Plant Communications, doi::https://doi.org/10.1016/j.xplc.2020.100092

Xiaojun Cheng ^†, Meiyao Pan ^†, E. Zhiguo, Yong Zhou, Baixiao Niu, Chen Chen*

Abstract

Cellularization is a key event in endosperm development. Polycomb group (PcG) genes, such as Fertilization-Independent Seed 2 (FIS2), are vital for the syncytium-to-cellularization transition in Arabidopsis plants. In this study, we found that OsEMF2a, a rice homolog of the Arabidopsis PcG gene Embryonic Flower2 (EMF2), plays a similar role of FIS2 in the aspect of seed development, although there are limited sequence similarities between the genes. Delayed cellularization was observed in osemf2a and associated with an unusual activation of type I MADS-box genes. The cell cycle was persistently activated in the osemf2a caryopses, which was likely caused by an overproduction of cytokinin. However, overaccumulation of auxin was not found to be associated with the delayed cellularization. As OsEMF2a is a maternally expressed gene in the endosperm, a paternally inherited functional allele was unable to recover the maternal defects of OsEMF2a. Many imprinted rice genes were deregulated in the defective hybrid seeds of osemf2a (♀)/9311 (♂) (m9). The paternal expression bias of some paternally expressed genes was disrupted in m9, due to either activation of maternal alleles or repression of paternal alleles. These findings suggest that OsEMF2a-PRC2-mediated H3K27me3 is necessary for the endosperm cellularization and genomic imprinting of rice.

全文链接：

https://www.cell.com/plant-communications/fulltext/S2590-3462(20)30116-4