Salt-Stress Induced Gene Expression in Kentucky Bluegrass.

Kentucky bluegrass (Poa pratensis L.) is susceptible to damage from salinity stress, with a browning and cessation of growth at relatively low EC levels. Irrigation water is increasingly in short supply in the western U.S. due to population growth, and landscape managers are asked to use less water or water from lower quality sources. In particular, the latter sources tend to have higher salinity levels, and therefore turfgrass with high quality and greater salinity tolerance is essential to meet these expectations. Several studies have identified germplasm or cultivars of Kentucky bluegrass that have higher tolerance to salinity stress, but the mechanism(s) of such stress is unknown. To better understand the genetic mechanisms of salinity stress response and tolerance, we have conducted transcript abundance assays of tolerant and intolerant germplasm. Shoots and roots of control and salinity treated plants were sampled and 100 clones selected from each pool for sequencing. Most transcripts had no homology-based annotations, while those with annotations showed homology to other grass genes involved in abiotic and biotic stress responses. One of the gene families identified in several comparisons was calreticulins, which have a role in calcium regulation. Other genes with implications in salinity stress response will also be highlighted.