Gene expression analysis of rice seedling under potassium deprivation

Potassium is one of the essential macronutrients required for plant growth and development. It plays a major role in different physiological processes like cell elongation, stomatal movement, turgor regulation, osmotic adjustment, and signal transduction by acting as a major osmolyte and component of the ionic environment in the cytosol and subcellular organelles. We used whole genome microarrays to determine the transcriptomic profile of rice seedlings exposed to short-term K+ deficiency followed by K+ resupply. Potassium treated seedlings were used for RNA extraction and hybridization on Affymetrix rice Genechip by microarrays. Three biological replicates of each sample were used for microarray analysis. We wanted to know the altered expression patterns of potassium-responsive genes majorly involved in metabolic processes, stress responses, signaling pathways, transcriptional regulation, and transport of multiple molecules including K+. Seeds of indica rice were surface sterilized and grown hydroponically in rice growing medium. Plants were grown in the rice growth room under the condition of 16 h light/8 h dark (28°C) photoperiod with 70 % humidity. After 5 days of normal growth, one half of the rice seedlings were transferred to nutrient media with normal concentration of potassium (KP, 0.409 mM K2SO4) and other one half to medium without potassium (KM, 0 mM). After 5 days, potassium (0.409 mM K2SO4) was resupplied to the plants grown in KM medium for 6 h.