PJB-2018-1081
A CALCIUM SENSOR CALCINEURIN B-LIKE 9 NEGATIVELY REGULATES COLD TOLERANCE VIA CALCIUM SIGNALLING IN ARABIDOPSIS THALIANA
Yuan-lin Gao
Abstract
Calcineurin B–like protein 9 (CBL9) plays important roles in response to ABA, K+ deprivation in plants. However, whether CBL9 modulates plant adaptation to low temperature stress is elusive. In this study, we demonstrated that the CBL9 gene mutant increase freezing tolerance under both cold-acclimating and nonacclimating conditions in Arabidopsis. Cold-induced changes of cytosolic free calcium concentration ([Ca2+]cyt) were then monitored by aequorin-expressed Arabidopsis plants. The results showed that cold-triggered increases in [Ca2+]cyt levels in cbl9 were clearly higher than those in WT, while cold affected changes cytosolic microdomain adjacent to the vacuolar membrane free calcium concentration ([Ca2+]md) in cbl9 were similar to those in WT. In addition, treatments of seedlings with Ca2+ chelator EGTA and Ca2+ channel blocker lanthanum chloride markedly inhibit changes of [Ca2+]cyt in cbl9, while lithium chloride inhibiting calcium release from intracellular pools demonstrate consistent suppression of [Ca2+]cyt in cbl9 and WT. Together, these results indicate that CBL9 negatively modulates cold tolerance through decreasing [Ca2+]cyt in Arabidopsis.
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