Spore Chains Research Articles

Streptomyces xanthii sp. nov. and Streptomyces roseirectus sp. nov. isolated from a Chinese medicinal plant.

Two strains of Actinobacteria, designated CRXT-Y-14T and CRXT-G-22T, were isolated from the healthy leaves and seeds, respectively, of a medicinal plant Xanthium sibiricum. Their taxonomic positions were determined using a polyphasic approach. Strain CRXT-Y-14T produced flexuous chains of smooth-surfaced spores. Strain CRXT-G-22T produced straight chains of smooth-surfaced spores. Their morphological features were consistent with the diagnostic characteristics of members of the genus Streptomyces. The results of 16S rRNA gene sequence analyses indicated two strains represented members of the genus Streptomyces. CRXT-Y-14T shared 99.3, 98.9, 98.8 % sequence similarities to Streptomyces atriruber NRRL B-24165T, Streptomyces avermitilis MA-4680T and Streptomyces davaonensis JCM 4913T, respectively. Whilst CRXT-G-22T exhibited highest similarity to Streptomyces acidiscabies ATCC 49003T (98.9 %). The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that the closest phylogenetic neighbours of strains CRXT-Y-14T and CRXT-G-22T were S. atriruber NRRL B-24165T and S. acidiscabies ATCC 49003T, respectively. The phylogenomic analyses further confirmed the relative relationship between strain CRXT-G-22T and S. acidiscabies ATCC 49003T, but indicated that CRXT-Y-14T could represent a novel species of the genus Streptomyce. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between CRXT-Y-14T and strain CRXT-G-22T, between CRXT-Y-14T and S. atriruber NRRL B-24165T, and between CRXT-G-22T and S. acidiscabies ATCC 49003T were 85.4 and 23.2 %, 85.8 and 23.9 % and 89.1 and 34.1 %, respectively, far below the 95~96 and 70 % cut-off points recommended for delineating species. Furthermore, these two novel isolates were distinctly differentiated from their relatives in the genus Streptomyces with respect to phenotypic and chemotaxonomic characteristics. On the basis of these data, CRXT-Y-14T and CRXT-G-22T clearly represent two novel species within the genus Streptomyces, for which the names Streptomyces xanthii sp. nov. (type strain CRXT-Y-14T = MCCC 1K04966T= JCM 34527T) and Streptomyces roseirectus sp. nov. (type CRXT-G-22T = MCCC 1K04979T= JCM 34565T) are proposed.

Exploring the diversity of endophytic fungi and screening for their pullulanase-producing capabilities

BackgroundPullulanases are the significant industrial group in the 13 glycosyl hydrolases category, known as the α-amylases family. There are very few reports on pullulanase from fungal sources. Based on the above research gap, the present study was undertaken to explore the endophytic fungi for their pullulanase-producing capabilities. ResultsA total of 126 endophytes were isolated from Tradescantia pallida, Zea mays, and Trifolium alexandrinum. Aspergillus, Penicillium, and Ganoderma species recovered highest from the stem of Tradescantia palida. Fusarium was dominant in the stem and leaf of Zea mays. Penicillium, Aspergillus, Ganoderma, Cladosporium, Fusarium, and Alternaria were recovered from the Trifolium alexandrium. The Shannon index in Tradescantia pallida was highest in leaves while in Zea mays and Trifolium alexandrinum, it is highest in the stem. The Simpson’s index is highest in the case of Zea mays stem and root. Species richness was indicated by Menhinick’s index, and it was found that this value was highest in the roots of Trifolium alexandrinum. As per our knowledge, no comparative data is available on the endophytic diversity of the above plants taken for the study. Out of 126 endophytes, only 2.38% produced pullulanase while 7.94% produced amylase. The recovery of pullulanase-producing endophytic fungi was very less. But the importance of pullulanase is high as compared to amylase because it has both α-1,6 and α-1,4 hydrolyzing ability. Therefore, the most promising isolates were identified by ITS sequence analysis. Based on spore chain morphology, isolates BHU-25 and BHU-30 were identified as Penicillium sp. and Aspergillus species, respectively. This is the first report of pullulanase from endophytic Aspergillus and Penicillium. ConclusionEndophytes Aspergillus sp. and Penicillium sp. produce pullulanase enzyme. This is the first report of pullulanase from endophytic Aspergillus and Penicillium.

Identification and phylogenetic differences of newly isolated Streptomyces sp.

Antimicrobial resistance and antibiotic use is a global health crisis today. Streptomyces is the source of most antimicrobials. Therefore, the similarities and differences within the species of Streptomyces are of great importance. In this study, isolation and identification of 3 different Streptomyces species isolated from sediment from the Dicle region were performed. Then, 16S rRNA gene sequence was obtained and the similarities and differences between species were revealed. As a result of the study, bacteria contained clorometric differences, when looking at the spore chain morphology in the SEM image, a knobby structure was formed, 16S rRNA sequences longer than 1000bp and in the phylogenetic tree created, 1 isolate was closely similar to the sequences obtained from GenBank (93

Streptomyces coffeae sp. nov., an endophytic actinomycete isolated from the root of Coffea arabica (L.).

An endophytic actinobacterium, designated strain CA1R205T, was isolated from the surface-sterilized root of Coffea arabica L. collected from Ratchaburi province, Thailand. The taxonomic position of this strain was evaluated using a polyphasic approach. The strain produced light yellowish brown to dark brownish black substrate mycelium and greyish white aerial mycelium. The spiral spore chains were produced directly on aerial mycelium. CA1R205T was found to have ll-diaminopimelic acid in the cell peptidoglycan, galactose, glucose, mannose and ribose as whole-cell reducing sugars, MK-10(H4), MK-9(H6), MK-10(H2), MK-9(H4), MK-10(H6) and MK-10(H8) as menaquinones and iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0 as major fatty acids. Diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol were detected in the cells. These characteristics were consistent the typical chemotaxonomic properties of members the genus Streptomyces. The taxonomic affiliation at the genus level of this strain could be confirmed using its 16S rRNA gene sequence data. CA1R205T showed the highest 16S rRNA gene sequence similarity value to Streptomyces rapamycinicus NRRL B-5491T (98.9 %), followed by Streptomyces iranensis HM 35T (98.8 %). Digital DNA-DNA hybridization and average nucleotide identity-by blast (ANIb) values between CA1R205T and S. rapamycinicus NRRL B-5491T were 27.2 and 81.5 %, respectively. The DNA G+C content of genomic DNA was 70.7 mol%. Due to the differences in physiological, biochemical and genotypic data, CA1R205T could be discriminated from its closest neighbour. Thus, CA1R205T should be recognized as representing a novel species of the genus Streptomyces, for which the name Streptomyces coffeae sp. nov. is proposed. The type strain is CA1R205T (=TBRC 11244T=NBRC 114295T).

Streptomyces adelaidensis sp. nov., an actinobacterium isolated from the root of Callitris preissii with potential for plant growth-promoting properties.

An endophytic actinobacterium, strain CAP261T was isolated from the surface sterilized root of Callitris preissii (Australian native pine tree). As a result of a polyphasic taxonomy study, this strain was identified as a member of the genus Streptomyces. This strain was an aerobic actinobacterium with well-developed substrate mycelia with loop spore chains and the spore surfaces are verrucose. The closest phylogenetic members which shared the highest 16S rRNA gene sequences similarity was Streptomyces bottropensis ATCC 25435T at 98.1%. Chemotaxonomic data including cell wall components, major menaquinones, and major fatty acids confirmed the affiliation of strain CAP261T to the genus Streptomyces. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with genome comparison study, allowed the genotypic and phenotypic differentiation of strain CAP261T and the closest species with validly published names. ANIb, ANIm and dDDH values of strain CAP261T and S. bottropensis ATCC 25435T were 86.7%, 89.2% and 33.9%, respectively. The name proposed for the new species is Streptomyces adelaidensis sp. nov. The type strain is CAP261T (= DSM 42026T = NRRL B-24814T).

Genome-based classification of the Streptomyces violaceusniger clade and description of Streptomyces sabulosicollis sp. nov. from an Indonesian sand dune

A polyphasic study was designed to determine the taxonomic provenance of a strain, isolate PRKS01-29T, recovered from an Indonesian sand dune and provisionally assigned to the Streptomyces violaceusniger clade. Genomic, genotypic and phenotypic data confirmed this classification. The isolate formed an extensively branched substrate mycelium which carried aerial hyphae that differentiated into spiral chains of rugose ornamented spores, contained LL-as the wall diaminopimelic acid, MK-9 (H6, H8) as predominant isoprenologues, phosphatidylethanolamine as the diagnostic phospholipid and major proportions of saturated, iso- and anteiso- fatty acids. Whole-genome sequences generated for the isolate and Streptomyces albiflaviniger DSM 41598T and Streptomyces javensis DSM 41764T were compared with phylogenetically closely related strains, the isolate formed a branch within the S. violaceusniger clade in the resultant phylogenomic tree. Whole-genome sequences data showed that isolate PRKS01-29T was most closely related to the S. albiflaviniger strain but was distinguished from the latter and from other members of the clade using combinations of phenotypic properties and average nucleotide identity and digital DNA:DNA hybridization scores. Consequently, it is proposed that isolate PRKS01-29T (= CCMM B1303T = ICEBB-02T = NCIMB 15210T) should be classified in the genus Streptomyces as Streptomyces sabulosicollis sp. nov. It is also clear that streptomycetes which produce spiral chains of rugose ornamented spores form a well-defined monophyletic clade in the Streptomyces phylogenomic tree., the taxonomic status of which requires further study. The genome of the type strain of S. sabulosicollis contains biosynthetic gene clusters predicted to produce new natural products.

Streptomyces polyasparticus sp. nov. isolated from cotton field soil by a medium applied with polyaspartic acid.

A novel Streptomyces strain (TRM66268-LWLT) was isolated from cotton field soil by a medium supplied with polyaspartic acid (PASP) at Alar, Xinjiang, Northwest PR China, and characterized using a polyphasic taxonomic approach. The strain was found to degrade PASP, and grow well on the medium to take PASP as the sole carbon source. The TRM66268-LWLT fermentation broth was applied to the surface of PASP, and there were pores on the surface of PASP after a period of time. The strain was observed to be Gram-stain-positive and to form greyish-white aerial mycelia that differentiated into straight spore chains with round spores. The whole-cell sugar pattern of TRM 66268-LWLT consisted of ribose, mannose and arabinose, and the principal phospholipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, phosphatidylinositol and two undetermined polar lipids. The predominant menaquinones were MK-7, MK-7(H4), MK-9(H8), MK-10(H6). The diagnostic cell wall amino acid was identified as LL-diaminopimelic acid. The G+C content of strain TRM66268-LWLT was 70.11mol%. The average nucleotide identity value between strain TRM66268-LWLT and the phylogenetically related strain Streptomyces indicus IH32-1T was calculated to be 85.49%. The digital DNA-DNA hybridization value between them was 30.40%. A multilocus sequence analysis of five house-keeping genes (atpD, gyrB, rpoB, recA and trpB) also illustrated that strain TRM66268-LWLT should be assigned to the genus Streptomyces. On the basis of evidence from polyphasic study, strain TRM66268-LWLT is designated as representing a novel species of the genus Streptomyces, for which the name Streptomyces polyasparticus sp. nov. is proposed. The type strain is TRM66268-LWLT (CCTCC AA 2020003T = LMG32106T).

Amycolatopsis pittospori sp. nov., an endophytic actinobacterium isolated from native apricot tree and genome mining revealed the biosynthesis potential as antibiotic producer and plant growth promoter.

An endophytic actinobacterium, strain PIP199T, was isolated from a root sample of a native apricot growing on the Bedford Park campus of Flinders University, Adelaide, South Australia. The result of a polyphasic study showed that this strain was identified as a new member of the genus Amycolatopsis. Strain PIP199T is an aerobic actinobacterium with well-developed substrate mycelia and aerial mycelia that form short chains of spores. Amycolatopsis keratiniphila subsp. keratiniphila DSM 44409T (99.7%), Amycolatopsis lurida DSM 43134T (99.6%) and Amycolatopsis keratiniphila subsp. nogabecina DSM 44586T (99.4%) shared the highest 16S rRNA gene sequence similarity. A. keratiniphila subsp. keratiniphila DSM 44409T and A. lurida DSM 43134T were the closest phylogenetic neighbors. Chemotaxonomic data including major fatty acids, cell wall components and major menaquinones confirmed the affiliation of strain PIP199T to the genus Amycolatopsis. The phylogenetic analysis, physiological and biochemical studies and genomic study, allowed the genotypic and phenotypic differentiation of strain PIP199T and the closely related species with valid names. ANIb and dDDH values when compared to Amycolatopsis keratiniphila subsp. keratiniphila DSM 44409T were 87.3% and 36.4%, respectively. The name proposed for the new species is Amycolatopsis pittospori sp. nov. The type strain is PIP199T (= NRRL B-65536T = TBRC 10618T).

Kibdelosporangium persicum sp. nov., a new member of the Actinomycetes from a hot desert in Iran.

Isolate 4NS15T was isolated from a neglected arid habitat in Kerman, Iran. The strain showed 16S rRNA gene sequence similarity values of 98.9 % to the type strains of Kibdelosporangium aridum subsp. aridum, Kibdelosporangium phytohabitans and Kibdelosporangium philippinense and 98.6 % to the type strain K. aridum subsp. largum, respectively. Genome-based phylogenetic analysis revealed that isolate 4NS15T is closely related to Kibdelosporangium aridum subsp. aridum DSM 43828T. The digital DNA-DNA hybridization value between the genome sequences of 4NS15T and strain DSM 43828T is 29.8 %. Strain 4NS15T produces long chains of spores without a sporangium-like structure which can be distinguished from other Kibdelosporangium species. Isolate 4NS15T has a genome size of 10.35 Mbp with a G+C content of 68.1 mol%. Whole-cell hydrolysates of isolate 4NS15T are rich in meso-diaminopimelic acid and cell-wall sugars such as arabinose, galactose, glucose and ribose. Major fatty acids (>10 %) are C16 : 0, iso-C16 : 0 and iso-C15 : 0. The phospholipid profile contains diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylhydroxyethanolamine, aminolipid and glycoaminolipid. The predominant menaquinone is MK-9(H4). Based on its phenotypic and genotypic characteristics, isolate 4NS15T (NCCB 100701=CIP 111705=DSM 110728) merits recognition as representing a novel species of the genus Kibdelosporangium, for which the name Kibdelosporangium persicum sp. nov. is proposed.

Biological characteristics and classification of thermophilic actinomycetes showed extracellular hydrolytic enzymes producing ability isolated from compost

Compost is a highly humified organic fertilizer, rich in nutrients and a source of a variety of aerobic microorganisms, including actinomycetes, which develop in response to different levels of temperature, humidity, oxygen and pH. Microbes growing on the compost are believed to have the ability to produce extracellular hydrolytic enzymes. The purpose of this study was to determine the ability of thermophilic actinomycetes XM21 isolated from compost in producing hydrolytic enzymes, namely cellulase, amylase, protease, and lipase. The confirmation tests of hydrolytic enzymes-producing ability were conducted by inoculating the microbes into media containing cellulose, starch, gelatin and tween 80, using the method of disc diffusion. The results showed that strain XM21 capable of extracellular enzymes producing, such as cellulase, protease, amylase, lipase. Strain XM21 can grow well with high cellulase activity in a wide range of temperature between 30-55oC, optimum at 45oC. The strain can grow well on different media, utilized carbon sources with pH 5-10, and salinity of 0-5%. On the agar plate, the strain has white aerial mycelia, the mature spore chains appeared spirals, moderately long, bearing 10 to 35 spores each. Based on the biological characteristics and phylogenetic analysis of 16S rDNA, it can be concluded that strain XM21 is close to Streptomyces flavovariabilis (98, 12%), hence identified as Streptomyces flavovariabilis XM21.

Antagonistic potential of Streptomyces cellulosae SM12 against Ganoderma sp. TB3 and Ganoderma sp. TB4

A study was carried out to screen 25 Actinomycetes isolates that have ability to act as biocontrol agents Actinomycetes against Ganoderma sp. TB3 and Ganoderma sp. TB4. Among 25 Actinomycetes isolates, only Actinomycetes SM12 can inhibit the growth of both Ganoderma sp. TB3 (52 %) and Ganoderma sp. TB4 (60 %). Antagonistic assay using cross streak method with a longer period of delayed antagonism showed higher inhibition effect to the growth of Ganoderma sp. TB3 (76 %) and Ganoderma sp. TB4 (85 %). Identification of Actinomycetes SM12 based on 16S rRNA revealed that Actinomycetes SM12 belong to Streptomyces cellulosae. The Actinomycetes SM12 isolate produces rectinaculum-apertum spore chain and forms a colony that exhibited white to greyish color. Enzyme activity test showed that the cultures are positive in amylase, protease, lipase and cellulase production respectively.

Isolation and Characterization of a New Streptomyces strain LG10 from an Unexploited Algerian Saharan Atlas

Abstract An actinobacterial strain named LG10 was isolated from a Saharan Atlas soil (Laghouat, Algeria). The aerial hyphae were yellowish-white on all culture media with rectiflexibiles spore chains, suggested that this bacterium attached to Streptomyces. Furthermore, LG10 contained chemical characteristics that were diagnostic for the genus Streptomyces, such as the presence of LL-diaminopimelic acid isomer (LL-DAP) and glycine amino acid. The hydrolysates of whole-cell included non-characteristic sugars. Comparative analysis of the 16S rDNA sequence displayed a similarity level of 100% with Streptomyces puniceus NRRL ISP-5058T. The antimicrobial activity of the LG10 strain was better in the culture medium MB5. Streptomyces strains are good sources of bioactive compounds with multiple biological activities.

Prodiginines Postpone the Onset of Sporulation in Streptomyces coelicolor.

Bioactive natural products are typically secreted by the producer strain. Besides that, this allows the targeting of competitors, also filling a protective role, reducing the chance of self-killing. Surprisingly, DNA-degrading and membrane damaging prodiginines (PdGs) are only produced intracellularly, and are required for the onset of the second round of programmed cell death (PCD) in Streptomyces coelicolor. In this work, we investigated the influence of PdGs on the timing of the morphological differentiation of S. coelicolor. The deletion of the transcriptional activator gene redD that activates the red cluster for PdGs or nutrient-mediated reduction of PdG synthesis both resulted in the precocious appearance of mature spore chains. Transcriptional analysis revealed an accelerated expression of key developmental genes in the redD null mutant, including bldN for the developmental σ factor BldN which is essential for aerial mycelium formation. In contrast, PdG overproduction due to the enhanced copy number of redD resulted in a delay or block in sporulation. In addition, confocal fluorescence microscopy revealed that the earliest aerial hyphae do not produce PdGs. This suggests that filaments that eventually differentiate into spore chains and are hence required for survival of the colony, are excluded from the second round of PCD induced by PdGs. We propose that one of the roles of PdGs would be to delay the entrance of S. coelicolor into the dormancy state (sporulation) by inducing the leakage of the intracellular content of dying filaments thereby providing nutrients for the survivors.

Steptomyces fagopyri sp. nov., a novel actinomycete isolated from rhizospheric soil of Fagopyrum dibotrys.

A novel actinomycete, designated strain QMT-28T, was isolated from rhizosphere soil of Fagopyrum dibotrys collected from Shuangfeng, Hunan Province, PR China. Strain QMT-28T grew well on International Streptomyces Project series media and formed well-developed, branched substrate hyphae and aerial mycelium that differentiated into loose spiral spore chains consisting of cylindrical spores with smooth surfaces. The diagnostic diamino acid was ll-diaminopimelic acid and the whole-cell sugars were galactose and glucose. The predominant fatty acids were C18 : 1 cis9, summed feature 6 (C18 : 2 cis 9,12/C18 : 0 a) and C16 : 0. The polar lipids included diphosphatidylglycerol, hydroxy phospatidylethanolamine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannosides, phospholipids of unknown structure containing glucosamine and several unidentified phospholipids. The major menaquinones were MK-9, MK-9(H2), MK-9(H4), MK-9(H6) and MK-9(H8). The genome size of strain QMT-28T was about 8.7 Mbp with a G+C content of 71.2 mol%. Phylogenetic analysis showed that the novel strain was closely related to Streptomyces olivochromogenes DSM 40451T (99.5 % similarity), Streptomyces mirabilis NBRC 13450T (98.9 %), Streptomyces kanamyceticus NBRC 13414T (98.9 %), Streptomyces kaempferi I37T (98.9 %) and Streptomyces arcticus ZLN234T (98.8 %). However, the average nucleotide identity values, the digital DNA-DNA hybridization values and the multilocus sequence analysis evolutionary distances between this strain and closely related strains showed that it belonged to a distinct species. In addition, these results were also supported by differences in the phenotypic characteristics between QMT-28T and five closely related type strains. Consequently, strain QMT-28T should represent a novel species of the genus Streptomyces, with the suggested name Streptomyces fagopyri sp. nov. The type strain is QMT-28T (=CICC 24808T=JCM 33796T).

Streptomyces alkaliterrae sp. nov., isolated from an alkaline soil, and emended descriptions of Streptomyces alkaliphilus, Streptomyces calidiresistens and Streptomyces durbertensis

A polyphasic study was undertaken to establish the taxonomic position of six representative streptomycetes isolated from an alkaline soil adjacent to a meteoric alkaline soda lake in India. Chemotaxonomic, cultural and morphological properties of the isolates were consistent with their classification in the genus Streptomyces. The isolates formed extensively branched substrate mycelia and aerial hyphae that differentiated in straight chains of spores with smooth surfaces. They contained LL-diaminopimelic acid in the wall peptidoglycan, produced either hexa- or octa-hydrogenated menaquinones with nine isoprene units, major amounts of saturated, iso- and anteiso- fatty acids and phosphatidylethanolamine as the characteristic polar lipid. The isolates grew well at 30 °C, pH 9 and in the presence of 3 to 5% (w/v) sodium chloride. Isolates OF1T, OF3 and OF8 formed a distinct clade within the Streptomyces 16S rRNA gene tree sharing relatively high sequence similarities with the type strains of Streptomyces durbertensis (99.3%), Streptomyces palmae (98.1%) and Streptomyces xinghaiensis (98.3%), but can be distinguished from them using combinations of phenotypic properties. A phylogenomic tree based on draft genome sequences of the isolates and S. durbertensis DSM 104538T confirmed the phylogenetic relationships. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values calculated from the whole genome sequences of isolate OF1T and S. durbertensis DSM 104538T were low at 92.0% and 45.2%, respectively, indicating that they belong to different genomic species. Consequently, on the basis of the genomic, phylogenetic and associated phenotypic data it is proposed that isolates OF1T, OF3 and OF8 be assigned to the genus Streptomyces as Streptomyces alkaliterrae sp. nov. with strain OF1T (NCIMB 15195T =PCM 3001T) as the type strain. Isolates IF11, IF17 and IF19, and S. alkaliphilus DSM 42118T were shown to belong to the same taxospecies and together with S. calidiresistens DSM 42108T comprised a well supported clade in the Streptomyces 16S rRNA gene tree. Isolate IF17 and S. alkaliphilus DSM 42118T formed a well-supported clade in the phylogenomic tree, had almost identical digital G + C similarity values, produced long straight chains of smooth-surfaced spores and shared ANI and dDDH values (98.0 and 79.6%, respectively) consistent with their assignment to the same genomic species. In light of all of the data isolates IF11, IF17 and IF19 should be seen as authentic stains of S. alkalihilus. Data acquired in the present study have also been used to emend the descriptions of S. alkaliphilus, S. calidiresistens and S. durbertensis. The genomes of isolates IF17, and OF1T, OF3 and OF8 contain relatively high numbers of biosynthetic gene clusters some of which were discontinously distributed indicating ones predicted to express for novel specialised metabolites.

Nocardiopsis dassonvillei subsp. crassaminis subsp. nov., isolated from freshwater sediment, and reappraisal of Nocardiopsis alborubida Grund and Kroppenstedt 1990 emend. Nouioui et al. 2018.

An actinomycete, strain D1T, was isolated from a freshwater sediment sample collected from the San Pablo river in the La Risueña community, Santiago de Cuba province, Cuba. The strain was identified as a member of the genus Nocardiopsis by means of a polyphasic taxonomic study. It produced a light yellow non-fragmented substrate mycelium, a white well-developed aerial mycelium and straight to flexuous hyphae. No specific spore chains were observed. Strain D1T contained meso-diaminopimelic acid, no diagnostic sugars, and MK-10(H2), MK-10(H4), MK-10 and MK-10(H6) as predominant menaquinones, but not phosphatidylcholine as diagnostic polar lipid of the genus Nocardiopsis. The predominant fatty acids were iso-C16 : 0, 10-methyl-C18 : 0 and anteiso-C17 : 0. Strain D1T showed the highest degree of 16S rRNA gene sequence similarity to Nocardiopsis synnematoformans DSM 44143T (99.8 %), Nocardiopsis dassonvillei subsp. albirubida NBRC 13392T (99.8 %) and Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111T (99.6 %). A genomic OrthoANIu value between D1T and N. dassonvillei subsp. dassonvillei DSM 43111T of 97.63 % and a dDDH value of 78.9 % indicated that strain D1T should be classified in N. dassonvillei. However, phenotypic characteristics distinguished strain D1T from its nearest neighbour taxon. On basis of these results we propose to classify strain D1T (=LMG 30468T=CECT 30033T) as a representative of a novel subspecies of the genus Nocardiopsis, for which the name Nocardiopsis dassonvillei subsp. crassaminis subsp. nov. is proposed. In addition, the genomic distance between N. dassonvillei subsp. albirubida NBRC 13392T and N. dassonvillei subsp. dassonvillei DSM 43111T as determined through OrthoANIu (93.64 %) and dDDH (53.40 %), along with considerable phenotypic and chemotaxonomic differences reported in earlier studies, indicated that the classification of this taxon as Nocardiopsis alborubida Grund and Kroppenstedt 1990 is to be preferred over its classification as N. dassonvillei subsp. albirubida Evtushenko et al. 2000.

Alternaria tenuissima Causing Leaf Spot Disease on Amygdalus triloba in Xinjiang of China.

Amygdalus triloba (Rosaceae; previously Prunus triloba) is a deciduous, flowering shrub that is widely used in the greening and beautification of lawns, parks and courtyards in China. In late May 2019, a leaf spot disease of A. triloba was observed on approximately 35% of plants in the Xinjiang Alaer city (40˚33'20''N, 81˚17'19''E). The disease symptoms began as small, suborbicular, brown spots on the leaves. As the disease progressed, the spots enlarged and coalesced into large necrotic areas and resulted in premature defoliation. Leaf sections (5 x 5 mm) from infected leaves were surface - sterilized with 75% ethanol for 30 s and 0.1% HgCl2 for 1 min, rinsed three times in sterile distilled water and then incubated on potato dextrose agar (PDA). Fifteen fungal isolates showing similar morphological characteristics were obtained by single-spore isolation. On the PDA plates, all fungal colonies had a dark olive color with loose, cottony mycelium. On the potato carrot agar, the fungus formed unbranched spore chains, but occasionally formed one or two lateral branches. Conidiophores were short, hazel-colored, septae, arising singly, and measuring 15.1 to 61.8 × 1.8 to 4.2 µm (35.2 ± 1.4 × 2.3 ± 0.1 µm, n = 50). Mature conidia were ellipsoidal to ovoid with a short conical beak at the tip, light brown with zero to three longitudinal septa and one to five transverse septa, and measuring 19.3 to 30.8 × 7.2 to 12.5 µm (21.8 ± 0.3 × 9.5 ± 0.2 µm, n = 50). Based on the cultural and morphological traits, the pathogen was preliminary identified as Alternaria tenuissima (Simmons 2007). Genomic DNA was extracted from the representative isolate YALAR-1, and the internal transcribed spacer (ITS) region, the partial coding sequence of endopolygalacturonase (endoPG), the glyceradehyde -3- phosphate dehydrogenase (GAPDA), the partial region of the histone 3 (H3) genes were amplified using primers ITS1/ITS4 (White et al. 1990), PG2b/PG3a (Andrew et al. 2009), GDF1/GDR1 (Berbee et al. 1999) and H3-1a/H3-1b (Glass and Donaldson 1995), respectively. The amplicons were sequenced and deposited in GenBank [MT459807 (ITS), MT459808 (endoPG), MT459805 (GAPDA), MT459806 (H3)]. MegaBLAST analyses revealed that our ITS, endoPG, GAPDA, and H3 sequences were 99-100% identical to those of A. tenuissima isolates in GenBank [AF347032 (ITS), KP124026 (endoPG), AY278809 (GAPDA), KF997086 (H3)], confirming the identity of the pathogen as A. tenuissima. Pathogenicity tests were performed by inoculating the fungus onto healthy, mature leaves of A. triloba in the field. Twenty five leaves (five leaves/plant) were sprayed with spore suspensions (1 × 106 spores/ml) of each fungal pathogen, and the same number of leaves were sprayed with distilled water as controls. Inoculated and control leaves were covered with clear plastic bags for 3 days. The experiment was repeated three times. Twelve days after inoculation, the observed symptoms were similar to the original symptoms and the same fungal pathogen was reisolated from the inoculated leaves and identified as A. tenuissima based on morphological features and sequence analysis. The control leaves remained asymptomatic and no fungus was isolated from these leaves. Previously, a leaf spot of A. triloba caused by Alternaria brassicae was reported in Dalian, China (Xie et al. 2017). In order to control this disease effectively, further studies are needed on the biology and ecology of A. tenuissima and A. brassicae respectively. To our knowledge, this is the first report of A. tenuissima associated with leaf spot disease on A. triloba in China. In late September 2020, the diseased plant rate increased to 38% in Alaer city. If the disease control and prevention is neglected, the landscape of Alaer city will be affected seriously. So, in order to effectively control the spread of the disease, it is urgent now to study the sensitivity of pathogen to fungicide and carry out the field efficacy trials.

Phytoactinopolyspora mesophila sp. nov., isolated from a saline-alkaline soil.

A novel moderately halophilic, filamentous actinobacterium, designated as XMNu-373T, was isolated from a saline-alkaline soil sample collected from the Mongolia Plateau, Dongwu County, Inner Mongolia Autonomous Region, PR China. The isolate grew optimally at 28‒37 °C, pH 7.0‒8.0 and with 2-5 % (w/v) NaCl. The substrate mycelia fragmented into rod-like elements, and the white aerial mycelia formed spore chains at maturity. The predominant menaquinone was MK-9(H4). The polar lipids were diphosphatidylglycerol, three unidentified phosphoglycolipids, an unidentified aminophospholipid, two phosphatidylinositol mannosides, four unidentified phospholipids, phosphatidylglycerol and two unidentified lipids. The major cellular fatty acids were iso-C16 : 0, anteiso-C17 : 0 and anteiso-C15 : 0. The genomic DNA G+C content was 66.2 mol%. It shared high 16S rRNA gene sequence similarities to Phytoactinopolyspora halotolerans YIM 96448T (96.1 %) and Phytoactinopolyspora endophytica EGI 60009T (96.0 %). Phylogenetic trees based on 16S rRNA gene sequences revealed that strain XMNu-373T resided in the clade of family Jiangellaceae, and it formed a monophyletic branch distinct from four other recognized type species in the subclade of the genus Phytoactinopolyspora. On the basis of polyphasic taxonomic evidence, strain XMNu-373T represents a novel species of the genus Phytoactinopolyspora, for which the name Phytoactinopolyspora mesophila sp. nov. is proposed. The type strain is XMNu-373T (=JCM 33740T=CGMCC 4.7654T).

Nonomuraea typhae sp. nov., an endophytic actinomycete isolated from the root of cattail pollen (Typha angustifolia L.).

A novel endophytic actinomycete, designated strain p1410T, was isolated from the root of cattail pollen (Typha angustifolia L.) and characterized using a polyphasic approach. The strain had morphological characteristics and chemotaxonomic properties identical to those of members of the genus Nonomuraea. It produced spiral chains of spores on aerial mycelium as well as forming a pseudosporangium. Whole-cell hydrolysates contained meso-diaminopimelic acid, glucose, ribose and madurose. The menaquinones detected were MK-9(H2), MK-9(H4) and MK-9(H0). The major fatty acids were 10-methyl C17 : 0, iso-C16 : 0 and C17 : 0. The polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol mannoside and an unknown glycolipid. The DNA G+C content of the draft genome sequence, consisting of 11.4 Mbp, was 70.9 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain p1410T belongs to the genus Nonomuraea with the highest sequence similarity to Nonomuraea candida HMC10T (98.6 %), but phylogenetically clustered with Nonomuraea endophytica YIM 65601T (98.4 %) and Nonomuraea longicatena NRRL 15532T (98.3 %). Based on its phenotypic characteristics, DNA-DNA relatedness and average nucleotide identity, the strain is considered to represent a novel species of the genus Nonomuraea, for which the name Nonomuraea typhae sp. nov. is proposed. The type strain is p1410T (=CCTCC AA 2019044T=JCM 33461T).

Evaluation of Antagonistic and Plant Growth Promoting Potential of Streptomycessp. TT3 Isolated from Tea(Camellia sinensis) Rhizosphere Soil.

The present study investigated the antagonistic and plant growth promoting (PGP) potential of actinobacteria TT3 isolated from tea rhizosphere soil of Tocklai tea germplasm preservation plot, Jorhat, Assam, India. It is a Gram-positive, filamentous with flexible spore chains actinobacteria. The 16S rRNA gene sequencing and phylogenetic analysis indicated that TT3 is closely related to genus Streptomyces for which it was referred to as Streptomyces sp. TT3. It showed very promising PGP traits such as phosphate solubilization, production of indole acetic acid (IAA), siderophore, and ammonia. Evaluation of ethyl acetate extract of TT3 exhibited broad spectrum antagonistic activity against various fungal pathogens. This antagonistic Streptomyces sp. TT3 showed positive for polyketide synthase type II (PKS-II) gene, which was predicted to be involved in the production of actinorhodin as a secondary metabolite pathway product using DoBISCUIT database. Further, the crude ethyl acetate extract of TT3 was analyzed by using GC-MS and revealed the presence of significant chemical constituents responsible for antimicrobial activity. Thus, the present study suggests that actinobacteria isolated from the rhizosphere soil may be explored for the production of bioactive compounds and use as a potential candidate for tea and other agricultural application.