Features of Ppd-B1 expression regulation and their impact on the flowering time of wheat near-isogenic lines

Abstract

BackgroundPhotoperiod insensitive Ppd-1a alleles determine early flowering of wheat. Increased expression of homoeologous Ppd-D1a and Ppd-A1a result from deletions in the promoter region, and elevated expression of Ppd-B1a is determined by an increased copy number.ResultsIn this study, using bread wheat cultivars Sonora and PSL2, which contrast in flowering time, and near-isogenic lines resulting from their cross, “Ppd-m” and “Ppd-w” with Ppd-B1a introgressed from Sonora, we investigated the putative factors that influence Ppd-B1a expression. By analyzing the Ppd-B1a three distinct copies, we identified an indel and the two SNPs, which distinguished the investigated allele from other alleles with a copy number variation.We studied the expression of the Ppd-A1, Ppd-B1a, and Ppd-D1 genes along with genes that are involved in light perception (PhyA, PhyB, PhyC) and the flowering initiation (Vrn-1, TaFT1) and discussed their interactions. Expression of Ppd-B1a in the “Ppd-m” line, which flowered four days earlier than “Ppd-w”, was significantly higher. We found PhyC to be up-regulated in lines with Ppd-B1a alleles. Expression of PhyC was higher in “Ppd-m”. Microsatellite genotyping demonstrated that in the line “Ppd-m”, there is an introgression in the pericentromeric region of chromosome 5B from the early flowering parental Sonora, while the “Ppd-w” does not have this introgression. FHY3/FAR1 is known to be located in this region. Expression of the transcription factor FHY3/FAR1 was higher in the “Ppd-m” line than in “Ppd-w”, suggesting that FHY3/FAR1 is important for the wheat flowering time and may cause earlier flowering of “Ppd-m” as compared to “Ppd-w”.ConclusionsWe propose that there is a positive bidirectional regulation of Ppd-B1a and PhyC with an FHY3/FAR1 contribution.The bidirectional regulation can be proposed for Ppd-A1a and Ppd-D1a. Using in silico analysis, we demonstrated that the specificity of the Ppd-B1 regulation compared to that of homoeologous genes involves not only a copy number variation but also distinct regulatory elements.Electronic supplementary materialThe online version of this article (10.1186/s12870-017-1126-z) contains supplementary material, which is available to authorized users.

Effects of Rht17 in combination with Vrn-B1 and Ppd-D1 alleles on agronomic traits in wheat in black earth and non-black earth regions

“…In addition to the VRN genes, the timing of heading in wheat is also determined by the allelic condition of the Ppd genes regulating the sensitivity of the plant to photoperiod. Furthermore, Ppd genes may be regulatory elements for other genes that are involved in light perception (PhyA, PhyB, PhyC) and flowering initiation (Vrn-1, TaFT1) [40][41][42]. According to their influence on the rate of plant development, these genes correlate with each other as follows: Ppd-D1 (strong influence) > Ppd-B1 > Ppd-A1 (weak influence) [43][44][45][46].…”

FAR1-RELATED SEQUENCE (FRS) and FRS-RELATED FACTOR (FRF) Family Proteins in Arabidopsis Growth and Development

“…Beside Arabidopsis thaliana , the physiological functions of FRS family members have not been investigated in other higher plant groups. However, recent studies have suggested that putative FRS members are the candidate genes for Panicle and Spikelet Degeneration ( PSD ) gene in rice ( Zhang et al, 2015 ), and a photoperiod-dependent flowering time regulator in wheat ( Kiseleva et al, 2017 ). In addition, genomic sequencing and population genomic analysis of silver birch ( Betula pendula ) also demonstrated that a putative FRS10 member might be the candidate gene correlated with the adaptation to environment ( Salojarvi et al, 2017 ).…”

De novo annotation of the wheat pan-genome reveals complexity and diversity within the hexaploid wheat pan-transcriptome

“…Table 8 ). These domains are known to be involved in phytochrome signalling in Arabidopsis 20 and in wheat are hypothesised to contribute to the regulation of Ppd-B1a and PhyC known to control photoperiodic sensitivity to flowering 21 .…”