Ultraviolet Resistance of Microorganisms Isolated from Uranium-Rich Minerals from Perus, Brazil

The district of Perus, located in the city of São Paulo, Brazil, is renowned for its weathered granitic-pegmatitic masses, which harbor a significant number of uraniferous minerals that contribute to ionizing radiation levels up to 20 times higher than the background levels. In this study, aseptically collected mineral samples from the area were utilized to isolate 15 microorganisms, which were subjected to pre-screening tests involving UV-C and UV-B radiation. The microorganisms that exhibited the highest resistance to ultraviolet (UV) radiation were selected for the construction of survival curves for UV-C, broad-band UV-B, and solar simulation resistance testing. Subsequently, the four strains that demonstrated superior survival capabilities under UV radiation exposure were chosen for 16S rRNA gene sequencing. Among these, Nocardioides sp. O4R and Nocardioides sp. MA2R demonstrated the most promising outcomes in the UV radiation resistance assessments, showcasing comparable performance to the well-established radioresistant model organism Deinococcus radiodurans. These findings underscore the potential of naturally occurring high-radiation environments as valuable resources for the investigation of UV-resistant microorganisms.

Polyphasic characterization and genomic insights into Nocardioides turkmenicus sp. nov. isolated from a desert soil

Strain KC13T, a novel desert-adapted, non-motile, Gram-stain-positive, rod-shaped, aerobic bacterium, was isolated from a soil sample collected from the Karakum Desert, Turkmenistan and characterised by a polyphasic approach. Phylogenetic analysis based on 16S rRNA sequences revealed that strain KC13T was a member of the genus Nocardioides, and formed a distinct cluster with Nocardioides luteus DSM 43366T (99.3% sequence identity), Nocardioides albus DSM 43109T (98.9%), Nocardioides panzhihuensis DSM 26487T (98.3%) and Nocardioides albertanoniae DSM 25218T (97.9%). The orthologous average nucleotide identity and digital DNA-DNA hybridization values were in the range of 85.8-91.0% and 30.2-35.9%, respectively, with the type strains of closely related species. The genome size of strain KC13T was 5.3 Mb with a DNA G + C content of 69.7%. Comprehensive genome analyses showed that strain KC13T, unlike its close relatives, had many genes associated with environmental adaptation. Strain KC13T was found to have chemotaxonomic and phenotypic characteristics of members of the genus Nocardioides and some differences from phylogenetic neighbours. Based on the chemotaxonomic, genomic, phenotypic and phylogenetic data, strain KC13T represents a novel species of the genus Nocardioides, for which the name Nocardioides turkmenicus sp. nov. is proposed, and the type strain is KC13T (= JCM 33525T = CGMCC 4.7619T).

Nocardioides cremeus sp. nov., Nocardioides abyssi sp. nov. and Nocardioides oceani sp. nov., three actinobacteria isolated from Western Pacific Ocean sediment

Three Gram-stain-positive, non-motile, short rod-shaped, catalase-positive and oxidase-negative actinomycete strains (SOB44T, SOB72T and SOB77T) were isolated from a deep-sea sediment sample collected from the Western Pacific Ocean. Cells of the three strains showed optimum growth at 30 °C and pH 7.0. Strains SOB44T, SOB72T and SOB77T could tolerate up to 10, 9 and 9 % (w/v) NaCl concentration and grow at pH 5.0-12.0, 5.0-11.0 and 5.0-11.0, respectively. Phylogenetic results based on 16S rRNA gene sequences showed that the three isolates belonged to the genus Nocardioides and were identified as representing three novel species based on 78.0-93.1 % average nucleotide identity and 21.3-50.0 % DNA-DNA hybridization values with closely related reference strains. Strains SOB44T, SOB72T and SOB77T showed highest 16S rRNA gene sequence similarity to Nocardioides salarius CL-Z59T (99.2 %), Nocardioides deserti SC8A-24T (99.2 %) and Nocardioides marmotae zg-579T (98.5 %), respectively. All three strains had MK-8(H4) as the respiratory quinone, iso-C16 : 0 as the major fatty acid, and phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol as the major polar lipids. The diagnostic diamino acid in the cell-wall peptidoglycan of all three isolates was ll-diaminopimelic acid. The DNA G+C contents of strains SOB44T, SOB72T and SOB77T were 71.1, 72.9 and 72.9 mol%, respectively. Based on the phenotypic, phylogenetic and genotypic data, strains SOB44T, SOB72T and SOB77T clearly represent three novel taxa within the genus Nocardioides, for which the names Nocardioides cremeus sp. nov. (type strain SOB44T=JCM 35774T= MCCC M28400T), Nocardioides abyssi sp. nov. (type strain SOB72T=JCM 35775T=MCCC M28318T) and Nocardioides oceani sp. nov. (type strain SOB77T=JCM 35776T=MCCC M28544T) are proposed.

Phycicoccus sonneraticus sp. nov., a Novel Endophytic Actinobacterium Isolated from the Bark of Sonneratia apetala

A novel endophytic actinobacterial strain, designated MQZ13P-5T, was isolated from a piece of bark of Sonneratia apetala, collected from Guangxi Zhuang Autonomous Region, China. This strain was Gram-stain positive, aerobic, non-spore-forming, non-motile and rod-shaped. Comparative 16S rRNA gene sequence analysis showed that strain MQZ13P-5T was related to the genus Phycicoccus with exhibiting the highest similarity (98.0%) to Phycicoccus endophyticus IP6SC6T. The phylogenetic trees based on 16S rRNA gene sequences and core genes indicated that strain MQZ13P-5T belonged to the genus Phycicoccus and could not be assigned to any described species. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain MQZ13P-5T and type strains of Phycicoccus species were less than 84% and 27%, respectively, below the thresholds for species delineation. This strain showed chemotaxonomic and phenotypic properties consistent with its classification in the genus Phycicoccus. Based on the taxonomic data, strain MQZ13P-5T should represent a novel species of the genus Phycicoccus, for which the name Phycicoccus sonneraticus sp. nov. is proposed, with the type strain MQZ13P-5T (= CGMCC 1.18744T = JCM 34337T).

Taxonomic Identification of the Arctic Strain Nocardioides Arcticus Sp. Nov. and Global Transcriptomic Analysis in Response to Hydrogen Peroxide Stress

Microorganisms living in polar regions rely on specialized mechanisms to adapt to extreme environments. The study of their stress adaptation mechanisms is a hot topic in international microbiology research. In this study, a bacterial strain (Arc9.136) isolated from Arctic marine sediments was selected to implement polyphasic taxonomic identification based on factors such as genetic characteristics, physiological and biochemical properties, and chemical composition. The results showed that strain Arc9.136 is classified to the genus Nocardioides, for which the name Nocardioides arcticus sp. nov. is proposed. The ozone hole over the Arctic leads to increased ultraviolet (UV-B) radiation, and low temperatures lead to increased dissolved content in seawater. These extreme environmental conditions result in oxidative stress, inducing a strong response in microorganisms. Based on the functional classification of significantly differentially expressed genes under 1 mM H2O2 stress, we suspect that Arc9.136 may respond to oxidative stress through the following strategies: (1) efficient utilization of various carbon sources to improve carbohydrate transport and metabolism; (2) altering ion transport and metabolism by decreasing the uptake of divalent iron (to avoid the Fenton reaction) and increasing the utilization of trivalent iron (to maintain intracellular iron homeostasis); (3) increasing the level of cell replication, DNA repair, and defense functions, repairing DNA damage caused by H2O2; (4) and changing the composition of lipids in the cell membrane and reducing the sensitivity of lipid peroxidation. This study provides insights into the stress resistance mechanisms of microorganisms in extreme environments and highlights the potential for developing low-temperature active microbial resources.

Description and genomic characterization of Jiella flava sp. nov., isolated from Acrostichum aureum

Two endophytic bacteria, designated strains CQZ9-1T and MQZ9-1, were isolated from semi-mangrove plant Acrostichum aureum collected from Maowei Sea Mangrove Nature Reserve in Guangxi Zhuang Autonomous Region, PR China. The two strains possessed almost identical 16S rRNA gene sequences (99.7 %). The average nucleotide identity (ANI), average amino acid identity (AAI) and the digital DNA-DNA hybridization (dDDH) values between the two strains were 100 %, indicating that they represented the same species. The 16S rRNA gene sequence similarities between strains CQZ9-1T, MQZ9-1 and the most closely related type strains, Jiella mangrovi KSK16Y-1T, Jiella sonneratiae MQZ13P-4T and Jiella endophytica CBS 5Q-3T were 98.0–98.1, 97.3–97.4 and 97.3–97.4 %, respectively. The results of phylogenetic analyses based on 16S rRNA gene sequences and genome sequences indicated that CQZ9-1T and MQZ9-1 formed a distinct lineage with J. endophytica CBS5Q-3T, Jiella pacifica 40Bstr34T, J. mangrovi KSK16Y-1T, J. sonneratiae MQZ13P-4T, Jiella aquimaris JCM 30119T and J. aquimaris 22II-16-19i. The draft genomes of strains CQZ9-1T and MQZ9-1 were 4  162  933 bp and 4  164  266 bp in size, respectively, and their DNA G+C contents were both 63.8 %. Comparative genome analysis of the two strains and the type strains of related species revealed ANI, AAI and dDDH values below the cut-off levels of 95-96, 95.5 and 70 %, respectively. The ubiquinone detected in CQZ9-1T was Q-10. The major cellular fatty acid of strains CQZ9-1T and MQZ9-1 was found to be C18:1ω7c. Combined data from phenotypic, phylogenetic and chemotaxonomic studies indicated that CQZ9-1T and MQZ9-1 represent a novel species of the genus Jiella , for which the name Jiella flava sp. nov. is proposed. The type strain is CQZ9-1T (= CGMCC 1.18725T = JCM 34331T).

Jiella sonneratiae sp. nov., a novel endophytic bacterium isolated from bark of Sonneratia apetala

A new endophytic bacterium, designated strain MQZ13P-4T was isolated from Sonneratia apetala collected from Maowei sea Mangrove Nature Reserve in Guangxi Zhuang Autonomous Region, PR China. The 16S rRNA gene sequence similarity between strain MQZ13P-4T and its closest phylogenetic neighbour Jiella endophytica CBS5Q-3T was 97.9 %. Phylogenetic analyses using 16S rRNA gene sequences and whole-genome sequences showed that strain MQZ13P-4T formed a distinct lineage with Jiella endophytica CBS5Q-3T, Jiella pacifica 40Bstr34T and Jiella aquimaris JCM 30119T. The draft genome of strain MQZ13P-4T was 5 153 243 bp in size and its DNA G+C content was 68.1 mol%. Comparative genome analysis revealed that the average nucleotide identity, digital DNA–DNA hybridization and average amino acid identity values among strain MQZ13P-4T and other related species were below the cut-off levels of 95, 70 and 95.5 %, respectively. The cell-wall peptidoglycan of strain MQZ13P-4T contained meso-diaminopimelic acid as the diagnostic diamino acid. The respiratory quinone was Q-10. The major cellular fatty acid was C18 : 1  ω7c. The polar lipids comprised phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminolipids and two unidentified lipids. Strain MQZ13P-4T had a typical chemical compositions of fatty acids, lipids, quinones and diagnostic diamino acid for Jiella species, but could be distinguished from known species of the genus Jiella . Based on polyphasic evidence, strain MQZ13P-4T represents novel species of the genus Jiella , for which the name Jiella sonneratiae sp. nov. is proposed. The type strain is MQZ13P-4T (=CGMCC 1.18727T=JCM 34333T).

Nocardioides humilatus sp. nov., isolated from farmland soil in the Republic of Korea

A Gram-stain positive, aerobic, irregularly rod-shaped, non-spore-forming bacterium, designated as BN130099T, was isolated from farmland soil sampled in Goesan-gun, Chungbuk, Republic of Korea. Phylogenetic analysis of its 16S rRNA gene sequence showed that the strain is closely related to Nocardioides pelophilus KACC 19192T with 98.11 % similarity. The DNA G+C content of strain BN130099T was 68.84 mol% (draft genome sequence). The genome sequence of BN130099T displayed key enzymes involved in bioremediation of organic pollutants and biosynthetic clusters of saquayamycin. The strain contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan and MK-8(H4) as the major respiratory quinone. The predominant fatty acid was iso-C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol. The results of physiological and biochemical characterization allowed the phenotypic differentiation of strain BN130099T from N. pelophilus KACC 19192T. The strain represents a novel species of the genus Nocardioides , for which we propose the name Nocardioides humilatus sp. nov. The type strain is BN130099T (=KCTC 49079T=CCTCC AB 2018135T).

Actinobacteria From Desert: Diversity and Biotechnological Applications

Deserts, as an unexplored extreme ecosystem, are known to harbor diverse actinobacteria with biotechnological potential. Both multidrug-resistant (MDR) pathogens and environmental issues have sharply raised the emerging demand for functional actinobacteria. From 2000 to 2021, 129 new species have been continuously reported from 35 deserts worldwide. The two largest numbers are of the members of the genera Streptomyces and Geodermatophilus, followed by other functional extremophilic strains such as alkaliphiles, halotolerant species, thermophiles, and psychrotolerant species. Improved isolation strategies for the recovery of culturable and unculturable desert actinobacteria are crucial for the exploration of their diversity and offer a better understanding of their survival mechanisms under extreme environmental stresses. The main bioprospecting processes involve isolation of target actinobacteria on selective media and incubation and selection of representatives from isolation plates for further investigations. Bioactive compounds obtained from desert actinobacteria are being continuously explored for their biotechnological potential, especially in medicine. To date, there are more than 50 novel compounds discovered from these gifted actinobacteria with potential antimicrobial activities, including anti-MDR pathogens and anti-inflammatory, antivirus, antifungal, antiallergic, antibacterial, antitumor, and cytotoxic activities. A range of plant growth-promoting abilities of the desert actinobacteria inspired great interest in their agricultural potential. In addition, several degradative, oxidative, and other functional enzymes from desert strains can be applied in the industry and the environment. This review aims to provide a comprehensive overview of desert environments as a remarkable source of diverse actinobacteria while such rich diversity offers an underexplored resource for biotechnological exploitations.

Jiella mangrovi sp. nov., a novel endophytic bacterium isolated from leaf of Rhizophora stylosa

A Gram-stain negative, non-motile, brilliant yellow and non-spore forming, coccoid- or short rod-shaped bacterium, designated strain KSK16Y-1^T, was isolated from surface-sterilised leaf of Rhizophora stylosa collected from Shankou Mangrove Nature Reserve, Guangxi Zhuang Autonomous Region, China. Genome of strain KSK16Y-1^T is 4.93 Mb with 68.1% DNA G + C content and encoded 4359 predicted proteins, 4 rRNAs, 45 tRNAs and 4 ncRNA. Comparative 16S rRNA gene sequence analysis showed that the strain KSK16Y-1^T has 98.1%, 97.9% and 96.9% 16S rRNA gene similarities with Jiella aquimaris JCM 30119^T, J. endophytica CBS5Q-3^T and J. pacifica 40Bstr34^T, respectively. Whole-genome comparisons between strain KSK16Y-1^T and J. aquimaris 22II-16-19i, J. endophytica CBS5Q-3^T, J. pacifica 40Bstr34^T, using average nucleotide identity (ANI) values (< 82.0%) and digital DNA-DNA hybridization (dDDH) values (< 25.1%), confirmed low genome relatedness. Strain KSK16Y-1^T grew at 20-30 °C (optimum, 30 °C), pH 6.0-11.0 (optimum, pH 6.0-7.0) and with 0-10% (w/v) NaCl (optimum, 0-2%). Cell wall contained meso-diaminopimelic acid and the major fatty acid was C_18:1ω7c. The polar lipid profile consists of phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, one unknown phospholipid, one unknown aminolipid, one unknown aminophospholipid and four unidentified lipids. The predominant respiratory quinone is ubiquinone-10 (Q-10). The polyphasic characterization indicated that strain KSK16Y-1^T represents a novel Jiella species. The name Jiella mangrovi sp. nov., type strain KSK16Y-1^T (= CGMCC 1.18745^T = JCM 34332^T) is proposed.

Phycicoccus avicenniae sp. nov., a novel endophytic actinomycete isolated from a branch of Avicennia mariana

A novel endophytic actinomycete, designated strain BSK3Z-2 ^T, was isolated from a surface-sterilised branch of Avicennia mariana from Shankou Mangrove Nature Reserve, Guangxi Zhuang Autonomous Region, China. Cells were observed to be Gram-stain positive, aerobic, asporogenous and rod-shaped. Strain BSK3Z-2 ^T was found to grow optimally at 30 °C, pH 7.0 and in the presence of 1% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain BSK3Z-2 ^T belongs to the genus Phycicoccus and has high 16S rRNA gene sequence similarity of 98.1% with Phycicoccus endophyticus IP6SC6^T. Phylogenetic analysis based on the genome of strain BSK3Z-2 ^T was performed by extracting and aligning 39 conserved proteins and 88 housekeeping genes, which further confirmed the phylogenetic assignment of strain BSK3Z-2 ^T. The draft genome of strain BSK3Z-2 ^T is 3.54 Mbp with a DNA G + C content of 73.8%. The average nucleotide identity (ANI), amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between strain BSK3Z-2 ^T and species of genus Phycicoccus were 73.8-85.6%, 64.5-75.9% and 19.5-23.8%, respectively, which are below the standard cut-off values for bacterial species delineation. Strain BSK3Z-2 ^T contains MK-8(H₄) as the dominant menaquinone. The cell wall peptidoglycan contains meso-diaminopimelic acid. The polar lipids profile of strain BSK3Z-2 ^T was found to contain diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The predominant fatty acids were identified as C_15:0, C_17:0, iso-C_16:0 and C_17:1ω8c. Comparing the phenotypic and phylogenetic features of the strain BSK3Z-2 ^T and related taxa, strain BSK3Z-2 ^T is concluded to represent a novel species of the genus Phycicoccus, for which the name Phycicoccus avicenniae sp. nov. is proposed. The type strain is BSK3Z-2 ^T (= CGMCC 1.18743 ^T = JCM 34335 ^T).

Nocardioides malaquae sp. nov., a novel actinobacterium isolated from sewage sludge of a fisheries processing factory

A Gram-stain-positive, rod-shaped, strictly aerobic bacterial strain (Y6^T) was isolated from a sewage sludge sample collected from a fisheries processing factory in Zhoushan, Zhejiang Province, PR China. The growth range of NaCl concentration was 0-6.0 % (w/v), with an optimum at 3.0 % (w/v). The temperature range for growth was 10-42 °C, with an optimum at 37 °C. The pH range for growth was pH 7.0-10.0, with an optimum at pH 9.0. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Y6^T belonged to the genus Nocardioides and showed the highest sequence similarity of 97.8 % to Nocardioides jishulii dk3136^T. The average nucleotide identity and in silico DNA-DNA hybridization values between strain Y6^T and the reference strains were 76.9-81.2 % and 20.6-23.6 %, respectively. Chemotaxonomic analysis indicated that the sole respiratory quinone was MK-8(H₄) and the predominant cellular fatty acids were iso-C_16 : 0, 10-methyl-C_17 : 0 and C_18 : 1  ω9c. The polar lipid profile was composed of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, four unidentified phospholipids, three unidentified aminolipids and five unidentified lipids. The peptidoglycan was ll-2,6-diaminopimelic acid. On the basis of the phenotypic, genotypic, phylogenetic and chemotaxonomic features, strain Y6^T is considered to represent a novel species, for which the name Nocardioides malaquae sp. nov. is proposed. The type strain is Y6^T (=KCTC 49504^T=MCCC 1K04765^T).

Description of Nocardioides piscis sp. nov., Sphingomonas piscis sp. nov. and Sphingomonas sinipercae sp. nov., isolated from the intestine of fish species Odontobutis interrupta (Korean spotted sleeper) and Siniperca scherzeri (leopard mandarin fish)

A polyphasic taxonomic approach was used to characterize three novel bacterial strains, designated as HDW12AT, HDW-15BT, and HDW15CT, isolated from the intestine of fish species Odontobutis interrupta or Siniperca scherzeri. All isolates were obligate aerobic, non-motile bacteria, and grew optimally at 30°C. Phylogenetic analysis based on 16S rRNA sequences revealed that strain HDW12AT was a member of the genus Nocardioides, and closely related to Nocardioides allogilvus CFH 30205T (98.9% sequence identities). Furthermore, strains HDW15BT and HDW15CT were members of the genus Sphingomonas, and closely related to Sphingomonas lutea JS5T and Sphingomonas sediminicola Dae 20T (97.1% and 97.9% sequence identities), respectively. Strain HDW12AT contained MK-8 (H4), and strains HDW15BT and HDW15CT contained Q-10 as the respiratory quinone. Major polar lipid components of strain HDW12AT were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylinositol, and those of strains HDW15BT and HDW15CT were sphingoglycolipid, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine. The G + C content of strains HDW12AT, HDW15BT, and HDW15CT were 69.7, 63.3, and 65.5%, respectively. The results of phylogenetic, phenotypic, chemotaxonomic, and genotypic analyses suggest that strain HDW12AT represents a novel species within the genus Nocardioides, and strains HDW15BT and HDW15CT represent two novel species within the genus Sphingomonas. We propose the names Nocardioides piscis for strain HDW12AT (= KACC 21336T = KCTC 49321T = JCM 33670T), Sphingomonas piscis for strain HDW15BT (= KACC 21341T = KCTC 72588T = JCM 33738T), and Sphingomonas sinipercae for strain HDW15CT (= KACC 21342T = KCTC 72589T = JCM 33739T).

Brachybacterium halotolerans sp. nov., a halotolerant, endophytic actinomycete isolated from branch of Bruguiera gymnoirhiza

A novel, aerobic, moderately halophilic Gram-positive actinomycete, strain MASK1Z-5^T was isolated from a surface-sterilized branch of Bruguiera gymnoirhiza in Shankou Mangrove Nature Reserve, Guangxi, China. The taxonomic position of the strain was investigated using a polyphasic approach. Strain MASK1Z-5^T tolerated up to 20% (w/v) NaCl (optimum 0-7%), and grew at pH 5.0-12.0 (optimum pH 7.0-8.0), 20-37 °C (optimum 30 °C). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain MASK1Z-5^T belonged to the genus Brachybacterium, and showed the highest 16S rRNA gene sequence similarity of 98.0% to B. endophyticum M1HQ-2^T. The cell-wall peptidoglycan contained meso-diaminopimelic acid as diagnostic diamino acid. MK-7 was the predominant menaquinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, one unidentified glycolipid and three unidentified lipids. The major fatty acids were anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. The DNA G + C content was calculated to be 71.8 mol% based on the whole genome sequence. The estimated values of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) based on whole genome sequences between strain MASK1Z-5^T and B. endophyticum M1HQ-2^T were 81.8% and 25.0%, respectively. The phenotypic, chemotaxonomic and genotypic properties clearly indicated that strain MASK1Z-5^T represents a novel species within the genus Brachybacterium, for which the name Brachybacterium halotolerans sp. nov. is proposed. The type strain is MASK1Z-5^T (= CGMCC1.18660^T = JCM 34339^T).

Nocardioides stalactiti sp. nov., isolated from a cave stalactite surface

An aerobic, rod-shaped, Gram-stain-positive, actinobacterial strain, designated 1.0914^T, was isolated from a stalactite sample collected from a cave located in Guizhou Province, southwest PR China. Based on 16S rRNA gene sequence analysis, strain 1.0914^T shared highest similarities values with Nocardioides pelophilus CGMCC 4.7388^T (97.7 %), Nocardioides immobilis CCTCC AB 2017083^T (97.5 %) and Nocardioides silvaticus CCTCC AB 2018079^T (97.3 %) and values lower than 97.0 % to other members of the genus Nocardioides. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain 1.0914^T formed an isolated branch with N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T and N. silvaticus CCTCC AB 2018079^T. The polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and one unidentified phospholipid in the cellular membrane. The major fatty acids were identified as iso-C_16 : 0, C_18 : 1 ω9c, C_17 : 1 ω8c and C_16 : 0. The predominant respiratory quinone was MK-8(H₄) and ll-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The genomic DNA G+C content was 71.1 mol%. The orthologous average nucleotide identiy values between N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T, N. silvaticus CCTCC 2018079^T and strain 1.0914^T were 82.3, 81.7 and 81.9 % respectively. DNA-DNA hybridization values between N. pelophilus CGMCC 4.7388^T, N. immobilis CCTCC AB 2017083^T, N. silvaticus CCTCC 2018079^T and strain 1.0914^T were 25.2, 24.6 and 24.5 % respectively. The phylogenetic, phenotypic and chemotaxonomic data supported the classification of strain 1.0914^T as representing a new species of Nocardioides, for which the name Nocardioides stalactiti sp. nov. is proposed. The type strain is 1.0914^T (=CCTCC AB 2018266^T=KCTC 49243^T).

Soil prokaryotic community shows no response to 2 years of simulated nitrogen deposition in an arid ecosystem in northwestern China

An arid ecosystem might be sensitive to nitrogen (N) deposition, but the associated ecosystem-specific response of soil microbes is not well studied. To assess the N enrichment effects on plant and prokaryotic community diversity, we performed a two-year NH₄ NO₃ treatment in a desert steppe in northwestern China. Results showed that N addition increased plant aboveground biomass and decreased plant Shannon diversity. A C₄ herb (Salsola collina) became dominant, and loss of legume species was observed. The concentrations of soil NH₄ ⁺ -N, NO₃ ^- -N, microbial biomass N, and the plant aboveground biomass N pool increased in contrast to total N, suggesting that the N input into the arid ecosystem might mainly be assimilated by plants and exit the ecosystem. Remarkably, the α-diversity and structure of the soil prokaryotic community did not vary even at the highest N addition rate. Structural equation modelling further found that the plant aboveground N pool counteracted the acidification effect of N deposition and maintained soil pH thus partially stabilizing the composition of prokaryotic communities in a desert steppe. These findings suggested that the plants and N loss might contribute to the lack of responsiveness of soil prokaryotic community to N deposition in a desert steppe.

Nocardioides jishulii sp. nov.,isolated from faeces of Tibetan gazelle (Procapra picticaudata)

Two novel Gram-stain-positive, irregular rod-shaped bacterial strains, dk3136^T and dk3543, were isolated from the faeces of Tibetan gazelle (Procapra picticaudata) in the Qinghai-Tibet Plateau of PR China. The cells were aerobic, oxidase-negative and catalase-positive. Colonies were yellowish, circular without any observable aerial mycelium after culturing at 28 ℃ for 3 days on brain-heart infusion (BHI) agar with 5 % sheep blood. The cells grew optimally at 28 °C, pH 7.5 and with 1 % (w/v) NaCl on BHI agar supplemented with 5 % sheep blood. Phylogenetic analysis of the 16S rRNA gene sequences revealed that their nearest phylogenetic relative was Nocardioides solisilvae Ka25^T (97.9 % similarity). The results of 16S rRNA gene sequence and phylogenetic/phylogenomic analyses illustrated that N. solisilvae Ka25^T, Nocardioides gilvus XZ17^T, Nocardioides houyundeii 78^T and Nocardioides daphniae D287^T were their nearest phylogenetic neighbours. The DNA G+C contents of strains dk3136^T and dk3543 were 70.3 mol% and 70.4 mol%, respectively. Their genomes exhibit lower than threshold (95-96 %) average nucleotide identity to known species of the genus Nocardioides. ll-2,6-diaminopimelic acid was the diagnostic diamino acid and MK-8(H₄) was the predominant respiratory quinone. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The two strains had C_18 : 1 ω9c, iso-C_16 : 0 and C_17 : 1 ω8c as the major fatty acids, and rhamnose and galactose as the main whole-cell sugars. On the basis of the results of our genotypic, phenotypic and biochemical analyses, we conclude that strains dk3136^T and dk3543 represent a novel species in genus Nocardioides, for which the name Nocardioides jishulii sp. nov. is proposed. The type strain is dk3136^T (=CGMCC 4.7570^T=JCM 33496^T=KCTC 49314^T).

Biodegradation of ritalinic acid by Nocardioides sp. - Novel imidazole-based alkaloid metabolite as a potential marker in sewage epidemiology

The consumption of methylphenidate, a nootropic drug used to improve mental performance, is becoming increasingly serious. Methylphenidate is metabolized in human liver to ritalinic acid, which has been commonly detected in sewage and surface waters. Additionally, ritalinic acid serves as a biomarker in sewage epidemiology studies. Thus knowledge of the stability and microbial degradation pathways of ritalinic acid is essential for proper estimation of methylphenidate consumption. In the study reported here, we describe the fast formation of a previously unknown, dead-end metabolite of ritalinic acid by Nocardioides sp. strain MW5. HRMS and 2D NMR analyses allowed precisely identification of the compound as an imidazole-based alkaloid cation with chemical formula 11-[3-(formylamino)propyl]-1,2,3,4,6,7,8,9-octahydrodipyrido[1,2-a:1',2'-c]imidazole-5-ium. In experiments, Nocardioides sp. strain MW5 transformed 34% of ritalinic acid into this metabolite, while 52% was mineralized into CO₂. Alkaloid was not biodegraded during the OECD 301 F test. This study provides new insight into the environmental fate of methylphenidate and its metabolites. The data collected are essential for assessing nootropic drug consumption by sewage epidemiology and should lead to a better understanding of microbial degradation of ritalinic acid.

Nocardioides sambongensis sp. nov., isolated from Dokdo Islands soil

Strain KUDC5002^T was isolated from soil sampled on the Dokdo Islands, Republic of Korea. This bacterial strain was Gram stain-positive, non-motile, rod-shaped, capable of growing at 25-37°C and pH 5.0-12.0, and showed optimal growth at 30 °C and pH 7.0-8.0. Strain KUDC5002^T could be grown in tryptic soy broth containing less than 7.0 % NaCl (w/v). The cell width ranged from 0.5 to 0.6 µm and length ranged from 0.8 to 1.0 µm. Strain KUDC5002^T was catalase- and oxidase-positive. Its genomic G+C content was 72.2 mol%. Its major fatty acids were C_18 : 1 ω9c (17.3 %), iso-C_16 : 0 (16.0 %) and iso-C_17 : 0 (11.4 %). Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain KUDC5002^T belongs to the genus Nocardioides and is most closely related to strain Nocardioides humi DCY24^T (97.0 %). Based on its phenotypic, phylogenetic, genetic and chemotaxonomic features, strain KUDC5002^T should be considered a novel species in the genus Nocardioides, for which we have proposed the name Nocardioides sambongensis sp. nov. The type strain is KUDC5002^T (=KCTC 39855^T=DSM 106604^T).

Actinobacteria and Cyanobacteria Diversity in Terrestrial Antarctic Microenvironments Evaluated by Culture-Dependent and Independent Methods

Bacterial diversity from McMurdo Dry Valleys in Antarctica, the coldest desert on earth, has become more easily assessed with the development of High Throughput Sequencing (HTS) techniques. However, some of the diversity remains inaccessible by the power of sequencing. In this study, we combine cultivation and HTS techniques to survey actinobacteria and cyanobacteria diversity along different soil and endolithic micro-environments of Victoria Valley in McMurdo Dry Valleys. Our results demonstrate that the Dry Valleys actinobacteria and cyanobacteria distribution is driven by environmental forces, in particular the effect of water availability and endolithic environments clearly conditioned the distribution of those communities. Data derived from HTS show that the percentage of cyanobacteria decreases from about 20% in the sample closest to the water source to negligible values on the last three samples of the transect with less water availability. Inversely, actinobacteria relative abundance increases from about 20% in wet soils to over 50% in the driest samples. Over 30% of the total HTS data set was composed of actinobacterial strains, mainly distributed by 5 families: Sporichthyaceae, Euzebyaceae, Patulibacteraceae, Nocardioidaceae, and Rubrobacteraceae. However, the 11 actinobacterial strains isolated in this study, belonged to Micrococcaceae and Dermacoccaceae families that were underrepresented in the HTS data set. A total of 10 cyanobacterial strains from the order Synechococcales were also isolated, distributed by 4 different genera (Nodosilinea, Leptolyngbya, Pectolyngbya, and Acaryochloris-like). In agreement with the cultivation results, Leptolyngbya was identified as dominant genus in the HTS data set. Acaryochloris-like cyanobacteria were found exclusively in the endolithic sample and represented 44% of the total 16S rRNA sequences, although despite our efforts we were not able to properly isolate any strain from this Acaryochloris-related group. The importance of combining cultivation and sequencing techniques is highlighted, as we have shown that culture-dependent methods employed in this study were able to retrieve actinobacteria and cyanobacteria taxa that were not detected in HTS data set, suggesting that the combination of both strategies can be usefull to recover both abundant and rare members of the communities.

Nocardioides astragali sp. nov., isolated from a nodule of wild Astragalus chrysopterus in northwestern China

A Gram-positive, non-motile, rod-shaped bacterial strain, designated HH06^T, was isolated from a nodule of Astragalus chrysopterus in northwestern China. Phylogenetic analysis of the 16S rRNA gene sequence showed that the strain is closely related to Nocardioides alpinus Cr7-14^T and Nocardioides furvisabuli DSM 18445^T with 98.5 and 98.1% similiarity, respectively. Growth was observed at 4–28 °C in R2A medium (optimum at 25 °C), at 10–30 °C in YMA and LB medium (optimum in both at 28 °C) and at pH 5.0–10.0 in R2A medium (optimum at pH 7.0–8.0). The cell wall peptidoglycan was found to contain LL-diaminopimelic acid as the principal diamino acid and MK-8(H4) was identified as the predominant menaquinone. The major polar lipids were identified as phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, two unidentified glycolipids and two unidentified polar lipids. The major fatty acids were identified as iso-C_16:0 (32.8%) and C_18:1ω9c (15.1%). The DNA G+C content of strain HH06^T was determined to be 71.4 mol%. Based on phenotypic, chemotaxonomic, phylogenetic properties and DNA–DNA relatedness, it is concluded that strain HH06^T represents a novel species of the genus Nocardioides, for which the name Nocardioides astragali sp. nov. is proposed. The type strain is HH06^T (= CGMCC 4.7327^T = NBRC 112322^T).

Nocardioides sonneratiae sp. nov., an endophytic actinomycete isolated from a branch of Sonneratia apetala

A Gram-staining-positive, aerobic non-spore-forming and short-rod-shaped endophytic actinomycete was isolated from a branch of Sonneratia apetala, designated strain BGMRC0092T and investigated in detail data to determine its taxonomic position. On the basis of the 16S rRNA gene sequence analysis, the results of the phylogenetic analyses indicated that BGMRC0092T was most closely related to Nocardioides alpinus Cr7-14T (96.9 %), Nocardioides oleivorans DSM16090T (96.4 %) and Nocardiodes exalbidus RC825T (96.3 %). The predominant cellular fatty acids of BGMRC0092T were iso-C16 : 0 and C18 : 1ω8c. The major menaquinone was MK-8(H4). The diagnostic diamino acid in the cell-wall peptidoglycan was ll-2,6-diaminopimelic acid. The predominant cell-wall sugars were composed of galactose, mannose, rhamnose and xylose. The polar lipid pattern contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, one unknown phospholipid and three unknown polar lipids. The DNA G+C content was 69.3 mol%. On the basis of phenotypic and chemotaxonomic characteristics and the results of phylogenetic analysis, BGMRC0092T represents a novel species of the genus Nocardioides, for which the name Nocardioides sonneratiae sp. nov. is proposed. The type strain is Nocardioides sonneratiae BGMRC0092T (=KCTC 39565T=NBRC 110251 T=DSM 100390T).

Nocardioides thalensis sp. nov., isolated from a desert

A novel actinobacterial strain, designated NCCP-696T, was isolated from the Thal desert in Punjab, Pakistan, and characterized by using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain NCCP-696T belongs to the genus Nocardioides and showed the highest level of sequence similarity with respect to Nocardioides panacisoliGsoil 346T (98.2 %) and less than 96.4 % to the strains of other species of the genus Nocardioides. Cells of strain NCCP-696T were Gram-positive, aerobic, non-motile rods and formed cream-coloured colonies. The strain was positive for oxidase and catalase. Growth occurred at 20-42 °C (optimum 30-37 °C) at pH 5.5-9.0 (optimum pH 7.0) and with 0-4 % NaCl (optimum 0-2 %, w/v). Strain NCCP-696T contained Iso-C16 : 0, C18 : 1ω9c, C17 : 1ω8c and C17 : 0 as the predominant fatty acids and was found to have LL-2,6-diaminopimelic acid in the cell-wall peptidoglycan. The polar lipid profile consisted of phosphatidylinositol, phosphatidylglycerol and one unknown phospholipid. The major menaquinone was MK-8(H4) (98.7 %) while a minor amount (1.3 %) of MK-9(H2) was also detected. The DNA G+C content of the genomic DNA was 71.6 mol%. The DNA-DNA hybridization value of the isolate against the closely related type strain Nocardioides panacisoliGsoil 346T was 56.3±1.4. On the basis of the phylogenetic inference, chemotaxonomic characteristics and phenotypic data, strain NCCP-696T should be classified as a novel species, for which the name Nocardioides thalensis sp. nov. is proposed. The type strain is NCCP-696T (=DSM 103833T=CCTCC AB 2016296T).

Friedmanniella endophytica sp. nov., an endophytic actinobacterium isolated from bark of Kandelia candel

A coccus-shaped, non-spore-forming actinobacterium, designated strain 4Q3S-3T, was isolated from surface-sterilized bark of the mangrove plant Kandelia candel collected from Cotai Ecological Zones in Macao, China, and tested by a polyphasic approach to clarify its taxonomic position. This actinobacterium was Gram-stain-positive and aerobic. Neither substrate nor aerial mycelia were formed, and no diffusible pigments were observed on the media tested. Strain 4Q3S-3T grew optimally without NaCl at 28-30 °C, pH 7.0-8.0. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain 4Q3S-3T belonged to the genus Friedmanniella and shared the highest 16S rRNA gene sequence similarity with Friedmanniellaflava W6T (96.57 %). The DNA G+C content of strain 4Q3S-3T was 69.5 mol%. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid, and MK-9(H4) was the predominant menaquinone. The polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, unidentified glycolipid, amino lipids and two unidentified phospholipids. The predominant fatty acids were anteiso-C15 : 0, iso-C16 : 0 and iso-C15 : 0. Based on phylogenetic, phenotypic and chemotaxonomic data, strain 4Q3S-3T represents a novel species of the genus Friedmanniella, for which the name Friedmanniella endophytica sp. nov. is proposed. The type strain is 4Q3S-3T (=DSM 100723T=CGMCC 4.7307T).

Nocardioides pakistanensis sp. nov., isolated from a hot water spring of Tatta Pani in Pakistan

A Gram-staining positive, non-spore forming, non-pigmented and non-motile bacterium, designated as NCCP-1340(T), was isolated from a hot water spring, Tatta Pani, Pakistan. Cells of strain NCCP-1340(T) were observed to be aerobic, rod shaped, catalase and urease positive but H2S production and oxidase negative. Growth was observed at pH 6.0-8.0 (optimum pH 7.0) and at 20-40 °C (optimum 37 °C). The strain could tolerate 0-8 % NaCl (optimum 2 %, w/v). Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain NCCP-1340(T) belongs to the genus Nocardioides and is closely related to Nocardioides iriomotensis JCM 17985(T) (96.8 %), Nocardioides daedukensis KCTC 19601(T) (96.6 %), Nocardioides jensenii KCTC 9134(T) (96.1 %) and Nocardioides daejeonensis KCTC 19772(T) (96.1 %). The DNA-DNA relatedness values of strain NCCP-1340(T) with N. iriomotensis JCM 17985(T), N. daedukensis KCTC 19601(T) and N. jensenii KCTC 9134(T) were found to be less than 53 %. The DNA G+C content of strain NCCP-1340(T) was determined to be 71.8 mol  %. The affiliation of strain NCCP-1340(T) to the genus Nocardioides was further supported by chemotaxonomic data which showed the presence of MK-8(H4) as major menaquinone system; iso-C16:0, C17:0, C16:0 10-methyl, iso-C15:0 and C 15:0 as major cellular fatty acids; and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and unidentified glycolipids and polar lipids in the polar lipids profile. The cell wall peptidoglycan contained LL-diaminopimelic acid as the diagnostic amino acid. On the basis of physiological and biochemical characteristics and the phylogenetic analyses, strain NCCP-1340(T) can be distinguished from the closely related taxa and thus represents a novel species of the genus Nocardioides, for which the name Nocardioides pakistanensis sp. nov. is proposed with the type strain NCCP-1340(T) (= DSM 29942(T) = JCM 30630(T)).

Nocardioides ginkgobilobae sp. nov., an endophytic actinobacterium isolated from the root of the living fossil Ginkgo biloba L

A Gram-stain-positive, aerobic and yellow actinobacterial strain, designated SYP-A7303T, was isolated from the root of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7303T belongs to the genus Nocardioides. The 16S rRNA gene sequence of strain SYP-A7303T showed highest similarity to Nocardioides marinus CL-DD14T ( = JCM 15615T) (98.3 %) and Nocardioides aquiterrae GW-9T ( = JCM 11813T) (97.1 %), and less than 96.9 % to the type strains of other species of the genus Nocardioides. Strain SYP-A7303T grew optimally at 28 °C, pH 7.0 and in the absence of NaCl. It contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, with mannose, ribose, rhamnose, glucose and galactose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown lipid. The menaquinone was MK-8(H4) and the predominant cellular fatty acids were iso-C16 : 0, C18 : 1ω9c and C17 : 1ω8c. The DNA G+C content was 72 mol%. Mean DNA-DNA relatedness values between strain SYP-A7303T and the closely related strains N. marinus JCM 15615T and N. aquiterrae JCM 11813T were 62.5 ± 2.4 and 56.5 ± 3.5 %, respectively. Based on the morphological, physiological, biochemical and chemotaxonomic characteristics presented in this study, strain SYP-A7303T represents a novel species of the genus Nocardioides, for which the name Nocardioides ginkgobilobae sp. nov. is proposed. The type strain is SYP-A7303T ( = DSM 100492T = KCTC 39594T).

Actinobacteria from Arid and Desert Habitats: Diversity and Biological Activity

The lack of new antibiotics in the pharmaceutical pipeline guides more and more researchers to leave the classical isolation procedures and to look in special niches and ecosystems. Bioprospecting of extremophilic Actinobacteria through mining untapped strains and avoiding resiolation of known biomolecules is among the most promising strategies for this purpose. With this approach, members of acidtolerant, alkalitolerant, psychrotolerant, thermotolerant, halotolerant and xerotolerant Actinobacteria have been obtained from respective habitats. Among these, little survey exists on the diversity of Actinobacteria in arid areas, which are often adapted to relatively high temperatures, salt concentrations, and radiation. Therefore, arid and desert habitats are special ecosystems which can be recruited for the isolation of uncommon Actinobacteria with new metabolic capability. At the time of this writing, members of Streptomyces, Micromonospora, Saccharothrix, Streptosporangium, Cellulomonas, Amycolatopsis, Geodermatophilus, Lechevalieria, Nocardia, and Actinomadura are reported from arid habitats. However, metagenomic data present dominant members of the communities in desiccating condition of areas with limited water availability that are not yet isolated. Furthermore, significant diverse types of polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes are detected in xerophilic and xerotolerant Actinobacteria and some bioactive compounds are reported from them. Rather than pharmaceutically active metabolites, molecules with protection activity against drying such as Ectoin and Hydroxyectoin with potential application in industry and agriculture have also been identified from xerophilic Actinobacteria. In addition, numerous biologically active small molecules are expected to be discovered from arid adapted Actinobacteria in the future. In the current survey, the diversity and biotechnological potential of Actinobacteria obtained from arid ecosystems, along with the recent work trend on Iranian arid soils, are reported.

Nakamurella endophytica sp. nov., a novel endophytic actinobacterium isolated from the bark of Kandelia candel

A Gram-stain-positive, aerobic, coccus-shaped, non-spore-forming actinobacterium, designated strain 2Q3S-4-2T, was isolated from the surface-sterilized bark of Kandelia candel, collected from Cotai Ecological Zones in Macao, PR China. It was tested using a polyphasic approach to determine its taxonomic position. Strain 2Q3S-4-2T grew optimally without NaCl at 28-30 °C and at pH 7.0. Substrate mycelia and aerial mycelia were not formed and no diffusible pigments were observed on the media tested. Phylogenetic analysis, based on 16S rRNA gene sequences, suggested that strain 2Q3S-4-2T belonged to the genus Nakamurella, sharing highest 16S rRNA gene sequence similarity with Nakamurella flavida DS-52T (96.76 %). The DNA G+C content of strain 2Q3S-4-2T was 67.8 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid and MK-8(H4) was the predominant menaquinone. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, unidentified aminophospholipids and phosphatidylinositol. The major fatty acids were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and C16 : 0. On the basis of the phylogenetic, phenotypic and chemotaxonomic analysis, strain 2Q3S-4-2T represents a novel species of the genus Nakamurella, for which the name Nakamurella endophytica sp. nov. is proposed. The type strain is 2Q3S-4-2T ( = DSM 100722T = CGMCC 4.7308T).

Microlunatus endophyticus sp. nov., an endophytic actinobacterium isolated from bark of Bruguiera sexangula

A Gram-stain-positive, aerobic, coccoid, non-motile, non-spore-forming bacterium, designated strain S3Af-1T, was isolated from surface-sterilized bark of Bruguiera sexangula collected from Dongzhaigang National Nature Reserve in Hainan, China, and examined using a polyphasic approach to clarify its taxonomic position. This bacterium did not produce substrate mycelia or aerial hyphae, and no diffusible pigments were observed on the media tested. Strain S3Af-1T grew optimally without NaCl, at 28-30 °C and at pH 7.0.Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S3Af-1T belonged to the genus Microlunatus and shared highest similarity with 'Microlunatus terrae' BS6 (97.43 %) and Microlunatus soli CC-12602T (97.08 %). DNA-DNA hybridization results indicated that the level of relatedness between strain S3Af-1T and M. soli CC-12602T was less than 70 %. The DNA G+C content of strain S3Af-1T was 67.1 mol%. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid. MK-9(H6) and MK-9(H4) were the predominant menaquinones. Phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid, two unidentified phospholipids and other lipids were detected in the polar lipid extracts. The major fatty acids were iso-C16 : 0, anteiso-C17 : 0 and anteiso-C15 : 0. On the basis of phylogenetic analysis, and phenotypic and chemotaxonomic characteristics, strain S3Af-1T represents a novel species of the genus Microlunatus, for which the name Microlunatus endophyticus sp. nov. is proposed. The type strain is S3Af-1T ( = DSM 100019T = CGMCC 4.7306T).