A transposon‐directed epigenetic change in ZmCCT underlies quantitative resistance to Gibberella stalk rot in maize. Issue 4 (19th July 2017)

• Record Type: Journal Article
• Authors: Wang, Chao; Yang, Qin; Wang, Weixiang; Li, Yipu; Guo, Yanling; Zhang, Dongfeng; Ma, Xuena; Song, Wei; Zhao, Jiuran; Xu, Mingliang
• Is Part Of: New phytologist. Volume 215:Issue 4(2017)
• Page Start: 1503
• Page End: 1515
• Publication Date: 2017-07-19
• Subjects: CACTA‐like transposon -- epigenetics -- maize -- quantitative resistance -- stalk rot; Botany -- Periodicals; 580
• DOI: 10.1111/nph.14688
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: A major resistance quantitative trait locus, qRfg1, 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 qRfg1 and examined the dynamic epigenetic changes during qRfg1 ‐mediated maize resistance to the disease. A CCT domain‐containing gene, ZmCCT, is the causal gene at the qRfg1 locus and a polymorphic CACTA‐like transposable element (TE1) c . 2.4 kb upstream of ZmCCT is the genetic determinant of allelic variation. The non‐TE1 ZmCCT 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‐TE1 ZmCCT allele was promptly induced by a rapid yet transient reduction in H3K27me3/H3K9me3 and a progressive decrease in H3K4me3, leading to disease resistance. However, TE1 insertion in ZmCCT caused selective depletion of H3K4me3 and enrichment of methylated GC to suppress the pathogen‐induced ZmCCT expression, resulting in disease susceptibility. Moreover, ZmCCT ‐mediated resistance to Gibberella stalk rot is not affected by photoperiod sensitivity. This chromatin‐based regulatory mechanism enables ZmCCT to be more precise and timely in defense against F. graminearum infection.