Control of NO level in rhizobium-legume root nodules: not only a plant globin story

Plant Signal Behav. 2013 Oct;8(10):doi: 10.4161/psb.25923. doi: 10.4161/psb.25923.

Abstract

Nitric oxide (NO ) is a gaseous signaling molecule which plays both regulatory and defense roles in animals and plants. In the symbiosis between legumes and rhizobia, NO has been shown to be involved in bacterial infection and nodule development steps as well as in mature nodule functioning. We recently showed that an increase in NO level inside Medicago truncatula root nodules also could trigger premature nodule senescence. Here we discuss the importance of the bacterial Sinorhizobium meliloti flavohemoglobin to finely tune the NO level inside nodules and further, we demonstrate that S. meliloti possesses at least two non redundant ways to control NO and that both systems are necessary to maintain efficient nitrogen fixing activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism
  • Fabaceae / metabolism*
  • Fabaceae / microbiology
  • Hemeproteins / metabolism
  • Medicago truncatula / metabolism
  • Medicago truncatula / microbiology
  • Nitric Oxide / metabolism*
  • Plant Roots / metabolism
  • Plant Roots / microbiology
  • Rhizobium / metabolism*
  • Root Nodules, Plant / metabolism*
  • Root Nodules, Plant / microbiology
  • Sinorhizobium meliloti / metabolism

Substances

  • Bacterial Proteins
  • Hemeproteins
  • flavohemoprotein, Bacteria
  • Nitric Oxide