Poly-3-hydroxybutyrate (PHB) supports survival and reproduction in starving rhizobia.

@article{Ratcliff2008Poly3hydroxybutyrateS,
  title={Poly-3-hydroxybutyrate (PHB) supports survival and reproduction in starving rhizobia.},
  author={William C Ratcliff and Supriya V. Kadam and Robert Ford Denison},
  journal={FEMS microbiology ecology},
  year={2008},
  volume={65 3},
  pages={391-9}
}
The carbon that rhizobia in root nodules receive from their host powers both N(2) fixation, which mainly benefits the host, and rhizobium reproduction. Rhizobia also store energy in the lipid poly-3-hydroxybutyrate (PHB), which may enhance rhizobium survival when they are carbon limited, either in nodules or in the soil between hosts. There can be a conflict of interest between rhizobia and legumes over the rate of PHB accumulation, due to a metabolic tradeoff between N(2) fixation and PHB… CONTINUE READING