An effector from the Huanglongbing-associated pathogen repressing host hypersensitive reaction to facilitate pathogenesis
Zhiqian Pang: University of Florida
<div><strong>An effector from the Huanglongbing-associated pathogen repressing host hypersensitive reaction to facilitate pathogenesis</strong></p> <p>Zhiqian Pang Jinyun Li Shuo Duan Nian Wang</p> <p>Citrus Research and Education Center, Department of Microbiology and Cell Science, University of Florida, Lake Alfred, FL 33850, USA.</p> <p><sup> </sup></p> <p> </p> <p>*Correspondence author: Nian Wang, <a href="mailto:nianwang@ufl.edu";>nianwang@ufl.edu<;/a></p> <p> </p> <p>Citrus Huanglongbing (HLB) also known as citrus greening disease is caused by the psyllid-transmitted, phloem-limited bacteria ‘<em>Candidatus</em> Liberibacter. asiaticus’ (CLas), ‘<em>Ca.</em> Liberibacter. africanus’ (CLaf), and ‘<em>Ca.</em> Liberibacter. americanus’ (CLam). HLB is the most destructive disease which eliminates the productivity of citrus trees, with reported losses of 30 to 100%. However, the pathogenicity mechanisms of Liberibacters remain unknown partially because ‘<em>Ca</em>. Liberibacter’ species have not been cultured. Sec-dependent effectors (SDEs) have been known to play critical roles in the pathogenicity of phloem-limited bacteria. It has been suggested that SDEs are secreted into phloem or companion cells and interact with host proteins that facilitate compatibility or disease development. Here, we characterized a Sec-dependent effector. This effector is highly expressed in citrus host at early stage of CLas infection. Constitutively expressing this effector in plants not only affects the growth and development, but also regulates plant innate immunity by prohibiting defense responses of plants to make plants more susceptible to pathogen infections. Its targets were identified by yeast-two-hybrid analysis, pull-down assay, or bimolecular fluorescence complementation. We also analyzed how those targets are involved in HLB disease development.</div>
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