Control of maize vegetative and reproductive development, fertility and rRNAs silencing by HISTONE DEACETYLASE 108 [PMeA and MiA]

Histone deacetylases (HDACs) catalyze the removal of acetyl groups from acetylated histone tails that consequently interact more closely with DNA, leading to chromatin state refractory to transcription. Zea mays HDA108 belongs to the Rpd3/HDA1 HDAC family and is ubiquitously expressed during development. The newly isolated hda108/hda108 insertional mutant exhibited many developmental defects: significant reduction in plant height, alterations of shoot and leaf development, alterations of inflorescence patterning and fertility. Western blot analyses and immunolocalization experiments revealed an evident increase in histone acetylation, accompanied by a marked reduction in H3K9 dimethylation, in mutant nuclei. The DNA methylation status, in the CHG sequence context, and the transcript level of ribosomal sequences were also affected in hda108 mutants, while enrichment in H3 and H4 acetylation characterizes both repetitive and non-repetitive transcriptional up-regulated loci. RNA-Seq both of young leaf and anthers indicated that transcription factor expression is highly affected and that the pollen developmental programme results as disrupted in hda108 mutants. Crosses between hda108/hda108 and epiregulator mutants did not produce any double mutant progeny indicating possible genetic interactions of HDA108 with distinct epigenetic pathways. Our findings indicate that HDA108 is directly involved in regulation of maize development, fertility and epigenetic regulation of genome activity. Overall design: Total RNA-Seq analysis of maize anthers at post-meiotic (PMeA) and mitotic (MiA) stages. 2 biological replicates for stage, each obtained by pooling anthers from three tassels per genotype were collected from wild-type and hda108 mutant plants. Strand-specific sequencing on a Illumina HiSeq2500

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Forestan C, Farinati S, Rouster J, Lassagne H, Lauria M, Dal Ferro N, Varotto S