The spermine synthase OsSPMS1 regulates seed germination, grain size, and yield (Plant Physiol)

Polyamines including spermine and spermidine are present in all eukaryotes and have diverse roles. In plants they have been implicated in responses ranging from abiotic and biotic stresses to grain filling. Tao et al. examined the function of OsPMS1, encoding a spermine synthase, through genetic methods including RNAi and overexpression approaches. Knocking out OsPMS1 leads to an accumulation of spermidine but reduced levels of spermine, and also an increase in grain yields (both grain size and number); overexpression lines showed the opposite effects. The RNAi lines also showed elevated levels of ethylene accumulation, possibly because polyamines and ethylene share a common precursor, S-adenosyl methionine. Plant Physiol. (Summary by Mary Williams)  10.1104/pp.18.00877