Root development and the expression of aquaporin genes in rice seedlings under osmotic stress

Abstract

We conducted hydroponic culture experiments to characterize root traits in a rice cultivar ‘Puluik Arang’ that has been identified in a previous study as a cultivar that is adaptable to unflooded conditions. Root morphological traits and the expression of 11 aquaporin genes in rice seedlings (cv. Puluik Arang and cv. Akitakomachi) subjected to osmotic stress by polyethylene glycol (PEG) treatments (10 and 20%) were analysed. ‘Puluik Arang’ exhibited significantly greater water uptake under 10% PEG treatment than ‘Akitakomachi’. Lateral root development was maintained in ‘Puluik Arang’ under PEG treatments. The expression of some aquaporin genes, particularly OsTIP2;1, was higher in ‘Puluik Arang’ than in ‘Akitakomachi’. Immunocytochemical analysis showed that the OsTIP2;1 protein mainly accumulated in endodermal cells. The results suggest that better lateral root development and the function of aquaporins could contribute to water uptake in ‘Puluik Arang’ under osmotic stress.