The poetry of reproduction: the role of LEAFY in Arabidopsis thaliana flower formation

Abstract

For successful reproduction, angiosperms must form fertile flowers at the appropriate positions and at the appropriate times. The reproductive transition is especially important for monocarpic plants that only flower once. In the model annual plant Arabidopsis thaliana, this transition is controlled through regulation of a group of genes termed floral meristem identity genes, of which LEAFY (LFY) is arguably the most important. LFY orthologs are found throughout land plants and are essential for angiosperm reproduction. These genes have also been implicated in reproductive development in gymnosperms. LFY encodes a plant-specific transcription factor that can act as either an activator or repressor depending on context, including what co-factors it is interacting with. It controls multiple aspects of floral morphogenesis, including phyllotaxis, organ number, organ identity and determinacy. Much progress has been made in elucidating the molecular mechanisms through which LFY and its orthologs contribute to a precise switch to flowering. We discuss the current state of knowledge in Arabidopsis, with an emphasis on known target genes and co-factors of LFY.

Master regulators in development: Views from the Drosophila retinal determination and mammalian pluripotency gene networks

“…Master control genes function in networks across kingdoms and in a variety of developmental contexts, ranging from establishment of mammalian embryonic pluripotency to plant organogenesis to myogenesis (Aziz et al, 2010; Chan and Kyba, 2013; Ciglar and Furlong, 2009; Desplan, 1997; Hamdi et al, 1987; Jaenisch and Young, 2008; Kumar, 2009; Nambu et al, 1991; Ó’Maoiléidigh et al, 2014; Ohno, 1979; Silva et al, 2016; Siriwardana and Lamb, 2012; Takahashi and Yamanaka, 2015; Tapscott, 2005). Positive cross-regulation within these hierarchies has been proposed to assemble unique linear pathways tailored to the control of specific cellular events and to produce the bistable switch-like responses associated with cell fate decisions, consequently expanding the number of distinct instructions that master regulators provide in a manner that would be impossible for a single transcription factor (Desplan, 1997; Ferrell Jr, 2002; Ferrell Jr and Xiong, 2001; Mitrophanov and Groisman, 2008).…”

An ortholog of LEAFY in Jatropha curcas regulates flowering time and floral organ development

“…LFY acts as a master regulator, orchestrating the floral gene network; it activates downstream genes that determine the unique identities of floral meristem (FM) tissue and floral organ primordia. LFY directly regulates flower organ identity genes including CAULIFLOWER ( CAL ), APETALA1 ( AP1 ), APETALA3 ( AP3 ), AGAMOUS ( AG ), SEPALLATA ( SEP ), and TERMINAL FLOWER1 ( TFL1 )2021. Accordingly, LFY controls multiple aspects of floral morphogenesis, including phyllotaxis, organ number, organ identity, and determinacy22.…”

OEP40, a Regulated Glucose-permeable β-Barrel Solute Channel in the Chloroplast Outer Envelope Membrane

“…To determine the transition to flowering also on a morphological and molecular basis, we followed the morphological changes at the shoot apical meristem (SAM) from oep40-1, oep40-3, and wild-type lines over a 3-week time period. We used LEAFY (LFY), a plant-specific transcription factor (27), as an RNA probe to identify emerging floral primor- dia. About 4 days earlier than in wild type, we detected strong LFY transcript-specific signals in apices of oep40-1 and oep40-3 lines (Fig.…”