An epiallele of rice AK1 affects photosynthetic capacity.

Epigenetic gene variants, termed epialleles, can broaden genetic and phenotypic diversity in eukaryotes. Here, we identify a natural epiallele of OsAK1, which encodes a rice adenylate kinase. The Epi-ak1 plants show albino in young leaf and panicle with abnormal chloroplast structures. We found that no nucleotide sequence variation but hypermethylation at promoter region caused silencing of OsAK1 (Os08g01770) in Epi-ak1 plants. OsAK1 localizes to chloroplast and many genes associated with photosynthesis processes were downregulated in Epi-ak1. Thus, the work identified a novel rice epiallele caused by DNA methylation changes, shedding light on significant roles of DNA methylation on rice development.