ABSTRACT
Mangrove plants are located on coastal area of sea and harbor diverse communities of microorganisms. The aim of our present study was to isolate bacteria from two different mangroves collected from the coastal area of Thuwal, Saudi Arabia and to further screen them for their antimicrobial activities. We have isolated 317 different rhizo and endophytic bacteria from mangroves using soil, roots and leave tissues. Bacteria were screened for their antifungal activities against oomycetes pathogens, Phytophthora capsici, Pythium ultimum. Only 25 bacterial strains found to be active against oomycetes fungal pathogens. These bacteria were tested further against other fungal pathogens like Magnaporthe grisea, Altenaria malli, and Fusarium oxysporum. Antagonistic bacteria were further screened for antibacterial activities against human pathogenic bacteria. Only few isolates exhibited antagonistic activity against these pathogenic bacteria. Hydrolytic enzymes production (cellulase, protease, lipase, and amylase) was also assessed. Most of the active isolates exhibited amylase and protease activities. Identification based on 16S rRNA gene revealed 92.8 to 99.9% sequence, similar to type strains of related species. Antagonistic bacteria belong to 5 different classes that is Gammaproteobacteria (γ-Proteobacteria), Alphaproteobacteria (α-Proteobacteria), Firmicutes, Bacteroidetes and Actinobacteria. Our results provide evidence that, mangroves plants harbor potentially useful bacteria producing active metabolites and enzymes.
Key words: Mangrove plants, antagonistic bacteria, enzymatic activities, 16S rRNA gene sequence, phylogenetic analysis.
Mangroves, the coastal ecosystems, are found in transitional zones between rivers, sea and land (Schaeffer-Novelli et al., 2000; Kathiresan and Bingham, 2001; Walters et al., 2008) in tropical and subtropical regions all around the world. Their distribution lies in 123 countries covering about 152,000 km2 (Spalding et al., 2010). Mangrove forests also have diverse microbial communities, which play critical role in maintenance and functioning of these complex and sensitive ecosystems (Sahoo and Dhal, 2009).
Mangroves sedimentation is the actual base for mangrove forests and organisms inhibiting them. In turn, these microorganisms release nutrients from the sediments and provides base for an enormous food web (Holguin et al., 2001; Spalding et al., 2010). Mangrove plants can tolerate a wide range of environmental factors. This tolerance is facilitated by rhizospheric and endophytic microorganisms, which play vital role in biogeochemical cycles and nutrient transformations (Kathiresan and Bingham, 2001). Bacteria are primary decomposers of organic matter (Saxena et al., 1988) and key players in nitrogen fixation (Abraham et al., 2004; Miransari, 2011). Mangrove sediments and organisms controlling these ecosystems are good targets to study (Kathiresan and Bingham, 2001). High salinity, organic matter, low aeration in mangroves provides conditions, favorable for the growth of diverse microbes of biotechnological importance (Sivaramakrishnan et al., 2006; Dias et al., 2009). Organisms present in mangrove ecosystems remains largely unexplored therefore, there is an excellent source for finding new and novel bioactive secondary metabolites with distinct functions such as enzymes, antibiotics and antitumor compounds (Das et al., 2014). Both rhizo and endophytic bacteria performing diverse functions have been isolated previously from mangrove ecosystem (
Hong et al., 2015).
Endophytes are microorganisms harboring internal tissues of plants and are important source of secondary metabolites for development of novel drugs against different diseases of human (Strobel et al., 2004). From biotechnological perspective, bacteria from mangrove plants are an important source of functional metabolites including enzymes and antibiotics (Dias et al., 2009; Thatoi et al., 2013). Several previous studies highlighted importance of beneficial bacteria isolated from mangrove habitats (Vazquez et al., 2000; Soares Junior et al., 2013; Zainal Abidin et al., 2016).
Many rhizo and endophytic bacteria from mangrove plants is a potential producers of important enzymes like amylase, esterase, cellulose and proteases (Dias et al., 2009; Castro et al., 2014). By considering mangroves as an important source of bacteria, these bacteria can produce both enzymes and antimicrobial compounds which are of great interest. Therefore, present study was designed to isolate and characterize rhizo and endophytic bacteria from two mangroves, Haplopeplis perfoliata and Cyperus conglomerates. Their antifungal and enzymatic characteristics have been examined and 16 SrRNA analysis placed them in different groups of bacteria.
Sample collection and isolation of bacteria
Plant samples were collected from the carbonated shore of Red sea in Thuwal, (22°15' 54" North, 39°6' 44" East) located in Jeddah, Saudi Arabia. Both plant samples that are H. perfoliata and C. conglomerates were put in sterile bag after collection and transferred to laboratory for bacterial isolation.
Soil, roots and leaves samples of plants were used for isolation of bacteria. For bacterial isolation from adhering soil, dipped roots in filtered autoclaved sea water (FAS) to remove adhering soil and serial dilutions were made (10-3, 10-4 and 10-5) in a filtered autoclaved sea water (FAS), to spread on different media used for culturing of bacteria for maximum isolation.
Half strength R2A (½ R2A) [0.25 g yeast extract, 0.25 g proteose peptone No. 3 (Difco), 0.25 g casamino acid, 0.25 g dextrose, 0.25 g soluble starch, 0.15 g sodium pyruvate, 0.15 g K2HPO4, 0.03 g MgSO4], half Tryptic soy agar (½ TSA) [Pancreatic digest of casein, 7.5 g Papaic Digest of soybean, 2.5 g sodium chloride, 2.5 g agar, 15.0 g], marine agar (MA) [peptone, 5.0 g yeast extract, 1.0 g ferric citrate, 0.1 g sodium chloride, 19.45 g magnesium chloride, 8.8 g sodium sulfate, 3.24 g calcium chloride, 1.8 g potassium chloride, 0.55 g sodium bicarbonate, 0.16 g potassium bromide, 0.08 g strontium chloride, 34.0 mg boric acid, 22.0 mg sodium silicate, 4.0 mg sodium fluoride, 2.4 mg ammonium nitrate, 1.6 mg disodium phosphate, 8.0 mg agar,15.0 g] and half nutrient agar (½ NA) [beef extract, 1.5 g peptone, 2.5 g agar, 15.0 g] (Difco Laboratories, Detroit, MI) for bacterial culturing.
Surface sterilization and isolation of endophytic bacteria
Roots and leaves tissues were also used for isolation of bacteria. To isolate endophytic bacteria from plant, roots and leaves samples were washed several times with tap water and was further sterilized by washing with disinfectants as described previously (Bibi et al., 2012).
To check sterilization, washed roots and leaf segments were placed on ½R2A agar to check the growth of bacteria, from these plant parts after incubation at 28°C for 5 days. After confirming sterilization of root and leaf segments, small pieces of sterilized root and leaf segments were ground in FAS using sterile mortar and pestle. Aliquots were further serially diluted (10-3, 10-4 and 10-5) and plated in duplicate on different media mentioned above.
To inhibit fungal contamination, 50 μg/ml cycloheximide was mixed to the medium before pouring. The plates were incubated at 25°C for 2 weeks for bacterial growth. Individual colonies were streak to check purity of the strains and all bacterial isolates were further subculture and stored in, 15% (v/v) glycerol stock of strains at -70°C.
Screening for antifungal activity
Bacteria isolated from soil, roots and leaves of the mangroves were used to check their antifungal potential. Five different test fungal pathogens Phytophthora capsici, Pythium ultimum and Magnaporthe grisea were obtained in our laboratory while Altenaria malli (KCTC 6972), and Fusarium oxysporum (KCTC 6149) were obtained from Korean type culture collection centre (KCTC).
Antagonistic activity against fungal pathogens was determined by using cross streak method. All isolates were striated on PDA media supplemented with ½ R2A in sea water. Each 6 mm mycelial disc of 4-day-old test fungal pathogens was placed in center of plate perpendicular to streak of isolates at 4 cm distance from edges of plate and incubated at 28°C for 4 to 6 days. All strains were checked twice for antagonistic activity. The antagonistic activity was then evaluated by measuring the inhibition zone of fungal mycelia around bacterial colony.
Screening of bacteria for antibacterial activity
Using overlay assay, all antagonistic bacteria have been checked for their antibacterial activity. Firstly, bacterial isolates were grown on ½ R2A in sea water at 28°C for 48 h. Pathogenic bacteria were grown in culture media for 24 h, mixed with 0.1% soft agar and overlaid on strains to be screened.
All test pathogenic bacterial strains were diluted to final concentration A600= 0.1. After applying overlay of soft agar, plates were incubated at 28°C for 36 h and the zone of inhibition was determined. The test strains of bacteria (Escherichia coli ATCC 8739, Enterococcus faecalis ATCC 29212, Enterococcus faecium ATCC 27270, Pseudomonas aeurigenosa ATCC 27853 and MRSA ATCC 43300) were grown in LB broth at 37°C.
Evaluation of hydrolytic enzyme activity
Amylase production was checked on starch media. Amylase producing bacteria showed starch hydrolysis as clear zone on starch ½ R2A agar plates (Kumar et al., 2012).
To check cellulase activity, CMC agar (carboxy methyl cellulose agar) media was used. Bacteria were streaked on plates and incubated at 28°C for 2 days. After, these plates were flooded with solution 0.1% Congo red and put on orbital shaker for 15min and washed with 1MNaCl (Hendricks et al., 1995). Positive activity was seen as halo zone around bacterial colonies on CMC agar. Protease activity was checked using skim milk ½ R2A agar plates. Bacteria producing protease made clear zone on skim milk agar plates.
For lipolytic activity, tributyrin ½ R2A agar media was used. After 48 h of incubation at 28°C clear zone was detected around bacteria after hydrolysis of tributyrin.
Bacterial DNA extraction and 16S rRNA gene analysis
Bacteria isolated from two mangrove plants were used for genomic DNA extraction using DNA extraction kit (Thermo Scientific, Waltham, USA). To identify bacterial strain 16S rRNA gene, full gene sequencing was performed. Using bacterial universal primers 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'- GGTTACCTTGTTACGACTT-3'), the 16S rRNA gene fragment was amplified. Amplifications were performed under the following conditions: one cycle of 95°C for 5 min followed by 30 cycles of 94°C for 1 min, an annealing of 58°C for 50s and extension at 72°C for 1 min, with a final extension step at 72°C for 10 min.
Using PCR purification kit (Thermo Scientific, Waltham, USA) PCR products were purified and were sequenced commercially by Macrogen (Seoul, Korea). Sequences obtained after 16S rRNA gene similarity were blast using EzTaxon server (http://eztaxon- e.ezbiocloud.net/) (Kim et al., 2012), for identification of bacteria. To determine the phylogenetic placement of antagonistic bacteria and related type strains, the 16S rRNA gene sequences of related type strains sequences were obtained from National Centre for Biotechnology Information (NCBI).
Phylogenetic analysis
For phylogenetic analysis using CLUSTALX (Thompson et al., 1997), multiple alignments of the sequences were performed and BioEdit software (Hall, 1999) was used for editing of gaps.
The neighbour-joining method in a MEGA6 Program with bootstrap values based on 1000 replications was used for construction of phylogenetic tree based on 16S rRNA gene sequences (Tamura et al., 2013).
Nucleotide sequence numbers
All nucleotide sequences of antagonistic strains have been deposited in the GenBank database under accession numbers KY234238- KY234262.
Isolation of rhizo and endophytic enzyme producing bacteria
A total of 317 rhizo and endophytic antagonistic bacteria were isolated from two mangrove plants C. conglomerates and H. perfoliata. All bacterial isolates were isolated from soil, roots and leaves tissues of plants. All bacterial strains isolated from different parts of the plants mentioned above were cultured on four different media ½ TSA and ½ R2A, MA and NA.
Bacterial number was high on ½ TSA and MA as compared to ½ R2A and ½ NA. But more antagonistic bacteria were recovered from ½ R2A culture media. As different parts of plants were used, more number of antagonistic rhizobacteria was isolated from C. conglomerates while endophytes were more in number from H. perfoliata (Table 1).
Screening for antimicrobial potential
Further these bacteria were used to check their antifungal potential against two different pathogenic fungi, Pythium ultimum and Phytophthora capsici. From these total 317 bacteria, when screened against these two fungi, 25 (7.8%) isolates were active against Py. ultimum and 21 (6.6%) were active against P. capsici.
These rhizo and endophytic antagonistic bacteria were checked for their antifungal potential against three different fungi that is Magnaporthe grisea, A. malli, and Fusarium oxysporum. Fourteen isolates (4.4%) showed inhibition against M. grisea. Only six bacterial isolates (1.8%) were active against A. malli while 8 showed inhibition to F. oxysporum (2.5%).
Inhibition pattern against different fungi was different where strongest inhibition was seen against oomycetes (Figure 1). Rhizobacteria EA208 from C. conglomerates showed strong activity with 7 to 9 mm mycelial inhibition against both pathogenic fungi tested. This strain has similarity to Bacillus licheniformis ATCC 14580(T). Another rhizobacteria EA216 from Halopeplis perfoliata showed strong inhibition against all fungi tested.
An endophytic isolate EA218 from same host plant has similar strong inhibition against pathogenic fungi. This strain belongs to class Firmicutes and has closest 16S rRNA similarity to Bacillus amyloliquefaciens subsp. plantarum FZB42 (T) (Table 1). Some bacteria have strong inhibition only against oomycetes pathogens which have weak or no inhibition against other fungi tested. Strain EA202, EA205, EA210 and EA223 showed strong inhibition for oomycetes which are weak or inactive against other fungi.
Antagonistic bacteria were further checked for their antibacterial activity using agar overlay method. Only few bacteria showed inhibition against human pathogenic bacteria. From them, 4 isolates were active against Enterococcus faecalis, 3 for E. coli following 2 against P. aeruginosa and MRSA and only 1 was active against Ent. faecium.
The antagonistic isolate EA208 and EA216 showed inhibition with three different test pathogenic bacteria. Where EA216 had strong inhibition against E. coli, Ent. faecium and Ent. faecalis. Both these isolates belong to genus Bacillus (Table 1).
Enzymatic activities of antagonistic bacteria
Of 25 antagonistic bacteria tested, only few were positive for enzymatic activities tested (Table 2). Protease activity was higher than other hydrolytic enzymatic activities. More number of bacteria were able to excrete protease enzyme (n=10; 40%). Strong activity was detected in strain EA202, EA205, EA206, EA218 and EA226. Eight bacteria were able to show amylase activity (32%). Most of the rhizobacteria exhibit amylase activity. Strain EA200, EA202, EA215 and EA216 showed strong amylase activity (Figure 2). Lipase production was observed in 7 (28%) isolates where strong lipase production was seen in EA208, EA209 and EA216. Both strains belong to genus Bacillus but only 2 strains EA208 and EA213 were able to exhibit cellulase activity in an in vitro assay. Both of them had moderate activity. Most of these antagonistic bacteria produce different hydrolytic enzymes belonging to γ-Proteobacteria.
Phylogenetic analysis of endophytic bacteria on the basis of 16S rRNA gene sequence
All antagonitsic bacteria were then identified by partial 16S rRNA gene sequence analysis. Seventeen different genera were encountered which in turn belong to four major classes: γ-Proteobacteria (n=15; 60%), α-Proteobacteria (n=4; 16%), Firmicutes (n=4; 16%), Bacteroidetes (n=1; 4%) and Actinobacteria (n=1; 4%) (Figure 3).
Phylogenetic analysis was performed and tree was generated from the distance data using, the neighbor-joining method with the Jukes and Cantor model in a MEGA6 Program (Figure 4). High bootstrap values have been seen which resulted in significant branching points of phylogenetic tree. Phylogenetic analysis on the basis of 16S rRNA gene sequences has revealed five main clusters. First include species of class γ-Proteobacteria, second include species related to class α-Proteobacteria, third include species from class Firmicutes and fourth and fifth cluster comprises of only one spp. which belongs to both class Bacteroidetes and Actinobacteria, respectively.
Bacterial isolates showed 16S rRNA gene sequence similarity of 92.8 to 99.9% with their closest type strain. High bootstrap values have been observed for all species making four different clusters. γ-Proteobacteria comprised of 10 different genera, clearly identified as separate cluster with bootstrap values of 89 to 100% (Figure 4). Representative of class α-Proteobacteria comprised of four different genera with high bootstrap values (98 to 100%). Bacteroidetes comprise only one strain EA210 Sinomicrobium pectinilyticum 5DNS001 (T) with low 16S rRNA gene sequence similarity (94%), which were also recovered. Actinobacteria consist of one strain (EA221) which is an endophyte, Celeribacter halophilus ZXM137 (T).
Mangrove plants are an excellent source of chemical compounds of medicinal and agricultural use (Miles et al., 1998). However, studies related to isolation and screening of antagonistic rhizo and endophytic bacteria from mangrove plants, from Saudi Arabia is not done before. To our knowledge, our study is the first report regarding isolation, screening and identification of rhizo and endophytic bacteria from H. perfoliata and C. conglomeratus in Saudi Arabia.
In microbial antagonism, different types of metabolites are secreted by microbes especially growth inhibitor due to competition for nutrients and living space (Whipps et al., 2001; Riley and Wertz, 2002). Endophytic bacteria produce such metabolites in defence of host plants against different plant pathogens (Strobel and Daisy, 2003). We have used different combinations of culturing media for isolation of bacteria. Great diversity have been seen in bacteria as well as their biological activities isolated on different culturing media. This variation in growth of bacteria on different media is also seen in previous studies, where specific group of bacteria recover on specific media and conditions (Vieira and Nahas, 2005; Chang et al., 2015).
317 rhizo and endophytic bacteria have been isolated and screen for their antifungal potential against five different pathogenic fungi mentioned above. Several previous studies also reported isolation of antagonistic bacteria from mangroves. Mainly endophytic bacteria, which produce secondary metabolites were isolated (Hu and Wu, 2010; Hu et al., 2010; Ding et al., 2012; Eldeen et al., 2015). These active bacterial isolates were further checked for their antibacterial activity where only few bacteria were active against human pathogenic bacteria.
Mostly, strains of Bacillus in our study showed antibacterial activity which is similar to finding reported previously (Hu et al., 2010; Eldeen et al., 2015), where strain of Bacillus isolated from mangrove plant exhibit antibacterial activity against different pathogenic bacteria.
Microorganisms from mangrove plants are capable of producing various groups of enzymes of industrial and biotechnological significance (Thatoi et al., 2013; Saravanakumar et al., 2016). Antagonistic bacteria from two mangroves were checked for ability to prodcue hydrolytic enzymes.
In a recent study from Thailand, endophytic bacteria isolated from mangrove plants were screened for hydrolytic enzymes production. Many bacteria were positive for production of proteases, lipases, amylases or cellulases where one strain of Bacillus safensis was able to produce all enzymes (Khianngam et al., 2013). In another study, enzymatic potential of the bacteria from mangroves have been evaluated, where four strains of Bacillus sp. exhibited strong enzyme production (Tabao and Moasalud, 2010).
In this study, Bacillus sp. showed strong enzymatic activities. From Saudi Arabia, mangroves were used for isolation of bacteria producing a polymer Polyhydroxybutyrate (PHB) (Alarfaj et al., 2015). A strain of B. thuringiensis from this study showed maximum production of PHB. In another study, 12 different fungi have been isolated from mangroves growing on Red Sea Coast of Saudi Arabia. These fungal isolates were able to produce different enzymes and help in biodegradation of diesel fuel (Ameen et al., 2016). This study is the first report on isolation, screening on the basis of antimicrobial activity and enzyme characterization of bacteria from C. conglomerates and H. perfoliata in Saudi Arabia.
In this study, Bacillus was the dominant genus that is similar to many previous studies where different strains of Bacillus were isolated from mangrove plants during screening for their antifungal potential (Liu et al., 2010; Ando et al., 2001). Two endophytic strains of Bacillus, B. thuringiensis and Bacillus pumilus were isolated from mangrove plants from India (Ravikumar et al., 2010). These two endophytic strains of Bacillus were able to inhibit many bacterial and fungal pathogens. Feng et al. (2009) have evaluated bacterial communities from mangroves for their antagonism. One endophytic strain Bacillus amyloliquefaciens was able to control Phytophthora blight caused by Phytophthora capsici in capsicum in an in vitro assay. In our work, we have many strains from α-Proteobacteria and Firmicutes, showing strong antagonistic activity against Py.ultimum and P.capsici suggest their application as biocontrol agent in future.
Twenty-five antagonistic rhizo and endophytic bacteria from mangroves exhibit both antifungal and antibacterial activities. Furthermore, bacteria exhibited different types of enzymatic activities of industrial importance. It is concluded from the study that rhizo and endophytic bacteria isolated from soil, roots and leaves of mangrove plants produce enzymes, antibacterial and antifungal metabolites, pointing their significant role in host plant. Further study is in progress to identify these active metabolites responsible for antimicrobial activity.
The authors have not declared any conflict of interests.
REFERENCES
|
Abraham TJ, Ghosh S, Nagesh T, Sasmal D (2004). Distribution of bacteria involved in nitrogen and sulphur cycles in shrimp culture systems of West Bengal, India. Aquaculture 239(1):275-288.
Crossref
|
|
|
|
Alarfaj AA, Arshad M, Sholkamy EN, Munusamy MA (2015). Extraction and Characterization of Polyhydroxybutyrates (PHB) from Bacillus thuringiensis KSADL127 Isolated from Mangrove Environments of Saudi Arabia. Braz. Arch. Biol. Technol. 58(5):781-8.
Crossref
|
|
|
|
Ameen F, Moslem M, Hadi S, Al-Sabri AE (2016). Biodegradation of diesel fuel hydrocarbons by mangrove fungi from Red Sea Coast of Saudi Arabia. Saudi J. Biol. Sci. 23(2):211-218.
Crossref
|
|
|
|
Ando Y, Mitsugi N, Yano K, Karube I (2001). Isolation of a bacterium from mangrove soil for degradation of sea sludge. Appl. Biochem. Biotechnol. 95(3):175-182.
Crossref
|
|
|
|
Bibi F, Yasir M, Song GC, Lee SY, Chung YR (2012). Diversity and characterization of endophytic bacteria associated with tidal flat plants and their antagonistic effects on oomycetous plant pathogens. Plant Pathol. J. 28(1):20-31.
Crossref
|
|
|
|
Castro RA, Quecine MC, Lacava PT, Batista BD, Luvizotto DM, Marcon J, Ferreira A, Melo IS, Azevedo JL (2014). Isolation and enzyme bioprospection of endophytic bacteria associated with plants of Brazilian mangrove ecosystem. SpringerPlus 38(1):1-9.
Crossref
|
|
|
|
Chang X, Liu W, Yin Q, Wang H, Zhang X (2015). Phylogenetic diversity and biological activities of marine actinomycetes isolated from sediments of the Yellow Sea Cold Water Mass, China. Mar. Biol. Res. 11(5):551-60.
Crossref
|
|
|
|
Das A, Bhattacharya S, Mohammed AY, Rajan SS (2014). In vitro antimicrobial activity and characterization of mangrove isolates of streptomycetes effective against bacteria and fungi of nosocomial origin. Braz. Arch. Biol. Technol. 57(3):349-356.
Crossref
|
|
|
|
Dias AC, Andreote FD, Dini-Andreote F, Lacava PT, Sá AL, Melo IS, Azevedo JL, Araújo WL (2009). Diversity and biotechnological potential of culturable bacteria from Brazilian mangrove sediment. World J. Microbiol. Biotechnol. 25(7):1305-1311.
Crossref
|
|
|
|
Ding L, Maier A, Fiebig HH, Lin WH, Peschel, G, Hertweck C (2012). Kandenols A-E, eudesmenes from an endophytic Streptomyces sp. of the mangrove tree Kandelia candel. J. Nat. Prod. 75(12):2223-2227.
Crossref
|
|
|
|
Eldeen IM, Alejandra LS, Saidin J, Zin NA (2015). Endophytic Bacillus species isolated from mangrove plants, and their antagonestic effects against some pathogenic bacterial strains. Int. J. Phytomed. 7(3):302- 309.
|
|
|
|
Feng L, Ou X, He H, Hu H, Zhang X (2009). Control of Capsicum phytophthora blight by endophytic bacteria RS261 from mangrove. Acta Phytopathol. Sin. 39:333-336.
|
|
|
|
Hall T (1999). BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucleic Acids Symp. Ser. 41(41):95-98.
|
|
|
|
Hendricks CW, Doyle JD, Hugley B (1995). A new solid medium for enumerating cellulose-utilizing bacteria in soil. Appl. Environ. Microbiol. 61(5):2016-2019.
|
|
|
|
Hong Y, Liao D, Hu A, Wang H, Chen J, Khan S, Su J, Li H (2015). Diversity of endophytic and rhizoplane bacterial communities associated with exotic Spartina alterniflora and native mangrove using Illumina amplicon sequencing. Can. J. Microbiol. 61(10):723-733.
Crossref
|
|
|
|
Hu HQ, Li XS, He H (2010). Characterization of an antimicrobial material from a newly isolated Bacillus amyloliquefaciens from mangrove for biocontrol of Capsicum bacterial wilt. Biol. Control 54(3):359-365.
Crossref
|
|
|
|
Hu W-M, Wu J (2010). Protoxylogranatin B, a key biosynthetic intermediate from Xylocarpus granatum: Suggesting an oxidative cleavage biogenetic pathway to limonoid. Open Nat. Prod. J. 3:1-5.
Crossref
|
|
|
|
Kathiresan K, Bingham BM (2001). Biology of mangroves and mangrove ecosystems. Adv. Mar. Biol. 40:81-251.
Crossref
|
|
|
|
Khianngam S, Techakriengkrai T, Raksasiri BV, Kanjanamaneesathian M, Tanasupawat S (2013). Isolation and screening of endophytic bacteria for hydrolytic enzymes from plant in mangrove forest at Pranburi, Prachuap Khiri Khan, Thailand. In. Schneider C, Leifert C, Feldmann F (ed) Endophytes for plant protection: the state of the art. Proc. 5th Int. Symp. Plant Protect Plant Health Europe, Deutsche Phytomedizinische Gesellschaft, Berlin, Pp. 279-284.
|
|
|
|
Kim OS, Cho Y, Lee K, Yoon SH, Kim M, Na H, Park SC, Jeon YS, Lee JH, Yi H, Won S (2012). Introducing EzTaxon-e: a prokaryotic 16S rRNA Gene sequence database with phylotypes that represent uncultured species. Int. J. Syst. Evol. Microbiol. 62(3):716-721.
Crossref
|
|
|
|
Kumar S, Karan R, Kapoor S, Singh SP, Khare SK (2012). Screening and isolation of halophilic bacteria producing industrially important enzymes. Braz. J. Microbiol. 43(4):1595-1603.
Crossref
|
|
|
|
Liu YL, Chen G, Chen XC (2010). Isolation of endophyte bacteria from mangrove and screening of antagonistic strains against dematiaceous fungi. China Trop. Med. 10(1):13-42.
|
|
|
|
Miles DH, Kokpol U, Chittawong V, Tip-Pyang S, Tunsuwan K, Nguyen C (1998). Mangrove forests-the importance of conservation as a bioresource for ecosystem diversity and utilization as a source of chemical constituents with potential medicinal and agricultural value. IUPAC 70:1-9.
|
|
|
|
Miransari M (2011). Soil microbes and plant fertilization. Appl. Microbiol. Biotechnol. 92(5):875-885.
Crossref
|
|
|
|
Ravikumar S, Inbaneson SJ, Sengottuvel R, Ramu A (2010). Assessment of endophytic bacterial diversity among mangrove plants and their antibacterial activity against bacterial pathogens. Ann Biol Res. 1(4):240-247.
|
|
|
|
Riley MA, Wertz JE (2002). Bacteriocins: evolution, ecology, and application. Annu. Rev. Microbiol. 56(1):117-137.
Crossref
|
|
|
|
Sahoo K, Dhal N (2009). Potential microbial diversity in mangrove ecosystems: a review. Indian J. Mar. Sci. 38:249.
|
|
|
|
Saravanakumar K, Rajendran N, Kathiresan K, Chen J (2016). Chapter Five-Bioprospects of Microbial Enzymes from Mangrove-Associated Fungi and Bacteria. Adv. Food Nutr. Res. 79:99-115
Crossref
|
|
|
|
Saxena D, Lokabharathi P, Chandramohan D (1988). Sulfate reducing bacteria from mangrove swamps of Goa, central west coast of India. Indian J. Mar. Sci. 17:153-157.
|
|
|
|
Schaeffer-Novelli Y, Cintrón-Molero G, Soares ML, De-Rosa T (2000). Brazilian mangroves. Aquat. Ecosyst. Health Manage. 3(4):561-570.
|
|
|
|
Sivaramakrishnan S, Gangadharan D, Nampoothiri KM, Soccol CR, Pandey A (2006). a-Amylases from microbial sources–an overview on recent developments. Food Technol. Biotechnol. 44(2):173-184.
|
|
|
|
Soares Júnior FL, Dias AC, Fasanella CC, Taketani RG, Lima AO, Melo IS, Andreote FD (2013). Endo-and exoglucanase activities in bacteria from mangrove sediment. Braz. J. Microbiol. 44(3):969-976.
Crossref
|
|
|
|
Spalding M, Kainuma M, Collins L (2010). World Atlas of Mangrove Earthscan, Routledge, London.
|
|
|
|
Strobel G, Daisy B (2003). Bioprospecting for microbial endophytes and their natural products. Microbiol. Mol. Biol. Rev. 67(4):491-502.
Crossref
|
|
|
|
Strobel G, Daisy B, Castillo U, Harper J (2004). Natural products from endophytic microorganisms. J. Nat. Prod. 67(2):257-268.
Crossref
|
|
|
|
Tabao NC, Moasalud RG (2010). Characterisation and identification of high cellulose-producing bacterial strains from Philippine mangroves. Philipp. J. Syst. Biol. 4:13-20.
|
|
|
|
Tamura K, Stecher G, Peterson D, Filipski A, Kumar S (2013). MEGA6:molecular evolutionary genetics analysis version 6.0. Mol. Biol. Evol. 30(12):2725-2729.
Crossref
|
|
|
|
Thatoi H, Behera BC, Mishra RR, Dutta SK (2013). Biodiversity and biotechnological potential of microorganisms from mangrove ecosystems: a review. Ann. Microbiol. 63(1):1-19.
Crossref
|
|
|
|
Thompson JD, Gibson TJ, Plewniak F, Jeanmougin F, Higgins DG (1997). The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Res. 25(24):4876-4882.
Crossref
|
|
|
|
Vazquez P, Holguin G, Puente ME, Lopez-Cortes A, Bashan Y (2002). Phosphate-solubilizing microorganisms associated with the rhizosphere of mangroves in a semiarid coastal lagoon. Biol. Fertil. Soils 30(5):460-468.
|
|
|
|
Vieira FC, Nahas E (2005). Comparison of microbial numbers in soils by using various culture media and temperatures. Microbiol. Res. 160(2):197-202.
Crossref
|
|
|
|
Walters BB, Rönnbäck P, Kovacs JM, Crona B, Hussain SA, Badola R, Primavera JH, Barbier E, Dahdouh-Guebas F (2008). Ethnobiology, socio-economics and management of mangrove forests: A review. Aquat. Bot. 89(2):220-236.
Crossref
|
|
|
|
Whipps JM (2001). Microbial interactions and biocontrol in the rhizosphere. J. Exp. Bot. 52(1):487-511.
Crossref
|
|
|
|
Zainal Abidin ZA, Abdul Malek N, Zainuddin Z, Chowdhury AJ (2016). Selective isolation and antagonistic activity of actinomycetes from mangrove forest of Pahang, Malaysia. Front. Life Sci. 9(1):24-31.
Crossref
|
