Characterization of Ppd-D1 alleles on the developmental traits and rhythmic expression of photoperiod genes in common wheat

Abstract

Photoperiodic response is an important characteristic that plays an important role in plant adaptability for various environments. Wheat cultivars grow widely and have high yield potential for the strong photoperiod adaptibility. To assess the photoperiodic response of different genotypes in wheat cultivars, the photoperiodic effects of the Ppd-D1 alleles and the expressions of the related TaGI, TaCO and TaFT genes in Liaochun 10 and Ningchun 36 were investigated under the short-day (6 h light, SD), moderate-day (12 h light, MD) and long-day (24 h light, LD) conditions. Amplicon length comparison indicated that the promoter of Ppd-D1 in Ningchun 36 is intact, while Liaochun 10 presented the partial sequence deletion of Ppd-D1 promoter. The durations of all developmental stages of the two cultivars were reduced by subjection to an extended photoperiod, except for the stamen and pistil differentiation stage in the Liaochun 10 cultivar. The expression levels of the Ppd-D1 alleles and the TaGI, TaCO and TaFT genes associated with the photoperiod pathway were examined over a 24-h period under SD and MD conditions. The relationships of different photoperiodic responses of the two cultivars and the expression of photoperiod pathway genes were analyzed accordingly. The photoperiod insensitive (PI) genotype plants flower early under SD; meanwhile, the abnormal expression of the Ppd-D1a allele is accompanied with an increase in TaFT1 expression and the TaCO expression variation. The results would facilitate molecular breeding in wheat.

Keywords

• wheat photoperiod
• spike differentiation
• heading
• gene expression
• Ppd-D1