Transcriptome Analysis of a New Peanut Seed Coat Mutant for the Physiological Regulatory Mechanism Involved in Seed Coat Cracking and Pigmentation

Liyun wan, Bei Li, Manish K Pandey, Yanshan Wu, Yong Lei, Liying Yan, Xiaofeng Dai, Huifang Jiang, Juncheng Zhang, Guo Wei, Rajeev Varshney, Boshou Liao. (31/10/2016). Transcriptome Analysis of a New Peanut Seed Coat Mutant for the Physiological Regulatory Mechanism Involved in Seed Coat Cracking and Pigmentation. Frontiers in Plant Science, 7 (1491), pp. 1-15.

Abstract

Seed-coatcrackingandundesirablecolorofseedcoathighlyaffectsexternalappearanceandcommercialvalueofpeanuts(ArachishypogaeaL.).Withanobjectivetofindgeneticsolutiontotheaboveproblems,apeanutmutantwithcrackingandbrowncoloredseedcoat(testa)wasidentifiedfromanEMStreatedmutantpopulationanddesignatedas“peanutseedcoatcrackandbrowncolormutantline(pscb).”Theseedcoatweightofthemutantwasalmosttwiceofthewildtype,andthegerminationtimewassignificantlyshorterthanwildtype.Further,themutanthadlowerleveloflignin,anthocyanin,proanthocyanidincontent,andhighlyincreasedlevelofmelanincontentascomparedtowildtype.UsingRNA-Seq,weexaminedtheseedcoattranscriptomeinthreestagesofseeddevelopmentinthewildtypeandthepscbmutant.TheRNA-Seqanalysisrevealedpresenceofhighlydifferentiallyexpressedphenylpropanoidandflavonoidpathwaygenesinallthethreeseeddevelopmentstges,especiallyat40daysafterflowering(DAF40).Also,theexpressionofpolyphenoloxidasesandperoxidasewerefoundtobeactivatedsignificantlyespeciallyinthelateseeddevelopmentalstage.Thegenome-widecomparativestudyoftheexpressionprofilesrevealed62differentiallyexpressedgenescommonacrossallthethreestages.Byanalyzingtheexpressionpatternsandthesequencesofthecommondifferentiallyexpressedgenesofthethreestages,threecandidategenesnamelyc36498_g1(CCoAOMT1),c40902_g2(kinesin),andc33560_g1(MYB3)wereidentifiedresponsibleforseed-coatcrackingandbrowncolorphenotype.Therefore,thisstudynotonlyprovidedcandidategenesbutalsoprovidedgreaterinsightsandmoleculargeneticcontrolofpeanutseed-coatcrackingandcolorvariation.Theinformationgeneratedinthisstudywillfacilitatefurtheridentificationofcausalgeneanddiagnosticmarkersforbreedingimprovedpeanutvrietieswithsmoothanddesirableseedcoatcolor.