Functional Analysis of the “Green Revolution” Gene Photoperiod-1 and Its Selection Trends During Bread Wheat Breeding

Abstract

Flowering is central to the transformation of plants from vegetative growth to reproductive growth. The circadian clock system enables plants to sense the changes in the external environment and to modify the growth and development process at an appropriate time. Photoperiod-1 (Ppd-1), which is controlled by the output signal of the circadian clock, has played an important role in the wheat “Green Revolution.” In the current study, we systematically studied the relationship between Ppd-1 haplotypes and both wheat yield- and quality-related traits, using genome-wide association analysis and transgenic strategies, and found that highly appropriate haplotypes had been selected in the wheat breeding programs. Genome-wide association analysis showed that Ppd-1 is associated with significant differences in yield-related traits in wheat, including spike length (SL), heading date (HD), plant height (PH), and thousand-grain weight (TGW). Ppd-1-Hapl-A1 showed increased SL by 4.72–5.93%, whereas Ppd-1-Hapl-B1 and Ppd-1-Hapl-D1 displayed earlier HD by 0.58–0.75 and 1.24–2.93%, respectively, decreased PH by 5.64–13.08 and 13.62–27.30%, respectively, and increased TGW by 4.89–10.94 and 11.12–21.45%, respectively. Furthermore, the constitutive expression of the Ppd-D1 gene in rice significantly delayed heading date and resulted in reduced plant height, thousand-grain weight, grain width (GW), and total protein content. With reference to 40years of data from Chinese wheat breeding, it was found that the appropriate haplotypes Ppd-1-Hapl-A1, Ppd-1-Hapl-B1, and Ppd-1-Hapl-D1 had all been subjected to directional selection, and that their distribution frequencies had increased from 26.09, 60.00, and 52.00% in landraces to 42.55, 93.62, and 96.23% in wheat cultivars developed in the 2010s. A Ppd-B1 methylation molecular marker was also developed to assist molecular wheat breeding. This research is of significance for fully exploring the function of the Ppd-1 gene and its genetic resource diversity, to effectively use the most appropriate haplotypes and to improve crop yield and sustainability.

Systematic mining and functional analysis of factors regulating wheat spike development for breeding selection

“…We found stage-specific expressed genes through clustering ( Figure 1C ), including known factors involved in flowering time regulation and inflorescence development. PPD1 , with Ppd-A1b/Ppd-B1a/Ppd-D1a alleles in KN9204 (Wu et al, 2021), is responsible for flowering time and expressed before the transition to flowering. (Beales et al, 2007; Boden et al, 2015; Perez-Gianmarco et al, 2020), is expressed before the transition to flowering.…”

Novel PHOTOPERIOD-1 gene variants associate with yield-related and root-angle traits in European bread wheat

“…Variations in the Ppd-1 photoperiod genes have long been recognized as major-effect genes that control both flowering time and above-ground shoot growth (González et al 2005 ; Beales et al 2007 ; Boden et al 2015 ; Royo et al 2016 , 2018 ; Steinfort et al 2017a , b ; Ramirez et al 2018 ; Arjona et al 2018 ; Pérez-Gianmarco et al 2019 ; Zhang et al 2019 ; Wu et al 2021 ). In this study, we observed that the photoperiod insensitivity allele Ppd-D1a (PpdD1-Hap3) had the most significant impact on the nodal root-angle index, showing a remarkable 57% increase compared to considerably lower effects on other traits (e.g., − 10% for biomass, − 6% for NRN).…”