Upon fertilization, the ovary increases in size and undergoes a complex developmental process to become a fruit. We show that cytokinins (CKs), which are required to determine ovary size before fertilization, have to be degraded to facilitate fruit growth. The expression of CKX7, which encodes a cytosolic CK-degrading enzyme, is directly positively regulated post-fertilization by the MADS-box transcription factor STK. Similar to stk, two ckx7 mutants possess shorter fruits than wild type. Quantification of CKs reveals that stk and ckx7 mutants have high CK levels, which negatively control cell expansion during fruit development, compromising fruit growth. Overexpression of CKX7 partially complements the stk fruit phenotype, confirming a role for CK degradation in fruit development. Finally, we show that STK is required for the expression of FUL, which is essential for valve elongation. Overall, we provide insights into the link between CKs and molecular pathways that control fruit growth.

• MeSH
• Arabidopsis anatomie a histologie   genetika   růst a vývoj   MeSH
• cytokininy metabolismus   MeSH
• cytosol metabolismus   MeSH
• down regulace genetika   MeSH
• květy metabolismus   MeSH
• modely genetické MeSH
• ovoce anatomie a histologie   růst a vývoj   MeSH
• proteiny domény MADS metabolismus   MeSH
• proteiny huseníčku metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• signální transdukce MeSH
• velikost orgánu MeSH
• zeatin metabolismus   MeSH
• zelené fluorescenční proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH