Phytohormones and Abiotic Stress Tolerance in Plants

311 Pages·2012·4.14 MB·English

by  F. Eyidogan

Phytohormones and Abiotic Stress Tolerance
in Plants
.
Nafees A. Khan Rahat Nazar Noushina Iqbal
l l
Naser A. Anjum
Editors
Phytohormones and Abiotic
Stress Tolerance in Plants
Editors
NafeesA.Khan NaserA.Anjum
RahatNazar CentreforEnvironmentaland
NoushinaIqbal MarineStud
AligarhMuslimUniversity DepartmentofChemistry
DepartmentofBotany Aveiro
Aligarh Portugal
India [email protected]
[email protected]
[email protected]
[email protected]
ISBN978-3-642-25828-2 e-ISBN978-3-642-25829-9
DOI10.1007/978-3-642-25829-9
SpringerHeidelbergDordrechtLondonNewYork
LibraryofCongressControlNumber:2012933369
#Springer-VerlagBerlinHeidelberg2012
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Preface
Plants are exposed to rapid and various unpredicted disturbances in the environ-
ment resulting in stressful conditions. Abiotic stress is the negative impact of
nonlivingfactorsonthelivingorganismsinaspecificenvironmentandconstitutes
amajorlimitationtoagriculturalproduction.Theadverseenvironmentalconditions
that plants encounter during their life cycle disturb metabolic reactions and ad-
versely affect growth and development at cellular and whole plant level. Under
abioticstress,plantsintegratemultipleexternalstresscuestobringaboutacoordi-
nated response and establish mechanism to mitigate the stress by triggering a
cascadeofeventsleadingtoenhancedtolerance.Responsestostressarecomplicat-
ed integrated circuits involving multiple pathways and specific cellular compart-
ments, and the interaction of additional cofactors and/or signaling molecules
coordinatesaspecifiedresponsetoagivenstimulus.Stresssignalisfirstperceived
bythereceptorspresentonthemembraneoftheplantcells.Thesignalinformation
isthentransduceddownstreamresultingintheactivationofvariousstress-responsive
genes.Theproductsofthesestressgenesultimatelyleadtostresstoleranceresponse
or plant adaptation and help the plant to survive and surpass the unfavorable
conditions. Abiotic stress conditions lead to production of signaling molecule(s)
thatinducethesynthesisofseveralmetabolites,includingphytohormonesforstress
tolerance.Phytohormonesarechemicalcompoundsproducedinonepartandexert
effect in another part and influence physiological and biochemical processes.
Phytohormonesarecriticalforplantgrowthanddevelopmentandplayanimportant
role in integrating various stress signals and controlling downstream stress
responsesandinteractincoordinationwitheachotherfordefensesignalnetwork-
ingtofine-tunedefense.Theadaptiveprocessofplantsresponseimposedbyabiotic
stresses such as salt, cold, drought, and wounding is mainly controlled by the
phytohormones. Stress conditions activate phytohormones signaling pathways
that are thought to mediate adaptive responses at extremely low concentration.
Thus,anunderstandingofthephytohormoneshomeostasisandsignalingisessen-
tialforimprovingplantperformanceunderoptimalandstressfulenvironments.
v
vi Preface
Traditionallyfivemajorclassesofplanthormoneshavebeenrecognized:auxins,
cytokinins, gibberellins, abscisic acid, and ethylene. Recently, other signaling
molecules that play roles in plant metabolism and abiotic stress tolerance have
also been identified, including brassinosteroids, jasmonic acid, salicylic acid, and
nitric oxide. Besides, more active molecules are being found and new families of
regulatorsareemergingsuchaspolyamines,plantpeptides,andkarrikins.Several
biologicaleffects ofphytohormones areinducedbycooperation ofmorethanone
phytohormone. Substantial progress has been made in understanding individual
aspects of phytohormones perception, signal transduction, homeostasis, or influ-
enceongeneexpression.However,thephysiological,biochemical,andmolecular
mechanisms induced by phytohormones through which plants integrate adaptive
responsesunderabioticstressarelargelyunknown.Thisbookupdatesthecurrent
knowledge on the role of phytohormones in the control of plant growth and
development, explores the mechanism responsible for the perception and signal
transduction of phytohormones, and also provides a further understanding of the
complexityofsignalcrosstalkandcontrollingdownstreamstressresponses.There
is next to none any book that provides update information on the phytohormones
significanceintolerancetoabioticstressinplants.
Weextendourgratitudetoallthosewhohavecontributedinmakingthisbook
possible.Simultaneously,wewouldliketoapologizeunreservedlyforanymistakes
orfailuretoacknowledgefully.
Aligarh,India NafeesA.Khan,RahatNazar,NoushinaIqbal
Aveiro,Portugal NaserA.Anjum
Contents
1 SignalTransductionofPhytohormonesUnderAbioticStresses ....... 1
F.Eyidogan,M.T.Oz,M.Yucel,andH.A.Oktem
2 Cross-TalkBetweenPhytohormoneSignalingPathwaysUnder
BothOptimalandStressfulEnvironmentalConditions ............... 49
MarciaA.Harrison
3 PhytohormonesinSalinityTolerance:EthyleneandGibberellins
CrossTalk ................................................................. 77
NoushinaIqbal,AsimMasood,andNafeesA.Khan
4 FunctionofNitricOxideUnderEnvironmentalStressConditions ... 99
MarinaLeterrier,RaquelValderrama,MouniraChaki,
MorakAiraki,Jose´ M.Palma,JuanB.Barroso,andFranciscoJ.Corpas
5 AuxinasPartoftheWoundingResponseinPlants ................... 115
ClaudiaA.Casalongue´,DiegoF.Fiol,RamiroPar´ıs,
AndreaV.Godoy,Sebastia´nD‘Ippo´lito,andMar´ıaC.Terrile
6 HowDoLettuceSeedlingsAdapttoLow-pHStressConditions?
AMechanismforLow-pH-InducedRootHairFormation
inLettuceSeedlings ...................................................... 125
HidenoriTakahashi
7 CytokininMetabolism ................................................... 157
SomyaDwivedi-Burks
8 OriginofBrassinosteroidsandTheirRoleinOxidative
StressinPlants ........................................................... 169
AndrzejBajguz
vii
viii Contents
9 HormonalIntermediatesintheProtectiveActionofExogenous
PhytohormonesinWheatPlantsUnderSalinity ..................... 185
FaridaM.Shakirova,AzamatM.Avalbaev,MarinaV.Bezrukova,
RimmaA.Fatkhutdinova,DilaraR.Maslennikova,RuslanA.Yuldashev,
ChulpanR.Allagulova,andOksanaV.Lastochkina
10 TheRoleofPhytohormonesintheControlofPlantAdaptation
toOxygenDepletion .................................................... 229
VladislavV.YemelyanovandMariaF.Shishova
11 StressHormoneLevelsAssociatedwithDroughtTolerancevs.
SensitivityinSunflower(HelianthusannuusL.) ..................... 249
CristianFerna´ndez,SergioAlemano,AnaVigliocco,
AndreaAndrade,andGuillerminaAbdala
12 AnInsightintotheRoleofSalicylicAcidandJasmonic
AcidinSaltStressTolerance .......................................... 277
M.IqbalR.Khan,ShabinaSyeed,RahatNazar,andNaserA.Anjum
Index .......................................................................... 301
Chapter 1
Signal Transduction of Phytohormones Under
Abiotic Stresses
F.Eyidogan,M.T.Oz,M.Yucel,andH.A.Oktem
Abstract Growth and productivity of higher plants are adversely affected by
various environmental stresses which are of two main types, biotic and abiotic,
dependingonthesourceofstress.Broadrangeofabioticstressesincludesosmotic
stresscausedbydrought,salinity,highorlowtemperatures,freezing,orflooding,
aswellasionic,nutrient,ormetalstresses,andotherscausedbymechanicalfactors,
light, or radiation. Plants contrary to animals cannot escape from these environ-
mental constraints, and over the course of evolution, they have developed some
physiological,biochemical,ormolecularmechanismstoovercomeeffectsofstress.
Phytohormones such as auxin, cytokinin, abscisic acid, jasmonic acid, ethylene,
salicylic acid, gibberellic acid, and few others, besides their functions during
germination, growth, development, and flowering, play key roles and coordinate
various signal transduction pathways in plants during responses to environmental
stresses. Complex networks of gene regulation by these phytohormones under
abioticstressesinvolvevariouscis-ortrans-actingelements.Someofthetranscrip-
tionfactorsregulatedbyphytohormonesincludeARF,AREB/ABF,DREB,MYC/
MYB, NAC,andothers. Changes ingene expression, proteinsynthesis,modifica-
tion, ordegradation initiatedby or coupled tothese transcription factors andtheir
correspondingcis-actingelementsarebrieflysummarizedinthiswork.Moreover,
crosstalk between signal transduction pathways involving phytohormones is
explained in regard to transcriptional or translational regulation under abiotic
stresses.
F.Eyidogan(*)
BaskentUniversity,Ankara,Turkey
e-mail:[email protected]
M.T.Oz•M.Yucel•H.A.Oktem
DepartmentofBiologicalSciences,MiddleEastTechnicalUniversity,Ankara,Turkey
N.A.Khanetal.(eds.),PhytohormonesandAbioticStressToleranceinPlants, 1
DOI10.1007/978-3-642-25829-9_1,#Springer-VerlagBerlinHeidelberg2012
2 F.Eyidoganetal.
1.1 Introduction
Plants have successfully evolved to integrate diverse environmental cues into
theirdevelopmentalprograms.Sincetheycannotescapefromadverseconstraints,
theyhavebeenforcedtocounteractbyelicitingvariousphysiological,biochemi-
cal,andmolecularresponses.Theseresponsesincludeorleadtochangesingene
expression,regulationofproteinamountoractivity,alterationofcellularmetab-
olite levels, and changes in homeostasis of ions. Gene regulation at the level of
transcription is one of the major control points in biological processes, and
transcriptionfactorsandregulatorsplaykeyrolesinthisprocess.Phytohormones
are a collection of trace amount growth regulators, comprising auxin, cytokinin,
gibberellic acid (GA), abscisic acid (ABA), jasmonic acid (JA), ethylene,
salicylicacid(SA),andfewothers(TutejaandSopory2008).Hormoneresponses
are fundamental to the development and plastic growth of plants. Besides their
regulatory functions during development, they play key roles and coordinate
varioussignaltransductionpathways during responsestoenvironmentalstresses
(WoltersandJ€urgens2009).
A range of stress signaling pathways have been elucidated through molecular
genetic studies. Research on mutants, particularly of Arabidopsis, with defects in
theseandotherprocesseshavecontributedsubstantiallytothecurrentunderstand-
ingofhormoneperceptionandsignaltransduction.Planthormones,suchasABA,
JA,ethylene,andSA,mediatevariousabioticandbioticstressresponses.Although
auxins, GAs, and cytokinins have been implicated primarily in developmental
processes in plants, they regulate responses to stress or coordinate growth under
stress conditions. The list of phytohormones is growing and now includes
brassinosteroids (BR), nitric oxide (NO), polyamines, and the recently identified
branchinghormonestrigolactone(Gray2004).
Treatment of plants with exogenous hormones rapidly and transiently alters
genome-wide transcript profiles (Chapman and Estelle 2009). In Arabidopsis,
hormone treatment for short periods (<1 h) alters expression of 10–300 genes,
with roughly equal numbers of genes repressed and activated (Goda et al. 2008;
Nemhauseretal.2006;Paponovetal.2008).Notsurprisingly,longerexposureto
most hormones ((cid:1)1 h) alters expression of larger numbers of genes. Complex
networks of gene regulation by phytohormones under abiotic stresses involve
variouscis-ortrans-actingelements.Someofthetranscriptionfactors,regulators,
and key components functioning in signaling pathways of phytohormones under
abioticstressesaredescribedinthiswork.Moreover,changesingeneexpression,
protein synthesis, modification, or degradation initiated by or coupled to plant
hormonesarebrieflysummarized.