Acclimation of rice leaves to varying temperatures

The extent to which light-saturated net CO2 assimilation (An) and leaf dark respiratory CO2 release (Rdark) jointly acclimate to abrupt and sustained changes in temperature (T) in rice (Oryza sativa L.) is unclear, as are the underlying mechanisms associated with thermal acclimation. To further our understanding of how sustained changes in temperature affect the carbon economy of rice, hydroponically-grown plants of the IR64 cultivar were developed at 30/25°C (day/night) in a temperature-controlled greenhouse before being shifted to 25/20°C or 40/35°C. Leaf RNA expression, protein abundance, sugar and starch content, gas-exchange and elongation rates were measured on pre-existing leaves (PE) already developed at 30/25°C, or leaves newly-developed (ND) subsequent to temperature transfer. To investigate changes in gene expression following temperature shifts in rice we employed total RNA-seq capturing both poly(A) and non-poly(A) transcripts. Rice plants were grown under control conditions at day/night temperatures of 30/25 °C (”warm”) for 2 weeks, then shifted to either 40/35 °C “hot” or 25/20 °C “cold” treatments. Samples were then collected for RNA-seq at 0 hr, 2 hr, 6 hr and 24 hr time points (n = 4).