Grant: Discovery Grants Program - Individual

Some insects survive internal ice formation (i.e. are freeze tolerant) in winter, but we do not currently know why some insects are freeze tolerant while others are not. My long-term goal is to build an integrative, experiment-based, understanding of the mechanisms underlying insect FT, leading to new ways to protect cells, tissues, and organisms against freezing. The Spring field cricket, Gryllus veletis, is easily reared in the lab, acquires freeze tolerance after a six week acclimation period, and is large enough to allow us to study freeze tolerance at the cellular and tissue levels through three short-term objectives: 1)to develop genomic tools to identify and manipulate candidate freeze tolerance mechanisms. My HQP and I will sequence and annotate the G. veletis genome, enabling deeper analysis of transcriptome data and genome editing, exploration of candidate FT mechanisms, and facilitating population and species comparisons and epigenetics to learn how freeze tolerance evolved. We will make a catalogue of gene expression throughout freeze, thaw, and recovery that will fast-track our physiological experiments, and develop RNA interference tools to enable us to manipulate the expression of genes associated with surviving freezing. 2)to determine the mechanisms underlying insect freeze tolerance. We will identify where in the body ice forms when crickets freeze. There are two ways that insects might survive freezing: by protecting their cells from freezing damage, or by repairing freezing damage after they have thawed. We will explore these hypotheses in mitochondria (which provide power to the cell) and the metathoracic ganglion, a `mini brain' that controls walking and escape responses. We will identify the mechanisms involved in protection and/or repair of these tissues. 3)to compare freeze tolerance in different G. veletis populations collected across North America. We will determine whether they all use the same cold tolerance strategy, and whether the mechanisms underlying it are the same. We will use genome sequencing to identify how cold tolerance has evolved in this species. This work will begin to reveal the cellular mechanisms underlying freeze tolerance and cellular responses to cold stress and freezing in general, with immediate potential to advance our ability to store frozen cells and tissues. The tools we will develop should make G. veletis the go-to model for insect freeze tolerance research broadening the research community studying freeze tolerant insects and leading to new discoveries about how animals protect their cells from environmental stress.