Plant Cell Physiol. 2022 Jun 30. pii: pcac092. [Epub ahead of print]
Yingmei Guo,
Yan Chen,
Jie Zhang,
Jiankun Li,
Kaijian Fan,
Rongrong Chen,
Yunjun Liu,
Jun Zheng,
Junjie Fu,
Riliang Gu,
Guoying Wang,
Yu Cui,
Xuemei Du,
Jianhua Wang.
Epialleles, the heritable epigenetic variants that are not caused by changes in DNA sequence, can broaden genetic and phenotypic diversity and benefit to crop breeding, but very few epialleles related to agricultural traits have been identified in maize. Here, we cloned a small kernel mutant, smk-wl10, from maize, which encoded a tubulin folding cofactor B (ZmTFCB) protein. Expression of ZmTFCB gene decreased in smk-wl10 mutant, which arrested embryo, endosperm, and basal endosperm transfer layer development. Over expression of ZmTFCB could complement the defective phenotype of smk-wl10. No nucleotide sequence variation of ZmTFCB could be found between smk-wl10 and wild type (WT). Instead, we detected hypermethylation of nucleotide CHG (where H is A, C or T nucleotide) sequence contexts and increased level of histone H3K9me2 methylation in the upstream sequence of ZmTFCB in smk-wl10 compared with WT, which might respond for the attenuating transcription of ZmTFCB. In addition, Yeast two-hybrid and bimolecular fluorescence complementation assay identified a strong interaction between ZmTFCB and its homolog ZmTFCE. Thus, our work identifies a novel epiallele of maize ZmTFCB gene, which might represent a common phenomenon in epigenetic regulation of important traits such as kernel development in maize.
Keywords: DNA methylation; epigenetic mutant; histone methylation; kernel development; maize; tubulin folding cofactor