Abstract
Plants respond to environmental stresses in multiple ways including changing the hormonal responses. The plant hormone auxin controls every aspect of growth and development. However, little is known about the effect of temperature stress on auxin response. To understand the mechanistic basis of cold temperature stress and auxin response, we characterized the root growth of Arabidopsis thaliana at 23degC after pre-incubating the seedlings at 4degC. The auxin-signaling mutant axr1-3 and tir1-1 responded to cold treatment like wild-type indicating that auxin transport is affected by cold stress. Auxin transport assay further confirmed that cold treatment inhibits root basipetal auxin transport. Additionally, trafficking of auxin efflux carrier PIN2 was dramatically reduced in cold stressed seedlings. Likewise, the endosomal movement was also affected by cold treatment. Taken together these results, we suggest that inhibition of gravity response by cold stress is part of global effect of cold stress on cellular protein trafficking machineries.
