Assoc.Prof. Panlada Tittabutr

Year	Title	Journal
2020	Co-inoculation of bacillus velezensis strain s141 and bradyrhizobium strains promotes nodule growth and nitrogen fixation Sibponkrung S., Kondo T., Tanaka K., Tittabutr P., Boonkerd N., Yoshida K.-I., Teaumroong N.	Microorganisms
Abstract: The objective of this research was to evaluate the PGPR effect on nodulation and nitrogen-fixing efficiency of soybean (Glycine max (L.) Merr.) by co-inoculation with Bradyrhizobium diazoefficiens USDA110. Co-inoculation of Bacillus velezensis S141 with USDA110 into soybean resulted in enhanced nodulation and N2-fixing efficiency by producing larger nodules. To understand the role of S141 on soybean and USDA110 symbiosis, putative genes related to IAA biosynthesis were disrupted, suggesting that co-inoculation of USDA110 with S141∆yhcX reduces the number of large size nodules. It was revealed that yhcX may play a major role in IAA biosynthesis in S141 as well as provide a major impact on soybean growth promotion. The disruption of genes related to cytokinin biosynthesis and co-inoculation of USDA110 with S141∆IPI reduced the number of very large size nodules, and it appears that IPI might play an important role in nodule size of soybean–Bradyrhizobium symbiosis. However, it was possible that not only IAA and cytokinin but also some other substances secreted from S141 facilitate Bradyrhizobium to trigger bigger nodule formation, resulting in enhanced N2-fixation. Therefore, the ability of S141 with Bradyrhizobium co-inoculation to enhance soybean N2-fixation strategy could be further developed for supreme soybean inoculants. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. Keyword: Bradyrhizobium; Co-inoculation; Nodulation; PGPR; Soybean Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084360033&doi=10.3390%2fmicroorganisms8050678&partnerID=40&md5=f86e6f8a2b86286dda4ecaf2295f2e97 DOI: 10.3390/microorganisms8050678
2020	Application of rice endophytic Bradyrhizobium strain SUTN9-2 containing modified ACC deaminase to rice cultivation under water deficit conditions Sarapat S., Longtonglang A., Umnajkitikorn K., Girdthai T., Boonkerd N., Tittabutr P., Teaumroong N.	Journal of Plant Interactions
Abstract: Bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase is a key factor for alleviating the plant ethylene biosynthesis, which is induced by stress. The ACC deaminase-improved strains of the rice endophytic Bradyrhizobium sp. SUTN9-2, SUTN9-2 (ACCDadap) and SUTN9-2:pMG103::acdRS, exhibit 1.4- and 8.9-fold higher ACC deaminase activity than the wild type, respectively (Sarapat S, Songwattana P, Longtonglang A, Umnajkitikorn K, Girdthai T, Tittabutr P, Boonkerd N, Teaumroong N. 2020. Effects of Increased 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase Activity in Bradyrhizobium sp. SUTN9-2 on Mung Bean Symbiosis under Water Deficit Conditions. Microbes Environ. 35). The effects of these on rice growth under water deficit conditions were evaluated. The bacterial inoculations reduced ethylene synthesis, leading to a reduction in membrane destruction and the chlorophyll content of rice. Furthermore, the bacterial inoculations improved the leaf relative water content, survival, recovery rates, and improved the crop yield in field conditions. Therefore, the water deficit tolerance of rice was improved by controlling ethylene biosynthesis by improving ACC deaminase activity with endophytic SUTN9-2. Moreover, the SUTN9-2 (ACCDadap) strain can be used as a bio-inoculant under field conditions to enhance rice growth, grain yield, and enhance drought tolerance. © 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. Keyword: 1-aminocyclopropane-1-carboxylate (ACC) deaminase; Bradyrhizobium sp. SUTN9-2; rice; rice endophytic bacteria; water deficit conditions Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85092003762&doi=10.1080%2f17429145.2020.1824028&partnerID=40&md5=8f3c9eba0e1981e7d5a6daa07659e422 DOI: 10.1080/17429145.2020.1824028
2020	Mechanisms of rice endophytic bradyrhizobial cell differentiation and its role in nitrogen fixation Greetatorn T., Hashimoto S., Maeda T., Fukudome M., Piromyou P., Teamtisong K., Tittabutr P., Boonkerd N., Kawaguchi M., Uchiumi T., Teaumroong N.	Microbes and Environments
Abstract: Bradyrhizobium sp. strain SUTN9-2 is a symbiotic and endophytic diazotrophic bacterium found in legume and rice plants and has the potential to promote growth. The present results revealed that SUTN9-2 underwent cell enlargement, increased its DNA content, and efficiently performed nitrogen fixation in response to rice extract. Some factors in rice extract induced the expression of cell cycle and nitrogen fixation genes. According to differentially expressed genes (DEGs) from the transcriptomic analysis, SUTN9-2 was affected by rice extract and the deletion of the bclA gene. The up-regulated DEGs encoding a class of oxidoreductases, which act with oxygen atoms and may have a role in controlling oxygen at an appropriate level for nitrogenase activity, followed by GroESL chaperonins are required for the function of nitrogenase. These results indicate that following its exposure to rice extract, nitrogen fixation by SUTN9-2 is induced by the collective effects of GroESL and oxidoreductases. The expression of the sensitivity to antimicrobial peptides transporter (sapDF) was also up-regulated, resulting in cell differentiation, even when bclA (sapDF) was mutated. This result implies similarities in the production of defensin-like antimicrobial peptides (DEFs) by rice and nodule-specific cysteine-rich (NCR) peptides in legume plants, which affect bacterial cell differentiation. © 2020, Japanese Society of Microbial Ecology. All rights reserved. Keyword: Bradyrhizobium; Cell differentiation; Endophyte; Nitrogen fixation; Rice Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088852241&doi=10.1264%2fjsme2.ME20049&partnerID=40&md5=c4fdd3548afe8b5c1d7a857a3b424ea7 DOI: 10.1264/jsme2.ME20049
2020	Type III secretion system of bradyrhizobium sp. Sutn9-2 obstructs symbiosis with lotus spp. Hashimoto S., Goto K., Pyromyou P., Songwattana P., Greetatorn T., Tittabutr P., Boonkerd N., Teaumroong N., Uchiumi T.	Microbes and Environments
Abstract: The rhizobial type III secretion system secretes effector proteins into host plant cells, which may either promote or inhibit symbiosis with legumes. We herein demonstrated that the type III secretion system of Bradyrhizobium sp. SUTN9-2 obstructed symbiosis with Lotus japonicus Miyakojima, L. japonicus Gifu, and Lotus burttii. A mutant of SUTN9-2 that is unable to secrete effector proteins showed better nodulation and plant growth promotion than wild-type SUTN9-2 when paired with these Lotus spp. We propose that SUTN9-2 is a useful strain for understanding the mechanisms by which effector proteins obstruct symbiosis between Bradyrhizobium and Lotus spp. © 2020, Japanese Society of Microbial Ecology. All rights reserved. Keyword: Bradyrhizobium; Effector protein; Lotus spp; Symbiosis; Type III secretion system Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087393730&doi=10.1264%2fjsme2.ME20041&partnerID=40&md5=d7d713ca5a81574b2c38ad50f1b1de93 DOI: 10.1264/jsme2.ME20041
2020	Effects of increased 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity in Bradyrhizobium sp. SUTN9-2 on mung bean symbiosis under water deficit conditions Sarapat S., Songwattana P., Longtonglang A., Umnajkitikorn K., Girdthai T., Tittabutr P., Boonkerd N., Teaumroong N.	Microbes and Environments
Abstract: Bacteria exhibiting 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, which inhibits the biosynthesis of ethylene in higher plants, promote plant growth through the degradation of ethylene precursors, such as ACC. ACC deaminase activity in Bradyrhizobium sp. SUTN9-2 was enhanced by genetic engineering and adaptive laboratory evolution (ALE)-based methods. The transferal of a plasmid containing the acdR and acdS genes into SUTN9-2 was genetic engineering improved, while the ALE method was performed based on the accumulation of an adaptive bacterial population that continuously grew under specified growth conditions for a long time. ACC deaminase enzyme activity was 8.9–fold higher in SUTN9-2:pMG103::acdRS and 1.4–fold higher in SUTN9-2 (ACCDadap) than in the wild-type strain. The effects of increased activity were examined in the host plant (Vigna radiata (L.) R.Wilczek SUT1). The improved strains enhanced nodulation in early stage of plant growth. SUTN9-2:pMG103::acdRS also maintained nitrogen fixation under water deficit conditions and increased the plant biomass after rehydration. Changes in nucleotides and amino acids in the AcdS protein of SUTN9-2 (ACCDadap) were then investigated. Some nucleotides predicted to be located in the ACC-binding site were mutated. These mutations may have increased ACC deaminase activity, which enhanced both symbiotic interactions and drought tolerance and promoted recovery after rehydration more than lower ACC deaminase activity. Adaptive evolution represents a promising strategy for further applications in the field. © 2020, Japanese Society of Microbial Ecology. All rights reserved. Keyword: 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity; Ethylene; Infection/nodulation; Vigna radiata; Water deficit conditions Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086690984&doi=10.1264%2fjsme2.ME20024&partnerID=40&md5=8053ae8e3bbb334e9d54af86870f12b2 DOI: 10.1264/jsme2.ME20024
2019	Symbiotic properties of a chimeric Nod-independent photosynthetic Bradyrhizobium strain obtained by conjugative transfer of a symbiotic plasmid Songwattana P., Tittabutr P., Wongdee J., Teamtisong K., Wulandari D., Teulet A., Fardoux J., Boonkerd N., Giraud E., Teaumroong N.	Environmental Microbiology
Abstract: The lateral transfer of symbiotic genes converting a predisposed soil bacteria into a legume symbiont has occurred repeatedly and independently during the evolution of rhizobia. We experimented the transfer of a symbiotic plasmid between Bradyrhizobium strains. The originality of the DOA9 donor is that it harbours a symbiotic mega-plasmid (pDOA9) containing nod, nif and T3SS genes while the ORS278 recipient has the unique property of inducing nodules on some Aeschynomene species in the absence of Nod factors (NFs). We observed that the chimeric strain ORS278-pDOA9* lost its ability to develop a functional symbiosis with Aeschynomene. indica and Aeschynomene evenia. The mutation of rhcN and nodB led to partial restoration of nodule efficiency, indicating that T3SS effectors and NFs block the establishment of the NF-independent symbiosis. Conversely, ORS278-pDOA9* strain acquired the ability to form nodules on Crotalaria juncea and Macroptillium artropurpureum but not on NF-dependent Aeschynomene (A. afraspera and A. americana), suggesting that the ORS278 strain also harbours incompatible factors that block the interaction with these species. These data indicate that the symbiotic properties of a chimeric rhizobia cannot be anticipated due to new combination of symbiotic and non-symbiotic determinants that may interfere during the interaction with the host plant. © 2019 Society for Applied Microbiology and John Wiley & Sons Ltd. Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066877554&doi=10.1111%2f1462-2920.14650&partnerID=40&md5=6dbf5cd4f25e45a7a1396a89d75739f1 DOI: 10.1111/1462-2920.14650
2019	Attitudes toward using e-courseware in a flipped classroom teaching and learning approach of Suranaree University of technology students in the application of biotechnology in crop production course Tantasawat P.A., Srisawat S., Damsugree N., Thepwichit A., Tittabutr P.	ACM International Conference Proceeding Series
Abstract: The objectives of this study were to survey 1) student attitudes, 2) student learning behaviors, and 3) satisfaction of students toward using e-Courseware in a flipped classroom teaching and learning approach of the 312340 Application of Biotechnology in Crop Production Course at Suranaree University of Technology. A sample group was obtained by purposive sampling and consisted of 44 fourth year undergraduate students in the School of Crop Production Technology who registered for the course in the first trimester of the academic year 2018. From the results of the questionnaire on student attitudes toward using e-Courseware in a flipped classroom teaching and learning approach, compared to the traditional lecture-based teaching and learning approach, using a 5 level rating scale (1 = the lowest to 5 = the highest), it was found that 37 students (84.1%) replied with significantly higher scores for their attitudes towards using e-Courseware in a flipped classroom approach compared to the traditional lecture-based approach in all aspects (p < 0.01) except learning difficulty (p = 0.104), resulting in a higher overall attitude score (4.36 ± 0.72), compared to that of the traditional lecture-based approach (3.01 ± 0.88). Although the score for learning difficulty, rated for using e-Courseware in a flipped classroom approach tended to be higher (3.71 ±0.93) than the score of 3.29 ±0.92 for a traditional lecture-based approach, 94.6% students still expressed their preference for using e-Courseware in a flipped classroom approach for future courses. From the behavior observation form for students using e-Courseware in a flipped classroom teaching and learning approach, using a 3 level rating scale (1 = low to 3 = high), it was found that learners' participation in the learning activities was at a high level (2.59 ±0.50) on average and learning behavior was also at a high level (2.63 ± 0.49) on average. The questionnaire on student satisfaction on using e-Courseware in a flipped classroom teaching and learning approach, using a 5 level rating scale (1 = the lowest to 5 = the highest) revealed that 32 students (72.7%) replied with the following ratings: for overall satisfaction, the rating was at the highest level (4.38 ±0.66), and for the usefulness of e-Courseware for teaching and learning, the rating was also at the highest level (4.59 ± 0.67). These results indicate positive attitudes, learning behaviors and satisfaction of the students toward using e-Courseware in a flipped classroom teaching and learning approach, suggesting the effectiveness and usefulness of this approach for improvements in future courses. © 2019 Association for Computing Machinery. Keyword: Attitude; E-Courseware; Flipped classroom; Learning behavior; Lecture-based; Satisfaction Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85074785554&doi=10.1145%2f3345120.3345162&partnerID=40&md5=e2b532240e4af4d3b7963607efec1c94 DOI: 10.1145/3345120.3345162
2019	Mutualistic co-evolution of T3SSs during the establishment of symbiotic relationships between Vigna radiata and Bradyrhizobia Piromyou P., Songwattana P., Teamtisong K., Tittabutr P., Boonkerd N., Tantasawat P.A., Giraud E., Göttfert M., Teaumroong N.	MicrobiologyOpen
Abstract: This study supports the idea that the evolution of type III secretion system (T3SS) is one of the factors that controls Vigna radiata–bradyrhizobia symbiosis. Based on phylogenetic tree data and gene arrangements, it seems that the T3SSs of the Thai bradyrhizobial strains SUTN9-2, DOA1, and DOA9 and the Senegalese strain ORS3257 may share the same origin. Therefore, strains SUTN9-2, DOA1, DOA9, and ORS3257 may have evolved their T3SSs independently from other bradyrhizobia, depending on biological and/or geological events. For functional analyses, the rhcJ genes of ORS3257, SUTN9-2, DOA9, and USDA110 were disrupted. These mutations had cultivar-specific effects on nodulation properties. The T3SSs of ORS3257 and DOA9 showed negative effects on V. radiata nodulation, while the T3SS of SUTN9-2 showed no effect on V. radiata symbiosis. In the roots of V. radiata CN72, the expression levels of the PR1 gene after inoculation with ORS3257 and DOA9 were significantly higher than those after inoculation with ORS3257 ΩT3SS, DOA9 ΩT3SS, and SUTN9-2. The T3Es from ORS3257 and DOA9 could trigger PR1 expression, which ultimately leads to abort nodulation. In contrast, the T3E from SUTN9-2 reduced PR1 expression. It seems that the mutualistic relationship between SUTN9-2 and V. radiata may have led to the selection of the most well-adapted combination of T3SS and symbiotic bradyrhizobial genotype. © 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd. Keyword: bradyrhizobial T3SS; mutualistic co-evolution; V. radiata–bradyrhizobia symbiosis Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85068512663&doi=10.1002%2fmbo3.781&partnerID=40&md5=67d93c1a9abf840e8bc0f7d55dc4492a DOI: 10.1002/mbo3.781
2019	Empowering rice seedling growth by endophytic Bradyrhizobium sp. SUTN9-2 Greetatorn T., Hashimoto S., Sarapat S., Tittabutr P., Boonkerd N., Uchiumi T., Teaumroong N.	Letters in Applied Microbiology
Abstract: Bradyrhizobium sp. strain SUTN9-2 was confirmed as rice endophytic bacteria and also as rice growth promotion agent. SUTN9-2 showed the capability of plant growth promotion characteristics, such as indole-3-acetic acid (IAA) and 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase productions and nitrogen fixation. In this study, the ability of SUTN9-2 to stimulate rice growth was investigated at different stages with N-free and NH4NO3 under in vivo condition. The rice dry weight and chlorophyll content could be enhanced when SUTN9-2 was inoculated in N-free, especially at seedling stage (7 and 14 dai). The rice dry weight was also increased when SUTN9-2 was inoculated with NH4NO3 at 7 and14 dai. The results of quantitative analysis of IAA and ACC deaminase were inconsistent with the expression of genes involved in IAA (nit) and ACC deaminase (acdS) productions. This inconsistently could implied that IAA and ACC deaminase produced from SUTN9-2 do not directly affect rice growth, but other factors resulting from the production of IAA and ACC deaminase could be involved. Moreover, the expression of genes involved in nitrogen fixation (nifH and nifV) of SUTN9-2 was also induced in rice tissues. This finding suggested that rice growth promotion may be supported by NH4NO3 together with nitrogen fixation by SUTN9-2. Significance and Impact of the Study: Indole-3-acetic acid, 1-amino-cyclopropane-1-carboxylic acid deaminase productions and nitrogen fixation may play important roles in rice growth promotion by endophytic SUTN9-2, especially at early rice seedling growth stage, which has the potential to be used as rice seedling growth promoter in the system of rice intensification. © 2019 The Society for Applied Microbiology Keyword: 1-amino-cyclopropane-1-carboxylic acid-deaminase; bradyrhizobia; early rice growth promotion; indole-3-acetic acid; nitrogen fixation Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061093607&doi=10.1111%2flam.13114&partnerID=40&md5=48a731f4c4df791cc37f461d33ff58e3 DOI: 10.1111/lam.13114
2019	Homocitrate synthase genes of two wide-host-range bradyrhizobium strains are differently required for symbiosis depending on host plants Hashimoto S., Wongdee J., Songwattana P., Greetatorn T., Goto K., Tittabutr P., Boonkerd N., Teaumroong N., Uchiumi T.	Microbes and Environments
Abstract: The nifV gene encodes homocitrate synthase, the enzyme that catalyzes the formation of homocitrate, which is essential for arranging the FeMo-cofactor in the catalytic center of nitrogenase. Some host plants, such as Lotus japonicus, supply homocitrate to their symbionts, in this case, Mesorhizobium loti, which lacks nifV. In contrast, Bradyrhizobium ORS285, a symbiont of Aeschynomene cross-inoculation (CI) groups 2 and 3, requires nifV for symbiosis with Aeschynomene species that belong to CI group 3, and some species belonging to CI group 2. However, it currently remains unclear whether rhizobial nifV is required for symbiosis with Aeschynomene species belonging to CI group 1 or with other legumes. We generated nifV-disruption (ΔnifV) mutants of two wide-host-range rhizobia, Bradyrhizobium SUTN9-2 and DOA9, to investigate whether they require nifV for symbiosis. Both ΔnifV mutant strains showed significantly less nitrogenase activity in a free-living state than the respective wild-type strains. The symbiotic phenotypes of SUTN9-2, DOA9, and their ΔnifV mutants were examined with four legumes, Aeschynomene americana, Stylosanthes hamata, Indigofera tinctoria, and Desmodium tortuosum. nifV was required for the efficient symbiosis of SUTN9-2 with A. americana (CI group 1), but not for that of DOA9. SUTN9-2 established symbiosis with all three other legumes; nifV was required for symbiosis with I. tinctoria and D. tortuosum. These results suggest that, in addition to Aeschynomene CI groups 2 and 3, CI group 1 and several other legumes require the rhizobial nifV for symbiosis. © 2019, Japanese Society of Microbial Ecology. All rights reserved. Keyword: Bradyrhizobium; Homocitrate; Legumes; NifV; Symbiotic nitrogen fixation Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85077399542&doi=10.1264%2fjsme2.ME19078&partnerID=40&md5=809aede61adb03b53216098034a308e7 DOI: 10.1264/jsme2.ME19078