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A versatile most probable number system to quantify lac ZY‐marked pseudomonads present at low cell numbers in the rhizosphere
Author(s) -
Fedi S.,
MoënneLoccoz Y.,
Dowling D.N.,
O'Gara F.
Publication year - 1995
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.1995.tb00432.x
Subject(s) - rhizosphere , most probable number , biology , botany , detection limit , microfauna , bacteria , chromatography , chemistry , genetics , fauna
Quantitation of introduced genetically modified micro‐organisms (GMMs) in the rhizosphere is a key issue when their release in the environment is planned. An improved most probable number (MPN) system, using a titration plate for incubation of rhizosphere extracts and two microcomputer programmes made recently available, MPNES (Woomer et al. 1990) and MPN 2.80 (Klee 1993) to generate the MPNs, is described. The MPN system was compared with colony counts to assess colonization of sugarbeet roots by an introduced lac ZY‐modified rhizosphere pseudomonad. The MPNs displayed wider confidence intervals compared with drop‐plate counts but allowed the quantitation limit to be lowered to 2.30 log 10 cfu per root system. The MPN system proved useful to quantify GMMs present at low cell numbers in the rhizosphere of sugarbeet.