Ectopic Expression of Two FOREVER YOUNG FLOWER Orthologues from Cattleya Orchid Suppresses Ethylene Signaling and DELLA Results in Delayed Flower Senescence/Abscission and Reduced Flower Organ Elongation in Arabidopsis
- 1 Downloads
Two orthologues of Arabidopsis FOREVER YOUNG FLOWER (FYF), CaFYF1 and CaFYF2, were identified from Cattleya intermedia. To investigate the function of these two genes, we performed ectopic expression of CaFYF1/2 in Arabidopsis. Delayed flower senescence and abscission were observed in 35S::CaFYF1/2 transgenic Arabidopsis plants. Furthermore, once CaFYF1/2 was fused with the strong repressor domain SRDX, severe delayed flower senescence and abscission were observed in 35S::CaFYF1/2+SRDX transgenic Arabidopsis plants. In contrast, when 35S::CaFYF1/2 was converted to a potent activator by fusion with the VP16-AD motif, flower senescence and abscission were promoted in these 35S::CaFYF1/2+VP16 transgenic dominant-negative mutant Arabidopsis plants. These results indicated that similar to Arabidopsis FYF, CaFYF1/2 also act as repressors in controlling floral organ senescence and abscission in transgenic Arabidopsis plants. The delayed senescence and abscission of the flower organs in 35S::CaFYF1/2 and 35S::CaFYF1/2+SRDX transgenic Arabidopsis plants were unaffected by ethylene treatment. Genes of the ethylene signaling and abscission-associated pathways, such as EDF1/2/3/4, BOP1/2, and IDA, were repressed in 35S::CaFYF1/2 and 35S::CaFYF1/2+SRDX transgenic Arabidopsis plants. Furthermore, 35S::CaFYF1/2 and 35S::CaFYF1/2+SRDX transgenic Arabidopsis plants showed additional morphological defects, such as short sepals and petals, which were correlated with the upregulation of the DELLA genes RGA, GAI, RGL1, and RGL2. These results suggested a possible role for Cattleya orchid CaFYF1/2 in controlling floral senescence/abscission by suppressing ethylene signaling and abscission-associated genes as well as controlling flower organ elongation through negative regulation of GA response by activating the expression of the DELLA genes during flower development.
KeywordsSenescence Abscission Cattleya intermedia Ethylene responses FOREVER YOUNG FLOWER MADS box gene Repressor
This work was supported by grants to C-H Y from the Ministry of Science and Technology, Taiwan, ROC, grant numbers MOST 106-2321-B-005-003 and MOST 106-2321-B-005-010. This work was also financially supported (in part) by the Advanced Plant Biotechnology Center from The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education (MOE) in Taiwan.
- Alonso JM, Stepanova AN, Leisse TJ, Kim CJ, Chen H, Shinn P, Stevenson DK, Zimmerman J, Barajas P, Cheuk R, Gadrinab C, Heller C, Jeske A, Koesema E, Meyers CC, Parker H, Prednis L, Ansari Y, Choy N, Deen H, Geralt M, Hazari N, Hom E, Karnes M, Mulholland C, Ndubaku R, Schmidt I, Guzman P, Aguilar-Henonin L, Schmid M, Weigel D, Carter DE, Marchand T, Risseeuw E, Brogden D, Zeko A, Crosby WL, Berry CC, Ecker JR (2003) Genome-wide insertional mutagenesis of Arabidopsis thaliana. Science 301:653–657CrossRefGoogle Scholar
- Arora A (2005) Ethylene receptors and molecular mechanism of ethylene sensitivity in plants. Curr Sci 89:1348–1361Google Scholar
- Fernandez DE, Wang CT, Zheng Y, Adamczyk BJ, Singhal R, Hall PK, Perry SE (2014) The MADS-domain factors AGAMOUS-LIKE15 and AGAMOUS-LIKE18, along with SHORT VEGETATIVE PHASE and AGAMOUS-LIKE24, are necessary to block floral gene expression during the vegetative phase. Plant Physiol 165:1591–1603CrossRefGoogle Scholar
- Stenvik GE, Tandstad NM, Guo Y, Shi CL, Kristiansen W, Holmgren A, Clark SE, Aalen RB, Butenko MA (2008) The EPIP peptide of INFLORESCENCE DEFICIENT IN ABSCISSION is sufficient to induce abscission in Arabidopsis through the receptor-like kinases HAESA and HAESA-LIKE2. Plant Cell 20:1805–1817CrossRefGoogle Scholar