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The small phytoplasma virulence effector SAP 11 contains distinct domains required for nuclear targeting and CIN ‐ TCP binding and destabilization
Author(s) -
Sugio Akiko,
MacLean Allyson M.,
Hogenhout Saskia A.
Publication year - 2014
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12721
Subject(s) - effector , biology , phytoplasma , mutant , virulence , microbiology and biotechnology , arabidopsis , aster yellows , morphogenesis , transcription factor , arabidopsis thaliana , genetics , gene , polymerase chain reaction , restriction fragment length polymorphism
Summary Phytoplasmas are insect‐transmitted bacterial phytopathogens that secrete virulence effectors and induce changes in the architecture and defense response of their plant hosts. We previously demonstrated that the small (± 10 kDa) virulence effector SAP 11 of A ster Y ellows phytoplasma strain W itches' B room ( AY ‐ WB ) binds and destabilizes Arabidopsis CIN ( CINCINNATA ) TCP ( TEOSINTE ‐ BRANCHED , CYCLOIDEA , PROLIFERATION FACTOR 1 AND 2) transcription factors, resulting in dramatic changes in leaf morphogenesis and increased susceptibility to phytoplasma insect vectors. SAP 11 contains a bipartite nuclear localization signal ( NLS ) that targets this effector to plant cell nuclei. To further understand how SAP 11 functions, we assessed the involvement of SAP 11 regions in TCP binding and destabilization using a series of mutants. SAP 11 mutants lacking the entire N ‐terminal domain, including the NLS , interacted with TCP s but did not destabilize them. SAP 11 mutants lacking the C ‐terminal domain were impaired in both binding and destabilization of TCP s. These SAP 11 mutants did not alter leaf morphogenesis. A SAP 11 mutant that did not accumulate in plant nuclei ( SAP 11Δ NLS ‐ NES ) was able to bind and destabilize TCP transcription factors, but instigated weaker changes in leaf morphogenesis than wild‐type SAP 11. Overall the results suggest that phytoplasma effector SAP 11 has a modular organization in which at least three domains are required for efficient CIN ‐ TCP destabilization in plants.