Understanding Effector Secretion and Function of two Proteobacteria: Pseudomonas syringae and Candidatus Liberibacter asiaticus
- Author(s): Hawara, Eva
- Advisor(s): Ma, Wenbo
- et al.
Gram-negative bacteria employ secretion systems to deliver virulence factors, such as effectors, to target plant immunity in hosts. My research focuses on secreted effectors from plant pathogenic bacteria Pseudomonas syringae and Candidatus Liberibacter asiaticus.
In chapter one, I focused on P. syringae type III secreted effector HopZ1a. I confirmed the relationship between HopZ1a-mediated acetylation and subsequent degradation of its target JAZs (JAZ10) in Arabidopsis thaliana. Next, I determined decreased susceptibility in JAZ10 plants mutated in acetylation sites during infection, indicating HopZ1a-mediated acetylation and subsequent degradation of JAZ10 affects bacterial growth. My findings in this chapter highlight the significance of HopZ1a’s acetylation modification of JAZs.
In chapter two, I optimized the use of CLas Sec-delivered effector 1 (SDE1) (CLIBASLIA_05315) for direct tissue blot immunoassay (DTBIA). I also generated Liberibacter crescens (L. crescens) cell and lipopolysaccharide (LPS) specific antibodies to serve as a cocktail primary antibody for enzyme-linked immunosorbent assay (ELISA). Furthermore, L. crescens LPS structural analysis by the Complex Carbohydrate Research Center (CCRC) revealed the presence of very long chain fatty acid (VLCFA 27OHC28:0). It is possible this VLCFA is required for culturing of Liberibacters.
In chapter three, I generated a functional model system to confirm CLas predicted secreted effectors using L. crescens. Our lab generated a list of predicted secreted effectors of CLas and we focused on some for detection biomarkers, and functional work was performed on one effector SDE1 (CLIBASIA_05315). Using this foundation of knowledge, I used SDE1 as my test subject for secretion in L. crescens. My research shows that L. crescens can serve as a tool to confirm and possibly study CLas secreted effectors.