Calcium and calcium-dependent protein kinases are involved in nitric oxide- and auxin-induced adventitious root formation in cucumber

Abstract

A few years ago it was demonstrated that nitric oxide (NO) and cGMP are involved in the auxin response during adventitious root (AR) formation in cucumber (Cucumis sativus). More recently, a mitogen-activated protein kinase cascade was shown to be induced by IAA in a NO-dependent, but cGMP-independent, pathway. In the present study, the involvement of Ca2+ and the regulation of Ca2+-dependent protein kinase (CDPK) activity during IAA- and NO-induced AR formation was evaluated in cucumber explants. The effectiveness of several broad-spectrum Ca2+ channel inhibitors and Ca2+ chelators in affecting AR formation induced by IAA or NO was also examined. Results indicate that the explants response to IAA and NO depends on the availability of both intracellular and extracellular Ca2+ pools. Protein extracts from cucumber hypocotyls were assayed for CDPK activity by using histone IIIS or syntide 2 as substrates for in-gel or in vitro assays, respectively. The activity of a 50 kDa CDPK was detected after 1 d of either NO or IAA treatments and it extended up to the third day of treatment. This CDPK activity was affected in both extracts from NO- and IAA-treated explants in the presence of the specific NO-scavenger cPTIO, suggesting that NO is required for its maximal and sustained activity. The in-gel and the in vitro CDPK activity, as well as the NO- or IAA-induced AR formation, were inhibited by calmodulin antagonists. Furthermore, the induction of CDPK activity by NO and IAA was shown to be reliant on the activity of the enzyme guanylate cyclase.

Molecular Characterization ofHbCDPK1, an Ethephon-Induced Calcium-Dependent Protein Kinase Gene ofHevea brasiliensis

“…5) CDPK genes have been found to be involved in plant stress signal transduction and defense responses, and also to be regulated by mechanical wounding and various plant hormones, such as jasmonic acid (JA), gibberellin (GA), auxin (IAA), abscisic acid (ABA), and ethylene. 5,13,[21][22][23][24][25][26][27] The biosynthesis of natural rubber, like other secondary metabolites, is affected by various plant hormones. JAstimulation can induce laticifer differentiation and can regulate rubber biosynthesis in laticifer.…”

A Soluble Guanylate Cyclase Mediates Negative Signaling by Ammonium on Expression of Nitrate Reductase in Chlamydomonas

“…In plants, synergistic effects of Ca 2+ , NO, and cGMP in various physiological processes, such as response to pathogen infection and development of cell polarity, have been reported (Sokolovski et al, 2005;Lanteri et al, 2006;Ali et al, 2007;Salmi et al, 2007). Implication of these second messengers in the same regulation pathways is often associated with Ca 2+ being an activator of a possible nitric oxide synthase (NOS).…”

The Heme Oxygenase/Carbon Monoxide System Is Involved in the Auxin-Induced Cucumber Adventitious Rooting Process

“…Some interesting results previously reported by Kobayashi and Fukuda (1994) and by Komatsu et al (1996) showed that Ca 2+ -binding proteins and protein kinases were involved in plant differentiation processes. Recently, Lanteri et al (2006) discovered that the activity of the 50-kD cucumber CDPK was induced by IAA and NO signal and was also required for cucumber adventitious root formation, suggesting that CDPK could be associated with cell dedifferentiation, division, and/or differentiation. Taking the above evidence into consideration along with our results, it can be suggested that CSDNAJ-1 and CSCDPK1/5 expression at the earlier stage might be required for auxin-induced adventitious root development.…”

“…Treatment of phytohormones, including indole acetic acid (IAA), 6-benzyladenine, abscisic acid, and GA, enhanced the accumulation of CSCPK5 transcript in etiolated cucumber cotyledons (Kumar et al, 2004). Recently, it was suggested that, together with nitric oxide (NO), which also increases the activity of CDPK and phospholipase D, IAA plays a role in a signaling pathway that regulates CDPK and phospholipase D activity, leading to cucumber adventitious root formation (Lanteri et al, 2006(Lanteri et al, , 2008.…”