Streptomyces spp. from different species. These studies found that the paddy plant which was inoculated with endophytic Streptomyces spp. AB131-1 and infected by Xoo could increase the height of plant and number of tillers.

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An actinomycete strain, ID05-A0528T , was isolated using the SDS-yeast extract pre-treatment method from soil under mahogany (Swietenia mahogani) trees in West Timor, Indonesia, and was examined by using a polyphasic taxonomic approach. Chemotaxonomic and phylogenetic characterizations demonstrated that the novel strain belongs to the genus Dietzia. 16S rRNA gene sequencing studies showed that the strain was related to Dietzia cinnamea (97.2 %).Results of phenotypic and phylogenetic analyses determined that strain ID05-A0528 T is different from the known species of the genus Dietzia. It is proposed that the isolate should be classified as a representative of a novel species of the genus Dietzia, with the name Dietzia timorensis sp. nov. The type strain is ID05-A0528 T (5BTCC B-560 T 5NBRC 104184 T ).The genus Dietzia is a member of the suborder Corynebacterineae (Stackebrandt et al., 1997) and encompasses eight species at the time of writing, including Dietzia papillomatosis, Dietzia schimae and Dietzia cercidiphylli (Jones et al., 2008;Li et al., 2008). Known species of the genus Dietzia were originally isolated from several sources, including clinical materials, such as an alkaline soda lake, a perianal swab, a drain pool of a fish-egg processing plant, soil, the skin of an immunocompetent patient, and plant tissue (Duckworth et al., 1998;Yumoto et al., 2002;Yassin et al., 2006;Mayilraj et al., 2006;Jones et al., 2008;Li et al., 2008). Some strains identified as representing species of the genus Dietzia show degradation of hydrocarbons, including n-alkanes (Rainey et al., 1995;Chaillan et al., 2004;Yumoto et al., 2002). Additionally, Takeishi et al. (2006) reported xylanolytic strains of the genus Dietzia isolated from the hindgut and faeces of Trypoxylus dichotomus larvae. Hence, the discovery of additional species of this genus will help in understanding their ecological roles and provide bioresources for industrial applications, including bioremediation.Strain ID05-A0528 T was isolated from a soil sample collected under mahogany trees in West Timor. The SDS-yeast extract pre-treatment method (Hayakawa & Nonomura, 1989) and humic acid-vitamin agar (Hayakawa & Nonomura, 1987) containing nalidixic acid (20 mg l -1 ) were used in the isolation. The pre-treatment method was used to enhance the spore germination of actinomycetes and to decrease the number of nonfilamentous bacteria on the isolation plates. The aim of the present study was to determine the taxonomic position of isolate ID05-A0528 T using a polyphasic approach.The colonial properties of strain ID05-A0528 T were recorded from a modified Bennett's agar plate (Jones, 1949) that had been incubated for 14 days at 28 u C. Gramstaining was examined by using Hucker's method (Gerhardt, 1981). Motility was examined in hanging drops by light microscopy using culture grown on Bennett's agar plates. Morphology of the cells was observed using light microscopy. Tests for aesculin and arbutin hydrolysis (Williams et al., 1983), nitrate reduction (Gordon & Mihm,The...

Six actinomycete strains isolated from soil and plant-litter samples in Indonesia were studied for their taxonomic position by using a polyphasic approach. Phylogenetically, all the strains were located in the broad cluster of the genus Actinokineospora. Chemotaxonomic data [cell-wall diamino acid, meso-diaminopimelic acid; cell-wall peptidoglycan, type III (A1γ); major sugars, galactose and arabinose; major menaquinone, MK-9(H4); major fatty acid, iso-C16 : 0; major phospholipid, phosphatidylethanolamine] supported the affiliation of all six strains to the genus Actinokineospora. The results of DNA–DNA hybridization with DNA from type strains of Actinokineospora species with validly published names revealed three DNA–DNA relatedness groups. Group I (ID03-0561T) showed low relatedness to the other strains studied. The three strains in group II (ID03-0784T, ID03-0808 and ID03-0809) formed a group with high relatedness (98–100 %) and showed low relatedness to the other strains studied. The two strains in group III (ID03-0810T and ID03-0813) showed 58–68 % relatedness to Actinokineospora terrae NBRC 15668T and showed low relatedness (2–24 %) to the other strains studied. The description of three novel species is proposed: Actinokineospora baliensis sp. nov., for the single strain in group I (type strain ID03-0561T =BTCC B-554T =NBRC 104211T), Actinokineospora cibodasensis sp. nov., for the strains in group II (type strain ID03-0784T =BTCC B-555T =NBRC 104212T), and Actinokineospora cianjurensis sp. nov., for the strains in group III (type strain ID03-0810T =BTCC B-558T =NBRC 105526T).