Speaker: Rebecca Roston, University of Nebraska, Lincoln

Title: Dynamic membrane adaptation to low temperatures: the search for conserved responses

Abstract: Biological membranes exist within a window of optimal fluidity that prevents breakage, fusion, and reduces ion leakage. Low temperatures cause rigidification of membranes, and dynamic adaptations are required to allow plants to survive. Current evidence suggests that membrane adaptations are controlled both transcriptionally and post-transcriptionally. We hypothesized that a core set of both transcriptional and membrane lipid changes are required to confer cold tolerance. First, we identified common responses of a core set of transcription factors, but not a core set of membrane lipids, from previously published studies. Then we investigated commonality within a related series of Panicoid grasses, including crop species maize, sorghum and foxtail millet. These grasses showed common lipid changes, and our results also indicated a strong lipid abundance diurnal cycle. The diurnal changes are large enough that they may have obscured a common membrane lipid response from previously published studies. Finally, we show that the accumulation of a novel lipid in response to freezing in Arabidopsis also occurs above freezing in response to severe cold in other species. Because the same novel lipid accumulates in response to dehydration, this result suggests that freezing-intolerant plants may also suffer from dehydration at low, non-freezing temperatures. We conclude that perceived stress severity and diurnal cycles must be considered when identifying conserved membrane responses.

Host: Marna Yandeau-Nelson