Receptor Properties and Features of Cytokinin Signaling

Lomin, Sergey N.; Krivosheev, Dmitry M.; Steklov, Mikhail; Osolodkin, Dmitry I.; Romanov, Georgy A.

doi:10.32607/20758251-2012-4-3-31-45

Cited by 60 publications

(69 citation statements)

References 98 publications

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“…Cytokinins are perceived by a small family of three receptors, AHK2, AHK3, and AHK4 (Lomin et al ., ). A triple ahk2 ahk3 ahk4 mutant shows small‐dwarf phenotype with a severe root growth reduction and short root meristems (Nishimura et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Role of cis‐zeatin in root responses to phosphate starvation

Silva‐Navas

Conesa

Saéz³

et al. 2019

New Phytologist

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Summary Phosphate (Pi) is an essential nutrient for all organisms. Roots are underground organs, but the majority of the root biology studies have been done on root systems growing in the presence of light. Root illumination alters the Pi starvation response (PSR) at different intensities. Thus, we have analyzed morphological, transcriptional and physiological responses to Pi starvation in dark‐grown roots. We have identified new genes and pathways regulated by Pi starvation that were not described previously. We also show that Pi‐starved plants increase the cis‐zeatin (cZ) : trans‐zeatin (tZ) ratio. Transcriptomic analyses show that tZ preferentially represses cell cycle and PSR genes, whereas cZ induces genes involved in cell and root hair elongation and differentiation. In fact, cZ‐treated seedlings show longer root system as well as longer root hairs compared with tZ‐treated seedlings, increasing the total absorbing surface. Mutants with low cZ concentrations do not allocate free Pi in roots during Pi starvation. We propose that Pi‐starved plants increase the cZ : tZ ratio to maintain basal cytokinin responses and allocate Pi in the root system to sustain its growth. Therefore, cZ acts as a PSR hormone that stimulates root and root hair elongation to enlarge the root absorbing surface and to increase Pi concentrations in roots.

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Section: Discussionmentioning

confidence: 97%

Role of cis‐zeatin in root responses to phosphate starvation

Silva‐Navas

Conesa

Saéz³

et al. 2019

New Phytologist

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“…; Lomin et al . ; Shi & Rashotte ). Surprisingly, clipping induced an increase in tZ and tZR only in Acer buds, but clipping with saliva application induced a significant increase in tZ and tZR levels in Fagus buds compared to the control (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Among the cytokinins detected in buds, trans-zeatin (tZ) and trans-zeatin riboside (tZR) were the most abundant in both tree species. tZ and tZR also belong to the most active cytokinins in many plant species (Stolz et al 2011;Lomin et al 2012;Shi & Rashotte 2012). Surprisingly, clipping induced an increase in tZ and tZR only in Acer buds, but clipping with saliva application induced a significant increase in tZ and tZR levels in Fagus buds compared to the control (Fig.…”

Section: H O R M O N a L R E S P O N S E Smentioning

confidence: 89%

Salivary cues: simulated roe deer browsing induces systemic changes in phytohormones and defence chemistry in wild‐grown maple and beech saplings

et al. 2016

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Summary Tree saplings in temperate forests world‐wide experience intense browsing from deer and other mammalian herbivores. However, when compared to insect herbivory, our knowledge about the cues that trigger mammalian‐induced defence responses in trees is limited. We studied responses of field‐grown saplings of European beech (Fagus sylvatica L.) and Sycamore maple (Acer pseudoplatanus L.) to simulated browsing by (i) clipping apical buds or leaves and (ii) additionally applying roe deer (Capreolus capreolus L.) saliva to the cut surface. We analysed induced changes in phytohormones and phenolics in the saplings’ remaining buds or leaves, respectively. In both species, jasmonates were activated after clipping of buds and leaves. Importantly, additional saliva application activated salicylic acid in beech leaves and led to increases in cytokinins in beech buds. Saliva application also led to an increased biosynthesis of several hydrolysable tannins (mainly ellagitannins) and flavonols in maple leaves. Condensed tannins, the most abundant phenolics in beech buds and leaves, did not change after either clipping or saliva application. However, clipping with additional saliva application decreased levels of phenolic acids (cinnamic acid derivatives) in beech buds. We conclude that the two tree species perceive and respond to unknown elicitors in the deer saliva, resulting in changes in phytohormone levels and defence‐associated secondary metabolites. We suggest that variation in induced defence responses between tree species as well as between buds and leaves is related to differences in morphological traits, which interrelate with chemical traits and result in species‐specific strategies to respond to mammalian herbivory.

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“…The isoprenoid CKs, such as trans -zeatin (tz; Figure 2B), are the ones most frequently found in plants. N 6 -benzyladenine (BA; also named 6-benzylaminopurine [BAP]; Figure 2B) and its derivatives, such as meta - and ortho -topolin and the most characterized CK kinetin, belong to the aromatic CKs (Sakakibara, 2006; Bajguz and Piotrowska, 2009; Lomin et al, 2012). Some derivatives of urea also display CK activity, like diphenurea and thidiazuron (Arata et al, 2010).…”

Section: Agonist and Antagonist Moleculesmentioning

confidence: 99%

Unraveling plant hormone signaling through the use of small molecules

Rigal

Robert

2014

Front. Plant Sci.

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Plants have acquired the capacity to grow continuously and adjust their morphology in response to endogenous and external signals, leading to a high architectural plasticity. The dynamic and differential distribution of phytohormones is an essential factor in these developmental changes. Phytohormone perception is a fast but complex process modulating specific developmental reprogramming. In recent years, chemical genomics or the use of small molecules to modulate target protein function has emerged as a powerful strategy to study complex biological processes in plants such as hormone signaling. Small molecules can be applied in a conditional, dose-dependent and reversible manner, with the advantage of circumventing the limitations of lethality and functional redundancy inherent to traditional mutant screens. High-throughput screening of diverse chemical libraries has led to the identification of bioactive molecules able to induce plant hormone-related phenotypes. Characterization of the cognate targets and pathways of those molecules has allowed the identification of novel regulatory components, providing new insights into the molecular mechanisms of plant hormone signaling. An extensive structure-activity relationship (SAR) analysis of the natural phytohormones, their designed synthetic analogs and newly identified bioactive molecules has led to the determination of the structural requirements essential for their bioactivity. In this review, we will summarize the so far identified small molecules and their structural variants targeting specific phytohormone signaling pathways. We will highlight how the SAR analyses have enabled better interrogation of the molecular mechanisms of phytohormone responses. Finally, we will discuss how labeled/tagged hormone analogs can be exploited, as compelling tools to better understand hormone signaling and transport mechanisms.

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Receptor Properties and Features of Cytokinin Signaling

Cited by 60 publications

References 98 publications

Role of cis‐zeatin in root responses to phosphate starvation

Role of cis‐zeatin in root responses to phosphate starvation

Salivary cues: simulated roe deer browsing induces systemic changes in phytohormones and defence chemistry in wild‐grown maple and beech saplings

Unraveling plant hormone signaling through the use of small molecules

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