It was proposed that increased synthesis of (p)ppGpp would cause polyphosphate (PolyP) accumulation in E. coli. The alarmone could interact with exopolyphosphatase PPX, which would inhibit the hydrolysis of PolyP, thus causing its accumulation in bacteria. Although it has recently been shown that it is actually DksA and not (p)ppGpp that causes this buildup.  It has been shown in Pseudomonas aeruginosa that the phoU mutant (phoU belongs to the Pho Regulon) synthesizes more (p)ppGpp and this would be one of the reasons that it accumulates more polyphosphate.