Deciphering gene regulatory networks that control seed development and maturation in Arabidopsis

Abstract

SummarySeeds represent the main source of nutrients for animals and humans, and knowledge of their biology provides tools for improving agricultural practices and managing genetic resources. There is also tremendous interest in using seeds as a sustainable alternative to fossil reserves for green chemistry. Seeds accumulate large amounts of storage compounds such as carbohydrates, proteins and oils. It would be useful for agro-industrial purposes to produce seeds that accumulate these storage compounds more specifically and at higher levels. The main metabolic pathways necessary for oil, starch or protein accumulation are well characterized. However, the overall regulation of partitioning between the various pathways remains unclear. Such knowledge could provide new molecular tools for improving the qualities of crop seeds (Focks and Benning, 1998, Plant Physiol. 118, 91). Studies to improve understanding of the genetic controls of seed development and metabolism therefore remain a key area of research.In the model plant Arabidopsis, genetic analyses have demonstrated that LEAFY COTYLEDON genes, namely LEC1, LEC2 and FUSCA3 (FUS3), are key transcriptional regulators of seed maturation, together with ABSCISIC ACID INSENSITIVE 3 (ABI3). Interestingly, LEC2, FUS3 and ABI3 are related proteins that all contain a 'B3' DNA-binding domain. In recent years, genetic and molecular studies have shed new light on the intricate regulatory network involving these regulators and their interactions with other factors such as LEC1, PICKLE, ABI5 or WRI1, as well as with sugar and hormonal signaling. Here, we summarize the most recent advances in our understanding of this complex regulatory network and its role in the control of seed maturation.

A Nuclear Gene Encoding the Iron-Sulfur Subunit of Mitochondrial Complex II Is Regulated by B3 Domain Transcription Factors during Seed Development in Arabidopsis

“…ABI3, FUS3, and LEC2 Are Involved in the Regulation of SDH2-3 Expression ABI3, FUS3, and LEC2 are considered master regulators of seed maturation (Santos-Mendoza et al, 2008). Accordingly, we analyzed SDH2-3 expression in a severe abi3-5 mutant allele (Ooms et al, 1993).…”

“…ABSCISIC ACID INSENSITIVE3 (ABI3), FUSCA3 (FUS3), and LEAFY COTYLEDON2 (LEC2) encode related plant-specific transcription factors containing the conserved B3 DNA-binding domain (Giraudat et al, 1992;Luerssen et al, 1998;Stone et al, 2001) and act in concert to regulate key pathways during seed maturation (Santos-Mendoza et al, 2008). They are interlocked in a cross-regulated network, resulting in overlapping or specific functions.…”

Predictive Modeling of Biomass Component Tradeoffs in Brassica napus Developing Oilseeds Based on in Silico Manipulation of Storage Metabolism

“…This may in part explain why the transcription of components of storage protein and oil synthesis seems to be under the control of a common network of transcriptional regulators specific for seed maturation. A number of these key regulators have been characterized in Arabidopsis, a close relative to rapeseed (Santos-Mendoza et al, 2008). LEAFY COTYLEDON2 (LEC2) appears to be the master regulator that directly and indirectly controls the expression of seed storage proteins.…”

Identification of Direct Targets of FUSCA3, a Key Regulator of Arabidopsis Seed Development

“…ABI3 is not a member of the LEC family but is a major regulator of programs during maturation. All of these genes are expressed specifically or primarily during seed development (Santos-Mendoza et al, 2008). Cross regulation and autoregulation have been demonstrated for the LEC genes and ABI3, both among these genes and in terms of the downstream programs that they control .…”