Downregulation of Polyamine and Diamine Oxidases in Silicon-Treated Cucumber.

Anita Szegő,Oyuntogtokh Bat-Erdene,Erzsébet Kiss-Bába,Zsolt Pónya,István Papp,Márta Gyöngyik,Iman Mirmazloum,Mohammad Omran

doi:10.3390/plants10061248

Anita Szegő, Oyuntogtokh Bat-Erdene + Show 6 more

Open Access

https://doi.org/10.3390/plants10061248

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Abstract

Silicon (Si) is a ubiquitous element in soil with well-known beneficial effects under certain conditions, in several plant species, if supplied in available form for uptake. It may alleviate damage in various stress situations and may also promote growth when no obvious stressors are applied. Effects of Si are often linked to mitigation of oxidative stress, in particular to the induction of antioxidant defense mechanisms. In the work presented, the impact of silicon provision on pro-oxidant systems was investigated in cucumber. Plants of the F1 cultivar hybrid ‘Joker’ were grown under in vitro conditions in the absence of any applied external stressor. Silicon provision decreased H2O2 content and lowered lipid peroxidation in the leaves of the treated plants. This was paralleled by declining polyamine oxidase (PAO) and diamine oxidase (DAO) activities. Several PAO as well as lipoxygenase (LOX) genes were coordinately downregulated in Si-treated plants. Unlike in similar systems studied earlier, the Si effect was not associated with an increased transcript level of gene coding for antioxidant enzymes. These results suggest an inhibitory effect of Si provision on pro-oxidant amine oxidases, which may decrease the level of reactive oxygen species by retarding their production. This extends the molecular mechanisms linked to silicon effects onto redox balance in plants.

Highlights

Silicon (Si) is an abundant element in the earth’s crust, which may be necessary and can have beneficial effects in several plant species in varying degrees [1,2]
Silicon provision decreased H2O2 content and lowered lipid peroxidation in the leaves of the treated plants. This was paralleled by declining polyamine oxidase (PAO) and diamine oxidase (DAO) activities
Unlike in similar systems studied earlier, the Si effect was not associated with an increased transcript level of gene coding for antioxidant enzymes. These results suggest an inhibitory effect of Si provision on prooxidant amine oxidases, which may decrease the level of reactive oxygen species by retarding their production

Summary

Introduction

Silicon (Si) is an abundant element in the earth’s crust, which may be necessary and can have beneficial effects in several plant species in varying degrees [1,2]. For example, Si nutrition triggered the elevated resistance of miniature roses towards the fungus Podosphaera pannosa. This effect was attributed to the accumulation of antifungal phenolic compounds [7]. As a concept for providing a general explanation of the diverse physiological effects of silicon, the ‘apoplastic obstruction hypothesis’ has recently been put forward [8] According to this model, Si may serve as an extracellular ‘prophylactic agent’, inhibiting cell wall related reactions/interactions. Observed effects of Si provision may be due to these apoplastic interferences with diverse downstream consequences ‘prophylactic agent’, inhibiting cell wall related reactions/interactions. In a well-characterized example, the salt stress tolerance of cucumber was improved by Si ttrheraotumgehncta, swcahdicinhgwmasolaesccurliabredevteonitns.crBeeanseefidcaianlteioffxeicdtasnotfesnilzicyomnetraecattimvietinetshaanvdepfroelqyuaemnitnlye abceceunmstuuldatieiodnin[9r,1el0a]t.iPonoltyoamabiinoeticmsettraebssoeliss.mInias awcetilvl-echinartahceteerxiztreadceelxlaumlapr lsep, athcee;sianltpsatrrteiscsutolalerr,aanmceinoef couxicduamsebsercownatrsibimutperotovepdrobdyuScititorneaotmf erenat,ctwivheicohxywgaesnasspcreicbieeds itno itnhcisrecaosmedpanatritomxeidnatn[t11en,1z2y].mBeeasicdtievsitaietsraandditipoonlaylarmolieneinacwcuomunudlartieosnpo[9n,s1e0,].liPpoolxyyagmeinnaesemsemtaabyolaislsmo cisoancttriivbeuitne tthoesehxatprainceglltuhlaerrsepdaocxe;binalpanarcteiciunladr,ivaemrsineeaobxioidtiacsesstrceosnstcriobnudteititoonpsro[1d3u]c. tIinonthoef wreoarcktivpereosxeyngteedn hspereec,iewseinsetht iosuctotmo pinavretmstiegnatt[e1w1,1h2e]t.hBerestihdeerseagutrlaadtiiotinonoaf larmolieneinowxioduasneds aarsreetnnrsgcdepuesollsiiannpctsiooeronxe,nsyldipgpoiotefoinnoxasanymesgseiten[son1e3amSo]si.aextsIyrindemdaattahsimseyepsealwnaalsnytoodriankcnloicpynpurtocecrxuihsbyemaungrtbateeeecndttraoe.shrseiehssrtaiempc, iawpnyagetdttsheiesretpnrolseaudyctooatxronrbeyianscplvahoenanscrtdeaigicinnatgetderitiswvoteihrcresepdethaoatexbtreiborthatnilecs-

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