Assoc.Prof. Panlada Tittabutr

Year	Title	Journal
2023	Selection and evaluation of Bradyrhizobium inoculum for peanut, Arachis hypogea production in the Lao People’s Democratic Republic Phimphong T., Sibounnavong P., Phommalath S., Wongdee J., Songwattana P., Piromyou P., Greetatorn T., Boonkerd N., Tittabutr P., Teaumroong N.	Journal of Applied and Natural Science
Abstract: The interaction between leguminous plants and Bradyrhizobium is limited, known as host specificity. Therefore, the selection of an appropriate Bradyrhizobia for use as biofertilizer inoculum for legumes is necessary. The Arachis hypogea L. is the most popular legume produced in the Lao People's Democratic Republic (PDR). Therefore, this research aimed to obtain the appropriate Bradyrhizobia that provides high efficiency in A. hypogea production in the Lao PDR. The 14 isolates were obtained from root nodules of A. hypogea L. trapped with Lao PDR soil samples. Three were the top isolates PMVTL-01, SMVTL-02, and BLXBL-03 showing high efficiency for peanut growth promotion. Strains PMVTL-01 and SMVTL-02 were closely related to the Bradyrhizobium geno sp. SA-3 Rp7b and B. zhanjiangense, respectively, whilst strain BLXBL-03 was closely related to Brady-rhizobium sp. CCBAU51745 and B. manausense BR3351. The competitiveness of these strains with Bradyrhizobium sp. SUT-N9-2::GFP was analyzed, and only Bradyrhizobium sp. SMVTL-02 performed a number of occupied nodules higher than SUT-N9-2::GFP. In addition, the competitiveness of the selected strain Bradyrhizobium sp. SMVTL-02 in a soil sample from the Lao PDR in the pot level was employed by tagging the SMVTL-02 with the DsRed gene. The results demonstrated that the DsRed-expressing tagged strain showed higher nodule occupancy than indigenous strains. Moreover, the results of the acetylene reduction assay (ARA), nodule number, nodule dry weight, and total plant dry weight from the pot experiment that inoculated with the SMVTL-02::DsRed were presented as having high potential to promote peanut growth as compared to non-inoculation. Thus, Bradyrhizobium sp. SMVTL-02 could be considered a potential biofertilizer inoculum for A. hypogea production in the Lao PDR. © 2023, Applied and Natural Science Foundation. All rights reserved. Keyword: Arachis hypogea L; Biofertilizer; Bradyrhizobium sp; Inoculum; Isolation; Nitrogen fixation Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85151355669&doi=10.31018%2fjans.v15i1.4270&partnerID=40&md5=1a43795c340d0d368b91e94c10223fc0 DOI: 10.31018/jans.v15i1.4270
2023	Role of two RpoN in Bradyrhizobium sp. strain DOA9 in symbiosis and free-living growth Wongdee J., Piromyou P., Songwattana P., Greetatorn T., Teaumroong N., Boonkerd N., Giraud E., Nouwen N., Tittabutr P.	Frontiers in Microbiology
Abstract: RpoN is an alternative sigma factor (sigma 54) that recruits the core RNA polymerase to promoters of genes. In bacteria, RpoN has diverse physiological functions. In rhizobia, RpoN plays a key role in the transcription of nitrogen fixation (nif) genes. The Bradyrhizobium sp. DOA9 strain contains a chromosomal (c) and plasmid (p) encoded RpoN protein. We used single and double rpoN mutants and reporter strains to investigate the role of the two RpoN proteins under free-living and symbiotic conditions. We observed that the inactivation of rpoNc or rpoNp severely impacts the physiology of the bacteria under free-living conditions, such as the bacterial motility, carbon and nitrogen utilization profiles, exopolysaccharide (EPS) production, and biofilm formation. However, free-living nitrogen fixation appears to be under the primary control of RpoNc. Interestingly, drastic effects of rpoNc and rpoNp mutations were also observed during symbiosis with Aeschynomene americana. Indeed, inoculation with rpoNp, rpoNc, and double rpoN mutant strains resulted in decreases of 39, 64, and 82% in the number of nodules, respectively, as well as a reduction in nitrogen fixation efficiency and a loss of the bacterium’s ability to survive intracellularly. Taken together, the results show that the chromosomal and plasmid encoded RpoN proteins in the DOA9 strain both play a pleiotropic role during free-living and symbiotic states. Copyright © 2023 Wongdee, Piromyou, Songwattana, Greetatorn, Teaumroong, Boonkerd, Giraud, Nouwen and Tittabutr. Keyword: Bradyrhizobium; extracellular polysaccharide; free-living; nitrogen fixation; nodulation; RpoN; symbiosis Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149634963&doi=10.3389%2ffmicb.2023.1131860&partnerID=40&md5=1eff8b23ad52ebcb7f0cdb7be3f78dc3 DOI: 10.3389/fmicb.2023.1131860
2022	Nod-Factor structure and functional redundancy of nod genes contribute the broad host range Bradyrhizobium sp. DOA9 Wulandari D., Songwattana P., Gressent F., Piromyou P., Teamtisong K., Boonkerd N., Giraud E., Tittabutr P., Teaumroong N.	Rhizosphere
Abstract: Bradyrhizobium sp. DOA9 has a broad host range and a highly divergent nodulation (nod) gene on the megaplasmid (pDOA9). Duplicated copies of the general regulator nodD (nodD1 and nodD2) and nodA (nodA1 and nodA2) genes were found on pDOA9. The nodA gene is encoding an acyltransferase that controls the transfer of an acyl chain to the chitooligosaccharides (COs) structure and contribute to the determination of host specify. In general, compatible recognition between transcriptional regulators NodD and plant flavonoid inducer able to activate the function of other nodulation (nod) genes which responsible to produce lipo-chitooligosaccharides (LCOs), calls Nod-Factor, a major determinants of host range, infection, and nodulation. In this study, the function of the duplicated nodD (nodD1 and nodD2) and nodA (nodA1 and nodA2) genes were disrupted to determine their role on the symbiotic nodulation. The results showed that the mutation of nodD1 or nodD2 did not affected to the symbiotic nodulation, indicating the functional redundancy of the regulatory nodD1 and nodD2 genes in strain DOA9. Whereas nodA2 and nodB genes plays as a central role in the Nod-Factor biosynthesis and the symbiotic nodulation in all plant tests. Moreover, Nod-Factor produced from DOA9 under genistein induction shared a high similarity with the major Nod-Factor of Rhizobium sp. NGR234. Interestingly, mutation of nodA1 (ΔnodA1) did not affect to the nodulation but lead to induce the production of Nod-Factor belonged to the wild type, with the absence of Nod-Factor bearing the C18:1 acyl group. All these results suggest that the host range of the strain DOA9 might acquire from the functional redundancy of regulatory nodD genes and the Nod-Factor structure. © 2022 Elsevier B.V. Keyword: Leguminous plant; nodA; nodD; Nodulation; Nodulation genes; Symbiosis Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85126526299&doi=10.1016%2fj.rhisph.2022.100503&partnerID=40&md5=09821a14e1261e5f2837765c93d09aa6 DOI: 10.1016/j.rhisph.2022.100503
2021	Application of Recombinant Human scFv Antibody as a Powerful Tool to Monitor Nitrogen Fixing Biofertilizer in Rice and Legume Khaing K.K., Rangnoi K., Michlits H., Boonkerd N., Teaumroong N., Tittabutr P., Yamabhai M.	Microbiology Spectrum
Abstract: Bradyrhizobium is an endophytic bacterium under investigation as an efficient biofertilizer for sustainable legume-rice rotational cropping system. Monitoring and bioimaging of this nitrogen fixing bacterium is essential for the study of plant-microbe evolution, soil microbiome, as well as quality control in organic farming. While phage display antibody technology has been widely used to generate recombinant antibody for myriad medical purposes, so far, this technology has been minimally applied in the agricultural sector. In this study, single-chain variable fragments (scFv) against two Bradyrhizobium strains SUTN9-2 (yiN92-1e10) and DOA9 (yiDOA9-162) were isolated from a human phage display antibody library. Specific binding of scFv was demonstrated by ELISA and confocalimmunofluorescence imaging techniques. Bradyrhizobium localization in both endophytic and bacteroid forms could be observed inside rice tissue and plant nodule, respectively. Moreover, successful application of the recombinant antibody for the evaluation of nodule occupancy was also demonstrated in comparison with standard GUS-staining method. The results of this study showed for the first time the potential use of human phage display scFv antibody for imaging and monitoring of Bradyrhizobium biofertilizer and thus could be further applied for point-of-detection of bacterial inoculum in the legume-rice rotational crop system. IMPORTANCE Human scFv antibody generated from phage display technology was successfully used for the generation of specific recombinant antibodies: yiN92-1e10 and yiDOA9-162 for the detection of Bradyrhizobium strains SUTN9-2 and DOA9, respectively. These two recombinant scFv antibodies could be used for precise detection of the rhizobia both in symbiosis with legume and endophyte in rice tissue by ELISA and immunofluorescent staining, during legume-rice rotational cropping system in the field. This methodology can be further employed for the study of other plant-microbe interactions and monitoring of biofertilizer in diverse sustainable cropping systems as well as in precision agriculture. Copyright © 2021 Khaing et al. Keyword: Antibody; Biofertilizer; Bradyrhizobium; Endophyte; Nitrogen fixation; Phage display; Rice-legume; ScFv; Symbiosis Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85122822752&doi=10.1128%2fSPECTRUM.02094-21&partnerID=40&md5=3b8cfb9dbf32e6912a87a2c36155616d DOI: 10.1128/SPECTRUM.02094-21
2021	Publisher Correction: Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species (Scientific Reports, (2021), 11, 1, (4874), 10.1038/s41598-021-84205-w) Songwattana P., Chaintreuil C., Wongdee J., Teulet A., Mbaye M., Piromyou P., Gully D., Fardoux J., Zoumman A.M.A., Camuel A., Tittabutr P., Teaumroong N., Giraud E.	Scientific Reports
Abstract: The original PDF version of this Article contained an error where part of the sentence “Considering that the T3SS has been shown to bypass the requirement of NF signalling during the interactions of some Bradyrhizobium strains including ORS3257 with some tropical legumes15,16, we constructed a mutant in which the nodABC genes were deleted and analysed its symbiotic properties.” was incorrectly placed next to Figure 1. This error has now been corrected in the PDF version of the Article; the HTML version was correct from the time of publication. © 2021, The Author(s). Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107627490&doi=10.1038%2fs41598-021-91376-z&partnerID=40&md5=9e1e4d5754960e27d3b8f74aeb6a106e DOI: 10.1038/s41598-021-91376-z
2021	Identification of type III effectors modulating the symbiotic properties of Bradyrhizobium vignae strain ORS3257 with various Vigna species Songwattana P., Chaintreuil C., Wongdee J., Teulet A., Mbaye M., Piromyou P., Gully D., Fardoux J., Zoumman A.M.A., Camuel A., Tittabutr P., Teaumroong N., Giraud E.	Scientific Reports
Abstract: The Bradyrhizobium vignae strain ORS3257 is an elite strain recommended for cowpea inoculation in Senegal. This strain was recently shown to establish symbioses on some Aeschynomene species using a cocktail of Type III effectors (T3Es) secreted by the T3SS machinery. In this study, using a collection of mutants in different T3Es genes, we sought to identify the effectors that modulate the symbiotic properties of ORS3257 in three Vigna species (V. unguiculata, V. radiata and V. mungo). While the T3SS had a positive impact on the symbiotic efficiency of the strain in V. unguiculata and V. mungo, it blocked symbiosis with V. radiata. The combination of effectors promoting nodulation in V. unguiculata and V. mungo differed, in both cases, NopT and NopAB were involved, suggesting they are key determinants for nodulation, and to a lesser extent, NopM1 and NopP1, which are additionally required for optimal symbiosis with V. mungo. In contrast, only one effector, NopP2, was identified as the cause of the incompatibility between ORS3257 and V. radiata. The identification of key effectors which promote symbiotic efficiency or render the interaction incompatible is important for the development of inoculation strategies to improve the growth of Vigna species cultivated in Africa and Asia. © 2021, The Author(s). Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85102227229&doi=10.1038%2fs41598-021-84205-w&partnerID=40&md5=3e27200b992b282f3a1ebfc824c6875d DOI: 10.1038/s41598-021-84205-w
2021	Investigation of microbial community structure and its potential for biomethane production by co-digestion of cassava pulp and distillery stillage Witchayapong C., Piromyou P., Boontawan P., Tittabutr P., Boontawan A.	Environmental Progress and Sustainable Energy
Abstract: Cassava pulp (CP), a by-product of the tapioca starch industry, has been recognized as a high potential substrate for bio-gas production due to its high carbon content. In this work, co-digestion between CP and distiller stillage (DS) was investigated with the main objective to improve the system stability as well as to enhance the biogas production. The effect of five different CP:DS ratios including 1:0, 1:0.5, 1:1, 0.5:1, and 0:1 based on volatile solids (VS) was carried out. The result showed that the co-digestion of CP and DS is a promising approach for increasing the cumulative methane yield by 65.57%–222.19% compared to the digestion of CP alone. The highest methane yield of 685.10 ml/g VS was obtained at the CP:DS of 1:1. The bacterial and archaeal communities were analyzed by denaturing gradient gel electrophoresis. The bacterial community of CP:DS ratio was dominated by Bacteroidetes, Firmicutes, and Chloroflexi phylum whilst Methanosarcina (Methanosarcina barkeri) dominated the methanogenic archaeal community. This work demonstrated the adaptation of co-digestion resulting in a higher methane production with a higher stability of the system. The result could pave a way for a highly efficient co-digestion system in a larger scale biogas production. © 2021 American Institute of Chemical Engineers. Keyword: anaerobic co-digestion; biomethane production; cassava pulp; distillery stillage; microbial community structure Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85107341257&doi=10.1002%2fep.13695&partnerID=40&md5=1693f2f755444d46ed910df4b5a8c0ed DOI: 10.1002/ep.13695
2021	Enhancing the efficiency of soybean inoculant for nodulation under multi-environmental stress conditions Wongdee J., Yuttavanichakul W., Longthonglang A., Teamtisong K., Boonkerd N., Teaumroong N., Tittabutr P.	Polish Journal of Microbiology
Abstract: The development of rhizobial inoculants with increased resistance to abiotic stress is critical to mitigating the challenges related to climate change. This study aims at developing a soybean stress-Tolerant Bradyrhizobium inoculant to be used under the mixed stress conditions of acidity, high temperature, and drought. Six isolates of Bradyrhizobium with high symbiotic performance on soybean were tested to determine their growth or survival abilities under in vitro conditions. The representative stress-Tolerant Bradyrhizobium isolates 184, 188, and 194 were selected to test their ability to promote soybean growth under stress conditions compared to the type strain Bradyrhizobium diazoefficiens USDA110. The plant experiment indicated that isolate 194 performed better in symbiosis with soybean than other Bradyrhizobium strains under stress conditions. Based on the stress tolerance index, soybeans inoculated with isolate 194 showed a high growth performance and significantly better nodulation competition ability than USDA110 under several stress conditions. Interestingly, supplementation of sucrose in the culture medium significantly enhances the survival of the isolate and leads to improved plant biomass under various stress conditions. Analysis of the intra-cellular sugars of isolate 194 supplemented with sucrose showed the accumulation of compatible solutes, such as trehalose and glycerol, that may act as osmoprotectants. This study indicates that inoculation of stress-Tolerant Bradyrhizobium together with sucrose supplementation in a medium could enhance bacterial survival and symbiosis efficiency under stress conditions. Although it can be applied for inoculant production, this strategy requires validation of its performance in field conditions before adopting this technology. © 2021 Polish Society of Microbiologists. All rights reserved. Keyword: Bradyrhizobium; Compatible solutes; Nodulation competition; Osmoprotectant; Stress conditions Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109611801&doi=10.33073%2fPJM-2021-024&partnerID=40&md5=d48f8bbe7f38ff2bcca05c2e0bf07961 DOI: 10.33073/PJM-2021-024
2020	Assessment of biofertilizer use for sustainable agriculture in the Great Mekong Region Atieno M., Herrmann L., Nguyen H.T., Phan H.T., Nguyen N.K., Srean P., Than M.M., Zhiyong R., Tittabutr P., Shutsrirung A., Bräu L., Lesueur D.	Journal of Environmental Management
Abstract: A growing concern on the deleterious effects of chemical inputs to the environment has been on the rise from the excessive use of chemical inputs leading to soil and water pollution, destruction to fauna and microbial communities, reduced soil fertility and increased crop disease susceptibility. In the Great Mekong Region (GMR), a large majority of the population relies on agriculture and faces severe challenges including decline in soil fertility, increased pests and diseases, leading to lower ecosystem productivity. In this region, over-dependence on chemical fertilizers also continues to impact negatively on soil health and the wider ecosystem. Agroecological practices, and beneficial microorganisms in particular, offer an affordable and sustainable alternative to mineral inputs for improved plant nutrition and soil health for optimal crop performance and sustainable production. Biofertilizers are a key component in integrated nutrient management as well as for increased economic benefits from reduced expenditure on chemical fertilizers, holistically leading to sustainable agriculture. To cope with the need for biofertilizer adoption for sustainable agricultural production, the countries in the GMR are putting efforts in promoting development and use of biofertilizers and making them available to farmers at affordable costs. Despite these efforts, farmers continue to use chemical fertilizers at high rates with the hope of increased yields instead of taking advantage of microbial products capable of providing plant nutrients while restoring or improving soil health. This study explored the current agricultural practices in the six countries in the GMR (China, Vietnam, Myanmar, Thailand, Cambodia and Lao PDR), the critical need for sustainable agroecological practices with a special emphasis on biofertilizers. We highlighted the current status, distribution, adoption and gaps of biofertilizer production in the GMR, in order to obtain an insight on the nature of biofertilizers, efficacy and production standards, adoption or lack of biofertilizers in the GMR. © 2020 Elsevier Ltd Keyword: Agroecological practices; Biofertilizers; Great Mekong Region; Soil health Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089913788&doi=10.1016%2fj.jenvman.2020.111300&partnerID=40&md5=1d11e14bfc5c7aa0b8bfbfd26d2f7c20 DOI: 10.1016/j.jenvman.2020.111300
2020	Secretion compounds from Brevibacillus sp. SUT47 promote spore propagation of Acaulospora tuberculata colonizing maize roots (Zea mays L. cultivar Suwan 5) Kiddee S., Yuttavanichakul W., Boonkerd N., Teaumroong N., Saito K., Tittabutr P.	ScienceAsia
Abstract: The substrate-based production system has been widely applied for farm arbuscular mycorrhizal fungi (AMF) inoculum production. Plant growth promoting rhizobacterium (PGPR), Brevibacillus sp. SUT47 has been discovered to promote AMF spore production when co-inoculating on maize roots. However, the application of whole cell bacteria may cause the adverse outcome with contamination of bacterial cells in AMF inoculum. In order to avoid the bacterial cell contamination, we attempted to develop a new methodology using the bacterial secretion compounds as an optional technique to promote AMF spore production in maize roots. Secretion compounds of strain SUT47 were concentrated by freeze-drying and co-inoculated with the spores of Acaulospora tuberculata on maize seedling. The results showed that the bacterial secretion compounds promoted AMF spore production. The highest number of spores was produced when 360 mg of concentrated secretion compounds were applied. In contrast, the significant reduction of spore number was found when the secretion compounds at the concentration higher than 360 mg were applied. These results indicate the production of AMF spore was responded to concentration of bacterial secretion compounds which possibly contain an effective substance to promote AMF spore propagation. © 2020 Science Society of Thailand under Royal Patronage. All rights reserved. Keyword: Acaulospora tuberculata; Brevibacillus sp; Secretion compounds; Spore propagation Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095778828&doi=10.2306%2fSCIENCEASIA1513-1874.2020.073&partnerID=40&md5=8255841910d2471000053078341e99bb DOI: 10.2306/SCIENCEASIA1513-1874.2020.073