Abstract
The sleeping chironomid Polypedilum vanderplanki is the largest animal among anhydrobiotes. The larvae can survive in an almost completely desiccated state. During desiccation, they accumulate stress-related proteins, including late embryogenesis abundant (LEA) proteins. However, there is little information about the function of LEA proteins in the larvae. Here, we focused on the function of the novel LEA protein in the P. vanderplanki, PvLEA4. The expression of PvLea4 mRNA was up-regulated by desiccation treatment and was rapidly decreased upon rehydration. As the same manner of the expression pattern of PvLea4 mRNA, PvLEA4 protein was accumulated in response to desiccation. We analyzed the protective effect of PvLEA4 protein on the enzyme activity using LDH (lactate dehydrogenase) during repetitive desiccation-rehydration treatments. LDH solution showed no activity once it was subjected to the desiccation-rehydration treatment. When PvLEA4 was added at 500 times molar ratio in LDH solution, LDH activity was maintained comparable to activity of the sample (LDH-PvLEA4 mixture) without the treatment. In addition, LDH activity of LDH-PvLEA4 mixture remained over 50% even after three drying cycles. These results indicate that PvLEA4 could play an important role in terms of the desiccation tolerance in larvae of P. vanderplanki.
