Assoc.Prof. Panlada Tittabutr

Year	Title	Journal
2015	Possible role of 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of Sinorhizobium sp. BL3 on symbiosis with mung bean and determinate nodule senescence Tittabutr P., Sripakdi S., Boonkerd N., Tanthanuch W., Minamisawa K., Teaumroong N.	Microbes and Environments
Abstract: Sinorhizobium sp. BL3 forms symbiotic interactions with mung bean (Vigna radiata) and contains lrpL-acdS genes, which encode the 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme that cleaves ACC, a precursor of plant ethylene synthesis. Since ethylene interferes with nodule formation in some legumes and plays a role in senescence in plant cells, BL3-enhancing ACC deaminase activity (BL3+) and defective mutant (BL3–) strains were constructed in order to investigate the effects of this enzyme on symbiosis and nodule senescence. Nodulation competitiveness was weaker in BL3– than in the wild-type, but was stronger in BL3+. The inoculation of BL3– into mung bean resulted in less plant growth, a lower nodule dry weight, and smaller nodule number than those in the wild-type, whereas the inoculation of BL3+ had no marked effects. However, similar nitrogenase activity was observed with all treatments; it was strongly detected 3 weeks after the inoculation and gradually declined with time, indicating senescence. The rate of plant nodulation by BL3+ increased in a time-dependent manner. Nodules occupied by BL3– formed smaller symbiosomes, and bacteroid degradation was more prominent than that in the wild-type 7 weeks after the inoculation. Changes in biochemical molecules during nodulation were tracked by Fourier Transform Infrared (FT-IR) microspectroscopy, and the results obtained confirmed that aging processes differed in nodules occupied by BL3 and BL3–. This is the first study to show the possible role of ACC deaminase activity in senescence in determinate nodules. Our results suggest that an increase in ACC deaminase activity in this strain does not extend the lifespan of nodules, whereas the lack of this activity may accelerate nodule senescence. © 2015 Japanese Society of Microbial Ecology. All rights reserved. Keyword: ACC deaminase; Competitiveness; Determinate nodule; Mung bean; Nodule senescence Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84951154862&doi=10.1264%2fjsme2.ME15120&partnerID=40&md5=5627c9efecb6bac8471c0103c805ff40 DOI: 10.1264/jsme2.ME15120
2015	The type III secretion system (T3SS) is a determinant for rice-endophyte colonization by non-photosynthetic Bradyrhizobium Piromyou P., Songwattana P., Greetatorn T., Okubo T., Kakizaki K.C., Prakamhang J., Tittabutr P., Boonkerd N., Teaumroong N., Minamisawa K.	Microbes and Environments
Abstract: Plant associations by bradyrhizobia have been detected not only in leguminous plants, but also in non-leguminous species including rice. Bradyrhizobium sp. SUTN9-2 was isolated from Aeschynomene americana L., which is a leguminous weed found in the rice fields of Thailand. This strain promoted the highest total rice (Oryza sativa L. cultivar Pathum Thani 1) dry weight among the endophytic bradyrhizobial strains tested, and was, thus, employed for the further characterization of rice-Bradyrhizobium interactions. Some known bacterial genes involved in bacteria-plant interactions were selected. The expression of the type III secretion component (rhcJ), type IV secretion component (virD4), and pectinesterase (peces) genes of the bacterium were up-regulated when the rice root exudate was added to the culture. When SUTN9-2 was inoculated into rice seedlings, the peces, rhcJ, virD4, and exopolysaccharide production (fliP) genes were strongly expressed in the bacterium 6–24 h after the inoculation. The gene for glutathione-S-transferase (gst) was slightly expressed 12 h after the inoculation. In order to determine whether type III secretion system (T3SS) is involved in bradyrhizobial infections in rice plants, wild-type SUTN9-2 and T3SS mutant strains were inoculated into the original host plant (A. americana) and a rice plant (cultivar Pathum Thani 1). The ability of T3SS mutants to invade rice tissues was weaker than that of the wild-type strain; however, their phenotypes in A. americana were not changed by T3SS mutations. These results suggest that T3SS is one of the important determinants modulating rice infection; however, type IV secretion system and peces may also be responsible for the early steps of rice infection. © 2015 Japanese Society of Microbial Ecology. All rights reserved. Keyword: Bradyrhizobium; Endophyte; Gene expression; Genome; Rice (Oryza sativa); Type III secretion system Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84951014311&doi=10.1264%2fjsme2.ME15080&partnerID=40&md5=dfc75f9419c6f45b88ee418d61f2cd2c DOI: 10.1264/jsme2.ME15080
2015	Genome analysis of a novel bradyrhizobium sp. doa9 carrying a symbiotic plasmid Okazaki S., Noisangiam R., Okubo T., Kaneko T., Oshima K., Hattori M., Teamtisong K., Songwattana P., Tittabutr P., Boonkerd N., Saeki K., Sato S., Uchiumi T., Minamisawa K., Teaumroong N.	PLoS ONE
Abstract: Bradyrhizobium sp. DOA9 isolated from the legume Aeschynomene americana exhibited a broad host range and divergent nodulation (nod) genes compared with other members of the Bradyrhizobiaceae. Genome analysis of DOA9 revealed that its genome comprised a single chromosome of 7.1 Mbp and a plasmid of 0.7 Mbp. The chromosome showed highest similarity with that of the nod gene-harboring soybean symbiont B. japonicum USDA110, whereas the plasmid showed highest similarity with pBBta01 of the nod gene-lacking photosynthetic strain BTAi1, which nodulates Aeschynomene species. Unlike in other bradyrhizobia, the plasmid of DOA9 encodes genes related to symbiotic functions including nodulation, nitrogen fixation, and type III/IV protein secretion systems. The plasmid has also a lower GC content (60.1%) than the chromosome (64.4%). These features suggest that the plasmid could be the origin of the symbiosis island that is found in the genome of other bradyrhizobia. The nod genes of DOA9 exhibited low similarity with those of other strains. The nif gene cluster of DOA9 showed greatest similarity to those of photosynthetic bradyrhizobia. The type III/IV protein secretion systems of DOA9 are similar to those of nod gene-harboring B. elkanii and photosynthetic BTAi1. The DOA9 genome exhibited intermediate characteristics between nod gene-harboring bradyrhizobia and nod gene-lacking photosynthetic bradyrhizobia, thus providing the evidence for the evolution of the Bradyrhizobiaceae during ecological adaptation. Bradyrhizobium sp. DOA9 isolated from the legume Aeschynomene americana exhibited a broad host range and divergent nodulation (nod) genes compared with other members of the Bradyrhizobiaceae. Genome analysis of DOA9 revealed that its genome comprised a single chromosome of 7.1 Mbp and a plasmid of 0.7 Mbp. The chromosome showed highest similarity with that of the nod gene-harboring soybean symbiont B. japonicum USDA110, whereas the plasmid showed highest similarity with pBBta01 of the nod gene-lacking photosynthetic strain BTAi1, which nodulates Aeschynomene species. Unlike in other bradyrhizobia, the plasmid of DOA9 encodes genes related to symbiotic functions including nodulation, nitrogen fixation, and type III/IV protein secretion systems. The plasmid has also a lower GC content (60.1%) than the chromosome (64.4%). These features suggest that the plasmid could be the origin of the symbiosis island that is found in the genome of other bradyrhizobia. The nod genes of DOA9 exhibited low similarity with those of other strains. The nif gene cluster of DOA9 showed greatest similarity to those of photosynthetic bradyrhizobia. The type III/IV protein secretion systems of DOA9 are similar to those of nod gene-harboring B. elkanii and photosynthetic BTAi1. The DOA9 genome exhibited intermediate characteristics between nod gene-harboring bradyrhizobia and nod gene-lacking photosynthetic bradyrhizobia, thus providing the evidence for the evolution of the Bradyrhizobiaceae during ecological adaptation. © 2015 Okazaki et al. Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84923328195&doi=10.1371%2fjournal.pone.0117392&partnerID=40&md5=1019543bb591e959d854ff142aab0319 DOI: 10.1371/journal.pone.0117392
2015	The Role of 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase Enzyme in Leguminous Nodule Senescence Tittabutr P., Boonkerd N., Teaumroong N.	Biological Nitrogen Fixation
Abstract: Delayed nodule senescence may improve nitrogen content in the legume seed and increase the yield of production. This review focuses on using the strategy of modulating ACC deaminase enzyme levels as an indirect way to delay nodule senescence. Nodule senescence occurs by developmental or aging processes, and by stress-induced nodule senescence. Both processes share several characteristics, including the decline in N2 fixation, leghemoglobin, and antioxidant enzyme levels, as well as the oxidative damage of cell components caused by induction of ethylene production inside the cell as a signal to activate other systems involved in the acceleration of nodule senescence. ACC deaminase-containing rhizobia can degrade ACC, a precursor of the ethylene biosynthesis pathway, leading to a reduction of ethylene production inside the cell and indirectly to a delay in nodule senescence. Details of nodule senescence processes and signaling, as well as the role of ACC deaminase in legume-rhizobia nodulation and delay of nodule senescence, are discussed in this review. © 2015 by John Wiley & Sons, Inc. All rights reserved. Keyword: ACC deaminase; Ethylene; Nodule senescence; Rhizobium; Stress Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85018848022&doi=10.1002%2f9781119053095.ch71&partnerID=40&md5=60802890cd774505b30a607e8852c1ca DOI: 10.1002/9781119053095.ch71
2015	Preferential association of endophytic bradyrhizobia with different rice cultivars and its implications for rice endophyte evolution Piromyou P., Greetatorn T., Teamtisong K., Okubo T., Shinoda R., Nuntakij A., Tittabutr P., Boonkerd N., Minamisawa K., Teaumroong N.	Applied and Environmental Microbiology
Abstract: Plant colonization by bradyrhizobia is found not only in leguminous plants but also in nonleguminous species such as rice. To understand the evolution of the endophytic symbiosis of bradyrhizobia, the effect of the ecosystems of rice plantations on their associations was investigated. Samples were collected from various rice (Oryza sativa) tissues and crop rotational systems. The rice endophytic bradyrhizobia were isolated on the basis of oligotrophic properties, selective medium, and nodulation on siratro (Macroptilium atropurpureum). Six bradyrhizobial strains were obtained exclusively from rice grown in a crop rotational system. The isolates were separated into photosynthetic bradyrhizobia (PB) and nonphotosynthetic bradyrhizobia (non-PB). Thai bradyrhizobial strains promoted rice growth of Thai rice cultivars better than the Japanese bradyrhizobial strains. This implies that the rice cultivars possess characteristics that govern rice-bacterium associations. To examine whether leguminous plants in a rice plantation system support the persistence of rice endophytic bradyrhizobia, isolates were tested for legume nodulation. All PB strains formed symbioses with Aeschynomene indica and Aeschynomene evenia. On the other hand, non-PB strains were able to nodulate Aeschynomene americana, Vigna radiata, and M. atropurpureum but unable to nodulate either A. indica or A. evenia. Interestingly, the nodABC genes of all of these bradyrhizobial strains seem to exhibit low levels of similarity to those of Bradyrhizobium diazoefficiens USDA110 and Bradyrhizobium sp. strain ORS285. From these results, we discuss the evolution of the plant-bradyrhizobium association, including nonlegumes, in terms of photosynthetic lifestyle and nod-independent interactions. © 2015, American Society for Microbiology. Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84927784735&doi=10.1128%2fAEM.04253-14&partnerID=40&md5=b777c60dc74fc0142194f92cafd1d20a DOI: 10.1128/AEM.04253-14
2015	Proposed some interactions at molecular level of PGPR coinoculated with Bradyrhizobium diazoefficiens USDA110 and B. japonicum THA6 on soybean symbiosis and its potential of field application Prakamhang J., Tittabutr P., Boonkerd N., Teamtisong K., Uchiumi T., Abe M., Teaumroong N.	Applied Soil Ecology
Abstract: The objectives of this research were to select the appropriate plant growth promoting rhizobacteria (PGPR) and evaluate their influence in promoting nodulation and N2-fixing efficiency of soybean (Glycine max) by coinoculation with Bradyrhizobium diazoefficiens USDA110 and B. japonicum THA6 strains. Selected 12 PGPR performed a significant capability of promoting N2-fixation, nodule number, nodule and plant dry weight with both of the commercial bradyrhizobial strains, USDA110 and THA6 (P<0.05). Furthermore, isolates S141 and S222, which are closely related to Bacillus subtilis and Staphylococcus sp., were selected for coinoculation with USDA110 and THA6. The effective coinoculation doses of PGPR:Bradyrhizobium on soybean were 106:106 colony forming unit (CFU)ml-1seed-1. The expression levels of soybean and Bradyrhizobium related genes including Glyma17g07330, otsA, phbC, dctA and nifH in nodule discontinuously triggered both up- and down-regulation at different time frames (2-7 WAI). The transmission electron microscopy (TEM) micrograph of coinoculated soybean nodule showed the compact cluster of bacteroids which was densely packed with poly-ß-hydroxybutyrate (PHB) granules. The amounts of PHBs remained in mature nodule of coinoculation treatments whilst single inoculation nodules were senescence. The induction of soybean root subsequently increased the nodulation signaling and then activated the trehalose accumulation and the transport of carbon that represented an increase in PHB accumulation, resulting in the enhancement of the nodulation and N2-fixation in soybean. These results were accordingly related with phenotypic characters in Leonard's jar experiment in terms of enhancing the nodulation and N2-fixation in soybean. The effect of coinoculation experiment under field condition could increase 9.7-43.6% of seed yield per hectare which was higher than those of uninoculation or single inoculation of PGPR or Bradyrhizobium. Therefore, the efficiency to enhance soybean N2-fixation by coinoculation of S141 and S222 with Bradyrhizobium strategy could be developed for supreme soybean inoculants. © 2014 Elsevier B.V. Keyword: B. diazoefficiens; Bradyrhizobium japonicum; Coinoculation; PGPR Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84907259229&doi=10.1016%2fj.apsoil.2014.08.009&partnerID=40&md5=eaf65502f9d6ebb97da7c18c2c0136e3 DOI: 10.1016/j.apsoil.2014.08.009
2014	Divergent Nod-containing Bradyrhizobium sp. DOA9 with a megaplasmid and its host range Teamtisong K., Songwattana P., Noisangiam R., Piromyou P., Boonkerd N., Tittabutr P., Minamisawa K., Nantagij A., Okazaki S., Abe M., Uchiumi T., Teaumroong N.	Microbes and Environments
Abstract: Bradyrhizobium sp. DOA9, a non-photosynthetic bacterial strain originally isolated from the root nodules of the legume Aeschynomene americana, is a divergent nod-containing strain. It exhibits a broad host range, being able to colonize and efficiently nodulate the roots of most plants from the Dalbergioid, Millettioid, and Robinioid tribes (7 species of Papilionoideae). In all cases, nodulation was determinate. The morphology and size of DOA9 bacteroids isolated from the nodules of various species of Papilionoideae were indistinguishable from the free-living form. However, they were spherical in Arachis hypogaea nodules. GusA-tagged DOA9 also colonized rice roots as endophytes. Since broad-host-range legume symbionts often carry multiple replicons in their genome, we analyzed the replicons for symbiosis genes by electrophoresis. DOA9 carried two replicons, a chromosome (cDOA9) and single megaplasmid (pDOA9) larger than 352 kb. The genes for nodulation (nodA, B, C) and nitrogen fixation (nifH) were localized on the megaplasmid. Southern blot hybridization revealed two copies of nodA on the megaplasmid, single copies of nodB and C on the megaplasmid, and one copy each of nifH on the chromosome and megaplasmid. These results suggested that Bradyrhizobium sp. DOA9 may have the unusual combination of a broad host range, bacteroid differentiation, and symbiosis-mediating replicons. © 2014, Japanese Society of Microbial Ecology. All rights received. Keyword: Aeschynomene americana; Bradyrhizobium; Broad host range; Megaplasmid Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84919461948&doi=10.1264%2fjsme2.ME14065&partnerID=40&md5=98a1ecc0d8f566da4112ed3b87c2d564 DOI: 10.1264/jsme2.ME14065
2014	Biases for detecting arbuscular mycorrhizal fungal mixture by terminal restriction fragment length polymorphism (T-RFLP) Watanarojanaporn N., Longtonglang A., Boonkerd N., Tittabutr P., Lee J., Teaumroong N.	World Journal of Microbiology and Biotechnology
Abstract: Terminal restriction fragment length polymorphism (T-RFLP) analysis of amplified ribosomal RNA genes is used for profiling microbial communities and sometimes for species richness and relative abundance estimation in environmental samples. However, the T-RFLP fingerprint may be subject to biases during the procedure, influencing the detection of real community structures in the environment. To investigate possible sources of T-RFLP bias, 18S rRNA gene clones derived from two arbuscular mycorrhizal fungal sequences were combined in simple pairwise mixes to assess the effects of polymerase chain reaction cycle number, plant genomic DNA purification method and varying template ratio on the template-to-product ratio as measured by relative T-RF peak area. Varying cycle numbers indicated that amplification was still in the exponential phase at the cycle numbers lower than 18, so these small cycle numbers were used for the comparison of template-to-product quantities. Relative abundance estimated from T-RF peak ratios varied with different purification procedures, but the best results, closest to input ratios, were obtained by using phenol-chloroform purification. The presence of an excess of unpurified non-target plant genomic DNA generated a bias towards lower or overestimation of relative abundance. We conclude that a low number of amplification cycles and stringent DNA purification are necessary for accurate mixed sample analysis by T-RFLP. © 2013 Springer Science+Business Media Dordrecht. Keyword: AMF plasmid DNA; Pairwise mixes; Plant genomic DNA; T-RFLP; T-RFs peak area Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891660066&doi=10.1007%2fs11274-013-1423-0&partnerID=40&md5=c7d04d8cd1bcbd16651ec04627774693 DOI: 10.1007/s11274-013-1423-0
2013	Effect of rice cultivation systems on indigenous arbuscular mycorrhizal fungal community structure Watanarojanaporn N., Boonkerd N., Tittabutr P., Longtonglang A., Young J.P.W., Teaumroong N.	Microbes and Environments
Abstract: Arbuscular mycorrhizal fungi (AMF) in an agricultural ecosystem are necessary for proper management of beneficial symbiosis. Here we explored how the patterns of the AMF community in rice roots were affected by rice cultivation systems (the system of rice intensification [SRI] and the conventional rice cultivation system [CS]), and by compost application during growth stages. Rice plants harvested from SRI-managed plots exhibited considerably higher total biomass, root dry weight, and seed fill than those obtained from conventionally managed plots. Our findings revealed that all AMF sequences observed from CS plots belonged (only) to the genus Glomus, colonizing in rice roots grown under this type of cultivation, while rice roots sown in SRI showed sequences belonging to both Glomus and Acaulospora. The AMF community was compared between the different cultivation types (CS and SRI) and compost applications by principle component analysis. In all rice growth stages, AMF assemblages of CS management were not separated from those of SRI management. The distribution of AMF community composition based on T-RFLP data showed that the AMF community structure was different among four cultivation systems, and there was a gradual increase of Shannon-Weaver indices of diversity (H') of the AMF community under SRI during growth stages. The results of this research indicated that rice grown in SRI-managed plots had more diverse AMF communities than those grown in CS plots. Keyword: Arbuscular mycorrhizal fungi; Compost application; Cultivation systems; Oryza sativa; Terminal restriction fragment length polymorphism (T-RFLP) Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84884469910&doi=10.1264%2fjsme2.ME13011&partnerID=40&md5=f93604c1a745fbc7fcafe56de73dc207 DOI: 10.1264/jsme2.ME13011
2013	Alleviation of the effect of environmental stresses using co-inoculation of mungbean by Bradyrhizobium and rhizobacteria containing stress-induced ACC deaminase enzyme Tittabutr P., Piromyou P., Longtonglang A., Noisa-Ngiam R., Boonkerd N., Teaumroong N.	Soil Science and Plant Nutrition
Abstract: Ethylene is synthesized at accelerated rate in response to stress conditions, and regarded as a stress hormone that inhibits overall plant growth. Apparently, the amount of ethylene can be reduced by using silver thiosulfate (STS) or bacteria containing 1-amino-cyclopropane-1-carboxylate (ACC) deaminase. In this study, we examined whether different concentrations of STS differently prevent legume growth under various environment stress conditions, and whether co-inoculation of mungbean (Vigna radiata (L.) R. Wilczek) by Bradyrhizobium and rhizobacteria containing ACC deaminase also alleviates legume stress. Mungbean is one of the most responsive plants among tested legume species, and different varieties of mungbean also respond differently to STS. Stress conditions and inappropriate concentrations of STS affect plant growth and symbiosis, while a suitable concentration of STS supports plant growth under stress conditions. Three isolates of bacteria containing ACC deaminase, Enterobacter sp. ACC1, Enterobacter sp. ACC2, and Chryseobacterium sp. ACC3, were selected according to their ACC deaminase activity and resistance abilities to high temperature, drought, and salt stress conditions. Interestingly, the gene encoding ACC deaminase, acdS, of selected ACC deaminase bacteria was highly induced when the cell culture was exposed to stress conditions. It coincided with co-inoculation of plants by Bradyrhizobium and rhizobacteria containing ACC deaminase. This co-inoculation obviously alleviated the stress of plants growing under stress conditions. These results revealed the role of bacteria containing ACC deaminase that can adjust its expression of ACC deaminase to different levels of stress conditions, which will be useful in agriculture under global warming. © 2013 Japanese Society of Soil Science and Plant Nutrition. Keyword: ACC deaminase; Environmental stresses; Legume species; Silver thiosulfate; Stress inducing acdS Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84890206996&doi=10.1080%2f00380768.2013.804391&partnerID=40&md5=8a05f5731afbafb422e6e08a01607de4 DOI: 10.1080/00380768.2013.804391