Screening for Abiotic Stress Tolerance in Rice: Salt, Cold, and Drought

Abstract

Rice (Oryza sativa) is the primary source of food for more than half of the world population. Most rice varieties are severely injured by abiotic stresses, with strong social and economic impact. Understanding rice responses to stress may help breeding for more tolerant varieties. However, papers dealing with stress experiments often describe very different experimental designs, thus making comparisons difficult. The use of identical setups is the only way to generate comparable data. This chapter is organized into three sections, describing the experimental conditions established at the Genomics of Plant Stress (GPlantS) unit of ITQB to assess the response of rice plants to three different abiotic stresses--high salinity, cold stress, and drought. All sections include a detailed description of the materials and methodology, as well as useful notes gathered from the GPlantS team's experience. We use rice seedlings as plants at this stage show high sensitivity to abiotic stresses. For the salt and cold stress assays we use hydroponic cultures, while for the drought assay plants are grown in soil and subjected to water withholding. All setups enable visual score determination and are suitable for sample collection along the imposition of stress. The proposed methodologies are simple and affordable to implement in most labs, allowing the discrimination of several rice genotypes at the molecular and phenotypic level.

Elicitor-Induced Biochemical and Molecular Manifestations to Improve Drought Tolerance in Rice (Oryza sativa L.) through Seed-Priming

“…Most of the rice varieties are severely affected by abiotic stresses (Almeida et al, 2016). Among the abiotic stresses, drought stress alone or in combination with other abiotic stress(es) causes severe damages to the crop plants, which result in reduced growth, development and productivity of the crop.…”

Rice calcium‐dependent protein kinase OsCPK17 targets plasma membrane intrinsic protein and sucrose‐phosphate synthase and is required for a proper cold stress response

“…The percentage of electrolyte leakage (EL) was measured before (datapoint 0) and after 4, 7, 10 and 18 d of cold stress imposition, as described in Almeida et al . (). The second fully expanded leaves (six replicates from three to five random plants per line and timepoint) were used for the measurements.…”

“…A cold acclimation assay was set as described in Almeida et al (). Briefly, after breaking dormancy and germinating the seeds in water‐soaked filter paper, the uniformly germinated seedlings were transferred to seedling floats on trays with Yoshida solution (Yoshida et al ).…”

Effect of Four Different Salts on Seed Germination and Morphological Characteristics of Oryza sativa L. cv. MR219

“…However, the response of crop plants to salinity during germination stage differs greatly among crops and variations. Rice is considered as salt-sensitive plant (Flowers and Yeo, 1981) but the sensitivity to salinity varies from one growth stage to the next (Almeida et al, 2016). R. Singh et al (2009) reported that rice shows tolerance during germination but becomes susceptible to salinity during early seedling development.…”