Acacia senegal and Prosopis chilensis-nodulating rhizobia Sinorhizobium arboris HAMBI 2361 and S. kostiense HAMBI 2362 produce tetra- and pentameric LCOs that are N-methylated, O-6-carbamoylated and partially sulfated

Stable isotope labelling reveals that NaCl stress decreases the production ofEnsifer(Sinorhizobium)arborislipochitooligosaccharide signalling molecules

“…To assess qualitative and quantitative changes in the production of LCOs, we devised a method where LCOs were differentially labelled by stable isotopes of nitrogen, 14 N and 15 N, and analysed by mass spectrometry. While testing the applicability of the method, in addition to the previously characterized S. arboris HAMBI 2361 LCOs (Nowak et al ., ) we found 16 new structural variants, whereas four of the previously characterized LCOs were not detected. As even the aeration status and age of the culture can affect LCO production (Demont et al ., ), the difference was probably due to the different growth conditions.…”

“…The LCO over‐producing Ensifer ( Sinorhizobium ) HAMBI 2361 (Nowak et al ., ; due to informative reasons, we maintain the genus name Sinorhizobium in the following text) was grown in tryptophan‐yeast extract (TY) medium (Beringer, ) or defined ammonium‐mannitol‐salts (AMS) medium, both supplemented with 5 mg mL −1 tetracycline, at 28 °C. The AMS medium was a modified MOPS [3‐(N‐morpholino) propanesulfonic acid]‐buffered glutamic acid‐mannitol‐salts (GMS) medium (Zevenhuizen, ) where glutamic acid was replaced with 0.45 g L −1 (NH 4 ) 2 SO 4 .…”

“…In the stress experiment, the 14 N‐ and 15 N‐cultures were combined in an equal ratio: a 15 N‐labelled stressed culture was combined with a 14 N‐labelled non‐stressed culture, and two 14 N stressed cultures were combined with two 15 N non‐stressed cultures. Thereafter, LCOs were extracted and purified as described (Nowak et al ., ) except that extracts were filtered through a 0.2 µm GHP filter (Whatman Inc., Clifton, NJ). LCO structures were determined in positive mode with electrospray mass spectrometry (Agilent 1100 series LC‐MSD with Ion Trap SCT Plus; Agilent Technologies, Palo Alto, CA) as described (Nowak et al ., ) except that 10 μL of LCO extract was separated over a 44–95% (vol%) aq.…”

“…Thereafter, LCOs were extracted and purified as described (Nowak et al ., ) except that extracts were filtered through a 0.2 µm GHP filter (Whatman Inc., Clifton, NJ). LCO structures were determined in positive mode with electrospray mass spectrometry (Agilent 1100 series LC‐MSD with Ion Trap SCT Plus; Agilent Technologies, Palo Alto, CA) as described (Nowak et al ., ) except that 10 μL of LCO extract was separated over a 44–95% (vol%) aq. MeCN gradient for 25 min followed by isocratic elution at 95% (vol%) aq.…”

Divergent genes in potential inoculant Sinorhizobium strains are related to DNA replication, recombination, and repair

“…Rm1021 and HAMBI 1552 have different host ranges; they nodulate herbaceous legumes and tropical trees, respectively. Also, the structures of their Nod factors are different . In line with these differences, the nodD2 , the nodL connected to acetylation of the Nod factor non‐reducing terminal and nodE linked to Nod factor acylation by polyunsaturated fatty acids were divergent (Table ).…”