Histone Methylation And D-Mannitol Modulate Primary Root Growth By Regulating Methylglyoxal Accumulation In Arabidopsis

Post-translational modifications of histone H3 are involved in many plant developmental processes including primary root growth.Methylglyoxal(MG),as an important metabolite of glycolysis,can modify H3 and inhibit primary root growth.However,the association between histone methylation and methylglyoxalation is still unclear.The mechanism of histone methylation-and MG-mediated primary root growth inhibition remains to be further studied.In this paper,the effects of histone methylation,D-Mannitol and MG on the primary root growth of Arabidopsis thaliana were further investigated.Our experimental results showed that atx1 and ashh3 mutants and D-Mannitol could affect the content of MG in vivo,and MG inhibited the transcription of PLT1 and PLT2,by modifying histone H3,thus affecting plant primary root growth.The main research results of this paper are as follows:1.atx1 and ashh3 mutants are more sensitive to MG.The root lengths of histone methylation-and acetylation-related mutants were assayed when treated with 0.1 m M MG.Two histone methyltransferase mutants atx1 and ashh3 were found to be more sensitive MG than the wild type.2.The mutants atx1 and ashh3 have higher MG accumulation,and thus enhanced histone H3 methylglyoxalation.Then,we found that the atx1 and ashh3 mutants had higher MG compared with the wild type.In addition,we detected histone H3 methylglyoxalation in atx1,ashh3,and wild-type plants treated with or without 0.1 m M MG with Western blot using Anti-MMP,and indicated that these mutants had enhanced MG modification compared with the control.3.MG regulates primary root growth by inhibiting the transcription of PLT1 and PLT2.The gene expression of wild-type seedlings treated with or without MG was detected by RNA-seq and q RT-PCR,and the results showed that MG down-regulated the expression of PLT1 and PLT2 genes.Futher,whereas MG treated or untreated plt1plt2 double mutant had similar root lengths,MG-treated wild type plants had shorter roots than untreated control.These results reveal that MG inhibits root elongation by suppressing the expression of PLT1 and PLT2.4.MG increases methylglyoxalation of histone H3 at PLT1 and PLT2.Anti-MMP was used for Ch IP-seq detection,and PLT1 and PLT2 genes were found to be enriched.These enrichment were also verified by Ch IP-q PCR.Combined with the results above,these results show that MG inhibits the transcription of PLT1 and PLT2 by modifying the chromatin proteins at these genes.5.D-mannitol inhibits the expression of PLT1 and PLT2 by inducing the accumulation of MG.We also found that D-mannitol treatment repressed root elongation and resulted in higher MG accumulation.In addition,the D-mannitol treatment also inhibited the transcription of PLT1 and PLT2 and leaded to enhanced MG modification of the chromatin proteins at PLT1 and PLT2.These results suggest that D-mannitol inhibits root growth by promoting chromatin methylglyoxalation at PLT1 and PLT2,and thus repressing their expression.