Zhang J, Yin Z, White F. TAL effectors and the executor R genes.
FRONTIERS IN PLANT SCIENCE 2015;
6:641. [PMID:
26347759 PMCID:
PMC4542534 DOI:
10.3389/fpls.2015.00641]
[Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/02/2015] [Indexed: 05/19/2023]
Abstract
Transcription activator-like (TAL) effectors are bacterial type III secretion proteins that function as transcription factors in plants during Xanthomonas/plant interactions, conditioning either host susceptibility and/or host resistance. Three types of TAL effector associated resistance (R) genes have been characterized-recessive, dominant non-transcriptional, and dominant TAL effector-dependent transcriptional based resistance. Here, we discuss the last type of R genes, whose functions are dependent on direct TAL effector binding to discrete effector binding elements in the promoters. Only five of the so-called executor R genes have been cloned, and commonalities are not clear. We have placed the protein products in two groups for conceptual purposes. Group 1 consists solely of the protein from pepper, BS3, which is predicted to have catalytic function on the basis of homology to a large conserved protein family. Group 2 consists of BS4C-R, XA27, XA10, and XA23, all of which are relatively short proteins from pepper or rice with multiple potential transmembrane domains. Group 2 members have low sequence similarity to proteins of unknown function in closely related species. Firm predictions await further experimentation on these interesting new members to the R gene repertoire, which have potential broad application in new strategies for disease resistance.
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