Table 2.

Described mutations affecting virulence and pathogenicity factors in tumorigenic pathovars of Pseudomonas savastanoi.

Trait affected	Gene	Pathovar	Function	Effect in knot development	Other phenotypes	Reference
Metabolism of IAA	p-IAAa	savastanoi/nerii	IAA biosynthesis	Absence of knot	Enhanced swarming	Comai and Kosuge, 1980; Surico et al., 1985; Soby et al., 1991
	iaaMHb	savastanoi	IAA biosynthesis	Absence of knot		Aragón et al., 2014
	iaaM	nerii	IAA biosynthesis	Absence of knot		Cerboneschi et al., 2016
	iaaL	nerii	IAA conjugation	Volume reduction		Glass and Kosuge, 1988
	iaaL	nerii	IAA conjugation	Volume increase		Cerboneschi et al., 2016
Production of cytokinins	Δp-ptzc	nerii	Cytokinin biosynthesis	Volume reduction		Iacobellis et al., 1994
	ΔpPsv48Ac	savastanoi	Cytokinin biosynthesis	Volume reduction		Bardaji et al., 2011
Type III secretion system	hrcC	savastanoi	Outer membrane pore protein	Absence of knot	No HRd in Nicotiana tabacum	Sisto et al., 2004
	hrpA	savastanoi	Pilin protein	Absence of knot	Unable to multiply in plant tissue No HRd in Nicotiana tabacum	Pérez-Martínez et al., 2010
		nerii	Pilin protein	Absence of knot		Cerboneschi et al., 2016
	hrpR	savastanoi	Transcriptional regulator	Absence of knot	Unable to multiply in plant tissue	Matas et al., 2012
	hrpL	savastanoi	Transcriptional regulator (sigma-54)	Absence of knot	No HRd in Nicotiana tabacum	Matas et al., 2014
	hopAO1	savastanoi	Phosphatase	Volume reduction Increased necrosis	Reduced competitiveness in olive plants	Castañeda-Ojeda et al., 2017b
c-di-GMP metabolism	bifA	savastanoi	Phosphodiesterase	Volume reduction	Reduced swimming	Aragón et al., 2015a
	dgcP	savastanoi	Diguanylate cyclase	Volume reduction	Increased swimming Reduced biofilm formation Decreased expression of T6SS genes (hcp1 and vgrG)	Aragón et al., 2015b
	pleDe	savastanoi	Diguanylate cyclase	Volume increase Reduction of necrotic tissue	Reduced swimming Increased biofilm formation	Perez-Mendoza et al., 2014
Quorum sensing	luxI	savastanoi	AHL synthase	Volume reduction	Reduced exopolysaccharide production	Hosni et al., 2011
	luxR	savastanoi	AHL receptor	Volume reduction	Reduced exopolysaccharide production	Hosni et al., 2011
Metabolism of phenolics	antA	savastanoi	Anthranilate catabolism	Volume reduction		Caballo-Ponce et al., 2017
	catB	savastanoi	Catechol catabolism	Volume reduction		Caballo-Ponce et al., 2017
	ipoABCb	savastanoi	Oxygenase on phenolics	Volume reduction		Caballo-Ponce et al., 2017

^aAnalyzed in strains cured of a plasmid encoding the iaaMH operon.

^bGenes iaaM-iaaH and ipoA-ipoB-ipoC are organized in operons.

^cAnalyzed in strains cured of a plasmid encoding the ptz gene.

^dHR, hypersensitive response.

^eOverexpression of pleD from Caulobacter crescentus.