Seed Maturation Events in Medicago truncatula: Focus on Desiccation Tolerance

Abstract

During seed maturation phase, a diverse and important set of compounds need to be accumulated to guarantee the correct acquisition of the physiological mechanisms that will promote seed survival and future plant development. One of these mechanisms is the acquisition of desiccation tolerance (DT), which is the capacity that a tissue has to survive extreme dehydration (called desiccation, with a drastic loss of water content to levels below 0.1 g H2O per gram of dry weight) and to remain alive in this dry state for an extended period of time. The ability of seeds to tolerate such stress is tightly regulated during seed development, being acquired at the onset of seed maturation, during the seed filling phase in Medicago truncatula, and later on, lost at early germination (DT switch). To date, a vast body of knowledge has been built around the understanding of DT resulting in the identification of compounds and genes induced during DT acquisition and potentially involved in protective cell functions allowing cellular survival in the dry state. Major efforts have focused on unraveling the nature of these protective compounds conferring DT, and the Medicago truncatula species has played a key role in these studies. Therefore, this review will focus on recent advances in desiccation tolerance comprehension focused on the use of M. truncatula for elucidating DT molecular mechanisms.KeywordsDesiccation toleranceSeedSeed maturationMedicago