Project description:Plants have evolved a unique and conserved developmental program that enables the conversion of leaves into floral organs. Elegant genetic and molecular work has identified key regulators of floral meristem identity. However, further understanding of flower meristem specification has been hampered by redundancy and by pleiotropic effects. The KNOXI gene STM transcription factor is a well-characterized regulator of shoot apical meristem maintenance. stm loss-of-function mutants arrest shortly after germination, and therefore the knowledge on later roles of STM, including flower development, is limited. Here, we uncover a role for STM in the specification of flower meristem identity. Silencing STM in the AP1 expression domain in the ap1-4 mutant background resulted in a complete leafy-like flower phenotype and an intermediate stm-2 allele enhanced the floral meristem identity phenotype of ap1-4. Transcriptional profiling of STM perturbation suggested that STM activity affects multiple meristem identity and flower transition genes, among them the F-Box gene UFO. In agreement, stm-2 enhanced the ufo-2 floral meristem fate phenotype, and ectopic UFO expression rescued the leafy flowers in genetic backgrounds with compromised AP1 and STM activities. This work suggests a molecular mechanism that underlies the activity of STM in the specification of flower meristem identity.
Project description:The aim of this experiment is to test the ability of the ortholog of Arabidopsis LFY gene from flowering and non flowering species to complement an Arabidopsis LFY mutant. <br>Plants expressing, in a homozygous lfy12 background, the open reading frame of LFY orthologs under the control of Arabidopsis LFY promoter were synchronously induced to flower by growing plants in short days for 30 days then shifting them to Long Day for an additional 8 days. Shoot apices were dissected at either d0 or d8 in long days. Two biological replicates were performed. The following genotypes were used: <br>Col - wild type arabidopsis; reference strain<br>LFY (lfy12; LFY::AthLFY) - Arabidopsis<br>UNI (lfy12; LFY::UNI) - Pisum<br>ALF (lfy12; LFY::ALF) - Petunia <br>WelNDLY (lfy12; LFY::WelNDLY) - Welwitschia mirabilis<br>CrLFY1 (lfy12; LFY::CrLFY1) - Ceratopteris richardii<br>CrLFY2 (lfy12; LFY::CrLFY2) - Ceratopteris richardii<br>lfy-2; weak lfy allele<br>lfy-9; intermediate leafy allele<br>lfy-12; strong leafy allele.
Project description:Investigation of gene expression level changes in snapdragon petals and sepals during flower development The flower developmental stages analyzed in this study are representative of distinct developmental events: (i) preanthesis, (ii) anthesis, (iii) maturation and (iv) presenescence and are further described in the accompanying article. A 24 chip study using total RNA recovered from samples of petal and sepal tissue of Antirrhinum majus cv. Maryland True Pink harvested at four different stages of flower development, namely (i) preanthesis (three days before flower opening=d-3), (ii) anthesis (day of flower opening=d1), (iii) maturation (four days after flower opening=d4) and (iv) presenescence (seven days after flower opening=d7). Three separate samples were extracted per tissue and developmental stages. Each chip measures the expression level of 11,959 ESTs from Antirrhinum majus cv. Maryland True Pink with up to six 60-mer probes per target.