Session 2C: Inaugural Lectures by Fellows/Associates

Naba Kumar Mondal, Saha Institute of Nuclear Physics, Kolkata

SKIP “JAZ” by SKIP31: A key event for seed maturation and desiccation tolerance

Seed desiccation tolerance is one of the remarkable adaptive traits in flowering plants, which played a decisive role in the evolution and colonization of land plants. These features allow seeds to extend their viability and germinability while remaining in a desiccated state for long periods of time. To achieve this feat, seeds engage multi-layered regulatory networks that activate many genes involved in various mechanisms that ultimately improve seed survival and vigor upon maturity. Among these networks, the phytohormone abscisic acid (ABA) and ABA-responsive master regulators play a key role in modulating seed maturation. In general, ABA signalling is essentially activated during seed maturation and onset of seed dormancy, while repressed during seed germination. However, how seeds attain differential ABA signalling during phase transition from seed maturation to germination events remains obscure. A recent study reveals a new module (AtSKIP31-JAZ-ABI5) in regulating seed maturation, desiccation tolerance and consequent seed vigor in Arabidopsis. The F-box protein AtSKIP31, which is upregulated during late seed maturation, targets JAZ proteins in JA/Ile in an independent manner for proteasomal degradation that releases the inhibitory effect of JAZ proteins on ABI5 and activates downstream signalling, that is important for seed maturation and consequent seed vigor.