the destructive citrus pathogen, ‘candidatus liberibacter asiaticus’ encodes a functional flagellin characteristic of a pathogen-associated molecular pattern破坏性的柑橘病原体,candidatus liberibacter asiaticus的编码功能鞭毛蛋白其分子模式的特征.pdf

The Destructive Citrus Pathogen, ‘Candidatus Liberibacter asiaticus’ Encodes a Functional Flagellin Characteristic of a Pathogen-Associated Molecular Pattern 1,4 2 1,3 2 4 1 Huasong Zou , Siddarame Gowda , Lijuan Zhou , Subhas Hajeri , Gongyou Chen , Yongping Duan * 1 United States Horticultural Research Laboratory, United States Department of Agriculture-Agricultural Research Service, Fort Pierce, Florida, United States of America, 2 Citrus Research and Education Center, University of Florida-Institute of Food and Agricultural Sciences, Lake Alfred, Florida, United States of America, 3 Indian River Research and Education Center, University of Florida, Fort Pierce, Florida, United States of America, 4 School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China Abstract Huanglongbing (HLB) is presently the most devastating citrus disease worldwide. As an intracellular plant pathogen and insect symbiont, the HLB bacterium, ‘Candidatus Liberibacter asiaticus’ (Las), retains the entire flagellum-encoding gene cluster in its significantly reduced genome. Las encodes a flagellin and hook-associated protein (Fla) of 452 amino acids that contains a conserved 22 amino acid domain (flg22) at positions 29 to 50 in the N-terminus. The phenotypic alteration in motility of a Sinorhizobium meliloti mutant lacking the fla genes was partially restored by constitutive expression of FlaLas. Agrobacterium-mediated transient expression in planta revealed that FlaLas induced cell death and callose deposition in Nicotiana benthamiana, and that the transcription of BAK1 and SGT1, which are associated with plant innate immunity, was upregulated. Amino acid substitution experim