Paper Details

Abstract

Low temperature is a common abiotic stress that leads to economic losses in agriculture. The earliest reported event in plant response to low temperature is a transient increase in the concentration of cytosolic free calcium ([Ca2+]cyt). Here, we report the novel function of a calcium sensor, the calcineurin B–like protein 9 (CBL9) in response to low temperature in plants. The cbl9 mutant plants have shown more tolerance to cold than wild-type plants under both cold-acclimating and nonacclimating conditions. To address the relationship between CBL9 and Ca2+, we measured cold-induced elevation of [Ca2+]cyt by using aequorin-expressed Arabidopsis plants. Cold-triggered [Ca2+]cyt responses in cbl9 mutant plants were higher than those in control, but the calcium signature of [Ca2+]md rose to similar levels. Pharmacological research indicated the main involvement of extracellular calcium in this response. Thus, these results indicated that as a Ca2+ sensor, the CBL9 participates in the cold signal transduction and acts as negative regulator to intracellular calcium concentration variation.

To Cite This Article