Systems biology and genome-wide approaches to unveil the molecular players involved in the pre-germinative metabolism: implications on seed technology traits

The pre-germinative metabolism is among the
most fascinating aspects of seed biology. The early seed
germination phase, or pre-germination, is characterized by
rapid water uptake (imbibition), which directs a series of
dynamic biochemical events. Among those are enzyme
activation, DNA damage and repair, and use of reserve
storage compounds, such as lipids, carbohydrates and
proteins. Industrial seedling production and intensive
agricultural production systems require seed stocks with
high rate of synchronized germination and low dormancy.
Consequently, seed dormancy, a quantitative trait related to
the activation of the pre-germinative metabolism, is probably
the most studied seed trait in model species and crops.
Single omics, systems biology, QTLs and GWAS mapping
approaches have unveiled a list of molecules and regulatory
mechanisms acting at transcriptional, post-transcriptional
and post-translational levels. Most of the identified
candidate genes encode for regulatory proteins targeting
ROS, phytohormone and primary metabolisms, corroborating
the data obtained from simple molecular biology
approaches. Emerging evidences show that epigenetic
regulation plays a crucial role in the regulation of thesementioned processes, constituting a still unexploited strategy
to modulate seed traits. The present review will provide
an up-date of the current knowledge on seed pregerminative
metabolism, gathering the most relevant
results from physiological, genetics, and omics studies
conducted in model and crop plants. The effects exerted by
the biotic and abiotic stresses and priming are also
addressed. The possible implications derived from the
modulation of pre-germinative metabolism will be discussed
from the point of view of seed quality and
technology.