Effects of diapause and cold-acclimation on the avoidance of freezing injury in fat body tissue of the rice stem borer, Chilo suppressalis Walker

Yohei Izumi, Shoji Sonoda, Hisaaki Tsumuki

    Research output: Contribution to journalArticlepeer-review

    26 Citations (Scopus)

    Abstract

    Overwintering freeze-tolerant larvae of Chilo suppressalis can survive at -25 °C, but non-diapausing larvae cannot. We reported earlier that to prevent intracellular freezing, which causes death in overwintering larvae of the Saigoku ecotype distributed in southwestern Japan, water leaves and glycerol enters fat body cells through water channels during freezing. However, it is still unclear how diapause and low-temperature exposure are related to the acquisition of freeze tolerance. We compared the extent of tissue damage, accumulation of glycerol, and transport of glycerol and water in fat body tissues between cold-acclimated and non-acclimated non-diapausing and diapausing larvae. The tissue from cold-acclimated diapausing larvae could survive only when frozen in Grace's insect medium with 0.25 M glycerol at -20 °C. The protection provided by glycerol was offset by mercuric chloride, which is a water-channel inhibitor. Fat body tissue isolated from non-acclimated diapausing larvae was injured by freezing even though glycerol was added to the medium, but the level of freezing injury was significantly lower than in non-diapausing larvae. Radiotracer assays in cold-acclimated diapausing larvae showed that during freezing, water left the cells into the medium and glycerol entered the cells from the medium at the same time. Therefore, in Saigoku ecotype larvae of the rice stem borer, both diapause and cold-acclimation are essential to accumulate glycerol and activate aquaporin for the avoidance of freezing injury.

    Original languageEnglish
    Pages (from-to)685-690
    Number of pages6
    JournalJournal of Insect Physiology
    Volume53
    Issue number7
    DOIs
    Publication statusPublished - Jul 2007

    Keywords

    • Chilo suppressalis
    • Cold-acclimation
    • Diapause
    • Freeze tolerance
    • Glycerol
    • Water

    ASJC Scopus subject areas

    • Physiology
    • Insect Science

    Fingerprint

    Dive into the research topics of 'Effects of diapause and cold-acclimation on the avoidance of freezing injury in fat body tissue of the rice stem borer, Chilo suppressalis Walker'. Together they form a unique fingerprint.

    Cite this