scholarly journals FLOWERING LOCUS T4 (HvFT4) delays flowering and decreases floret fertility in barley

2020 ◽  
Author(s):  
Rebecca Pieper ◽  
Filipa Tomé ◽  
Maria von Korff

AbstractFLOWERING LOCUS T-like genes (FT-like) control the photoperiodic regulation of flowering in many angiosperm plants. The family of FT-like genes is characterised by extensive gene duplication and subsequent diversification of FT functions which occurred independently in modern angiosperm lineages. In barley, there are 12 known FT-like genes (HvFT) but the function of most of them remains uncharacterised. This study aimed to characterise the role of HvFT4 in flowering time control and development in barley. The overexpression of HvFT4 in the spring cultivar Golden Promise delayed flowering time under long-day conditions. Microscopic dissection of the shoot apical meristem (SAM) revealed that overexpression of HvFT4 specifically delayed spikelet initiation and reduced the number of spikelet primordia and grains per spike. Furthermore, ectopic overexpression of HvFT4 was associated with floret abortion and with the downregulation of the barley MADS-box genes VRN-H1, HvBM3 and HvBM8 which promote floral development. This suggests that HvFT4 functions as a repressor of reproductive development in barley. Unraveling the genetic basis of FT-like genes can contribute to the identification of novel breeding targets to modify reproductive development and thereby spike morphology and grain yield.HighlightWe identify the FLOWERING LOCUS T (FT)-like gene HvFT4 as a negative regulator of reproductive development, spikelet initiation, floret fertility and grain number in barley.

Author(s):  
Rebecca Pieper ◽  
Filipa Tomé ◽  
Artem Pankin ◽  
Maria von Korff

Abstract FLOWERING LOCUS T-like (FT-like) genes control the photoperiodic regulation of flowering in many angiosperm plants. The family of FT-like genes is characterized by extensive gene duplication and subsequent diversification of FT functions which occurred independently in modern angiosperm lineages. In barley, there are 12 known FT-like genes (HvFT), but the function of most of them remains uncharacterized. This study aimed to characterize the role of HvFT4 in flowering time control and development in barley. The overexpression of HvFT4 in the spring cultivar Golden Promise delayed flowering time under long-day conditions. Microscopic dissection of the shoot apical meristem revealed that overexpression of HvFT4 specifically delayed spikelet initiation and reduced the number of spikelet primordia and grains per spike. Furthermore, ectopic overexpression of HvFT4 was associated with floret abortion and with the down-regulation of the barley MADS-box genes VRN-H1, HvBM3, and HvBM8 which promote floral development. This suggests that HvFT4 functions as a repressor of reproductive development in barley. Unraveling the genetic basis of FT-like genes can contribute to the identification of novel breeding targets to modify reproductive development and thereby spike morphology and grain yield.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaorui Xu ◽  
Jingya Xu ◽  
Chen Yuan ◽  
Yikai Hu ◽  
Qinggang Liu ◽  
...  

Abstract Background The TGACG-binding (TGA) family has 10 members that play vital roles in Arabidopsis thaliana defense responses and development. However, their involvement in controlling flowering time remains largely unknown and requires further investigation. Results To study the role of TGA7 during floral transition, we first investigated the tga7 mutant, which displayed a delayed-flowering phenotype under both long-day and short-day conditions. We then performed a flowering genetic pathway analysis and found that both autonomous and thermosensory pathways may affect TGA7 expression. Furthermore, to reveal the differential gene expression profiles between wild-type (WT) and tga7, cDNA libraries were generated for WT and tga7 mutant seedlings at 9 days after germination. For each library, deep-sequencing produced approximately 6.67 Gb of high-quality sequences, with the majority (84.55 %) of mRNAs being between 500 and 3,000 nt. In total, 325 differentially expressed genes were identified between WT and tga7 mutant seedlings. Among them, four genes were associated with flowering time control. The differential expression of these four flowering-related genes was further validated by qRT-PCR. Conclusions Among these four differentially expressed genes associated with flowering time control, FLC and MAF5 may be mainly responsible for the delayed-flowering phenotype in tga7, as TGA7 expression was regulated by autonomous pathway genes. These results provide a framework for further studying the role of TGA7 in promoting flowering.


2020 ◽  
Vol 71 (16) ◽  
pp. 4903-4913 ◽  
Author(s):  
Zulkarnain Chowdhury ◽  
Devasantosh Mohanty ◽  
Mrunmay K Giri ◽  
Barney J Venables ◽  
Ratnesh Chaturvedi ◽  
...  

Abstract Abietane diterpenoids are tricyclic diterpenes whose biological functions in angiosperms are largely unknown. Here, we show that dehydroabietinal (DA) fosters transition from the vegetative phase to reproductive development in Arabidopsis thaliana by promoting flowering time. DA’s promotion of flowering time was mediated through up-regulation of the autonomous pathway genes FLOWERING LOCUS D (FLD), RELATIVE OF EARLY FLOWERING 6 (REF6), and FVE, which repress expression of FLOWERING LOCUS C (FLC), a negative regulator of the key floral integrator FLOWERING LOCUS T (FT). Our results further indicate that FLD, REF6, and FVE are also required for systemic acquired resistance (SAR), an inducible defense mechanism that is also activated by DA. However, unlike flowering time, FT was not required for DA-induced SAR. Conversely, salicylic acid, which is essential for the manifestation of SAR, was not required for the DA-promoted flowering time. Thus, although the autonomous pathway genes FLD, REF6, and FVE are involved in SAR and flowering time, these biological processes are not interdependent. We suggest that SAR and flowering time signaling pathways bifurcate at a step downstream of FLD, REF6, and FVE, with an FLC-dependent arm controlling flowering time, and an FLC-independent pathway controlling SAR.


2019 ◽  
Vol 60 (9) ◽  
pp. 2040-2050 ◽  
Author(s):  
Alexander Steffen ◽  
Mareike Elgner ◽  
Dorothee Staiger

Abstract The timing of floral initiation is a tightly controlled process in plants. The circadian clock regulated glycine-rich RNA-binding protein (RBP) AtGRP7, a known regulator of splicing, was previously shown to regulate flowering time mainly by affecting the MADS-box repressor FLOWERING LOCUS C (FLC). Loss of AtGRP7 leads to elevated FLC expression and late flowering in the atgrp7-1 mutant. Here, we analyze genetic interactions of AtGRP7 with key regulators of the autonomous and the thermosensory pathway of floral induction. RNA interference- mediated reduction of the level of the paralogous AtGRP8 in atgrp7-1 further delays floral transition compared of with atgrp7-1. AtGRP7 acts in parallel to FCA, FPA and FLK in the branch of the autonomous pathway (AP) comprised of RBPs. It acts in the same branch as FLOWERING LOCUS D, and AtGRP7 loss-of-function mutants show elevated levels of dimethylated lysine 4 of histone H3, a mark for active transcription. In addition to its role in the AP, AtGRP7 acts in the thermosensory pathway of flowering time control by regulating alternative splicing of the floral repressor FLOWERING LOCUS M (FLM). Overexpression of AtGRP7 selectively favors the formation of the repressive isoform FLM-β. Our results suggest that the RBPs AtGRP7 and AtGRP8 influence MADS-Box transcription factors in at least two different pathways of flowering time control. This highlights the importance of RBPs to fine-tune the integration of varying cues into flowering time control and further strengthens the view that the different pathways, although genetically separable, constitute a tightly interwoven network to ensure plant reproductive success under changing environmental conditions.


2019 ◽  
Author(s):  
Marco Todesco ◽  
Gregory L. Owens ◽  
Natalia Bercovich ◽  
Jean-Sébastien Légaré ◽  
Shaghayegh Soudi ◽  
...  

Species often include multiple ecotypes that are adapted to different environments. But how do ecotypes arise, and how are their distinctive combinations of adaptive alleles maintained despite hybridization with non-adapted populations? Re-sequencing of 1506 wild sunflowers from three species identified 37 large (1-100 Mbp), non-recombining haplotype blocks associated with numerous ecologically relevant traits, and soil and climate characteristics. Limited recombination in these regions keeps adaptive alleles together, and we find that they differentiate several sunflower ecotypes; for example, they control a 77 day difference in flowering between ecotypes of silverleaf sunflower (likely through deletion of a FLOWERING LOCUS T homolog), and are associated with seed size, flowering time and soil fertility in dune-adapted sunflowers. These haplotypes are highly divergent, associated with polymorphic structural variants, and often appear to represent introgressions from other, possibly extinct, congeners. This work highlights a pervasive role of structural variation in maintaining complex ecotypic adaptation.


Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2631-2638 ◽  
Author(s):  
A. Ray ◽  
J.D. Lang ◽  
T. Golden ◽  
S. Ray

The short integument (sin1) mutation causes a female-specific infertility, and a defect in the control of time to flowering in Arabidopsis. Female sterility of Sin- plants is due to abnormal ovule integument development and aberrant differentiation of the megagametophyte in a subset of ovules. An additional defect of sin1 mutants is the production of an increased number of vegetative leaf and inflorescence primordia leading to delayed flowering. The delayed flowering phenotype of sin1-1 is not due to a defect in the perception of day length periodicity or in gibberellic acid metabolism. Phenotypes of double mutant combinations of sin1 with terminalflower (tfl1) indicate that SIN1 activity is required for precocious floral induction typical in a tfl1 mutant. Unexpectedly, sin1-1 tfl1-1 plants do not make pollen, thus revealing a novel role for TFL1 in the anther. Early flowers of sin1-1 ap1-1 double mutants are transformed to long inflorescence-like shoots. A genetic model for the role of SIN1 in flowering time control is proposed.


2020 ◽  
Vol 36 (6) ◽  
pp. 49-54
Author(s):  
A.A. Nalbandyan ◽  
T.P. Fedulova ◽  
I.V. Cherepukhina ◽  
T.I. Kryukova ◽  
N.R. Mikheeva ◽  
...  

The flowering time control gene of various sugar beet plants has been studied. The BTC1 gene is a regulator for the suppressor (flowering time 1) and inducer (flowering time 2) genes of this physiological process. The F9/R9 primer pair was used for polymerase chain reaction; these primers are specific to the BTC1 gene region containing exon 9, as well as intron and exon 10. For the first time, nucleotide substitutions in exon 10 of BTC1 gene were identified in bolting sensitive samples (HF1 and BF1), which led to a change in the amino acid composition of the coded polypeptide chain. Based on the results of bioinformatic analysis, it can be assumed that certain nucleotide polymorphisms in the BTC1 gene may determine with a high probability the predisposition of sugar beet genotypes to early flowering. The use of the Geneious Prime tool for the analysis of the BTC1 gene sequences may allow the culling of genotypes prone to early flowering at early stages of selection. sugar beet, flowering gene, BTC1, genetic polymorphism, PCR, molecular genetic markers, selection


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