Symbiotic effectiveness, rate of respiration and glutamine synthetase activity of sodium azide‐resistant strains of Rhizobium leguminosarum biovar trifolii

Abstract

A .S . Y A DA V, M . V AS U DE VA , K. K. U PA DH Y AY , S . K. SA W HN EY A ND R. K . V AS H IS HA T . 1999. Nitrogen fixing efficiency of sodium azide-resistant strains of Rhizobium leguminosarum bv. trifolii was studied in symbiosis with berseem clover plants in chillum jars. Rate of respiration and glutamine synthetase activity were tested in cultured cells and nodules, respectively. It was observed that shoot dry weight and percentage shoot nitrogen were maximum in plants inoculated with strains resistant to 15 mg ml −1 sodium azide. Rate of respiration in cultured cells was lowest in strains resistant to 15 mg ml −1 sodium azide and highest in strains resistant to 5 mg ml −1 sodium azide. A negative correlation was observed between rate of respiration (in cultured cells) and shoot dry weight of host plants. Glutamine synthetase activity was maximum in nodule extracts of host plants inoculated with strains resistant to 5 and 10 mg ml −1 sodium azide, whereas it was minimum for strains resistant to 15 mg ml −1 sodium azide. Hence, resistance to low doses (15 mg ml ) of sodium azide, together with lower respiratory and glutamine synthetase activities, could be used as a potential method for isolating the symbiotically effective strains of Rh. leguminosarum bv. trifolii.

Tetraponeraants have gut symbionts related to nitrogen–fixing root–nodule bacteria

“…Four were Proteobacteria and were statistically sufficiently supported (figure 2) to assign them unambiguously to the genera Rhizobium and Methylobacterium (α-Proteobacteria), Burkholderia (β-Proteobacteria) and Pseudomonas (γ-Proteobacteria). Nitrogen fixation has previously been demonstrated for each of these genera (Yadav et al 1999;Ghiglione et al 2000;Minerdi et al 2001;Sy et al 2001). This proteobacterial branch in the phylogeny was also obtained with maximum-likelihood and maximum-parsimony analysis, which is not surprising given the high bootstrap support values both for the external and internal branches in the neighbour-joining analysis (figure 2).…”

Rhizobium leguminosarum Glutathione Peroxidase Is Essential for Oxidative Stress Resistance and Efficient Nodulation

“…In addition, RL3549 codes for glutamine synthetase involved in assimilation of ammonium, RL1559 codes for the acyl carrier protein required for the biosynthesis of lipid A, and pRL100169 is a rhizosphere-expressed gene rhiA . These three genes have been reported by others to be functionally linked with symbiosis ( Table 4 ) ( Kannenberg and Carlson, 2001 ; Yadav et al, 2002 ; Crespo-Rivas et al, 2019 ). Finally, RL0843 codes Ribosomal RNA large subunit methyltransferase E, which is involved in ribosomal RNA maturation, and the loss of GpxA resulted in the differential expression of proteins ( pRL100106 , RL2820 , RL1124 , and pRL90221 ) of unknown function.…”