Novel potent inhibitors of A. thaliana cytokinin oxidase/dehydrogenase

Zatloukal, Marek; Gemrotová, Markéta; Doležal, Karel; Havlı́cěk, Libor; Spíchal, Lukáš; Strnad, Miroslav

doi:10.1016/j.bmc.2008.09.008

Cited by 73 publications

(57 citation statements)

References 29 publications

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“…1B). Treatment with the CKX inhibitor INCYDE (Zatloukal et al, 2008) prior to stress application dramatically reduced photoinhibition in cytokinin-deficient 35S:CKX4 plants, as shown by only a minor decrease in F v /F m in comparison with mocktreated plants (Fig. 1C).…”

Section: A Reduced Cytokinin Status Causes Increased Photooxidative Smentioning

confidence: 97%

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A Novel Protective Function for Cytokinin in the Light Stress Response Is Mediated by the ARABIDOPSIS HISTIDINE KINASE2 and ARABIDOPSIS HISTIDINE KINASE3 Receptors

et al. 2014

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Cytokinins are plant hormones that regulate diverse processes in plant development and responses to biotic and abiotic stresses. In this study, we show that Arabidopsis (Arabidopsis thaliana) plants with a reduced cytokinin status (i.e. cytokinin receptor mutants and transgenic cytokinin-deficient plants) are more susceptible to light stress compared with wild-type plants. This was reflected by a stronger photoinhibition after 24 h of high light (approximately 1,000 mmol m 22 s 21), as shown by the decline in maximum quantum efficiency of photosystem II photochemistry. Photosystem II, especially the D1 protein, is highly sensitive to the detrimental impact of light. Therefore, photoinhibition is always observed when the rate of photodamage exceeds the rate of D1 repair. We demonstrate that in plants with a reduced cytokinin status, the D1 protein level was strongly decreased upon light stress. Inhibition of the D1 repair cycle by lincomycin treatment indicated that these plants experience stronger photodamage. The efficiency of photoprotective mechanisms, such as nonenzymatic and enzymatic scavenging systems, was decreased in plants with a reduced cytokinin status, which could be a cause for the increased photodamage and subsequent D1 degradation. Additionally, slow and incomplete recovery in these plants after light stress indicated insufficient D1 repair. Mutant analysis revealed that the protective function of cytokinin during light stress depends on the ARABIDOPSIS HISTIDINE KINASE2 (AHK2) and AHK3 receptors and the type B ARABIDOPSIS RESPONSE REGULATOR1 (ARR1) and ARR12. We conclude that proper cytokinin signaling and regulation of specific target genes are necessary to protect leaves efficiently from light stress.Light absorption, the subsequent conversion into biochemical energy, and the production of oxygen of plants play an essential role for life on earth. Although light is a prerequisite for this process, high light (HL) easily exceeds the plant's capacity to assimilate CO 2 , causing an overreduction of the electron transport chain that results in the inactivation of PSII (photoinhibition; Barber and Andersson, 1992; Aro et al., 1993;Yamamoto et al., 2008). One of the major targets of photoinhibition is the PSII core protein D1 (for review, see Adir et al., 2003;Edelman and Mattoo, 2008).Damaged D1 proteins are continuously replaced by de novo-synthesized D1 in a process called the D1 repair cycle (Aro et al., 1993(Aro et al., , 2005Baena-González and Aro, 2002). This cycle consists of (1) migration of damaged D1 protein from the grana to the stroma lamellae, (2) proteolytic degradation of damaged D1 protein by FILA-MENTATION TEMPERATURE SENSITIVE H (FTSH) protease and DEGRADATION OF PERIPLASMIC PRO-TEINS PROTEASE (DEGP), (3) de novo synthesis of precursor D1 protein (preD1) and cotranslational insertion into the thylakoid membrane, (4) C-terminal processing of preD1 catalyzed by the C-TERMINAL PEPTIDASE (CTP), and (5) migration to the grana thylakoids and formation of a fully functional PSII comple...

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Section: A Reduced Cytokinin Status Causes Increased Photooxidative Smentioning

confidence: 97%

“…Five days before HL treatment, 4-week-old plants were sprayed once per day with a solution containing 10 mM INCYDE (Zatloukal et al, 2008) and 0.01% (v/v) Silwet L-77. Mock-treated samples were sprayed with a solution containing only Silwet L-77.…”

Section: Incyde Treatmentmentioning

confidence: 99%

A Novel Protective Function for Cytokinin in the Light Stress Response Is Mediated by the ARABIDOPSIS HISTIDINE KINASE2 and ARABIDOPSIS HISTIDINE KINASE3 Receptors

et al. 2014

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“…Thus, this very stable phenylurea may remain in tissues and continue to perturb CK profiles and signaling for a long time (months), as recorded in Phaseolus lunatus callus tissue treated with TDZ (Capelle et al 1983). TDZ reportedly acts by directly binding to CK receptors (Spíchal et al 2004) or indirectly by inhibiting CK oxidase/dehydrogenase (CKX) activity (Hare and van Staden 1994;Zatloukal et al 2008). Both of these activities could contribute to the effects observed in our study.…”

Section: Discussionmentioning

confidence: 99%

Endogenous cytokinin dynamics in micropropagated tulips during bulb formation process influenced by TDZ and iP pretreatment

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et al. 2014

Plant Cell Tiss Organ Cult

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“…To examine the possible effects of protoplast isolation on CK metabolism, chemical treatments were applied during the 2 h of enzymatic degradation of the cell walls. Inhibiting CK irreversible degradation with 2-chloro-6-(3-methoxyphenyl)aminopurine (INCYDE) (Zatloukal et al, 2008;Aremu et al, 2012) resulted in elevated levels of the CK bases iP and tZ and the riboside iPR, while cZ levels were reduced ( Figure 1A). Treatments with adenine, previously used as a cytokinin transport antagonist (Bürkle et al, 2003;Cedzich et al, 2008), mainly caused a small decrease of all CK bases detected and slightly increased levels of all ribosides ( Figure 1B).…”

Section: The Protoplast Isolation Process Does Not Greatly Alter Endomentioning

confidence: 99%

“…Root protoplasts were isolated as described above from Col-0 wild-type roots while being simultaneously treated with either 10 mΜ INCYDE (Zatloukal et al, 2008), 100 mM adenine, 3 mM NaN 3 , or the DMSO control, by adding the chemicals into the protoplast isolation buffer. The isolated protoplasts were collected by centrifugation and resuspended in 200 mL of sorting buffer.…”

Section: Protoplast Treatmentsmentioning

confidence: 99%

Cell-Type-Specific Cytokinin Distribution within the Arabidopsis Primary Root Apex

et al. 2015

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Cytokinins (CKs) play a crucial role in many physiological and developmental processes at the levels of individual plant components (cells, tissues, and organs) and by coordinating activities across these parts. High-resolution measurements of intracellular CKs in different plant tissues can therefore provide insights into their metabolism and mode of action. Here, we applied fluorescence-activated cell sorting of green fluorescent protein (GFP)-marked cell types, combined with solid-phase microextraction and an ultra-high-sensitivity mass spectrometry (MS) method for analysis of CK biosynthesis and homeostasis at cellular resolution. This method was validated by series of control experiments, establishing that protoplast isolation and cell sorting procedures did not greatly alter endogenous CK levels. The MS-based method facilitated the quantification of all the well known CK isoprenoid metabolites in four different transgenic Arabidopsis thaliana lines expressing GFP in specific cell populations within the primary root apex. Our results revealed the presence of a CK gradient within the Arabidopsis root tip, with a concentration maximum in the lateral root cap, columella, columella initials, and quiescent center cells. This distribution, when compared with previously published auxin gradients, implies that the well known antagonistic interactions between the two hormone groups are cell type specific.

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Novel potent inhibitors of A. thaliana cytokinin oxidase/dehydrogenase

Cited by 73 publications

References 29 publications

A Novel Protective Function for Cytokinin in the Light Stress Response Is Mediated by the ARABIDOPSIS HISTIDINE KINASE2 and ARABIDOPSIS HISTIDINE KINASE3 Receptors

A Novel Protective Function for Cytokinin in the Light Stress Response Is Mediated by the ARABIDOPSIS HISTIDINE KINASE2 and ARABIDOPSIS HISTIDINE KINASE3 Receptors

Endogenous cytokinin dynamics in micropropagated tulips during bulb formation process influenced by TDZ and iP pretreatment

Cell-Type-Specific Cytokinin Distribution within the Arabidopsis Primary Root Apex

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