Trans-acting siRNA-mediated repression of ETTIN and ARF4 regulates heteroblasty in Arabidopsis

摘要: Mutations in the ARGONAUTE gene ZIPPY(ZIP)/AGO7 Arabidopsis accelerate juvenile-to-adult transition. A screen for mutations that suppress this precocious phenotype yielded alleles of two auxin-related transcription factors known to be upregulated zip: ETTIN (ETT)/ARF3 and ARF4. ETT/ARF3 ARF4 delay expression adult traits, demonstrating these genes have non-redundant roles shoot maturation. ZIP is not generally required production trans-acting (ta) siRNAs, but and/or stability tasiR-ARF, a ta-siRNA targets both tasiR-ARF absent zip-2, overexpression tasiR-ARF-insensitive form ETT mimics zip phenotype. We conclude attributable absence tasiR-ARF-mediated repression The abundance RNA does change during vegetative development. This result suggests regulation establishes threshold at which leaves respond temporal signal, rather than being component signal.