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Mutants in the imprinted PICKLE RELATED 2 gene suppress seed abortion of fertilization independent seed class mutants and paternal excess interploidy crosses in Arabidopsis
Author(s) -
Huang Fang,
Zhu Qianhao,
Zhu Anyu,
Wu Xiaoba,
Xie Liqiong,
Wu Xianjun,
Helliwell Chris,
Chaudhury Abed,
Finnegan E. Jean,
Luo Ming
Publication year - 2017
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.13500
Subject(s) - endosperm , biology , arabidopsis , microbiology and biotechnology , gene , mutant , genetics
Summary Endosperm cellularization is essential for embryo development and viable seed formation. Loss of function of the FERTILIZATION INDEPENDENT SEED ( FIS ) class Polycomb genes, which mediate trimethylation of histone H3 lysine27 (H3K27me3), as well as imbalanced contributions of parental genomes interrupt this process. The causes of the failure of cellularization are poorly understood. In this study we identified PICKLE RELATED 2 ( PKR 2 ) mutations which suppress seed abortion in fis1 / mea by restoring endosperm cellularization. PKR 2 , a paternally expressed imprinted gene ( PEG ), encodes a CHD 3 chromatin remodeler. PKR 2 is specifically expressed in syncytial endosperm and its maternal copy is repressed by FIS 1 . Seed abortion in a paternal genome excess interploidy cross was also partly suppressed by pkr2 . Simultaneous mutations in PKR 2 and another PEG , ADMETOS ( ADM ), additively rescue the seed abortion in fis1 and in the interploidy cross, suggesting that PKR 2 and ADM modulate endosperm cellularization independently and reproductive isolation between plants of different ploidy is established by imprinted genes. Genes upregulated in fis1 and downregulated in the presence of pkr2 are enriched in glycosyl‐hydrolyzing activity, while genes downregulated in fis1 and upregulated in the presence of pkr2 are enriched with microtubule motor activity, consistent with the cellularization patterns in fis1 and the suppressor line. The antagonistic functions of FIS 1 and PKR 2 in modulating endosperm development are similar to those of PICKLE ( PKL ) and CURLY LEAF ( CLF ), which antagonistically regulate root meristem activity. Our results provide further insights into the function of imprinted genes in endosperm development and reproductive isolation.