The stringent response regulator (p)ppGpp mediates virulence gene expression and survival in Erwinia amylovora

This RNA-seq analysis mainly examined the global effect of stringent resonse in E. amylovora under the T3SS-inducing condition. The (p)ppGpp mutant showed differential expression of more than 30% genes in the genome, which include significant down-regulation of T3SS genes and gene related to motiliey. On the other hand, genes involved in amino acid biosynthesis, translation, SOS response, DNA replication, chromosome segregation, as well as nucleotide metabolism, fatty acid and lipid biosynthesis were significantly up-regulated in (p)ppGpp mutant. These findings sugested that (p)ppGpp mediate the balance between virulence and survival. Overall design: Differential gene expression of the (p)ppGpp mutants versus wild type grown in the T3SS-inducing condition for 3 hours; Differential gene expression of WT under 6 hours versus 3 hours T3SS-inducing condition.