Identification of high temperature and daylength responsive genes in barley

High temperature influences plant development and can reduce crop yields. We used the Agilent Barley Gene Expression Microarray to identify high temperature responsive genes in cereals. In temperate cereals, such as wheat and barley, high temperature results in rapid progression through reproductive development in long-days but inhibits early stages of reproductive development in short-days. We examined the transcriptome of barley plants grown at two different temperatures, 15°C or 25°C, in either long or short-days. Under these conditions early reproductive development was accelerated by high temperature in long-days but inhibited by high temperature in short-days. To control for the effect of temperature on vegetative growth, plants were sampled at the same stage of vegetative development (leaf emergence) in all treatments. Transcriptome analysis identified genes that show changed transcript levels in response to daylength (long versus short-days), genes that show changed transcript levels in response to temperature (15°C versus 25°C), and small groups of genes that show changed transcript levels only in response to specific combinations of daylength and temperature. For example, genes that are upregulated only under long-days and high temperature: conditions in which early reproductive development proceeds rapidly. The temperature responsive genes identified here offer potential candidates for developmental regulators controlling the developmental response of cereal crops to high temperatures. Gene expression was assayed in vernalized barley plants grown at 15°C or 25°C in short or long-days until leaf 4 was visible on the main stem. Three replicate samples, consisting of 3 plants per sample, were assayed for each treatment.