Accumulation of Glycogen and Upregulation of LEA-1 in Support Stress Resistance, Not Longevity.

DAF-16-dependent activation of a dauer-associated genetic program in the insulin/IGF-1 mutant leads to accumulation of large amounts of glycogen with concomitant upregulation of glycogen synthase, GSY-1. Glycogen is a major storage sugar in that can be used as a short-term energy source for survival, and possibly as a reservoir for synthesis of a chemical chaperone trehalose. Its role in mitigating anoxia, osmotic and oxidative stress has been demonstrated previously. Furthermore, mutants show increased abundance of the group 3 late embryogenesis abundant protein LEA-1, which has been found to act in synergy with trehalose to exert its protective role against desiccation and heat stress in vitro, and to be essential for desiccation tolerance in dauer larvae. Here we demonstrate that accumulated glycogen is not required for longevity, but specifically protects against hyperosmotic stress, and serves as an important energy source during starvation. Similarly, does not act to support longevity. Instead, it contributes to increased resistance of mutants to heat, osmotic, and UV stress. In summary, our experimental results suggest that longevity and stress resistance can be uncoupled in IIS longevity mutants.