Assoc.Prof. Panlada Tittabutr

Year	Title	Journal
2013	Indigenous Microbial Community Structure in Rhizosphere of Chinese Kale as Affected by Plant Growth-Promoting Rhizobacteria Inoculation Piromyou P., Noisangiam R., Uchiyama H., Tittabutr P., Boonkerd N., Teaumroong N.	Pedosphere
Abstract: Plant growth-promoting rhizobacteria (PGPR) have been widely recognized as an important agent, especially as a biofertilizer, in agricultural systems. The objectives of this study were to select effective PGPR for Chinese kale ( Brassica oleracea var. alboglabra) cultivation and to investigate the effect of their inoculation on indigenous microbial community structure. The Bacillus sp. SUT1 and Pseudomonas sp. SUT19 were selected for determining the efficiency in promoting Chinese kale growth in both pot and field experiments. In the field experiment, PGPR amended with compost gave the highest yields among all treatments. The Chinese kale growth promotion may be directly affected by PGPR inoculation. The changes of microbial community structure in the rhizosphere of Chinese kale following PGPR inoculation were examined by denaturing gradient gel electrophoresis (DGGE) and principal coordinate analysis. The DGGE fingerprints of 16S rDNA amplified from total community DNA in the rhizosphere confirmed that our isolates were established in the rhizosphere throughout this study. The microbial community structures were slightly different among all the treatments, and the major changes depended on stages of plant growth. DNA sequencing of excised DGGE bands showed that the dominant species in microbial community structure in the rhizosphere were not mainly interfered by PGPR, but strongly influenced by plant development. The microbial diversity as revealed by diversity indices was not different between the PGPR-inoculated and uninoculated treatments. In addition, the rhizosphere soil had more influence on eubacterial diversity, whereas it did not affect archaebacterial and fungal diversities. © 2013 Soil Science Society of China. Keyword: Brassica oleracea var. alboglabra; Inoculum; Structure of microbial population Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883257575&doi=10.1016%2fS1002-0160%2813%2960051-X&partnerID=40&md5=0a3a4410926ffd4a6c4673e587a49212 DOI: 10.1016/S1002-0160(13)60051-X
2012	Improvement of peanut rhizobial inoculant by incorporation of plant growth promoting rhizobacteria (PGPR) as biocontrol against the seed borne fungus, Aspergillus niger Yuttavanichakul W., Lawongsa P., Wongkaew S., Teaumroong N., Boonkerd N., Nomura N., Tittabutr P.	Biological Control
Abstract: The inhibition of Aspergillus niger that causes root rot diseases in peanut (Arachis hypogaea L.) was investigated by using 765 bradyrhizobial and 350 soil-isolated plant growth promoting rhizobacteria (PGPR) strains as biological controllers. Only 11 PGPR isolates were found to be able to inhibit A. niger growth. Based on their ability to inhibit A. niger growth and root colonization, the best four PGPR isolates, A20, A45, A62, and A106, were selected, and their 16S rRNA sequences were highly homologous to Bacillus megaterium, B. subtilis, B. subtilis subsp. subtilis, and Pseudomonas sp., respectively. The production of a lytic protease enzyme was detected in A20, A45, and A62, but not in A106. Some antifungal activities were clearly found in cell-free supernatants of A20 and A62. Interestingly, the antifungal activity of isolates A45 and A62 was proteinase K resistant. All PGPR isolates could produce an auxin (indole-3-acetic acid, IAA) hormone and biofilms. IAA produced from PGPR isolates could clearly promote peanut root growth. When either isolate A20 or A45 (10 8cellsper ml) was co-inoculated with Bradyrhizobium sp. TAL 173 (10 8cells per ml), the peanut root rot disease caused by A. niger (10 5 and 10 6spores per seed) could be inhibited. Incorporating rhizobia with selected PGPR increases nitrogen fixation and reduces fungicide usage in peanut, providing an appropriate approach for sustainable agriculture. © 2012 Elsevier Inc. Keyword: Aspergillus niger; Biocontrol; Bradyrhizobium; Peanut; PGPR; Rhizobial inoculant Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867649795&doi=10.1016%2fj.biocontrol.2012.06.008&partnerID=40&md5=24bccd142cff62979fc00da52cfd285a DOI: 10.1016/j.biocontrol.2012.06.008
2012	Genetic diversity, symbiotic evolution, and proposed infection process of bradyrhizobium strains isolated from root nodules of Aeschynomene americana L. in Thailand Noisangiam R., Teamtisong K., Tittabutr P., Boonkerd N., Toshiki U., Minamisawa K., Teaumroong N.	Applied and Environmental Microbiology
Abstract: The diversity of bacteria nodulating Aeschynomene americana L. in Thailand was determined from phenotypic characteristics and multilocus sequence analysis of the 16S rRNA gene and 3 housekeeping genes (dnaK, recA, and glnB). The isolated strains were nonphotosynthetic bacteria and were assigned to the genus Bradyrhizobium, in which B. yuanmingense was the dominant species. Some of the other species, including B. japonicum, B. liaoningense, and B. canariense, were minor species. These isolated strains were divided into 2 groups-nod-containing and divergent nod-containing strains-based on Southern blot hybridization and PCR amplification of nodABC genes. The divergent nod genes could not be PCR amplified and failed to hybridize nod gene probes designed from B. japonicum USDA110, but hybridized to probes from other bradyrhizobial strains under lowstringency conditions. The grouping based on sequence similarity of nod genes was well correlated with the grouping based on that of nifH gene, in which the nod-containing and divergent nod-containing strains were obviously distinguished. The divergent nod-containing strains and photosynthetic bradyrhizobia shared close nifH sequence similarity and an ability to fix nitrogen in the free-living state. Surprisingly, the strains isolated from A. americana could nodulate Aeschynomene plants that belong to different cross-inoculation (CI) groups, including A. afraspera and A. indica. This is the first discovery of bradyrhizobia (nonphotosynthetic and nod-containing strain) originating from CI group 1 nodulating roots of A. indica (CI group 3). An infection process used to establish symbiosis on Aeschynomene different from the classical one is proposed. © 2012, American Society for Microbiology. All Rights Reserved. Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84866161282&doi=10.1128%2fAEM.00897-12&partnerID=40&md5=3e78966e86cdee74d29f26505f865560 DOI: 10.1128/AEM.00897-12
2011	Phn and Nag-like dioxygenases metabolize polycyclic aromatic hydrocarbons in Burkholderia sp. C3 Tittabutr P., Cho I.K., Li Q.X.	Biodegradation
Abstract: Burkholderia sp. C3 can transform polycyclic aromatic hydrocarbons (PAHs), a class of ubiquitous pollutants, through multiple pathways, indicating existence of multiple dioxygenases (Seo et al., in Biodegradation 18:123-131, 2006a). Both phn and nag-like genes in C3 were cloned and identified with the DNA sequence alignment and the gene organization in the clusters. When cloned and expressed in Escherichia coli, either the alpha- and beta-subunits of dioxygenase of the phn genes or the ferredoxin-, alpha- and beta-subunits of the nag-like genes transformed naphthalene, phenanthrene and dibenzothiophene but at different rates. The E. coli transformant containing the phn genes transformed phenanthrene faster than that containing the nag-like genes, which was consistent with higher transcription of the phnAc gene than the nagAc-like gene in C3 in response to phenanthrene. 1-Hydroxy-2-naphthanoic acid (1H2NA) and 2-hydroxy-1-naphthanoic acid (2H1NA) (3,4- and 1,2-dioxygenation metabolites of phenanthrene, respectively) were detected in the culture medium of the phn genes transformed E. coli. The concentration of 1H2NA was 262-fold higher than 2H1NA in the medium of the phn genes transformed E. coli. The results suggested that the phn genes play a major role in 1,2-/3,4-dioxygenation and 3,4-dioxygenation dominates. Twenty-eight PAH degradation-associated enzymes including those encoded by the nag-like and phn genes in phenanthrene-grown C3 cells were identified via alignment of amino acid sequences of the detected polypeptides with those in protein databases. The polypeptides were determined with nano liquid chromatography-ion trap mass spectrometry after tryptic in-gel digestion of the enzymes on 1D SDS-PAGE. © 2011 Springer Science+Business Media B.V. Keyword: Biodegradation; Bioremediation; Burkholderia; Dioxygenase; Metabolism; PAH Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054002467&doi=10.1007%2fs10532-011-9468-y&partnerID=40&md5=33290be4aaab90425fbe6581d663c709 DOI: 10.1007/s10532-011-9468-y
2011	Effect of plant growth promoting rhizobacteria (PGPR) inoculation on microbial community structure in rhizosphere of forage corn cultivated in Thailand Piromyou P., Buranabanyat B., Tantasawat P., Tittabutr P., Boonkerd N., Teaumroong N.	European Journal of Soil Biology
Abstract: Plant Growth Promoting Rhizobacteria (PGPR) play an important role in agricultural systems, especially as biofertilizer. The objectives of this study were to select effective PGPR for forage corn (Zea mays L.) cultivation and to investigate the effect of their inoculation on indigenous microbial community structure. The putative genera Pseudomonas sp. SUT 19 and Brevibacillus sp. SUT 47 were selected for determining their efficiency in forage corn growth promotion in both pot and field experiments. In field experiment, PGPR amended with compost gave the highest results in comparison to all treatments. Denaturing Gradient Gel Electrophoresis (DGGE) fingerprints of 16S rDNA amplified from total community DNA from rhizosphere confirmed that our isolates existed in rhizosphere throughout this study. The microbial community structures were slightly different among all treatments whereas major changes depended on stages of plant growth. In order to evaluate whether PGPR have effect on species diversity in rhizosphere, DNA sequencing of excised DGGE bands was done. The results demonstrated that dominant species in microbial community structure were not interfered by PGPR, but strongly influenced by plant development. © 2010 Elsevier Masson SAS. Keyword: Forage corn; Inoculum; PGPR; Rhizosphere microbial community structure Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650679087&doi=10.1016%2fj.ejsobi.2010.11.004&partnerID=40&md5=5f0f6d44bf83436ca1da3814e6c29965 DOI: 10.1016/j.ejsobi.2010.11.004
2010	Identification of salt-tolerant Sinorhizobium sp. strain Bl3 membrane proteins based on proteomics Tanthanuch W., Tittabutr P., Mohammed S., Matthiesen R., Yamabhai M., Manassila M., Jensen O.N., Boonkerd N., Teaumroong N.	Microbes and Environments
Abstract: Sinorhizobium sp. BL3 is a salt-tolerant strain that can fix atmospheric nitrogen in symbiosis with leguminous host plants under salt-stress conditions. Since cell membranes are the first barrier to environmental ch nge, it is interesting to explore the membrane proteins within this protective barrier under salt stress. The protein contents of membraneenriched fractions obtained from BL3 were analyzed by nanoflow liquid chromatography interfaced with electrospray ionization tandem mass spectrometry. A total of 105 membrane proteins were identified. These proteins could be classified into 17 functional categories, the two biggest of which were energy production and conv ersion, and proteins not in clusters of orthologous groups (COGS). In addition, a comparative analysis of membrane proteins between salt-stressed and non-stressed BL3 cells was conducted using a membrane enrichment method and off-line SCX fractionation coupled to nanoLC-MS/MS. These techniques would be useful for further comparative analysis of membrane proteins that function in the response to environmental stress. Keyword: Mass tag; Membrane proteome analysis; Salt stress; Sinorhizobium sp.; Strong cationic micro-columns Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650057543&doi=10.1264%2fjsme2.ME09185&partnerID=40&md5=ac3c89a7427a9e9397ab927548f75c73 DOI: 10.1264/jsme2.ME09185
2008	Pyruvate carboxylase is involved in metabolism of mimosine by Rhizobium sp. strain TAL1145 Awaya J.D., Tittabutr P., Li Q.X., Borthakur D.	Archives of Microbiology
Abstract: The objective of this study was to determine the role of midK, which encodes a protein similar to pyruvate carboxylase, in mimosine degradation by Rhizobium sp. strain TAL1145. The midK gene is located downstream of midR in the cluster of genes for mimosine degradation in Rhizobium sp. strain TAL1145. The midK mutants of TAL1145 degraded mimosine slower than the wild-type. These mutants could utilize pyruvate as a source of carbon, indicating that there is another pyruvate carboxylase (pyc) gene in TAL1145. Two classes of clones were isolated from the library of TAL1145 by complementing a pyc mutant of Rhizobium etli, one class contained midK, while the other carried pyc. Both midK and pyc of TAL1145 complemented the midK mutant for mimosine degradation, and also the R. etli pyc mutant for pyruvate utilization. The midK-encoded pyruvate carboxylase was required for an efficient conversion of mimosine into 3-hydroxy-4-pyridone (HP). © 2008 Springer-Verlag. Keyword: Mimosine degradation; Pyruvate carboxylase; Rhizobium Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-52449084192&doi=10.1007%2fs00203-008-0384-4&partnerID=40&md5=cc5b21fee47f085be2b14be9394fbb1b DOI: 10.1007/s00203-008-0384-4
2008	The cloned 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene from Sinorhizobium sp. strain BL3 in Rhizobium sp. strain TAL1145 promotes nodulation and growth of Leucaena leucocephala Tittabutr P., Awaya J.D., Li Q.X., Borthakur D.	Systematic and Applied Microbiology
Abstract: The objective of this study was to determine the role of 1-aminocyclopropane-1-carboxylate (ACC) deaminase of symbionts in nodulation and growth of Leucaena leucocephala. The acdS genes encoding ACC deaminase were cloned from Rhizobium sp. strain TAL1145 and Sinorhizobium sp. BL3 in multicopy plasmids, and transferred to TAL1145. The BL3-acdS gene greatly enhanced ACC deaminase activity in TAL1145 compared to the native acdS gene. The transconjugants of TAL1145 containing the native or BL3 acdS gene could grow in minimal media containing 1.5 mM ACC, whereas BL3 could tolerate up to 3 mM ACC. The TAL1145 acdS gene was inducible by mimosine and not by ACC, while the BL3 acdS gene was highly inducible by ACC and not by mimosine. The transconjugants of TAL1145 containing the native- and BL3-acdS genes formed nodules with greater number and sizes, and produced higher root mass on L. leucocephala than by TAL1145. This study shows that the introduction of multiple copies of the acdS gene increased ACC deaminase activities of TAL1145 and enhanced its symbiotic efficiency on L. leucocephala. © 2008 Elsevier GmbH. All rights reserved. Keyword: ACC deaminase; Leucaena leucocephala; Nodulation; Rhizobium; Sinorhizobium Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-44349165598&doi=10.1016%2fj.syapm.2008.03.001&partnerID=40&md5=e9feaf84e82ddb3dace57cc6be5cdacc DOI: 10.1016/j.syapm.2008.03.001
2007	Growth, survival and field performance of bradyrhizobial liquid inoculant formulations with polymeric additives Tittabutr P., Payakapong W., Teaumroong N., Singleton P.W., Boonkerd N.	ScienceAsia
Abstract: Liquid inoculant has become a preferred method for inoculating legumes with bradyrhizobia. Finely ground peat has been the standard of quality for inoculants for many years. Suitable peat for an inoculant carrier is difficult to find and limited in supply in many locations. We evaluated six different polymeric additives (polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), polyvinyl alcohol (PVA), gum arabic, cassava starch, and sodium alginate) for their ability to support growth and promote survival of several strains of bradyrhizobia and rhizobia during storage. Some concentrations of various additives to yeast extract mannitol (YEM) media promoted higher cell density compared to cells cultured in YEM media alone. There was a large interaction between strains of rhizobia and the additives in relation to cell survival. Shelf-life of liquid inoculant formulations depended on the strain of rhizobia and additives, when stored at room temperature. Liquid inoculants formulated with sodium alginate promoted long-term survival of all rhizobial strains, but its effect on cell survival was not as great as peat. Peat also provided the greatest protection to cells of bradyrhizobia after application to the seed surface followed by incubation at 40°C. Survival of bradyrhizobia was maintained at 105 cells/seed after 48 hours of incubation. Liquid inoculant formulated with gum arabic, sodium alginate, PVP, or cassava starch supported survival at only 104-105 cells/seed, while PEG and PVA additives performed poorly and cell numbers fell to 103 cells/seed at 48 hours after inoculation. One-week old liquid inoculants with bradyrhizobia were tested for their ability to nodulate and fix nitrogen under field conditions. We found that liquid inoculant performance was as good as that of peat based inoculant. Keyword: Additive; Bradyrhizobia; Liquid inoculant; Polymeric substance; Survival Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-34247152839&doi=10.2306%2fscienceasia1513-1874.2007.33.069&partnerID=40&md5=65fe264edbbb800d445cbb4bdf113072 DOI: 10.2306/scienceasia1513-1874.2007.33.069
2006	The alternative sigma factor RpoH2 is required for salt tolerance in Sinorhizobium sp. strain BL3 Tittabutr P., Payakapong W., Teaumroong N., Boonkerd N., Singleton P.W., Borthakur D.	Research in Microbiology
Abstract: The objectives of this investigation were to isolate the rpoH2 gene encoding an alternative sigma factor from Sinorhizobium sp. BL3 and to determine its role in exopolysaccharide (EPS) synthesis, salt tolerance and symbiosis with Phaseolus lathyroides. The rpoH2 gene of Rhizobium sp. strain TAL1145 is known to be required for EPS synthesis and effective nodulation of Leucaena leucocephala. Three overlapping cosmid clones containing the rpoH2 gene of BL3 were isolated by complementing an rpoH2 mutant of TAL1145 for EPS production. From one of these cosmids, rpoH2 of BL3 was identified within a 3.0-kb fragment by subcloning and sequencing. The cloned rpoH2 gene of BL3 restored both EPS production and nodulation defects of the TAL1145 rpoH2 mutants. Three rpoH2 mutants of BL3 were constructed by transposon-insertion mutagenesis. These mutants of BL3 grew normally in complete or minimal medium and were not defective in EPS synthesis, nodulation and nitrogen fixation, but they failed to grow in salt stress conditions. The mutants complemented with cloned rpoH2 from either BL3 or TAL1145 showed higher levels of salt tolerance than BL3. The expression of rpoH2 in BL3 started increasing during the exponential phase and reached the highest level in the mid-stationary phase. These results indicate that RpoH2 is required for salt tolerance in Sinorhizobium sp. BL3, and it may have additional roles during the stationary phase. © 2006 Elsevier SAS. All rights reserved. Keyword: Alternative sigma factor; Exopolysaccharide; rpoH2; Salt tolerance; Sinorhizobium Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-33749534259&doi=10.1016%2fj.resmic.2006.07.001&partnerID=40&md5=7a1363e70cf581d998d3fed166db3b25 DOI: 10.1016/j.resmic.2006.07.001