Cold‐activation of Brassica napus BN115 promoter is mediated by structural changes in membranes and cytoskeleton, and requires Ca²⁺ influx

Abstract

SummaryPrevious studies on cold-triggered events leading to Ca 2+ in¯ux during cold acclimatization have been conducted on either unicellular cyanobacterium Synechocystis or plant cell suspensions, and used transcript levels of cold-induced genes as end-point markers. Whether the results of these studies are valid for intact plants or their organs is not known. Here we examine cold signaling in transgenic Brassica napus seedlings carrying, in addition to the endogenous cold-inducible BN115 gene, the b-glucuronidase (GUS) gene placed under control of the BN115 promoter. The activity of BN115 promoter was monitored at the transcriptional and translational levels by determining accumulation of BN115 transcripts and by histochemical assay of GUS activity. Cold-activation of BN115 was strongly inhibited by the membrane¯uidizer benzyl alcohol, but mimicked at 25°C by the membrane rigidi®er dimethylsulfoxide (DMSO). The cold induction of BN115 was also inhibited by stabilizers of microtubules and actin micro®laments, taxol and jasplakinolide, respectively, but was mimicked at 25°C by microtubule destabilizer oryzalin or colchicine, or by micro®lament destabilizer latrunculin B. Gd 3+ or ruthenium red prevented the cold activation of BN115, but Ca 2+ ionophore A23187 or cyclic ADP-ribose activated it at 25°C. Inhibitors of tyrosine kinases, protein kinase C and phosphoinositide kinases prevented the cold activation of BN115, but inhibitors of protein phosphatases (PP) 1 and 2 A activated BN115 at 25°C. Constitutively expressed GUS activity in another transgenic line of the same cultivar of B. napus, was not affected by cold or any of the chemical treatments used in the experimentation. Activation of BN115 at 25°C by DMSO, Ca 2+ ionophore, cADPR, and by inhibitors of PP1 and 2A was accompanied by an increased freezing tolerance. It was concluded that the cold-activation of BN115 requires membrane rigidi®cation, cytoskeleton reorganization, Ca 2+ in¯ux and action of several types of protein kinases.

Functional Analysis of the Cellulose Synthase-Like Genes CSLD1, CSLD2, and CSLD4 in Tip-Growing Arabidopsis Cells

“…However, a more subtle explanation can be suggested based on the fact that microtubule polymer status is also known to be related to adaptive responses. For example, many environmental triggers, such as cold and osmotic stress, are associated with the reorganization of the cytoskeleton (Blancaflor and Hasenstein, 1995;Sangwan et al, 2001;Wojtaszek et al, 2007). The recent discovery that a receptor-like kinase may act as a cell wall integrity sensor suggests that internal as well as external stresses could be an aspect of the adaptive response (Hématy et al, 2007).…”

A Subset of Cytokinin Two-component Signaling System Plays a Role in Cold Temperature Stress Response in Arabidopsis

“…ies have previously shown that changes in membrane fluidity appear to be a potential mechanism for the sensing of cold temperatures in higher plants as well (57)(58)(59)(60). As proposed for bacterial Hik33 (61), it can be speculated that the plant AHK proteins might utilize a similar mechanism for the detection of cold temperatures.…”

Hydrogen sulfide is involved in the chilling stress response in Vitis vinifera L.

“…Many signal molecules can improve plant tolerance to low temperature stress by altering the expression levels of COR, CBFs and ICE1 genes. For example, ethylene molecules negatively regulate cold tolerance by repressing expression of CBFs [25]. Inositol 1, 4, 5-trisphosphate (IP3) and Ca 2+ induce CBFs and COR expression in plant [25].…”

“…For example, ethylene molecules negatively regulate cold tolerance by repressing expression of CBFs [25]. Inositol 1, 4, 5-trisphosphate (IP3) and Ca 2+ induce CBFs and COR expression in plant [25]. NO positively regulate the expression of cold related genes COR15a, LT130 and LTI78 in Arabidopsis under low temperature conditions [17].…”