U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 Subtropical Plant Pathology Research: Fort Pierce, FL
 close



    Research

                    Research Projects
                                    Publications
                                    Collaborations
                                    News
                People

                    Staff Listing
                                    CareersSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Southeast Area Fort Pierce, Florida U.S. Horticultural Research Laboratory Subtropical Plant Pathology Research Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            Pitino, Marcoitem
                                            Armstrong, Cherylitem
                                            CANO, LILIANA - University Of Floridaitem
                                            Duan, Ping
  Submitted to: Frontiers in Plant Science
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 6/21/2016
                                    Publication  Date: 7/6/2016
                                    Publication URL: https://handle.nal.usda.gov/10113/5425116Citation: Pitino, M., Armstrong, C.M., Cano, L.M., Duan, Y. 2016. Transient expression of Candidatus Liberibacter asiaticus effector induces cell death in Nicotiana benthamiana. Frontiers in Plant Science. 7:982. doi: 10.3389/fpls.2016.00982.Interpretive Summary: Candidatus Liberibacter asiaticus (Las), a bacterial plant pathogen, is the most prevalent species of Liberibacter associated with the devastating disease of citrus known as huanglongbing. Host-pathogen relationships encompass a myriad of protein-protein interactions including those that help the pathogen colonize and subsequently multiply within the plant. Effectors are proteins expressed by the pathogen that are known to aid in the infection process and understanding their roles often leads to more successful methods of pathogen control. However, the effector proteins of Las remain largely unknown. Because of this, a novel approach utilizing the Las secretome and a transient expression system in Nicotiana benthamiana was used to identify and assess the function of candidate effector proteins. In total, we revealed the diverse subcellular locations of the 16 candidate Las effectors. Moreover, one of the candidate effectors localized to the chloroplasts, Las5315, not only induced cell death in N. benthamiana at 3 days post inoculation but also suppressed pathogen-associated molecular pattern triggered immunity induced by the flagellin from Xanthomonas citri ssp. citri. This study helps understand how Las bacteria cause citrus HLB through their effectors, and therefore, we can control HLB by blocking the function of these effectors.
                                Technical Abstract: Candidatus Liberibacter asiaticus (Las) is a phloem-limited bacterial plant pathogen, and the most prevalent species of Liberibacter associated with citrus huanglongbing (HLB), a devastating disease of citrus worldwide. Although the complete sequence of the Las genome provides the basis for studying functional genomics of Las and molecular mechanisms of Las-plant interactions, the functional characterization of Las effectors remains a slow process since Las has a significantly reduced genome and remains to be cultured. Like other plant pathogens, Las may deliver effector proteins that modulate a variety of host cellular functions during the infection progress. In this study, we identified 16 candidate Las effectors via bioinformatics, and transiently expressed them in Nicotiana benthamiana plants. Using this heterologous expression system, diverse subcellular localization patterns with different shapes and aggregates of the effector candidates were revealed by UV- microscopy. Intriguingly, one of the sixteen candidates, Las5315, was found to localize to the chloroplasts and induced cell death at 3 days post inoculation in N. benthamiana. Moreover, Las5315 also suppressed pathogen-associated molecular patterns (PAMP)-triggered immunity (PTI) induced by Xcc-flg22. Overall, this study provides new insight into the localization and potential roles of these Las effectors in planta.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov