Biology and Fertility of Soils

, Volume 18, Issue 4, pp 302–310 | Cite as

Effects of drying/rewetting stress on microbial auxin production and L-tryptophan catabolism in soils

  • Michael Lebuhn
  • B. Heilmann
  • A. Hartmann
Original Paper


The presence of tryptophan in soil and auxin production by indigenous soil microbes are considered to be important natural plant growth-promoting factors. In order to elucidate the natural regulation of microbial auxin synthesis, we treated different soils by an air drying/rewetting cycle and measured pool sizes of auxins, auxin precursors, and degradation products of tryptophan together with a range of respiration parameters. Potential (tryptophan addition) microbial production of indole-3-acetic acid (auxin) was predominant in the equilibrated fresh soils. Auxin production depended on the soil nutrient content, and the size and metabolic status of the microbial biomass. Immediately after rewetting, potential auxin production was low, whereas potential indole-3-ethanol and anthranilic acid production as well as basal respiration were transitionally enhanced. This was concurrent with proliferation ofr-strategist microbes. After the respiration flush, the natural tryptophan contents increased, indicating cell lysis, probably caused by a rise in protozoan grazing on ther-strategists. Auxin production was high in fresh and in re-equilibrating rewetted soils, probably due to nutritional limitations under stationary conditions. Hence, this high production was attributed to theK-strategist component of the soil microflora. The differences observed in the recovery of auxin production between the different rewetted soils suggest that original activities can become re-established rapidly when the indigenous microbial community is pre-adapted to the stress. We propose that the release of tryptophan, microbial auxin, and the shift towards indole-3-ethanol production function as stimulants for root development induced by environmental fluctuations.

Key words

Indole-3-acetic acid Indole-3-ethanol L-tryptophan metabolism Water potential stress Soil microbes 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Ahmed M, Oades JM, Ladd JN (1982) Determination of ATP in soils: Effect of soil treatments. Soil Biol Biochem 14:273–279Google Scholar
  2. Anderson JPE, Domsch KH (1978) A physiological method for the quantitative measurement of microbial biomass in soils. Soil Biol Biochem 10:215–221Google Scholar
  3. Andrews JH, Harris RF (1986)r- andK-Selection and microbial ecology. In: Marshall KC (ed) Advances in Microbial Ecology, vol. 9. Plenum Press, New York, pp 99–148Google Scholar
  4. Arshad M, Frankenberger WT Jr (1992) Microbial production of plant growth regulators. In: Metting FB Jr (ed) Soil Microbial Ecology. Dekker, New York, pp 307–347Google Scholar
  5. Baldani VLD, Baldani JI, Döbereiner J (1987) Inoculation of fieldgrown wheat (Triticum aestivum) withAzospirillum spp. in Brazil. Biol Fertil Soils 4:37–40Google Scholar
  6. Beck T (1991) Einsatzmöglichkeiten der substratinduzierten Atmungsmessung bei bodenmikrobiologischen Untersuchungen. Mitt Dtsch Bodenkd Ges 66:459–462Google Scholar
  7. Bloem J, De Reiter PC, Koopman GJ, Lebbink F, Brussaard L (1992) Microbial numbers and activity in dried and rewetted arable soil under integrated and conventional management. Soil Biol Biochem 24:655–665Google Scholar
  8. Bottner P (1985) Response of microbial biomass to alternate moist and dry conditions in a soil incubated with14C- and15N-labelled plant material. Soil Biol Biochem 17:329–337Google Scholar
  9. Brown AE, Hamilton JTG (1992) Indole-3-ethanol produced byZygorrhynchus moelleri, an indole-3-acetic analogue with antifungal activity. Mycol Res 96:71–74Google Scholar
  10. Brown HM, Purves WK (1976) Isolation and characterization of indole-3-acetaldehyde reductase fromCucumis sativus. J Biol Chem 251:907–913Google Scholar
  11. Curl EA, Truelove B (1986) The rhizosphere. Advanced Series in Agricultural Sciences, vol. 15. Springer, Berlin Heidelberg New York TokyoGoogle Scholar
  12. Denenu EO, Demain AL (1981) Relationship between genetic deregulation of Hansenula polymorpha and production of tryptophan metabolites. Eur J Appl Microbiol Biotechnol 13:202–207Google Scholar
  13. Frankenberger WT Jr, Brunner W (1983) Method of detection of auxin-indole-3-acetic acid in soils by high performance liquid chromatography. Soil Sci Soc Am J 47:237–241Google Scholar
  14. Hartmann A, Singh M, Klingmüller W (1983) Isolation and characterization ofAzospirillum mutants excreting high amounts of indoleacetic acid. Can J Microbiol 29:916–923Google Scholar
  15. Heilmann B, Beese F (1991) Variabilität der mikrobiellen Aktivität und Biomasse eines großen Bodenkollektivs in Abhängigkeit von verschiedenen Standortsparametern. Mitt Dtsch Bodenkd Ges 66:495–498Google Scholar
  16. Heilmann B, Lebuhn M, Beese F (1994) Methods to investigate metabolic activities and shifts in microbial community in a soil treated with a fungicide. Biol Fertil Soils (in press)Google Scholar
  17. Heinemeyer O, Insam H, Kaiser EA, Walenzik G (1989) Soil microbial biomass and respiration measurements: An automated technique based on infra-red gas analysis. Plant and Soil 116:191–195Google Scholar
  18. Horemans S, Vlassak K (1985) Production of indole-3-acetic acid byAzospirillum brasilense. In: Klingmüller W (ed) Azospirillum III. Genetics, physiology, ecology. Springer, Berlin, pp 98–108Google Scholar
  19. Kapulnik Y, Okon Y, Henis Y (1987) Yield response of spring wheat cultivars (Triticum aestivum andT. turgidum) to inoculation withAzospirillum brasilense und field conditions. Biol Fertil Soils 4:27–35Google Scholar
  20. Kieft TL, Soroker E, Firestone MK (1987) Microbial biomass response to a rapid increase in water potential when dry soil is rewetted. Soil Biol Biochem 19:119–126Google Scholar
  21. Kradolfer P, Niederberger P, Hütter R (1982) Tryptophan degradation inSaccharomyces cerevisiae: Characterization of two aromatic aminotransferases. Arch Microbiol 133:242–248Google Scholar
  22. Lebuhn M, Hartmann A (1993) Method for the determination of indole-3-acetic acid and related compounds ofL-tryptophan catabolism in soils. J Chromatogr 629:255–266Google Scholar
  23. Lebuhn M, Hartmann A (1994) Production of auxin andL-tryptophan related indolic and phenolic compounds byAzospirillum brasilense andAzospirillum lipoferum. In: Ryder MH, Stephens PM, Bowen GD (eds) Improving plant productivity with rhizosphere bacteria, CSIRO, Australia, pp 145–147Google Scholar
  24. Lebuhn M, Heilmann B, Hartmann A (1992) Einfluß von Umweltfaktoren auf die mikrobielle Auxinbiosynthese im Boden. VDLUFA Schriftenreihe 35:854–857Google Scholar
  25. Lundgren B (1981) Fluorescein diacetate as a stain of metabolically active bacteria in soil. OIKOS 36:17–22Google Scholar
  26. Martens DA, Frankenberger WT Jr (1993) Stability of microbial-produced auxins derived fromL-tryptophan added to soil. Soil Sci 155:263–271Google Scholar
  27. Martin P, Glatzle A, Kolb W, Omay H, Schmidt W (1989) N2-fixing bacteria in the rhizosphere: Quantification and hormonal effects on root development. Z Pflanzenernaehr Bodenkd 152:237–245Google Scholar
  28. Müller M, Deigele C, Ziegler H (1989) Hormonal interactions in the rhizosphere of maize (Zea mays L.) and their effects on plant development. Z Pflanzenernaehr Bodenkd 152:247–254Google Scholar
  29. Narumiya S, Takai K, Tokuyama T, Noda Y, Ushiro H, Hayaishi O (1979) A new metabolic pathway of tryptophan intiated by tryptophan side chain oxidase. J Biol Chem 254:7007–7015Google Scholar
  30. Rajagopal R (1968) Metabolism of indole-3-acetaldehyde. II. On dismutation. Physiol Plant 21:1076–1096Google Scholar
  31. Rigaud J (1970) La biosynthèse de l'acide indolyl-3-acétique en liaison avec le métabolisme du tryptophol et de l'indolyl-3-acétaldéhyde chezRhizobium. Physiol Plant 23:171–178Google Scholar
  32. Sandberg G (1984) Biosynthesis and metabolism of indole-3-ethanol and indole-3-acetic acid byPinus sylvestris L. needles. Planta 161:398–403Google Scholar
  33. Sandberg G, Crozier A, Ernstsen A (1987) Indole-3-acetic acid and related compounds. In: Rivier L, Crozier A (eds) The principle and practice of plant hormone analysis, vol. 2. Academic Press, London, pp 169–301Google Scholar
  34. Schnürer J, Clarholm M, Bostrom S, Rosswall T (1986) Effects of moisture on soil microorganisms and nematodes: a field experiment. Micro Ecol 12:217–230Google Scholar
  35. Selvadurai EM, Brown AE, Hamilton JTG (1991) Production of indole-3-acetic acid analogues by strains ofBacillus cereus in relation to their influence on seedling development. Soil Biol Biochem 23:401–403Google Scholar
  36. Sembdner G, Gross D, Liebisch HW, Schneider G (1980) Biosynthesis and metabolism of plant hormones. In: MacMillan J (ed) Hormonal regulation of development. I. Molecular aspects of plant hormones. Springer, New York, pp 281–444Google Scholar
  37. Sparling GP, Cheshire MV (1979) Effects of soil drying and storage on subsequent microbial growth. Soil Biol Biochem 1:317–319Google Scholar
  38. Vandenhove H, De Coninck K, Coorvits K, Merckx R, Vlassak K (1991) Microcalorimetry as a tool to detect changes in soil microbial biomass. Toxicol Environ Chem 30:201–206Google Scholar
  39. Walworth JL (1992) Soil drying and rewetting, or freezing and thawing, affects soil solution composition. Soil Sci Soc Am J 56:433–437Google Scholar
  40. West AS, Sparling GP, Grant WD (1987) Relationship between mycelial and bacterial populations in stored air-dried and glucose amended arable and grassland soils. Soil Biol Biochem 18:569–576Google Scholar
  41. West AW, Sparling GP, Feltham CW, Reynolds J (1992) Microbial activity and survival in soils dried at different rates. Aust J Soil Res 30:209–222Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Michael Lebuhn
    • 1
  • B. Heilmann
    • 1
  • A. Hartmann
    • 1
  1. 1.GSF-Forschungszentrum für Umwelt und Gesundheit GmbH, NeuherbergInstitut für BodenökologieOberschleissheimGermany

Personalised recommendations