Rhizobium leguminosarum glutathione peroxidase is essential for oxidative stress resistance and efficient nodulation

ABSTRACT: Glutathione plays a tremendous role in regulating the homeostasis of redox state, and appears to be essential for proper development of the root nodules. Glutathione peroxidase catalyzes the reduction of peroxides by oxidation of GSH to oxidized GSH (GSSG), which can in turn be reduced by glutathione reductase (GR). However, it has not been determined whether the R. leguminosarum Gpx or GR is required during symbiotic interactions with pea. To characterise the role of glutathione-dependent enzymes in the symbiotic process, single and double mutants were made in gpxA and gorA genes. All the mutations did not affect the growth of R. leguminosarum, but they increased the sensitivity of R. leguminosarum strains to H2O2. The gorA mutant can induce the formation of normal nodules, while the gpxA single and double mutants exhibited an abnormal nodulation phenotype coupled to more than 50% reduction in nitrogen-fifixing capacity, this defect in nodulation was characterized by the formation of undeveloped and ineffective nodules. In addition, the gorA and gpxA double mutant was severely impaired in rhizosphere colonization. LC-MS/MS analysis quantitative proteomics techniques were employed to compare differential gpxA mutant root bacteroids in response to the wild type infection. Sixty differentially expressed proteins were identified including seven up-regulated and twenty down-regulated proteins. By sorting the down-regulated proteins according to metabolic function, eight proteins were transporter protein, seven proteins were dehydrogenases and deoxygenases. Moreover, three down-regulation proteins are directly involved in nodule process.

INSTRUMENT(S): Q Exactive Plus

ORGANISM(S): Rhizobium Leguminosarum Bv. Viciae

SUBMITTER: Guojun Cheng  

LAB HEAD: Guojun Cheng

PROVIDER: PXD022029 | Pride | 2020-11-16

REPOSITORIES: Pride