Caracterization of TAL-effector mediated resistance to citrus canker using a new variant of Xanthomonas citri

ROESCHLIN, ROXANA A.; UVIEDO, F; GARCÍA, M.L.; MOLINA, M.C; FAVARO, M.A; CHIESA, M.A; TASELLI, S; FRANCO-ZORRILLA; FORMENT, J; GADEA, J; MARANO, M.R

MOLECULAR PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019 vol. 20 p. 1394 - 1407

1464-6722

Transcription-activator like effectors (TALEs) are important effectors ofXanthomonas spp. that manipulate the transcriptome of the host plant, conferringsusceptibility or resistance to bacterial infection. Xanthomonas citri subsp. citri^variant AT (X. citri AT) triggers a host-specific hypersensitive response (HR) thatsuppresses citrus canker development. However, the bacterial effector that elicits thisprocess is unknown.In this study, we show that a 7.5-repeats TALE is responsible for triggering the HR. PthA4AT was identified within the pthA repertoire of X. citri AT followed by assay of the effects on different hosts. The mode of action of PthA4AT was characterized using protein-binding microarrays and testing the effects of deletion of the nuclear localization signals and activation domain on plant responses. PthA4AT is able to bind DNA and activate transcription in an effector binding element-dependent manner. Moreover, HR requires PthA4AT nuclear localization, suggesting the activation of executor resistance (R) genes in host and also non-hostplants.This is the first case where a TALE of unusually short length performs a biological function by means of its repeat domain, indicating that the action of these effectors toreprogram the host transcriptome following nuclear localization is not limited to classical? TALEs.