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A transposon‐directed epigenetic change in ZmCCT underlies quantitative resistance to Gibberella stalk rot in maize
Author(s) -
Wang Chao,
Yang Qin,
Wang Weixiang,
Li Yipu,
Guo Yanling,
Zhang Dongfeng,
Ma Xuena,
Song Wei,
Zhao Jiuran,
Xu Mingliang
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14688
Subject(s) - biology , genetics , epigenetics , transposable element , locus (genetics) , chromatin , gibberella zeae , allele , gene , quantitative trait locus , fusarium , genome
Summary A major resistance quantitative trait locus, qR fg1 , significantly enhances maize resistance to Gibberella stalk rot, a devastating disease caused by Fusarium graminearum . However, the underlying molecular mechanism remains unknown. We adopted a map‐based cloning approach to identify the resistance gene at qR fg1 and examined the dynamic epigenetic changes during qR fg1 ‐mediated maize resistance to the disease. A CCT domain‐containing gene, Zm CCT , is the causal gene at the qR fg1 locus and a polymorphic CACTA ‐like transposable element ( TE 1) c . 2.4 kb upstream of Zm CCT is the genetic determinant of allelic variation. The non‐ TE 1 Zm CCT allele is in a poised state, with predictive bivalent chromatin enriched for both repressive (H3K27me3/H3K9me3) and active (H3K4me3) histone marks. Upon pathogen challenge, this non‐ TE 1 Zm CCT allele was promptly induced by a rapid yet transient reduction in H3K27me3/H3K9me3 and a progressive decrease in H3K4me3, leading to disease resistance. However, TE 1 insertion in Zm CCT caused selective depletion of H3K4me3 and enrichment of methylated GC to suppress the pathogen‐induced Zm CCT expression, resulting in disease susceptibility. Moreover, Zm CCT ‐mediated resistance to Gibberella stalk rot is not affected by photoperiod sensitivity. This chromatin‐based regulatory mechanism enables Zm CCT to be more precise and timely in defense against F. graminearum infection.