title: Evaluation of the effects of different liquid inoculant formulations on the survival and plant-growth-promoting efficiency of Rhodopseudomonas palustris strain PS3.
abstract: Biofertilizers can help improve soil quality, promote crop growth, and sustain soil health. The photosynthetic bacterium Rhodopseudomonas palustris strain PS3 (hereafter, PS3), which was isolated from Taiwanese paddy soil, can not only exert beneficial effects on plant growth but also enhance the efficiency of nutrient uptake from applied fertilizer. To produce this elite microbial isolate for practical use, product development and formulation are needed to permit the maintenance of the high quality of the inoculant during storage. The aim of this study was to select a suitable formulation that improves the survival and maintains the beneficial effects of the PS3 inoculant. Six additives (alginate, polyethylene glycol [PEG], polyvinylpyrrolidone-40 [PVP], glycerol, glucose, and horticultural oil) were used in liquid-based formulations, and their capacities for maintaining PS3 cell viability during storage in low, medium, and high temperature ranges were evaluated. Horticultural oil (0.5 %) was chosen as a potential additive because it could maintain a relatively high population and conferred greater microbial vitality under various storage conditions. Furthermore, the growth-promoting effects exerted on Chinese cabbage by the formulated inoculants were significantly greater than those of the unformulated treatments. The fresh and dry weights of the shoots were significantly increased, by 10-27 and 22-40 %, respectively. Horticultural oil is considered a safe, low-cost, and easy-to-process material, and this formulation would facilitate the practical use of strain PS3 in agriculture.
authors.affiliation: Department of Agronomy, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 106, Taiwan.|Institute of Biotechnology, National Taiwan University, R412, No. 81, Chang-Xing St, Taipei, 106, Taiwan.
authors.forename: Sook-Kuan
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Agronomy, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 106, Taiwan.|Institute of Biotechnology, National Taiwan University, R412, No. 81, Chang-Xing St, Taipei, 106, Taiwan.
authors.forename: Huu-Sheng
authors.initials: HS
authors.lastname: Lur
authors.affiliation: Institute of Biotechnology, National Taiwan University, R412, No. 81, Chang-Xing St, Taipei, 106, Taiwan.
authors.forename: Kai-Jiun
authors.initials: KJ
authors.lastname: Lo
authors.affiliation: Institute of Biotechnology, National Taiwan University, R412, No. 81, Chang-Xing St, Taipei, 106, Taiwan.|Graduate Institute of Food Science and Technology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 106, Taiwan.|Agricultural Biotechnology Research Center, Academia Sinica, No. 128 Sec. 2, Academia Rd., Nankang, Taipei, 115, Taiwan.
authors.forename: Kuan-Chen
authors.initials: KC
authors.lastname: Cheng
authors.affiliation: Taoyuan District Agricultural Research and Extension Station, Council of Agriculture, Executive Yuan, 139, Sec. 2, Dongfu Rd., Houzhuang, Sinwu Dist., Taoyuan City, 32745, Taiwan.
authors.forename: Chun-Chao
authors.initials: CC
authors.lastname: Chuang
authors.affiliation: Taoyuan District Agricultural Research and Extension Station, Council of Agriculture, Executive Yuan, 139, Sec. 2, Dongfu Rd., Houzhuang, Sinwu Dist., Taoyuan City, 32745, Taiwan.
authors.forename: Shiueh-Jung
authors.initials: SJ
authors.lastname: Tang
authors.affiliation: Taoyuan District Agricultural Research and Extension Station, Council of Agriculture, Executive Yuan, 139, Sec. 2, Dongfu Rd., Houzhuang, Sinwu Dist., Taoyuan City, 32745, Taiwan.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Yang
authors.affiliation: Institute of Biotechnology, National Taiwan University, R412, No. 81, Chang-Xing St, Taipei, 106, Taiwan. chiteliu@ntu.edu.tw.|Agricultural Biotechnology Research Center, Academia Sinica, No. 128 Sec. 2, Academia Rd., Nankang, Taipei, 115, Taiwan. chiteliu@ntu.edu.tw.
authors.forename: Chi-Te
authors.initials: CT
authors.lastname: Liu
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D029741:Brassica rapa / Q000254:growth & development* / Q000382:microbiology*; D050296:Microbial Viability; D018520:Plant Shoots / Q000254:growth & development; D011309:Preservation, Biological / Q000379:methods*; D012241:Rhodopseudomonas / Q000502:physiology*; D013696:Temperature
keywords: Biofertilizer; Formulation; Plant growth-promoting rhizobacteria (PGPR); Rhodopseudomonas palustris; Shelf life