Prof. Nantakorn Boonkerd

Year	Title	Journal
2017	Salicylic acid-induced accumulation of biochemical components associated with resistance against Xanthomonas oryzae pv. Oryzae in rice Le Thanh T., Thumanu K., Wongkaew S., Boonkerd N., Teaumroong N., Phansak P., Buensanteai N.	Journal of Plant Interactions
Abstract: Seed treatment and foliar sprays of salicylic acid (SA) provided protection in rice against bacterial leaf blight (BLB) caused by bacterial Xanthomonas oryzae pv. oryzae (Xoo). Treatment of rice with exogenous SA reduced disease severity by more than 38%. Superoxide anion production and hypersensitive response increased approximately 28% and 110% at 6 and 48 h after Xoo inoculation, respectively, for plants treated with SA. Moreover, the Xoo in treated rice plants grew more slowly, resulting in a population that was half of that observed in the control. Fourier transform infrared spectroscopy analysis revealed that the higher ratios of 1233/1517, 1467/1517, and 1735/1517 cm-1 observed in treated rice suggested alteration of monomer composition of lignin and pectin in the rice cell wall. Exogenous SA-treated rice had more amide I ß-sheet structure and lipids as shown by the peaks at 1629, 2851, and 1735 cm-1. These biochemical changes of rice treated with SA and inoculated with Xoo were related to primed resistance of the rice plants to BLB disease. © 2017 The Author(s). Keyword: Bacterial leaf blight; Biochemical change; Defence reactions; FTIR; Rice; Salicylic acid Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85033454075&doi=10.1080%2f17429145.2017.1291859&partnerID=40&md5=12968cfe05a8818350c66b2f6a6ee42b DOI: 10.1080/17429145.2017.1291859
2013	Diversity of endophytic actinomycetes in mandarin grown in northern Thailand, their phytohormone production potential and plant growth promoting activity Shutsrirung A., Chromkaew Y., Pathom-Aree W., Choonluchanon S., Boonkerd N.	Soil Science and Plant Nutrition
Abstract: The rapid expansion of mandarin (Citrus reticulata L.) production areas with high agrochemical input in the highland areas of northern Thailand has resulted in negative effects in terms of production, environment, soil quality, and public health. The use of microorganisms as plant growth promoters is an alternative method to reduce agrochemical input. Thus, we studied the diversity of endophytic actinomycetes in mandarin and their potential as plant growth promoters. A total of 252 endophytic actinomycete isolates were recovered from mandarin. Based on spore chain morphology, cell wall type, and 16S rRNA gene sequence, the isolates were classified into six genera: Streptomyces, Nocardia, Nocardiopsis, Spirillospora, Microbispora and Micromonospora. The most frequent isolates recovered were members of Streptomyces (85.3%). Selected isolates (64 isolates) from these genera were evaluated for their indole-3-acetic acid (IAA) production potential in a medium with 2 mg mL-1 tryptophan, and all the selected isolates showed the potential to produce IAA, with average values of IAA production of 13.34, 3.36, 140.38, 12.55, 1.40, and 6.19 μg IAA mL-1, respectively. Isolates of genus Nocardiopsis showed a very high ability to produce IAA that was the highest among all the genera, with values ranging from 62.23 to 222.75 μg mL-1. Twelve isolates selected from these genera were inoculated onto mandarin seedlings, and the results indicated that the shoot height, fresh shoot weight and fresh root weight of the seedlings were promoted by the inoculation of endophytic actinomycetes, with values ranging from 20.2 to 49.1%, 14.9 to 53.6%, and 1.6 to 102% over the control, respectively. © 2013 Copyright Japanese Society of Soil Science and Plant Nutrition. Keyword: 16S rRNA gene; diversity; endophytic actinomycetes; IAA; mandarin Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881662498&doi=10.1080%2f00380768.2013.776935&partnerID=40&md5=20c593a6cffdcffccf4961a009bf2200 DOI: 10.1080/00380768.2013.776935
2013	Effects of nitrogen, potassium fertilizers and clusters per vine on yield and anthocyanin content in cabernet sauvignon grape Boonterm V., Silapapun A., Boonkerd N.	Acta Horticulturae
Abstract: The experiment was carried out in a humid subtropical climate located in the south of China, in Xichang, Sichuan province, (27°N, 102°E, and 1650 m above mean sea level) during the 2005 and 2006 seasons. An eight-years-old, irrigated Cabernet Sauvignon vineyard was selected at Xichang Chia Tai Wine & Spirits Co. Ltd. Vines were spaced at 1.25 m x 2.0 m and oriented approximately north/south. Vines were trained to the vertical shoot positioned training system (VSP), and were bilaterally cordon-trained, spur-pruned and shoots were vertically positioned upright. Irrigation was by drip system. Treatments were 3 different levels of N-K application: 0-0, 100-20 and 200-60 g/plant and 3 different levels of clusters per vine: 10, 20 and 30. Each plot consisted of 1 vine, with 6 replications per treatment in a split plot design, in which the main plots were clusters per vine. Shoot lengths were maintained at 15 nodes by shoot trimming. The yield of grape in 2005 was higher than 2006. Increasing the rate of N-K in both years did not increase yield, but increased the number of clusters enhanced yield in both years. Colour and phenolic compounds in the berries were higher in 2006 than 2005. The phenolic compounds in the grape were the highest under the highest rate of fertilizer. Cabernet Sauvignon berries contained more malvidin than other anthocyanins. Wine quality (colour and balance of acidity, tannins, and alcohol) were better when derived from grape berries with higher quality, which could be quantified by colour and phenolic compounds in the berries. Keyword: Phenolic compounds; Pruning; Trimming; Wine colour Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84879204468&doi=10.17660%2fActaHortic.2013.984.54&partnerID=40&md5=808aac179d065b352373aa42c13b0d71 DOI: 10.17660/ActaHortic.2013.984.54
2011	Selection of arbuscular mycorrhizal fungi for citrus growth promotion and Phytophthora suppression Watanarojanaporn N., Boonkerd N., Wongkaew S., Prommanop P., Teaumroong N.	Scientia Horticulturae
Abstract: In order to reduce unnecessary amount of P-fertilizer and severity of Phytophthora root rot in citrus orchards, the experiment was set up. Thirteen indigenous arbuscular mycorrhiza (AM) fungi species were isolated from rhizosphere soil of citrus orchards in Thailand and were then propagated into three host plants [sorghum (Sorghum bicolor), maize (Zea mays), and leek (Allium cepa)] by trap culture. We also tested whether indigenous AMF species (13 different species) could colonize into three cultivars of citrus scions and rootstocks (Shogun: Citrus reticulata Blanco cv. Shogun; Tangerine: C. reticulata; and C-35 citrange: Citrus sinensis×. Poncirus trifoliata). With root colonization rates, the results indicated that Acaulospora tuberculata and Glomus etunicatum provided the best colonization in all citrus cultivars. We selected, therefore, those AMF species to verify their influences on citrus growth and Phytophthora root rot resistance. Three cultivars of citrus scions and rootstocks, Shogun, Tangerine and C-35 citrange, were inoculated with two effective indigenous AMF species, G. etunicatum or A. tuberculata in order to determine the influences on citrus growth. The plants were investigated to determine the mycorrhizal efficiency index (MEI), AM colonization, P content, and other parameters. Co-inoculation of AMF species (G. etunicatum or A. tuberculata) with Phytophthora nicotianae was also carried out in Shogun scion/C-35 citrange rootstocks. The results of citrus growth revealed that Shogun and Tangerine inoculated with G. etunicatum produced the highest MEI. Tangerine and C-35 citrange amended with fertilizers and G. etunicatum showed the highest P content in leaves. This indicated that G. etunicatum has an influence on citrus growth and P uptake, suggesting it to be the highly effective strain. Shogun scion/C-35 citrange rootstock combinations that were inoculated by both P. nicotianae and different AM fungi (G. etunicatum or A. tuberculata) showed root injury at low level of root rot symptom. However, the part of Shogun scions grafted on rootstocks showed severe symptom of shoot die back in treatment inoculated with P. nicotianae alone, while treatment inoculated with different AM species (G. etunicatum or A. tuberculata) and P. nicotianae rendered lower shoot die back symptoms than that of Phytophthora treatment. The low level of shoot die back symptom was shown at first, then healthy young shoot was restored. Our results indicated the facts that different host plants and different AMF species produced different outcomes of growth and pathogen resistance. The application of both AM isolates, therefore, has an enormous potential to be produced the inoculum for citrus orchards. © 2011 Elsevier B.V. Keyword: Acaulospora tuberculata; Citrus; Glomus etunicatum; Phytophthora Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953312037&doi=10.1016%2fj.scienta.2011.02.007&partnerID=40&md5=675855c1765eac19ed6656a05312aa6b DOI: 10.1016/j.scienta.2011.02.007
2011	Erratum to "Heavy metal tolerant Metalliresistens boonkerdii gen. nov., sp. nov., a new genus in the family Bradyrhizobiaceae isolated from soil in Thailand" [Syst. Appl. Microbiol. 33 (2010) 374-382]. Proposal of Rhodopseudomonas boonkerdii sp. nov., a new heavy metal tolerant bacterium isolated from Thailand Noisangiam R., Nuntagij A., Pongsilp N., Boonkerd N., Denduangboripant J., Ronson C., Teaumroong N.	Systematic and Applied Microbiology
Abstract: [No abstract available] Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-79952534338&doi=10.1016%2fj.syapm.2011.01.002&partnerID=40&md5=4ca3e5e6ed8f10bbdcaf7da3dbeeed3c DOI: 10.1016/j.syapm.2011.01.002
2011	Optimization of malting conditions for two black rice varieties, black non-waxy rice and black waxy rice (Oryza sativa l. Indica) Usansa U., Burberg F., Geiger E., Back W., Wanapu C., Arendt E.K., Kreisz S., Boonkerd N., Teaumroong N., Zarnkow M.	Journal of the Institute of Brewing
Abstract: Two black rice varieties, "black non-waxy" and "black waxy", were investigated as possible raw materials for the production of malt. The malting conditions were optimised using response surface methodology. The three process parameters were steeping, germination time and temperature. Each parameter was tested at three levels: adjustment degrees of steeping were 38, 41, and 44%, germination times were 6, 7, and 8 days, and the temperatures were 20, 25 and 30°C. At the end of the germination process, all samples were kilned at 50°C for 24 h, and shoot/rootlets were removed before a detailed quality assessment was performed. Data analysis was performed using the Design Expert Statistic Program. The optimal conditions found for both rice varieties were as follows: germination time of 8 days at 30°C and 44% grain moisture. Although the extract yield, and α-amylase and β-amylase activities of both rice malts were lower than barley malt, the higher activity of limit-dextrinase enzyme and apparent attenuation limit (AAL), which was higher than 80%, suggests that rice malt has potential for use in brewing. © 2011 The Institute of Brewing & Distilling. Keyword: Black rice; Brewing; Malting; Response surface methodology (rsm) Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-79956147591&doi=10.1002%2fj.2050-0416.2011.tb00441.x&partnerID=40&md5=aa879c787e8529b3cd477097cf1ef90f DOI: 10.1002/j.2050-0416.2011.tb00441.x
2010	Heavy metal tolerant Metalliresistens boonkerdii gen. nov., sp. nov., a new genus in the family Bradyrhizobiaceae isolated from soil in Thailand Noisangiam R., Nuntagij A., Pongsilp N., Boonkerd N., Denduangboripant J., Ronson C., Teaumroong N.	Systematic and Applied Microbiology
Abstract: Bacterial strains from inoculated soybean field soil in Thailand were directly isolated using Bradyrhizobium japonicum selective medium (BJSM), on the basis of Zn2+ and Co2+ resistance of B. japonicum and B. elkanii. The isolates were classified into symbiotic and non-symbiotic groups by inoculation assays and Southern hybridization of nod and nif genes. In this study, a nearly full-length 16S rRNA gene sequence showed that the non-symbiotic isolates were more closely related to members of Rhodopseudomonas and to a number of uncultured bacterial clones than to members of Bradyrhizobium. Therefore, a polyphasic study was performed to determine the taxonomic positions of four representatives of the non-symbiotic isolates. Multilocus phylogenetic analysis of individual genes and a combination of the 16S rRNA and three housekeeping genes (atpD, recA and glnII) supported the placement of the non-symbiotic isolates in a different genus. The ability of heavy metal resistance in conjunction with phenotypic analyses, including cellular fatty acid content and biochemical characteristics, showed that the non-symbiotic isolates were differentiated from the other related genera in the family Bradyrhizobiaceae. Therefore, the non-symbiotic isolates represented a novel genus and species, for which the name Metalliresistens boonkerdii gen. nov., sp. nov. is proposed. The type strain is NS23 (= NBRC 106595T=BCC 40155T). © 2010 Elsevier GmbH. Keyword: Bradyrhizobiaceae; Heavy metal tolerance; Housekeeping genes; Metalliresistens boonkerdii; Multilocus sequence analysis; Phylogenetic analysis Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-78249267220&doi=10.1016%2fj.syapm.2010.06.002&partnerID=40&md5=f8cd94f47a2c006775b3acbc41c70e29 DOI: 10.1016/j.syapm.2010.06.002
2010	Arthrobacter sp. strain KU001 isolated from a Thai soil degrades atrazine in the presence of inorganic nitrogen sources Sajjaphan K., Heepngoen P., Sadowsky M.J., Boonkerd N.	Journal of Microbiology and Biotechnology
Abstract: An atrazine-degrading bacterium, strain KU001, was obtained from a sugarcane field at the Cane and Sugar Research and Development Center at the Kasetsart University, Kamphaeng Saen Campus, Thailand. Strain KU001 had a rod-to-coccus morphological cycle during growth. Biolog carbon source analysis indicated that the isolated bacterium was Arthrobacter histidinolovorans. Sequence analysis of the PCR product indicated that the 16S rRNA gene in strain KU001 was 99% identical to the same region in Arthrobacter sp. The atrazine degradation pathway in strain KU001 consisted of the catabolic genes trzN, atzB, and atzC. Strain KU001 was able to use atrazine as a sole nitrogen source for growth, and surprisingly, atrazine degradation was not inhibited in cells grown on ammonium, nitrate, or urea, as compared with cells cultivated on growthlimiting nitrogen sources. During the atrazine degradation process, the supplementation of nitrate completely inhibited atrazine degradation activity in strain KU001, whereas ammonium and urea had no effect on atrazine degradation activity. The addition of strain KU001 to sterile or nonsterile soils resulted in the disappearance of atrazine at a rate that was 4- to 5-fold more than that achieved by the indigenous microbial community. The addition of citrate to soils resulted in enhanced atrazine degradation, where 80% of atrazine disappeared within one day following nutrient supplementation. Keyword: Arthrobacter; Atrazine-degrading bacteria; Inorganic nitrogen Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-77954264077&partnerID=40&md5=ea380a72acf892f284dfe33f057c216e DOI:
2010	Characterization of root-nodule bacteria isolated from the medicinal legume Indigofera tinctoria Leelahawonge C., Nuntagij A., Teaumroong N., Boonkerd N., Pongsilp N.	Annals of Microbiology
Abstract: Fourteen root-nodule bacteria isolated from the medicinal legume Indigofera tinctoria were characterized for their phenotypic features including growth curves, utilization of carbon and nitrogen sources, antibiotic resistance, vitamin requirement and growth under different conditions. The partial sequences of the 16S rDNA of these strains were obtained and BLASTN analysis revealed that the microsymbionts of I. tinctoria were related to members of five distinct genera: Rhizobium, Sinorhizobium, Bradyrhizobium, Cupriavidus and Pseudoalteromonas. The partial nifH gene of Pseudoalteromonas-like strain DASA 57075 had 96% similarity with nifH genes of members of Bradyrhizobium. The partial nodC gene of Pseudoalteromonas-like strain DASA 57075 showed 88% similarity with the nodC gene of several rhizobia including Sinorhizobium, Bradyrhizobium and Mesorhizobium. We propose a bacterium that is related to Pseudoalteromonas from the gamma-class of Proteobacteria as a new legume symbiont. This is also the first report that the same species of legume can be nodulated by bacteria from up to five different genera in three distinct classes. © 2010 Springer-Verlag and the University of Milan. Keyword: 16S rDNA; Indigofera tinctoria; NifH gene; NodC gene; Pseudoalteromonas-like strain; Root-nodule bacteria Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-77951666524&doi=10.1007%2fs13213-009-0005-8&partnerID=40&md5=51630e697aec0556b9eabd244820798b DOI: 10.1007/s13213-009-0005-8
2010	Production and application of bioorganic fertilizers for organic farming systems in Thailand: A case study Teaumroong N., Wanapu C., Chankum Y., Arjharn W., Sang-Arthit S., Teaimthaisong K., Boonkerd N.	Microbes at Work: From Wastes to Resources
Abstract: As organic farming in Thailand has gained more momentum in recent years, many organic production projects have been initiated. Owing to the regulation of organic farming, synthetic chemical fertilizers are not allowed to be used. Therefore, the combination of organic fertilizers and plant growth-promoting rhizobacteria has been developed, commonly known as bioorganic fertilizers. Amendment of mature compost with mixed microbe cultures (Azotobacter sp. + Azospirillum sp. + Trichoderma harzianum) was conducted. In addition, the use of Azolla microphylla as a green manure together with bioorganic fertilizer for rice cultivation showed a satisfactory yield. In the case of vegetable (Chinese kale), Sesbania rostrata and cowpea cultivation were also used as green manures prior to bioorganic fertilizer application. The combination of green manures and bioorganic fertilizers demonstrated that green manures enhance the effect of bioorganic fertilizers so that it can become a potential alternative to conventional farming systems. © Springer-Verlag Berlin Heidelberg 2010. All rights reserved. Keyword: Scopus Link: https://www.scopus.com/inward/record.uri?eid=2-s2.0-78650679483&doi=10.1007%2f978-3-642-04043-6_15&partnerID=40&md5=282a004dd601e23e9633cad0ce5caf81 DOI: 10.1007/978-3-642-04043-6_15