Emails: maolong@caas.cn

Plant height and heading date are important agronomic traits in wheat (Triticum aestivum L.) that affect final grain yield. In wheat, knowledge of pseudo-response regulator (PRR) genes on agronomic traits is limited. Here, we identify a wheat TaPRR95 gene by genome-wide association study (GWAS) associated with plant height.

The CRISPR/Cas9-editing prr95aabbdd mutant plants show increased plant height, particularly at the peduncle, with an earlier heading date. The longer peduncle is mainly caused by the increased cell elongation at its upper part, whilst the early heading date is accompanied with elevated expression of flowering genes, including TaFT and TaCO1.

A peduncle-specific transcriptome analysis reveals up-regulated photosynthesis genes and down-regulated IAA/Aux genes, key negative regulators of auxin signaling, in prr95aabbdd plants, which may act as a regulatory mechanism to promote robust plant growth.

A haplotype analysis identifies a TaPRR95-B haplotype (Hap2) closely associated with reduced plant height and the increased thousand-grain weight. Moreover, the Hap2 frequency is higher in cultivars than in landraces, suggestive of the presence of artificial selection of the allele during wheat breeding.

These findings suggest that TaPRR95 is a key regulator of plant height and heading date, thereby providing an important target for yield improvement in wheat.