TABLE 1.

List of common Gram-negative fish pathogens, including taxonomy information, disease type, virulence factors and virulence-related secretion systems obtained from experimental and/or genomic data.

Phylum	Strain	Disease	Virulence factors	Secretion systems (SS)	References
Gram-negatives
Bacteroidetes	Flavobacterium columnare	Columnaris	Adhesins, gliding motility, Fe-acquisition systems, proteases, hemolysins chondroitin sulfate lyase	T9SS, T6SSiii	Boyd and Cornelis, 2001; Secades et al., 2001; Stringer-Roth et al., 2002; Kumru et al., 2017; Li et al., 2017; Kunttu et al., 2021
	Flavobacterium psychrophilum	Rainbow trout fry syndrome (RTFS) and cold water disease (CWD)	Adhesins, gliding motility, proteases, hemolysins elastase	T9SS	Ostland et al., 2000; Duchaud et al., 2007; Rochat et al., 2019; Barbier et al., 2020
	Flavobacterium branchiophilum	Gill disease	Adhesins, proteases, toxins	T9SS, T6SSiii	Ostland et al., 1997; Touchon et al., 2011; Kumru et al., 2020
	Flavobacterium spartansii	Pathological lesions, systemic infection	Adhesins, gliding motility, hemolysins toxins	T9SS, T6SSiii	Chen et al., 2017; Kumru et al., 2020
	Tenacibaculum maritimum	Tenacibaculosis	Adhesins, gliding motility, Fe-acquisition systems, chondroitin sulfate lyase	T9SS	Pérez-Pascual et al., 2017
Proteobacteria	Vibrio anguillarum	Vibriosis	Surface-hydrophobicity, Flagella, type IV pili, Fe-acquisition systems, metalloprotease, hemolysins	T2SS, T6SS	Rodkhum et al., 2005; Lopez and Crosa, 2007; Cianciotto and White, 2017
	Vibrio harveyi	Vibriosis	Flagella, non-pilus adhesins, Fe-acquisition systems	T3SS	Zane et al., 2014; Osorio, 2018; Zhang et al., 2021
	Vibrio vulnificus	Warm-water vibriosis	Flagella, Type IV pili, non-pilus adhesins, Fe-acquisition systems, protease, hemolysin, phospholipase	T1SS	Litwin and Byrne, 1998; Valiente et al., 2008; Jang et al., 2017; Guo et al., 2018
	Vibrio parahaemolyticus	Gastroenteritis, wound infections, and septicemia	Fe-acquisition systems, metalloprotease and serine protease, effectors	T2SS, T3SS*, T6SS*	Tanabe et al., 2003; Hiyoshi et al., 2010; Cianciotto and White, 2017; Li L. et al., 2019
	V. alginolyticus		Flagella, Fe-acquisition systems proteases, effectors	T3SS, T6SS	Cai et al., 2007; Wang Q. et al., 2007; Zhao et al., 2010; Salomon et al., 2015
	V. ordalii		Fe-acquisition systems	T3SS	Osorio et al., 2015; Ruiz et al., 2019
	V. splendidus		Flagella, Fe-acquisition systems non-pilus adhesins, effectors	T3SS	Song et al., 2018; Dai et al., 2020; Zhuang et al., 2020, 2021
	Allivibrio salmonicida	Cold-water vibriosis	Surface-hydrophobicity, Fe-acquisition systems, proteases, effectors	T3SS	Espelid et al., 1987; Winkelmann et al., 2002; Frey and Origgi, 2016
	Photobacterium damselae	Photobacteriosis, Skin ulcer	Fe-acquisition systems endopeptidase, toxin hemolysin, lipase, esterase-lipase, phospholipase	T2SS, T3SS	Labella et al., 2010; Rivas et al., 2011; Valderrama et al., 2019
Enterobacterials	Yersinia ruckeri	Enteric red mouth (ERM)	Type IV pilus, Fe-acquisition systems, proteases, toxins	T1SS, T4SS, T5SS	Fernández et al., 2002, 2004; Wrobel et al., 2018, 2019
	Edwardsiella ictaruli	Edwardsiellosis	Adhesin, Fe-acquisition system, proteases, effectors	T3SS	Thune et al., 2007; Abayneh et al., 2013; Abdelhamed et al., 2016; Castro et al., 2016
	Edwardsiella tarda (New name: Edwardsiella piscicida)	Edwardsiellosis	Adhesin, Fe-acquisition systems hemolysin, proteases, effectors	T3SS, T5SS, T6SS,	Wang X. et al., 2010; Jiao et al., 2010; Hu et al., 2016, 2019; Cheng et al., 2017
	Citrobacter freundii	Gastroenteritis and hemorrhagic septicemia	Adhesin, Fe-acquisition systems	T3SS	Leo et al., 2015; Pan et al., 2021
Aeromonadales	Aeromonas bestiarum	Motile Aeromonas septicemia (MAS)	Fe-acquisition systems,	T1SS, T2SS	Ali, 1996
	Aeromonas salmonicida	Furunculosis	Surface hydrophobicity, Fe-acquisition systems, hemolysin, lipase	T1SS, T2SS, T3SS*, T6SS	Titball and Munn, 1981; Burr et al., 2003; Dacanay et al., 2006; Reith et al., 2008; Balado et al., 2015
	Aeromonas hydrophila	Motile Aeromonas septicemia (MAS)	Surface hydrophobicity, adhesin, Fe-acquisition systems, hemolysins, proteases	T1SS, T2SS* T3SS, T6SS	Barghouthi et al., 1989b; Chopra et al., 1993; Fadl et al., 2006; Barger et al., 2020
	Aeromonas veronii	Motile Aeromonas septicemia (MAS)	Adhesin, Fe-acquisition systems	T3SS	Namba et al., 2008; Silver and Graf, 2009; Li et al., 2011; Tekedar et al., 2019b
	Aeromonas sobria	Motile Aeromonas septicemia (MAS)	Pili, hemolysin	T1SS, T2SS	Chakraborty et al., 1990
Thiotrichales	Piscirickettsia salmonis	Piscirickettsiosis	Adhesin, Fe-acquisition systems, chaperonin, toxins	T3SS, T4SS, T6SS	Rojas et al., 2013; Rozas and Enríquez, 2014; Ortiz-Severín et al., 2019
Alteromonadales	Moritella viscosa	Winter ulcer	Flagella, Type IV pili, hemolysin, peptidase	T1SS, T2SS, T6SS	Løvoll et al., 2009; Björnsdóttir, 2011; Bjornsdottir et al., 2012
Pseudomonadales	Pseudomonas anguilliseptica	“Red spot disease” also known as “sekiten-byo”	Flagella, capsular antigen	NA	Lönnström et al., 1994; Berthe et al., 1995; López-Romalde et al., 2003a

* Secretion systems where the direct involvement in fish disease still has to be established, as most data was generated with non-fish models. NA, data not available.