micromonospora taraxaci sp. nov., a novel endophytic actinomycete isolated from dandelion root...

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ORIGINAL PAPER Micromonospora taraxaci sp. nov., a novel endophytic actinomycete isolated from dandelion root (Taraxacum mongolicum Hand.-Mazz.) Junwei Zhao Lifeng Guo Hairong He Chongxi Liu Yuejing Zhang Chuang Li Xiangjing Wang Wensheng Xiang Received: 25 April 2014 / Accepted: 14 July 2014 / Published online: 1 August 2014 Ó Springer International Publishing Switzerland 2014 Abstract A novel actinomycete, designated strain NEAU-P5 T , was isolated from dandelion root (Tarax- acum mongolicum Hand.-Mazz.). Strain NEAU-P5 T showed closest 16S rRNA gene sequence similarity to Micromonospora chokoriensis 2–19/6 T (99.5 %), and phylogenetically clustered with Micromonospora vio- lae NEAU-zh8 T (99.3 %), M. saelicesensis Lupac 09 T (99.0 %), M. lupini Lupac 14N T (98.8 %), M. zeae NEAU-gq9 T (98.4 %), M. jinlongensis NEAU- GRX11 T (98.3 %) and M. zamorensis CR38 T (97.9 %). Phylogenetic analysis based on the gyrB gene sequence also indicated that the isolate clustered with the above type strains except M. violae NEAU- zh8 T . The cell-wall peptidoglycan consisted of meso- diaminopimelic acid and glycine. The major menaqui- nones were MK-9(H 8 ), MK-9(H 6 ) and MK-10(H 2 ). The phospholipid profile contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. The major fatty acids were C 16:0 , iso-C 15:0 and C 17:0 . Furthermore, some physiological and biochemical properties and low DNA–DNA relatedness values enabled the strain to be differentiated from members of closely related species. Therefore, it is proposed that strain NEAU-P5 T represents a novel species of the genus Micromonospora, for which the name Micromo- nospora taraxaci sp. nov. is proposed. The type strain is NEAU-P5 T (=CGMCC 4.7098 T = DSM 45885 T ). Keywords Micromonospora taraxaci sp. nov. Polyphasic taxonomy 16S rRNA gene gyrB gene Introduction Endophytic actinobacteria, which are ubiquitous in living plants, have aroused more and more attention in recent years. These microorganisms may be underex- plored sources of novel species and novel natural products for exploitation in pharmaceutical and agri- culture (Qin et al. 2009, 2011). Dandelion is a Junwei Zhao and Lifeng Guo have contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s10482-014-0237-x) contains supple- mentary material, which is available to authorized users. J. Zhao L. Guo H. He C. Liu Y. Zhang C. Li X. Wang (&) W. Xiang (&) Key Laboratory of Agriculture Biological Functional Gene of Heilongjiang Provincial Education Committee, Northeast Agricultural University, No. 59 Mucai Street, Xiangfang District, Harbin 150030, People’s Republic of China e-mail: [email protected] W. Xiang e-mail: [email protected] W. Xiang State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China 123 Antonie van Leeuwenhoek (2014) 106:667–674 DOI 10.1007/s10482-014-0237-x

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Page 1: Micromonospora taraxaci sp. nov., a novel endophytic actinomycete isolated from dandelion root (Taraxacum mongolicum Hand.-Mazz.)

ORIGINAL PAPER

Micromonospora taraxaci sp. nov., a novel endophyticactinomycete isolated from dandelion root (Taraxacummongolicum Hand.-Mazz.)

Junwei Zhao • Lifeng Guo • Hairong He •

Chongxi Liu • Yuejing Zhang • Chuang Li •

Xiangjing Wang • Wensheng Xiang

Received: 25 April 2014 / Accepted: 14 July 2014 / Published online: 1 August 2014

� Springer International Publishing Switzerland 2014

Abstract A novel actinomycete, designated strain

NEAU-P5T, was isolated from dandelion root (Tarax-

acum mongolicum Hand.-Mazz.). Strain NEAU-P5T

showed closest 16S rRNA gene sequence similarity to

Micromonospora chokoriensis 2–19/6T (99.5 %), and

phylogenetically clustered with Micromonospora vio-

lae NEAU-zh8T (99.3 %), M. saelicesensis Lupac 09T

(99.0 %), M. lupini Lupac 14NT (98.8 %), M. zeae

NEAU-gq9T (98.4 %), M. jinlongensis NEAU-

GRX11T (98.3 %) and M. zamorensis CR38T

(97.9 %). Phylogenetic analysis based on the gyrB

gene sequence also indicated that the isolate clustered

with the above type strains except M. violae NEAU-

zh8T. The cell-wall peptidoglycan consisted of meso-

diaminopimelic acid and glycine. The major menaqui-

nones were MK-9(H8), MK-9(H6) and MK-10(H2). The

phospholipid profile contained diphosphatidylglycerol,

phosphatidylethanolamine and phosphatidylinositol.

The major fatty acids were C16:0, iso-C15:0 and C17:0.

Furthermore, some physiological and biochemical

properties and low DNA–DNA relatedness values

enabled the strain to be differentiated from members

of closely related species. Therefore, it is proposed that

strain NEAU-P5T represents a novel species of the

genus Micromonospora, for which the name Micromo-

nospora taraxaci sp. nov. is proposed. The type strain is

NEAU-P5T (=CGMCC 4.7098T = DSM 45885T).

Keywords Micromonospora taraxaci sp. nov. �Polyphasic taxonomy � 16S rRNA gene � gyrB gene

Introduction

Endophytic actinobacteria, which are ubiquitous in

living plants, have aroused more and more attention in

recent years. These microorganisms may be underex-

plored sources of novel species and novel natural

products for exploitation in pharmaceutical and agri-

culture (Qin et al. 2009, 2011). Dandelion is a

Junwei Zhao and Lifeng Guo have contributed equally to this

work.

Electronic supplementary material The online version ofthis article (doi:10.1007/s10482-014-0237-x) contains supple-mentary material, which is available to authorized users.

J. Zhao � L. Guo � H. He � C. Liu � Y. Zhang �C. Li � X. Wang (&) � W. Xiang (&)

Key Laboratory of Agriculture Biological Functional

Gene of Heilongjiang Provincial Education Committee,

Northeast Agricultural University, No. 59 Mucai Street,

Xiangfang District, Harbin 150030, People’s Republic of

China

e-mail: [email protected]

W. Xiang

e-mail: [email protected]

W. Xiang

State Key Laboratory for Biology of Plant Diseases and

Insect Pests, Institute of Plant Protection, Chinese

Academy of Agricultural Sciences, Beijing, People’s

Republic of China

123

Antonie van Leeuwenhoek (2014) 106:667–674

DOI 10.1007/s10482-014-0237-x

Page 2: Micromonospora taraxaci sp. nov., a novel endophytic actinomycete isolated from dandelion root (Taraxacum mongolicum Hand.-Mazz.)

traditional Chinese medicine, which was widely used

to treat liver diseases, kidney diseases and spleen

problems (Ling and Zheng 1998). During the inves-

tigation of exploring potential sources of actinomy-

cetes with novel natural products in the root of

dandelion (Taraxacum mongolicum Hand.-Mazz.), a

total of 15 isolates of endophytic actinomycetes were

isolated from dandelion root sample. Out of 15

isolates, Streptomyces was the dominant genus

(n = 9, 60 % of isolates), followed by Micromonos-

pora sp. (n = 5, 33.33 %) and Streptosporangium sp.

(n = 1, 6.67 %). In this study, we performed poly-

phasic taxonomy on strain NEAU-P5T, and proposed

that the novel isolate is a new species of the genus

Micromonospora, for which the name Micromonos-

pora taraxaci sp. nov. is proposed.

Materials and methods

Isolation and maintenance of the organisms

Strain NEAU-P5T was isolated from dandelion root (T.

mongolicum Hand.-Mazz.) collected from Harbin, Hei-

longjiang province, north China (45�450N, 126�410E).

The root sample was processed as described by Wang

et al. (2013) and placed on a plate of humic acid-vitamin

agar (HV) (Hayakawa and Nonomura 1987) supple-

mented with cycloheximide (50 mg L-1) and nalidixic

acid (50 mg L-1). After 2 weeks of aerobic incubation at

28 �C, colonies were transferred and purified on Interna-

tional Streptomyces Project (ISP) medium 3 (Shirling and

Gottlieb 1966) and maintained as glycerol suspensions

(20 %, v/v) at -80 �C.

Antifungal activity bioassay in vitro

Strain NEAU-P5T was point-inoculated at the periph-

ery of potato dextrose agar (PDA: potato 200 g,

dextrose 20 g, agar 20 g, distilled water 1 L), carrot

agar (CA: carrot 200 g; agar 20 g; distilled water 1 L)

and rye sucrose agar (RSA: rye 60 g, sucrose 18 g,

agar 20 g, distilled water 1 L) plates and incubated for

7 days at 28 �C, after which a fresh mycelial PDA, CA

and RSA agar plug of fungi was transferred to the

center of the corresponding plate. After an additional

7 days of incubation at 18 and 28 �C, respectively,

inhibition of hyphal growth of fungal strains was

scored (Mendes et al. 2011). The fungal strains:

Phytophthora sojae (CA medium, 28 �C) was kindly

provided by Soybean Research Institute of Northeast

Agricultural University (Harbin, China); Alternaria

solani (PDA medium, 28 �C), Corynespora cassiicola

(PDA medium, 28 �C), Phytophthora infestans (RSA

medium, 18 �C), Colletotrichum orbiculare (PDA

medium, 28 �C), Rhizoctonia solani (PDA medium,

28 �C), Sclerotinia sclerotiorum (PDA medium,

18 �C) and P. capsici (CA medium, 18 �C) were

kindly provided by the Institute of Vegetables and

Flowers, Chinese Academy of Agricultural Sciences

(Beijing, China).

Morphological, cultural, physiological

characteristics

Morphological characteristics were observed by light

microscopy (Nikon ECLIPSE E200) and scanning

electron microscopy (Hitachi S-3400 N) after cultivation

on ISP 3 medium at 28 �C for 3 weeks. Cultural

characteristics were determined after growth for 3 weeks

at 28 �C on SA1 agar (Trujillo et al. 2005), N-Z amine

agar (Trujillo et al. 2007), Bennett’s agar (Jones 1949),

ISP media 2–7 (Shirling and Gottlieb 1966). ISCC-NBS

colour charts Standard Samples No 2106 (Kelly 1964)

was used to determine the color of colonies and soluble

pigments. The growth temperature range (4, 10, 15, 20,

28, 35, 37, 40, 45 �C) was determined on ISP 3 medium

after culturing for 2 weeks. Tolerance of various pH (3, 4,

5, 6, 7, 8, 9, 10, 11, 12) and NaCl (0, 1, 2, 3, 4 and 5 %,

w/v) were determined in GY medium (Jia et al. 2013) in

shake flasks (250 r.p.m.) at 28 �C for 7 days. Reduction

of nitrate, degradation of gelatin, cellulose and urea,

hydrolysis of starch and aesculin, coagulation of milk and

production of catalase and H2S were examined as

described by Gordon et al. (1974). Utilization of sole

carbon sources was tested on ISP 9 medium (Shirling and

Gottlieb 1966). Utilization of amino acids as nitrogen

sources was tested as described by Williams et al. (1983).

The reference strains M. chokoriensis 2–19(6)T, M.

saelicesensis Lupac 09T, M. lupini Lupac 14NT and M.

zamorensis CR38T were obtained from Japan Collection

of Microorganisms (JCM) and DSMZ (German Collec-

tion of Microorganisms and Cell Cultures), M. violae

NEAU-zh8T (Zhang et al. 2014), M. zeae NEAU-gq9T

(Shen et al. 2014) and M. jinlongensis NEAU-GRX11T

(Gao et al. 2014) were from our laboratory. These strains

were cultured under the same conditions for comparative

analyses.

668 Antonie van Leeuwenhoek (2014) 106:667–674

123

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Chemotaxonomic characterization

Biomass for chemical studies was obtained by growing

the strain in GY medium in shake flasks (250 r.p.m.) at

28 �C for 7 days. Cells were harvested by centrifuga-

tion, then washed with distilled water and freeze-dried.

Phospholipids in cells were extracted and identified

using the method of Minnikin et al. (1984). Whole-cell

sugar composition was analyzed according to the

method of Lechevalier and Lechevalier (1980). The

isomer of diaminopimelic acid (DAP) in the whole cell

hydrolysates was derivatised according to McKerrow

et al. (2000) and analyzed by a HPLC method.

Menaquinones were extracted from freeze-dried bio-

mass and purified according to Collins (1985) then

analyzed by a HPLC–UV method as described previ-

ously (Gao et al. 2014). Mycolic acids were checked by

the acid methanolysis method as described previously

(Minnikin et al. 1980). Biomass for fatty acids analysis

was obtained by growing strain NEAU-P5T in GY

medium at 28 �C for 7 days and detected by GC–MS

using the method of Gao et al. (2014).

DNA preparation, amplification and determination

of 16S rRNA gene sequence

Genomic DNA of strain NEAU-P5T was extracted as

described previously by Lee et al. (2003) and PCR

amplification of 16S rRNA gene was carried out using

the method of Loqman et al. (2009). The PCR product

was purified and cloned into the pMD19-T vector

(Takara) and sequenced using an Applied Biosystems

DNA sequencer (model 3730XL) and software provide

by the manufacturer. Almost full-length 16S rRNA

gene sequence (1,509 nt) was obtained and aligned

with multiple sequences obtained from the GenBank/

EMBL/DDBJ databases using Clustal X 1.83. The

alignment was manually verified and adjusted prior to

the construction of phylogenetic trees. Phylogenetic

trees were generated with the neighbour-joining (Sa-

itou and Nei 1987) and maximum-likelihood (Felsen-

stein 1981) algorithms using Molecular Evolutionary

Genetics Analysis (MEGA) software version 5.05

(Tamura et al. 2011). The stability of the clades in the

trees was appraised by bootstrap analysis with 1,000

replicates (Felsenstein 1985). A distance matrix was

generated using the Kimura’s two-parameter model

(Kimura 1980). All positions containing gaps and

missing data were eliminated from the dataset

(complete deletion option). 16S rRNA gene sequence

similarities between strains were calculated on the

basis of pairwise alignment using the EzTaxon-e server

(Kim et al. 2012). PCR amplification of the gyrB gene

was carried out using primers GYF1 and GYR3B

(Garcia et al. 2010). Sequencing and phylogenetic

analysis was performed as described above. Signature

nucleotide pattern in the 16S rRNA gene of the novel

strain was determined after manual verification of the

CLUSTAL_X sequence alignment (Zhi et al. 2009).

Nucleotide positions were numbered according to the

corresponding position in the 16S rRNA gene sequence

of Escherichia coli (Brosius et al. 1978).

DNA base composition and DNA–DNA

hybridization

The G?C content of the genomic DNA was deter-

mined by the thermal denaturation method as described

by Mandel and Marmur (1968), with E. coli JM109 as

the reference strain.

DNA–DNA hybridization was carried out between

strain NEAU-P5T and M. chokoriensis 2–19/6T, M.

violae NEAU-zh8T, M. saelicesensis Lupac 09T, M.

lupini Lupac 14NT, M. zeae NEAU-gq9T, M. jinlong-

ensis NEAU-GRX11T and M. zamorensis CR38T in a

model Cary 100 Bio UV/VIS-spectrophotometer

equipped with a Peltier-thermostatted 6 9 6 multicell

changer and a temperature controller with in situ

temperature probe (Varian) as described previously

(De Ley et al. 1970; Huss et al. 1983). The DNA

concentration was adjusted spectrophotometrically at

260 nm to around 1 using 0.1 9 saline sodium citrate

(SSC). The renaturation rates of sheared DNA were

determined at 70 �C.

Results and discussion

Morphological observation of a 21-day-old culture of

strain NEAU-P5T grown on ISP3 agar revealed it had

the typical characteristics of genus Micromonospora.

Substrate mycelium was well-developed without frag-

mentation. Spores (0.6 9 0.8 lm) were borne singly

on the substrate mycelia and the spore surface was

smooth (Suppl. Fig. S1). Good growth was observed on

N-Z amine, ISP2, ISP3 and ISP4 agar; moderate

growth was observed on SA1, Bennett’s, ISP5 and

Antonie van Leeuwenhoek (2014) 106:667–674 669

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ISP7 agar and poor growth was observed on ISP6 agar.

The colour of colonies was dark orange yellow on N-Z

amine agar, strong yellowish brown on Bennett’s agar,

strong orange yellow on SA1 agar, deep orange yellow

on ISP2 agar, moderate orange yellowish brown on

ISP3 agar, brilliant orange yellow on ISP4 agar, deep

yellow on ISP5 agar, moderate yellow on ISP6 agar and

light yellow on ISP7 agar. No aerial mycelium was

observed on any of the tested media. Grayish purple

and light grayish purplish red soluble pigments were

observed on ISP3 and ISP5 agar, respectively. Melanin

was not observed on ISP6 and ISP7 agar. Growth of

strain NEAU-P5T occurred in the pH range 6–12 and

0–2 % NaCl (w/v), with optimum growth at pH 7.0 and

0 % NaCl (w/v). The temperature range for growth was

10–37 �C, with the optimum temperature being 28 �C.

Detailed physiological and biochemical properties are

presented in the species description. No antifungal

activity of strain NEAU-P5T was observed in this

study. Micromonospora species are also able to

produce antitumor compounds, for example, the

endophytic M. lupini Lupac 08T, which is closely

related to strain NEAU-P5T, produces two novel

antitumoral compounds lupinadicins A and B (Igarashi

et al. 2007). Therefore, the antitumor activity of

NEAU-P5T will be assayed in the following research.

Cells of strain NEAU-P5T were observed to contain

meso-diaminopimelic acid and glycine as diagnostic

amino acids. Whole-cell hydrolysates were found to

contain rhamnose, xylose, glucose and galactose. The

major menaquinones detected were MK-9(H8)

(50.5 %), MK-9(H6) (10.6 %), MK-10(H2) (10.1 %),

MK-8(H8) (6 %), MK-9(H10) (5.9 %), MK-10(H8)

(5.7 %), MK-10(H4) (5.6 %), MK-9(H4) (3.6 %) and

MK-9(H2) (1.9 %). The phopholipids was found to

consist of diphosphatidylglycerol, phosphatidyletha-

nolamine, phosphatidylinositol and an unknown phop-

holipid (Suppl. Fig. S2). The cellular fatty acid profile

was determined to be composed of C16:0 (27.2 %), iso-

C15:0 (23.3 %), C17:0 (13.0 %), C15:0 (6.6 %), C17:1

x7c (6.2 %), anteiso-C17:0 (5.7 %), C18:0 (5.3 %),

C17:0 cyclo (4.6 %), C18:1 x9c (2.9 %), C17:0

10-methyl (1.9 %), iso-C14:0 (1.3 %), C16:1 x7c

(1.2 %) and C18:0 10-methyl (0.7 %). Mycolic acids

were not detected.

The almost complete 16S rRNA gene sequence

(1,509 nt) of strain NEAU-P5T was determined and

deposited as KC439463 in the GenBank/EMBL/DDBJ

databases. Comparative 16S rRNA gene sequence

analysis showed that strain NEAU-P5T was phyloge-

netically related to members of the genus Micromo-

nospora. The position of strain NEAU-P5T in the

family Micromonosporaceae was also supported by

the presence of a complete set of family-specific

signature nucleotides (Zhi et al., 2009) in its 16S rRNA

gene sequence (Suppl. Table S1). Phylogenetic ana-

lysis based on the 16S rRNA gene sequence indicated

that strain NEAU-P5T clustered with M. chokoriensis

2–19/6T (99.5 %), M. violae NEAU-zh8T (99.3 %), M.

saelicesensis Lupac 09T (99.0 %), M. lupini Lupac

14NT (98.8 %), M. zeae NEAU-gq9T (98.4 %), M.

jinlongensis NEAU-GRX11T (98.3 %) and M. zamor-

ensis CR38T (97.9 %), which was supported by a

bootstrap value of 63 % in the neighbour-joining tree

(Fig. 1) and also recovered with the maximum-likeli-

hood algorithm. Partial sequence of gyrB gene was

obtained (1,162 nt) and deposited as KJ608999 in the

GenBank/EMBL/DDBJ databases. The similarities of

gyrB nucleotide sequence between strain NEAU-P5T

and M. chokoriensis 2–19/6T, M. violae NEAU-zh8T,

M. saelicesensis Lupac 09T, M. lupini Lupac 14NT, M.

zeae NEAU-gq9T, M. jinlongensis NEAU-GRX11T

and M. zamorensis CR38T were 98.0, 92.9, 94.9, 95.2,

94.7, 94.8, and 94.7 %, respectively. Phylogenetic

analysis of gyrB nucleotide sequence supported that

strain NEAU-P5T was placed in the genus Micromo-

nospora, near to M. chokoriensis 2–19/6T, M. saelic-

esensis Lupac 09T, M. lupini Lupac 14NT, M. zeae

NEAU-gq9T, M. jinlongensis NEAU-GRX11T and M.

zamorensis CR38T by a 66 % bootstrap value but far

away from M. violae NEAU-zh8T (Suppl. Fig. S3).

Other studies have also reported similar results that the

topology of phylogenetic trees based on gyrB gene

sequences differed from those based on 16S rRNA

gene sequence data (Wang et al. 2011; Carro et al.

2012; Li et al. 2014). To establish the precise

taxonomic position of strain NEAU-P5T, DNA–DNA

hybridizations performed between the novel isolate

and M. chokoriensis 2–19/6T, M. violae NEAU-zh8T,

M. saelicesensis Lupac 09T, M. lupini Lupac 14NT, M.

zeae NEAU-gq9T, M. jinlongensis NEAU-GRX11T

and M. zamorensis CR38T; the levels of DNA–DNA

relatedness between them were 53.8 ± 3.9,

57.1 ± 2.5, 33.8 ± 1.1, 54.1 ± 2.7, 41.9 ± 1.2,

34.6 ± 1.9 and 38.5 ± 2.1 %, respectively. These

values were below the threshold value of 70 %

recommended by Wayne et al. (1987) for assigning

strains to the same genomic species.

670 Antonie van Leeuwenhoek (2014) 106:667–674

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Besides the genotypic evidence above, the strain

could also be distinguished from the seven related

Micromonospora type strains by morphological,

physiological and biochemical characteristics as sum-

marized in Table 1, such as the clearly different

colony colours on ISP2, ISP3 and ISP4 media after

being incubated at 28 �C for 3 weeks (Suppl. Fig. S4)

and the differences in production of urease, hydrolysis

of starch, decomposition of cellulose and patterns of

carbon and nitrogen utilization (Table 1). Therefore,

strain NEAU-P5T represents a novel species of the

genus Micromonospora, for which the name Micro-

monospora taraxaci sp. nov. is proposed. It is quite

interesting that several Micromonospora species iso-

lated from different endophytic root origins are

clustering together after 16S rRNA and gyrB gene

sequencing and worthy of further research.

Description of Micromonospora taraxaci sp.nov

Micromonospora taraxaci (ta.ra.xa’ci. L. n. Taraxa-

cum, name of a plant, and also a botanical generic

name (Taraxacum); L. gen. n. taraxaci of Taraxacum,

referring to the isolation of the organism from T.

mongolicum Hand.-Mazz.).

Aerobic, Gram-staining positive actinomycete that

forms extensively branched, non-fragmenting substrate

mycelium but no aerial hypha. Good growth is observed

on N-Z amine, ISP2, ISP3 and ISP4 agar; moderate

growth is observed on SA1, Bennett’s, ISP5 and ISP7

agar; poor growth is observed on ISP6 agar. Colonies are

orange yellow colour-series. Grayish purple and light

grayish purplish red soluble pigments are observed on

ISP3 and ISP5 agar, respectively. Spores are single, oval

with smooth surface. Growth occurs at pH values

Fig. 1 Neighbour-joining

tree based on 16S rRNA gene

sequence (1,354 nt) showing

relationship between strain

NEAU-P5T and members of

the genus Micromonospora.

The out-group used was

Catellatospora citrea subsp.

citrea DSM 44097T. Only

bootstrap values above 50 %

(percentages of 1,000

replications) are indicated.

Asterisks indicate branches

also recovered in the

maximum-likelihood tree;

Bar 0.005 nucleotide

substitutions per site

Antonie van Leeuwenhoek (2014) 106:667–674 671

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between 6 and 12, the optimum being pH 7.0. Tolerates

up to 2 % NaCl and grows at temperatures between 10

and 37 �C, with an optimum temperature of 28 �C.

Positive for liquefaction of gelatin, hydrolysis of aescu-

lin, starch, cellulose and Tween 40, production of

catalase and urease and negative for reduction of nitrate,

coagulation of milk, hydrolysis of Tween 20 and 80 and

production of H2S. L-arabinose, D-galactose, D-glucose,

lactose, D-maltose, D-mannose, D-raffinose, D-mannitol,

D-sorbitol D-ribose, D-sucrose and D-xylose are utilized as

sole carbon sources but D-fructose, inositol and L-

rhamnose are not. L-alanine, L-arginine, L-asparagine,

L-aspartic acid, L-threonine, creatine, L-glutamic acid and

L-serine are utilized as sole nitrogen sources but L-

glutamine, glycine and L-tyrosine are not. No inhibition

was observed against A. solani, C. cassiicola, P.

infestans, C. orbiculare, P. sojae, R. solani, S. sclerotio-

rum and P. capsici. Cell wall contains meso-diamino-

pimelic acid and glycine, and the characteristic whole-

cell sugars are rhamnose, xylose, glucose and galactose.

The phopholipids include diphosphatidylglycerol,

phosphatidylethanolamine, phosphatidylinositol and

an unknown phopholipid. The major menaquinones

are MK-9(H8), MK-9(H6) and MK-10(H2). The major

cellular fatty acids are C16:0, iso-C15:0 and C17:0.

Mycolic acids are absent. The G?C content of the

DNA of the type strain is 68.3 ± 0.25 mol %.

The type strain, NEAU-P5T (=CGMCC

4.7098T = DSM 45885T), was isolated from a root

of dandelion (T. mongolicum Hand.-Mazz.) collected

from Harbin, Northeast China. The GenBank/EMBL/

DDBJ accession numbers for the 16S rRNA gene and

gyrB gene sequences of strain NEAU-P5T are

KC439463 and KJ608999, respectively.

Acknowledgments This work was supported in part by grants

from the National Outstanding Youth Foundation (No.

31225024), the National Key Project for Basic Research (No.

2010CB126102), the National Key Technology R&D Program

(No. 2012BAD19B06), the Program for New Century Excellent

Talents in University (NCET-11-0953), the National Natural

Science Foundation of China (No.31372006, 31171913 and

31071750), the Outstanding Youth Foundation of Heilongjiang

Province (JC201201), the Chang Jiang Scholar Candidates

Program for Provincial Universities in Heilongjiang (CSCP),

the Sicence and Technology Research Project of Heilongjiang

Table 1 Differential characteristics of strain NEAU-P5T and the closely related species

Characteristics 1 2 3 4 5 6 7 8

Spore ornamentation Smooth Rough to nodulara Smooth Smoothb Smoothb Smooth Smooth Smoothc

Maximum NaCl tolerance (%, w/v) 2 2 2 3 3 3 3 3

Cellulose decomposition ? ? - ? ? - - -

Production of urease ? ? ? ? ? - - ?

Hydrolysis of starch ? - - - - - ? -

Use as sole carbon source:

D-maltose ? ? ? - ? ? ? -

D-mannose ? ? ? ? ? ? - -

D-sorbitol ? - - - - - ? -

L-rhamnose - ? - ? ? ? ? ?

D-mannitol ? ? - - - ? ? -

Use as sole nitrogen source:

Creatine ? ? - ? ? ? - ?

L-threonine ? - - ? ? ? ? ?

L-glutamic acid ? - ? ? - - ? -

L-glutamine - ? ? ? ? ? ? ?

Strains: 1, NEAU-P5T; 2, M. chokoriensis 2–19(6)T; 3, NEAU-zh8T; 4, M. saelicesensis Lupac 09T; 5, M. lupini Lupac 14NT; 6, M.

zeae NEAU-gq9T; 7, M. jinlongensis NEAU-GRX11T; 8, M. zamorensis CR38T. (?) positive, (-) negative. Data are from this study

except where markeda Data from Ara and Kudo (2007)b Data from Trujillo et al. (2007)c Data from Carro et al. (2012)

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Provincial Educational Commission (No. 12541001) and the

Youth Science Foundation of Heilongjiang Province (No.

QC2014C013).

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