Effect of different fertilization treatments on indole-3-acetic acid producing bacteria in soil
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Soil microorganisms directly affect the growth of plants. Especially, plant growth-promoting rhizobacteria (PGPR) play an important role in plant growth. There are many studies about the effects of different fertilization treatments on soil microbial community structure; however, the effects on PGPR, including indole-3-acetic acid (IAA)-producing bacteria have not been previously reported. The objective of this study is to determine the effects of different types of fertilizers on IAA-producing bacteria.
Materials and methods
The field trial was completed in the North China with a winter wheat and summer corn rotation system. IAA-producing bacteria were screened from soil treated with different fertilizer (non-nitrogen fertilizer (CK), controlled-release fertilizer (CR), chemical fertilizer (CF), and organic fertilizer (OF)) which was established in September 2005. Quantity of IAA produced by bacteria was determined by spectrophotometer. IAA-producing bacteria were identified based on 16S rDNA sequence. Community structures and phylogenetic relationships of IAA-producing bacteria were analyzed by online Basic Local Alignment Search Tool search engine, biosoftware of DNAMAN and Molecular Evolutionary Genetics Analysis.
Results and discussion
Compared with CK treatment, CF and CR treatment increased soil pH values, while OF treatment decreased pH. The three types of fertilizers all increased soil organic carbon and total nitrogen, with OF treatment causing the significant increase. Soils treated with OF or CR fertilizer could significantly increase the number of culturable bacteria compared with CF or CK treatment. Fifty-three IAA-producing bacteria (14 strains from CK, nine from CF, eight from CR, and 22 from OF) were identified based on 16S rDNA sequence. The Shannon–Weiner index of IAA-producing bacteria isolated from CK and OF (2.06 and 2.45, respectively) was significantly higher than those from CF and CR (0.50 and 0.95, respectively). Arthrobacter sp. was the most prevalent group of IAA-producing bacteria.
The fertilizers increased soil organic carbon and total nitrogen, particularly the organic fertilizers. Controlled-release fertilizers and organic fertilizers can promote growth of soil-culturable bacteria and IAA-producing bacteria. These may be reasons why organic fertilizers and controlled-release fertilizers can promote crop growth. Different fertilization treatments affected IAA yield mainly through modifying the quantities of microorganisms, rather than changing the IAA-producing ability of the same microorganisms. Pedobacter sp. which can produce IAA has not been described previously.
KeywordsBiodiversity Fertilization treatments IAA-producing bacteria PGPR
This work was supported by the Specialized Research Fund for Doctor Program in University (20090008120043), China Agricultural University Basic Research Fund (2009JS108), Special Fund for Agro-scientific Research in the Public Interest (200803033), and China International Science and Technology Partnership Program (2009DFA91790).
- Cai Y, Liao Z, Je H, Kong W, He C (2003) Effect of ecological organic fertilizer on tomato bacterial wilt and soil microbial diversities (in Chinese). J Appl Ecol Sin 14(3):349–353Google Scholar
- Chapin FS, Matson PA, Mooney HA (2002) Principles of terrestrial ecosystem ecology. Springer, New York, pp 200Google Scholar
- Egamberdieva D (2008) Plant growth promoting properties of rhizobacteria isolated from wheat and pea grown in loamy sand soil. Turk J Biol 32:9–15Google Scholar
- FAO/UNESCO (1988) Soil map of the world. Revised legend. FAO, RomeGoogle Scholar
- Forni C, Riov J, Grilli Caiola M, Tel-Or E (1992) Indole-3-acetic acid (IAA) production by Arthrobacter species isolated from azolla. J Gen Microbiol 138(2):377–381Google Scholar
- Jones D, Keddie R (2006) The genus Arthrobacter. In: The prokaryotes. Springer: New York, pp 945–960Google Scholar
- Li F, Ping S, Su B, Lin M (2000) Tn5 mutagenesis and the characteristics of indole-3-acetic acid biosynthesis in Alcaligenes faecalis A1501 (in Chinese). Acta Microbiol Sin 40(5):551–555Google Scholar
- Loper JE, Schroth MN (1986) Influence of bacterial sources of indole-3-acetic acid on root elongation of sugar beet. Physiol Biochem 76:386–389Google Scholar
- Mongodin EF, Shapir N, Daugherty SC, DeBoy RT, Emerson JB, Shvartzbeyn A, Radune D, Vamathevan J, Riggs F, Grinberg V, Khouri H, Wackett LP, Nelson KE, Sadowsky MJ (2006) Secrets of soil survival revealed by the genome sequence of Arthrobacter aurescens TC1. PLoS Genet 2(12):e214CrossRefGoogle Scholar
- Sun R (2002) Basic ecology (in Chinese). Higher Education Press, Beijing, p 144Google Scholar
- Xu Y, Zhao Z, Zhang F, Liu J (2007) Advances in development and application of controlled-release fertilizers (in Chinese). Acta Agriculturae Boreali-Sinica 22(supplement):190–194Google Scholar