Study on regulation of carbohydrate usage in a heterogeneous rice population under submergence

Abstract

Deleterious effect of flood causes drastic reduction of rice production in low elevated agricultural areas of Asia due to global climate change. Plants face oxygen deprivation under water and start low oxygen dependent metabolic activity for proper utilization of carbohydrates with the activity of fermentative enzymes. In this study, leaf tissue of nine rice genotypes including aus-type submergence tolerant variety FR13A and high yielding submergence sensitive line IR42 were used to establish a relationship between carbohydrate level and anaerobic enzyme activities. Three test sets for each accession were submerged for 7, 14 and 21 days for quantitative estimation of soluble and insoluble sugar content along with differential expression of three enzymes [Pyruvate decarboxylase (pdc1), Alcohol dehydrogenase (adh1) and sucrose synthase (susy1)] involved in carbohydrate metabolism in plants. From the findings it was observed that under submer gence, FR13A showed higher insoluble sugar and lower soluble sugar along with higher expression of pdc1 and adh1. Among the elongating categories var. Kumrogarh showed the highest level of soluble and insoluble sugars with lower level of pdc1, and higher level of adh1 and susy1. This promotes var. Kumrogarh to lower down the accumulation of cellular toxic acetaldehyde via ethanol production and increased amount of sucrose. Keeping all in view, var. Kumrogarh can be selected as submergence tolerant deep water line for lowland rice fields.