A novel deletion in FLOWERING LOCUS T modulates flowering time in winter oilseed rape

Abstract Key message A novel structural variant was discovered in the FLOWERING LOCUS T orthologue BnaFT.A02 by long-read sequencing. Nested association mapping in an elite winter oilseed rape population revealed that this 288 bp deletion associates with early flowering, putatively by modification of binding-sites for important flowering regulation genes. Abstract Perfect timing of flowering is crucial for optimal pollination and high seed yield. Extensive previous studies of flowering behavior in Brassica napus (canola, rapeseed) identified mutations in key flowering regulators which differentiate winter, semi-winter and spring ecotypes. However, because these are generally fixed in locally adapted genotypes, they have only limited relevance for fine adjustment of flowering time in elite cultivar gene pools. In crosses between ecotypes, the ecotype-specific major-effect mutations mask minor-effect loci of interest for breeding. Here, we investigated flowering time in a multiparental mapping population derived from seven elite winter oilseed rape cultivars which are fixed for major-effect mutations separating winter-type rapeseed from other ecotypes. Association mapping revealed eight genomic regions on chromosomes A02, C02 and C03 associating with fine modulation of flowering time. Long-read genomic resequencing of the seven parental lines identified seven structural variants coinciding with candidate genes for flowering time within chromosome regions associated with flowering time. Segregation patterns for these variants in the elite multiparental population and a diversity set of winter types using locus-specific assays revealed significant associations with flowering time for three deletions on chromosome A02. One of these was a previously undescribed 288 bp deletion within the second intron of FLOWERING LOCUS T on chromosome A02, emphasizing the advantage of long-read sequencing for detection of structural variants in this size range. Detailed analysis revealed the impact of this specific deletion on flowering-time modulation under extreme environments and varying day lengths in elite, winter-type oilseed rape.

Download Full-text

Massive haplotypes underlie ecotypic differentiation in sunflowers

10.1101/790279 ◽

2019 ◽

Cited By ~ 9

Author(s):

Marco Todesco ◽

Gregory L. Owens ◽

Natalia Bercovich ◽

Jean-Sébastien Légaré ◽

Shaghayegh Soudi ◽

...

Keyword(s):

Soil Fertility ◽

Flowering Time ◽

Seed Size ◽

Structural Variation ◽

Structural Variants ◽

Flowering Locus T ◽

Ecotypic Differentiation ◽

Haplotype Blocks ◽

Flowering Locus

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.

Download Full-text

Isolation and Functional Characterization of MsFTa, a FLOWERING LOCUS T Homolog from Alfalfa (Medicago sativa)

International Journal of Molecular Sciences ◽

10.3390/ijms20081968 ◽

2019 ◽

Vol 20 (8) ◽

pp. 1968 ◽

Cited By ~ 2

Author(s):

Junmei Kang ◽

Tiejun Zhang ◽

Tao Guo ◽

Wang Ding ◽

Ruicai Long ◽

...

Keyword(s):

Flowering Time ◽

Functional Characterization ◽

Flowering Locus T ◽

Over Expression ◽

Long Day ◽

Gfp Fusion Protein ◽

Intron Structure ◽

Flowering Locus ◽

Flowering Regulation

The production of hay and seeds of alfalfa, an important legume forage for the diary industry worldwide, is highly related to flowering time, which has been widely reported to be integrated by FLOWERING LOCUS T (FT). However, the function of FT(s) in alfalfa is largely unknown. Here, we identified MsFTa, an FT ortholog in alfalfa, and characterized its role in flowering regulation. MsFTa shares the conserved exon/intron structure of FTs, and MsFTa is 98% identical to MtFTa1 in Medicago trucatula. MsFTa was diurnally regulated with a peak before the dark period, and was preferentially expressed in leaves and floral buds. Transient expression of MsFTa-GFP fusion protein demonstrated its localization in the nucleus and cytoplasm. When ectopically expressed, MsFTa rescued the late-flowering phenotype of ft mutants from Arabidopsis and M. trucatula. MsFTa over-expression plants of both Arabidopsis and M. truncatula flowered significantly earlier than the non-transgenic controls under long day conditions, indicating that exogenous MsFTa strongly accelerated flowering. Hence, MsFTa functions positively in flowering promotion, suggesting that MsFTa may encode a florigen that acts as a key regulator in the flowering pathway. This study provides an effective candidate gene for optimizing alfalfa flowering time by genetically manipulating the expression of MsFTa.

Download Full-text

Dehydroabietinal promotes flowering time and plant defense in Arabidopsis via the autonomous pathway genes FLOWERING LOCUS D, FVE, and RELATIVE OF EARLY FLOWERING 6

Journal of Experimental Botany ◽

10.1093/jxb/eraa232 ◽

2020 ◽

Vol 71 (16) ◽

pp. 4903-4913 ◽

Cited By ~ 1

Author(s):

Zulkarnain Chowdhury ◽

Devasantosh Mohanty ◽

Mrunmay K Giri ◽

Barney J Venables ◽

Ratnesh Chaturvedi ◽

...

Keyword(s):

Flowering Time ◽

Systemic Acquired Resistance ◽

Defense Mechanism ◽

Acquired Resistance ◽

Early Flowering ◽

Negative Regulator ◽

Flowering Locus T ◽

Autonomous Pathway ◽

Abietane Diterpenoids ◽

Flowering Locus

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.

Download Full-text

GWAS hints at pleiotropic roles for FLOWERING LOCUS T in flowering time and yield-related traits in canola

BMC Genomics ◽

10.1186/s12864-019-5964-y ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 13

Author(s):

Harsh Raman ◽

Rosy Raman ◽

Yu Qiu ◽

Avilash Singh Yadav ◽

Sridevi Sureshkumar ◽

...

Keyword(s):

Flowering Time ◽

Flowering Locus T ◽

Flowering Locus

Download Full-text

Natural Variation of the RICE FLOWERING LOCUS T 1 Contributes to Flowering Time Divergence in Rice

PLoS ONE ◽

10.1371/journal.pone.0075959 ◽

2013 ◽

Vol 8 (10) ◽

pp. e75959 ◽

Cited By ~ 52

Author(s):

Eri Ogiso-Tanaka ◽

Kazuki Matsubara ◽

Shin-ichi Yamamoto ◽

Yasunori Nonoue ◽

Jianzhong Wu ◽

...

Keyword(s):

Flowering Time ◽

Natural Variation ◽

Flowering Locus T ◽

Flowering Locus

Download Full-text

BBX19 Interacts with CONSTANS to Repress FLOWERING LOCUS T Transcription, Defining a Flowering Time Checkpoint in Arabidopsis

The Plant Cell ◽

10.1105/tpc.114.130252 ◽

2014 ◽

Vol 26 (9) ◽

pp. 3589-3602 ◽

Cited By ~ 53

Author(s):

C.-Q. Wang ◽

C. Guthrie ◽

M. K. Sarmast ◽

K. Dehesh

Keyword(s):

Flowering Time ◽

Flowering Locus T ◽

Flowering Locus

Download Full-text

Arabidopsis TERMINAL FLOWER 2 Gene Encodes a Heterochromatin Protein 1 Homolog and Represses both FLOWERING LOCUS T to Regulate Flowering Time and Several Floral Homeotic Genes

Plant and Cell Physiology ◽

10.1093/pcp/pcg091 ◽

2003 ◽

Vol 44 (6) ◽

pp. 555-564 ◽

Cited By ~ 142

Author(s):

Toshihisa Kotake ◽

Shinobu Takada ◽

Kenji Nakahigashi ◽

Masaaki Ohto ◽

Koji Goto

Keyword(s):

Flowering Time ◽

Homeotic Genes ◽

Flowering Locus T ◽

Heterochromatin Protein 1 ◽

Heterochromatin Protein ◽

Floral Homeotic Genes ◽

Terminal Flower ◽

Flowering Locus ◽

Floral Homeotic

Download Full-text

Contrasting Patterns of Colonization with Verticillium longisporum in Winter- and Spring-Type Oilseed Rape (Brassica napus) in the Field and Greenhouse and the Role of Soil Temperature

Plant Disease ◽

10.1094/pdis-01-19-0236-re ◽

2019 ◽

Vol 103 (8) ◽

pp. 2090-2099 ◽

Cited By ~ 3

Author(s):

Xiaorong Zheng ◽

Annette Pfordt ◽

Laxman Khatri ◽

Alice Bisola Eseola ◽

Antonia Wilch ◽

...

Keyword(s):

Soil Temperature ◽

Oilseed Rape ◽

Temporal Pattern ◽

Field Experiments ◽

Growth Stages ◽

Juvenile Growth ◽

Root Infection ◽

Winter Oilseed Rape ◽

Winter Type ◽

Spring Type

Oilseed rape, an important source of vegetable plant oil, is threatened by Verticillium longisporum, a soil-borne vascular fungal pathogen so far occurring in oilseed rape growing regions in Europe and Canada. Despite intensive research into V. longisporum in the last decades in controlled conditions, basic knowledge is still lacking about the time course of infection, temporal pattern of colonization, and disease development on field-grown plants. In this study, colonization of roots, stem bases, and stems with V. longisporum was followed by real-time PCR from the seedling until mature plant stages in 2-year field experiments with microsclerotia-infested plots and either spring-type or autumn-sown (winter-type) oilseed rape cultivars. The temporal pattern of plant colonization differed between greenhouse and field-grown oilseed rape and between spring- and winter-type plants in the field. Within 28 to 35 days, a continuous systemic colonization with V. longisporum was detected in roots and shoots of young plants in the greenhouse associated with significant stunting. In contrast, real-time PCR analysis of V. longisporum in field-grown winter oilseed rape plants displayed a strongly discontinuous colonization pattern with low fungal growth in roots during juvenile growth stages until flowering, whereas in spring oilseed rape, no root colonization was observed until early flowering stages. Hence, stem colonization with the pathogen required 6 months in winter oilseed rape and 1 month in spring oilseed rape from the time of initial root infection. The different patterns of stem colonization were related to soil temperature. Average soil temperatures in 5-cm depth during 7 days before sampling time points from 2 years of field experiments displayed a significant relationship with fungal colonization in the root. A climate chamber inoculation trial with soil temperature levels that varied from 6 to 18°C revealed a threshold temperature of >12°C in the soil to enable root invasion. This soil condition is reached in winter-type oilseed rape in the field in Germany either until the eight-leaf stage in early autumn or after pod stage in spring, whereas in spring-sown oilseed rape early root infection is delayed owing to the cool conditions during juvenile growth stages. The delay of stem colonization in field-grown oilseed rape may explain the lack of stunting as observed in the greenhouse and the previously reported inconsistent effects of V. longisporum on yield levels and seed quality, which were confirmed in this study.

Download Full-text