The Ins and Outs of Ovule Development

Abstract

In the past few years, ovule development has been widely studied in different plant species, both from a morphological and a more molecular point of view. At early stages of flower development, the placenta becomes specified inside the carpel and ovules develop from this tissue as meristematic protuberances. Shortly after, a complicated genetic network regulates ovule patterning controlling the differentiation of three regions named funiculus, chalaza and nucellus. In the past decade, genes playing important roles during ovule development have been identified, and in a few cases, genetic models that could explain the molecular relationship among these genes have been proposed. Here we focus our attention on the molecular genetic mechanisms that stand at the base of ovule development in the model speciesArabidopsis thalianaand we report an updated description of the molecular networks controlling both sporophytic and gametophytic tissue development in the ovule. Furthermore, we observe that the mechanisms controlling ovule development seem to be evolutionary conserved, even in a distantly related species such as rice.

Dissection of the Arabidopsis HUA‐PEP gene activity reveals that ovule fate specification requires restriction of the floral A‐function

“…Shifting the composition of MADS‐box complexes (tetramers), from those combining E (SEPALLATA, SEP), C (AG) and D proteins (thus specifying ovule fate; Fig. 7a), to those including only AG and SEP proteins, may result in the promotion of carpel identity (Pelaz et al , 2000; Theissen & Saedler, 2001; Favaro et al , 2003; Ditta et al , 2004; Battaglia et al , 2009; Immink et al , 2009; Fig. 7b).…”

“…Ovules, proposed as a model organ, provide an excellent platform to study differentiation because they recapitulate fundamental aspects of plant development during its morphogenesis and are fundamental for reproduction and crop yield (Skinner et al , 2004; Battaglia et al , 2009; Kelley & Gasser, 2009; Bencivenga et al , 2012; Cucinotta et al , 2014; Gasser & Skinner, 2019). Evolutionary conservation of A‐class gene function, as originally defined in Arabidopsis, is limited (Causier et al , 2010; Heijmans et al , 2012b).…”