%0 Journal Article %T Breathing air to save energy--new insights into the ecophysiological role of high-affinity [NiFe]-hydrogenase in Streptomyces avermitilis. %+ Institut Armand Frappier (INRS-IAF) %A Liot, Quentin %A Constant, Philippe %Z This work was supported by a Natural Sciences and Engineering Research Council of Canada (NSERC)–Discovery grant to P. C. The authors are grateful to the personnel staff members of Centre d'Innovation Génome Québec et Université McGill for the preparation of libraries and sequencing services. %Z This work was supported by the Natural Sciences and Engineering Research Council of Canada (Grant/Award Number: “Discovery/418252-2012”) %< avec comité de lecture %@ 2045-8827 %J MicrobiologyOpen %I Wiley %V 5 %N 1 %P 47-59 %8 2016-01-31 %D 2016 %R 10.1002/mbo3.310 %M 26541261 %K Actinobacteria %K H2-oxidizing bacteria %K microbial seed bank %K trace gas %Z Life Sciences [q-bio] %Z Life Sciences [q-bio]/Microbiology and Parasitology/BacteriologyJournal articles %X The Streptomyces avermitilis genome encodes a putative high-affinity [NiFe]-hydrogenase conferring the ability to oxidize tropospheric H2 in mature spores. Here, we used a combination of transcriptomic and mutagenesis approaches to shed light on the potential ecophysiological role of the enzyme. First, S. avermitilis was either exposed to low or hydrogenase-saturating levels of H2 to investigate the impact of H2 on spore transcriptome. In total, 1293 genes were differentially expressed, with 1127 and 166 showing lower and higher expression under elevated H2 concentration, respectively. High H2 exposure lowered the expression of the Sec protein secretion pathway and ATP-binding cassette-transporters, with increased expression of genes encoding proteins directing carbon metabolism toward sugar anabolism and lower expression of NADH dehydrogenase in the respiratory chain. Overall, the expression of relA responsible for the synthesis of the pleiotropic alarmone ppGpp decreased upon elevated H2 exposure, which likely explained the reduced expression of antibiotic synthesis and stress response genes. Finally, deletion of hhySL genes resulted in a loss of H2 uptake activity and a dramatic loss of viability in spores. We propose that H2 is restricted to support the seed bank of Streptomyces under a unique survival-mixotrophic energy mode and discuss important ecological implications of this finding. %G English %2 https://riip.hal.science/pasteur-01351429/document %2 https://riip.hal.science/pasteur-01351429/file/Liot_et_al-2016-MicrobiologyOpen%281%29.pdf %L pasteur-01351429 %U https://riip.hal.science/pasteur-01351429 %~ RIIP %~ INRS-IAF