The analysis of an Arabidopsis triple knock-down mutant reveals functions for MBF1 genes under stress conditions

ARCE, D.; GODOY, A.V.; TSUDA, K.; YAMAZAKI, K.; VALLE, E.; IGLESIAS, M. J.; DI MAURO, M.F.; CASALONGUE, C.

JOURNAL OF PLANT PHYSIOLOGY

Elsevier

Año: 2009 vol. 167 p. 194 - 200

0176-1617

Transcriptionalco-activatorsofthemultiproteinbridgingfactor1(MBF1)typebelongtoasmall multigenic familythatcontrolsgeneexpressionbyconnectingtranscriptionfactorsandthebasal transcription machinery.Inthisreport,atripleknock-downmutant(abc) forthe Arabidopsisthaliana MBF1 genes AtMBF1a, AtMBF1b and AtMBF1c wasgenerated.Thephenotypiccharacterizationusing oxidativeagentssuchashydrogenperoxideandmethylviologenrevealedthatthe abc mutant was more sensitivetooxidativestress.Thetripleknock-downmutant, abc wasalsosensitivetoosmotic stress mediatedbyhighconcentrationsofsorbitol.Furthermore,the abc phenotype waspartiallyor completelyrescuedby AtMBF1c cDNAover-expression(abc +c)dependingonphysiologicaland developmental conditions. AtMBF1s regulatetheexpressionof ABR1, whichisamemberoftheethylene- response factorfamilyandactsasABArepressor.Thus,weconcludethat AtMBF1 genefamilymay functionasaregulatorycomponentofthecross-talknodebetweenethylene,ABAandstresssignal pathways.Furthermore,higherlevelsofaHSP70mRNAandanimmunoreactiveHSP70proteinwere detected inthe abc mutant.Theparticipationof MBF1c asapossiblenegativeregulatorof HSP genes wasdiscussed