Large-scale expression profiling and physiological characterization of jasmonic acid mediated adaptation of barley to salinity stress

Authors: WALIA, HARKAMAL - UC RIVERSIDE, CA; Wilson, Clyde; CONDAMINE, PASCAL - UC RIVERSIDE, CA; ISMAIL, ABDELBAGI - INT'L RICE RESEARCH INST; CLOSE, TIMOTHY - UC RIVERSIDE, CA

Submitted to: Plant Cell and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2006
Publication Date: 1/25/2007
Citation: Walia, H., Wilson, C., Condamine, P., Ismail, A.M., Close, T.J. 2007. Large-scale expression profiling and physiological characterization of jasmonic acid mediated adaptation of barley to salinity stress. Plant Cell and Environment. Vol. 30:410-421

Interpretive Summary: Because of increases in global population, world agriculture must produce a greater yield per unit area than ever before. Irrigated agriculture takes on a special importance in this regard as it has a high yield per unit area and is less dependent on the uncertainties of weather. It has been estimated that one-half of all irrigated lands are seriously affected by salinity or water logging. Barley (Hordeum vulgare L.) is considered moderately salt-tolerant compared to other cereals. Recent genetic studies on salinity stress response in barley indicated regulation of the biosynthesis of jasmonic acid (JA), a chemical with hormone-like activity. We eamined the role of JA the adaptation of barley to salt stress. Here we applied JA to barley plants and observed the physiological response and genetic or, more accurately, transcriptome changes. Photosynthetic and sodium-ion accumulation responses were also compared after 1) salinity stress, 2) JA treatment, and 3) JA pretreatment followed by salinity stress. The JA-pretreated salt-stressed plants accumulated strikingly low levels of Na+ in the shoot compared to untreated salt-stressed plants. Also, pretreatment with JA partially alleviated photosynthetic inhibition caused by salinity stress. Expression profiling after a short-term exposure to salinity stress indicated a considerable overlap between genes regulated by salinity stress and JA application. We found three JA-regulated genes which may be candidates involved in salinity tolerance mediated by JA: arginine decarboxylase, rubisco activase, and apoplastic invertase. This work provides a reference dataset for further study of the role of JA in salinity tolerance in barley and other plants species.

Technical Abstract: Barley (Hordeum vulgare L.) is considered moderately salt-tolerant compared to other cereals. Recent transcriptome studies on salinity stress response in barley indicated regulation of jasmonic acid (JA) biosynthesis and JA-responsive genes by salt stress. From that observation it was hypothesized that JA is involved in the adaptation of barley to salt stress. Here we tested that hypothesis by applying JA to barley plants and observing the physiological response and transcriptome changes. Photosynthetic and sodium-ion accumulation responses were compared after 1) salinity stress, 2) JA treatment, and 3) JA pretreatment followed by salinity stress. The JA-pretreated salt-stressed plants accumulated strikingly low levels of Na+ in the shoot tissue compared to untreated salt-stressed plants. Also, pretreatment with JA partially alleviated photosynthetic inhibition caused by salinity stress. Expression profiling after a short-term exposure to salinity stress indicated a considerable overlap between genes regulated by salinity stress and JA application. Three JA-regulated genes, arginine decarboxylase, rubisco activase, and apoplastic invertase are candidates involved in salinity tolerance mediated by JA. This work provides a reference dataset for further study of the role of JA in salinity tolerance in barley and other plants species.