TY - JOUR

T1 - Features of Ppd-B1 expression regulation and their impact on the flowering time of wheat near-isogenic lines

AU - Kiseleva, Antonina A.

AU - Potokina, Elena K.

AU - Salina, Elena A.

N1 - Publisher Copyright: © 2017 The Author(s). Copyright: Copyright 2017 Elsevier B.V., All rights reserved.

PY - 2017/11/14

Y1 - 2017/11/14

N2 - Background: Photoperiod 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. Results: In 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". Conclusions: We 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.

AB - Background: Photoperiod 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. Results: In 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". Conclusions: We 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.

KW - Common wheat

KW - Flowering time

KW - Photoperiod sensitivity

KW - Phytochrome

KW - Ppd-B1

UR - http://www.scopus.com/inward/record.url?scp=85033787175&partnerID=8YFLogxK

U2 - 10.1186/s12870-017-1126-z

DO - 10.1186/s12870-017-1126-z

M3 - Article

C2 - 29143607

AN - SCOPUS:85033787175

VL - 17

SP - 71

EP - 85

JO - BMC Plant Biology

JF - BMC Plant Biology

SN - 1471-2229

M1 - 172

ER -