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Thermophilic methanogens in rice field soil
Author(s) -
Fey Axel,
Chin Kuk Jeong,
Conrad Ralf
Publication year - 2001
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1046/j.1462-2920.2001.00195.x
Subject(s) - thermophile , biology , terminal restriction fragment length polymorphism , paddy field , library , ribosomal rna , 16s ribosomal rna , botany , restriction fragment length polymorphism , gene , agronomy , bacteria , genotype , genetics
The soil temperature in flooded Italian rice fields is generally lower than 30°C. However, two temperature optima at ≈ 41°C and 50°C were found when soil slurries were anoxically incubated at a temperature range of 10–80°C. The second temperature optimum indicates the presence of thermophilic methanogens in the rice field soil. Experiments with 14 C‐labelled bicarbonate showed that the thermophilic CH 4 was exclusively produced from H 2 /CO 2 . Terminal restriction fragment length polymorphism (T‐RFLP) of archaeal SSU rRNA gene fragments revealed a dramatic change in the archaeal community structure at temperatures > 37°C, with the euryarchaeotal rice cluster I becoming the dominant group (about 80%). A clone library of archaeal SSU rRNA gene fragments generated at 49°C was also dominated (10 out of 11 clones) by rice cluster I. Our results demonstrate that Italian rice field soil contains thermophilic methanogenic activity that was most probably a result of members of the as yet uncultivated euryarchaeotal rice cluster I.