Selection and Characterisation of the Awake Mutants with Altered Seed Dormancy in Response to Temperature in Arabidopsis Thaliana (L.) Heyn.

Abstract

Seed dormancy is a mechanism with great importance in plant fitness and it inhibits seed germination until is broken and seeds can germinate under optimal environmental conditions favorable for successful reproduction. Primary dormancy is contingent to the environment that seeds and the mother plant experience. Temperature is a major factor participating in the regulation of this complex trait. High and low levels of dormancy are induced during seed maturation by cold and warm temperatures respectively but the mechanism at the basis of temperature signaling in seeds is not well understood. Climate change and increased weather variability threaten the constant supply of high quality seeds into the market hence agriculture productivity. Therefore, understanding and taking control of the molecular mechanism behind the regulation of seed dormancy and germination will help to control and predict seed behavior in the field.

Here I describe and discuss a forward genetic screen for the selection of mutant seed lines with altered seed dormancy in response to cool temperature during seed set. Putative mutant seed lines designated awake1 to awake52, were preliminarily characterized. Eleven awake lines were selected for further analysis and one was investigated in more detail. It was revealed that awake1 seeds shares common phenotype with seeds of a suberin deficient mutant which were previously reported to display increased dormancy but, here, I show they also display a reduction of seed dormancy. Segregation analysis suggests that the reduced dormancy phenotype is maternally inherited as the suberin deficient mutants. Also, transcriptomic analysis shows that many suberin associated genes are temperature-regulated. I conclude that control of suberin deposition may play a role in the regulation of dormancy in response to cool temperature.