@article {1422,
	title = {Identification and characterization of a NaCl-responsive genetic locus involved in survival during desiccation in Sinorhizobium meliloti.},
	journal = {Appl Environ Microbiol},
	volume = {79},
	year = {2013},
	month = {2013 Sep},
	pages = {5693-700},
	abstract = {<p>The Rhizobiaceae are a bacterial family of enormous agricultural importance due to the ability of its members to fix atmospheric nitrogen in an intimate relationship with plants. Their survival as naturally occurring soil bacteria in agricultural soils as well as popular seed inocula is affected directly by drought and salinity. Survival after desiccation in the presence of NaCl is enabled by underlying genetic mechanisms in the model organism Sinorhizobium meliloti 1021. Since salt stress parallels a loss in water activity, the identification of NaCl-responsive loci may identify loci involved in survival during desiccation. This approach enabled identification of the loci asnO and ngg by their reduced ability to grow on increased NaCl concentrations, likely due to their inability to produce the osmoprotectant N-acetylglutaminylglutamine (NAGGN). In addition, the mutant harboring ngg::Tn5luxAB was affected in its ability to survive desiccation and responded to osmotic stress. The desiccation sensitivity may have been due to secondary functions of Ngg (N-acetylglutaminylglutamine synthetase)-like cell wall metabolism as suggested by the presence of a d-alanine-d-alanine ligase (dAla-dAla) domain and by sensitivity of the mutant to \&beta;-lactam antibiotics. asnO::Tn5luxAB is expressed during the stationary phase under normal growth conditions. Amino acid sequence similarity to enzymes producing \&beta;-lactam inhibitors and increased resistance to \&beta;-lactam antibiotics may indicate that asnO is involved in the production of a \&beta;-lactam inhibitor.</p>
},
	keywords = {Desiccation, DNA Transposable Elements, Gene Expression Regulation, Bacterial, Gene Knockout Techniques, Genes, Bacterial, Genetic Loci, Microbial Viability, Mutagenesis, Insertional, Osmotic Pressure, Sinorhizobium meliloti, Sodium Chloride, Stress, Physiological},
	issn = {1098-5336},
	doi = {10.1128/AEM.01037-13},
	author = {Vriezen, Jan A C and de Bruijn, Frans J and N{\"u}sslein, Klaus}
}
@article {727,
	title = {Desiccation induces viable but Non-Culturable cells in Sinorhizobium meliloti 1021.},
	journal = {AMB Express},
	volume = {2},
	year = {2012},
	month = {2012},
	pages = {6},
	abstract = {ABSTRACT: Sinorhizobium meliloti is a microorganism commercially used in the production of e.g. Medicago sativa seed inocula. Many inocula are powder-based and production includes a drying step. Although S. meliloti survives drying well, the quality of the inocula is reduced during this process. In this study we determined survival during desiccation of the commercial strains 102F84 and 102F85 as well as the model strain USDA1021.The survival of S. meliloti 1021 was estimated during nine weeks at 22\% relative humidity. We found that after an initial rapid decline of colony forming units, the decline slowed to a steady 10-fold reduction in colony forming units every 22 days. In spite of the reduction in colony forming units, the fraction of the population identified as viable (42-54\%) based on the Baclight live/dead stain did not change significantly over time. This change in the ability of viable cells to form colonies shows (i) an underestimation of the survival of rhizobial cells using plating methods, and that (ii) in a part of the population desiccation induces a Viable But Non Culturable (VBNC)-like state, which has not been reported before. Resuscitation attempts did not lead to a higher recovery of colony forming units indicating the VBNC state is stable under the conditions tested. This observation has important consequences for the use of rhizobia. Finding methods to resuscitate this fraction may increase the quality of powder-based seed inocula.},
	issn = {2191-0855},
	doi = {10.1186/2191-0855-2-6},
	author = {Vriezen, Jan Ac and de Bruijn, Frans J and N{\"u}sslein, Klaus R}
}
@article {745,
	title = {Responses of rhizobia to desiccation in relation to osmotic stress, oxygen, and temperature.},
	journal = {Appl Environ Microbiol},
	volume = {73},
	year = {2007},
	month = {2007 Jun},
	pages = {3451-9},
	keywords = {Adaptation, Physiological, Dehydration, Hot Temperature, Osmotic Pressure, Oxidative Stress, Rhizobiaceae},
	issn = {0099-2240},
	doi = {10.1128/AEM.02991-06},
	author = {Vriezen, Jan Ac and de Bruijn, Frans J and N{\"u}sslein, K}
}
