Abscisic Acid and Flowering Regulation: Many Targets, Different Places

Plants can react to drought stress by anticipating flowering, an adaptive strategy for plant survival in dry climates known as drought escape (DE). In Arabidopsis, the study of DE brought to surface the involvement of abscisic acid (ABA) in controlling the floral transition. A central question concerns how and in what spatial context can ABA signals affect the floral network. In the leaf, ABA signaling affects flowering genes responsible for the production of the main florigen FLOWERING LOCUS T (FT). At the shoot apex, FD and FD-like transcription factors interact with FT and FT-like proteins to regulate ABA responses. This knowledge will help separate general and specific roles of ABA signaling with potential benefits to both biology and agriculture.

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Under salt stress guard cells rewire ion transport and abscisic acid (ABA) signaling

New Phytologist ◽

10.1111/nph.17376 ◽

2021 ◽

Author(s):

Sohail M. Karimi ◽

Matthias Freund ◽

Brittney M. Wager ◽

Michael Knoblauch ◽

Jörg Fromm ◽

...

Keyword(s):

Abscisic Acid ◽

Salt Stress ◽

Ion Transport ◽

Guard Cells ◽

Aba Signaling

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A Screen for Genes That Function in Abscisic Acid Signaling in Arabidopsis thaliana

Genetics ◽

10.1093/genetics/161.3.1247 ◽

2002 ◽

Vol 161 (3) ◽

pp. 1247-1255 ◽

Cited By ~ 1

Author(s):

Eiji Nambara ◽

Masaharu Suzuki ◽

Suzanne Abrams ◽

Donald R McCarty ◽

Yuji Kamiya ◽

...

Keyword(s):

Abscisic Acid ◽

Growth And Development ◽

Plant Hormone ◽

The Other ◽

Aba Signaling ◽

Wild Type ◽

Plant Growth And Development ◽

Diverse Range ◽

Abscisic Acid Signaling ◽

Aba Insensitive

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.

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AtMybL-O modulates abscisic acid biosynthesis to optimize plant growth and ABA signaling in response to drought stress

Applied Biological Chemistry ◽

10.1007/s13765-018-0376-2 ◽

2018 ◽

Vol 61 (4) ◽

pp. 473-477 ◽

Cited By ~ 6

Author(s):

Chan Young Jeong ◽

Won Je Lee ◽

Hai An Truong ◽

Cao Sơn Trịnh ◽

Suk-Whan Hong ◽

...

Keyword(s):

Abscisic Acid ◽

Drought Stress ◽

Plant Growth ◽

Aba Signaling ◽

Acid Biosynthesis ◽

Abscisic Acid Biosynthesis

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Analysis of the quinoa genome reveals conservation and divergence of the flowering pathways

Functional & Integrative Genomics ◽

10.1007/s10142-019-00711-1 ◽

2019 ◽

Vol 20 (2) ◽

pp. 245-258 ◽

Cited By ~ 5

Author(s):

Agnieszka A. Golicz ◽

Ursula Steinfort ◽

Hina Arya ◽

Mohan B. Singh ◽

Prem L. Bhalla

Keyword(s):

Crop Improvement ◽

Chenopodium Quinoa ◽

Flower Initiation ◽

Flowering Genes ◽

The Andes ◽

Grain Crop ◽

Improvement Programs ◽

Flowering Regulation ◽

High Yields ◽

Modern Breeding

Abstract Quinoa (Chenopodium quinoa Willd.) is a grain crop grown in the Andes renowned as a highly nutritious plant exhibiting tolerance to abiotic stress such as drought, cold and high salinity. Quinoa grows across a range of latitudes corresponding to differing day lengths, suggesting regional adaptations of flowering regulation. Improved understanding and subsequent modification of the flowering process, including flowering time, ensuring high yields, is one of the key factors behind expansion of cultivation zones and goals of the crop improvement programs worldwide. However, our understanding of the molecular basis of flower initiation and development in quinoa is limited. Here, we use a computational approach to perform genome-wide identification and analysis of 611 orthologues of the Arabidopsis thaliana flowering genes. Conservation of the genes belonging to the photoperiod, gibberellin and autonomous pathways was observed, while orthologues of the key genes found in the vernalisation pathway (FRI, FLC) were absent from the quinoa genome. Our analysis indicated that on average each Arabidopsis flowering gene has two orthologous copies in quinoa. Several genes including orthologues of MIF1, FT and TSF were identified as homologue-rich genes in quinoa. We also identified 459 quinoa-specific genes uniquely expressed in the flower and/or meristem, with no known orthologues in other species. The genes identified provide a resource and framework for further studies of flowering in quinoa and related species. It will serve as valuable resource for plant biologists, crop physiologists and breeders to facilitate further research and establishment of modern breeding programs for quinoa.

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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.

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ABI5 regulates ABA-induced anthocyanin biosynthesis by modulating the MYB1-bHLH3 complex in apple

Journal of Experimental Botany ◽

10.1093/jxb/eraa525 ◽

2020 ◽

Author(s):

Jian-Ping An ◽

Xiao-Wei Zhang ◽

Ya-Jing Liu ◽

Xiao-Fei Wang ◽

Chun-Xiang You ◽

...

Keyword(s):

Abscisic Acid ◽

Target Genes ◽

Anthocyanin Biosynthesis ◽

Aba Signaling ◽

Plant Growth And Development ◽

Biochemical Tests ◽

Positive Role ◽

Helix Loop Helix ◽

Transcriptional Regulatory ◽

Transcriptional Regulatory Mechanisms

Abstract Abscisic acid (ABA) induces anthocyanin biosynthesis in many plant species. However, the molecular mechanism of ABA-regulated anthocyanin biosynthesis remains unclear. As a crucial regulator of ABA signaling, ABSCISIC ACID-INSENSITIVE5 (ABI5) is involved in many aspects of plant growth and development, yet its regulation of anthocyanin biosynthesis has not been elucidated. In this study, we found that MdABI5, the apple homolog of Arabidopsis ABI5, positively regulated ABA-induced anthocyanin biosynthesis. A series of biochemical tests showed that MdABI5 specifically interacts with basic helix-loop-helix 3 (MdbHLH3), a positive regulator of anthocyanin biosynthesis. MdABI5 enhanced the binding of MdbHLH3 to its target genes dihydroflavonol 4-reductase (MdDFR) and UDP flavonoid glucosyl transferase (MdUF3GT). In addition, MdABI5 directly bound to the promoter of MdbHLH3 to activate its expression. Moreover, MdABI5 enhanced ABA-promoted interaction between MdMYB1 and MdbHLH3. Finally, antisense suppression of MdbHLH3 significantly reduced anthocyanin biosynthesis promoted by MdABI5, indicating that MdABI5-promoted anthocyanin biosynthesis was dependent on MdbHLH3. Taken together, our data suggest that MdABI5 plays a positive role in ABA-induced anthocyanin biosynthesis by modulating the MdbHLH3-MdMYB1 complex. Our work broadens the regulatory network of ABA-mediated anthocyanin biosynthesis, providing new insights to further study the transcriptional regulatory mechanisms behind this process.

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A histone H4 gene prevents drought-induced bolting in Chinese cabbage by attenuating the expression of flowering genes

Journal of Experimental Botany ◽

10.1093/jxb/eraa452 ◽

2020 ◽

Author(s):

Xiaoyun Xin ◽

Tongbing Su ◽

Peirong Li ◽

Weihong Wang ◽

Xiuyun Zhao ◽

...

Keyword(s):

Chinese Cabbage ◽

Chromatin Modification ◽

Normal Growth ◽

Fine Tuning ◽

Homeodomain Protein ◽

Aba Signaling ◽

Histone H4 ◽

Flowering Genes ◽

Photoperiodic Flowering ◽

Drought Conditions

Abstract Flowering is an important trait in Chinese cabbage, because premature flowering reduces yield and quality of the harvested products. Water deficit, caused by drought or other environmental conditions, induces early flowering. Drought resistance involves global reprogramming of transcription, hormone signaling, and chromatin modification. We show that a histone H4 protein, BrHIS4.A04, physically interacts with a homeodomain protein BrVIN3.1, which was selected during the domestication of late-bolting Chinese cabbage. Over-expression of BrHIS4.A04 resulted in premature flowering under normal growth conditions, but prevented further premature bolting in response to drought. We show that the expression of key abscisic acid (ABA) signaling genes, and also photoperiodic flowering genes was attenuated in BrHIS4.A04-overexpressing (BrHIS4.A04OE) plants under drought conditions. Furthermore, the relative change in H4-acetylation at these gene loci was reduced in BrHIS4.A04OE plants. We suggest that BrHIS4.A04 prevents premature bolting by attenuating the expression of photoperiodic flowering genes under drought conditions, through the ABA signaling pathway. Since BrHIS4.A04OE plants displayed no phenotype related to vegetative or reproductive development under laboratory-induced drought conditions, our findings contribute to the potential fine-tuning of flowering time in crops through genetic engineering without any growth penalty, although more data are necessary under field drought conditions.

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Arabidopsis exoribonuclease USB1 interacts with the PPR-domain protein SOAR1 to negatively regulate abscisic acid signaling

Journal of Experimental Botany ◽

10.1093/jxb/eraa315 ◽

2020 ◽

Vol 71 (19) ◽

pp. 5837-5851

Author(s):

Yu Ma ◽

Shang Zhang ◽

Chao Bi ◽

Chao Mei ◽

Shang-Chuan Jiang ◽

...

Keyword(s):

Abscisic Acid ◽

Regulation Of Gene Expression ◽

Mrna Splicing ◽

Plant Responses ◽

Aba Signaling ◽

Pentatricopeptide Repeat ◽

Spliceosome Assembly ◽

Early Seedling ◽

Post Transcriptional Regulation ◽

Early Seedling Development

Abstract Signaling by the phytohormone abscisic acid (ABA) involves pre-mRNA splicing, a key process of post-transcriptional regulation of gene expression. However, the regulatory mechanism of alternative pre-mRNA splicing in ABA signaling remains largely unknown. We previously identified a pentatricopeptide repeat protein SOAR1 (suppressor of the ABAR-overexpressor 1) as a crucial player downstream of ABAR (putative ABA receptor) in ABA signaling. In this study, we identified a SOAR1 interaction partner USB1, which is an exoribonuclease catalyzing U6 production for spliceosome assembly. We reveal that together USB1 and SOAR1 negatively regulate ABA signaling in early seedling development. USB1 and SOAR1 are both required for the splicing of transcripts of numerous genes, including those involved in ABA signaling pathways, suggesting that USB1 and SOAR1 collaborate to regulate ABA signaling by affecting spliceosome assembly. These findings provide important new insights into the mechanistic control of alternative pre-mRNA splicing in the regulation of ABA-mediated plant responses to environmental cues.

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Expression of a FLOWERING LOCUS T homologue is temporally associated with annual flower bud initiation in Eucalyptus globulus subsp. globulus (Myrtaceae)

Australian Journal of Botany ◽

10.1071/bt11251 ◽

2011 ◽

Vol 59 (8) ◽

pp. 756 ◽

Cited By ~ 7

Author(s):

Rebecca C. Jones ◽

Valérie F. G. Hecht ◽

Brad M. Potts ◽

René E. Vaillancourt ◽

James L. Weller

Keyword(s):

Eucalyptus Globulus ◽

Expression Patterns ◽

Flower Initiation ◽

Flowering Locus T ◽

Flower Bud ◽

Reproductive Growth ◽

Environmental Signals ◽

Flowering Genes ◽

Flowering Locus ◽

Bud Initiation

The transition to flowering in plants is the result of the balance of endogenous processes and environmental signals that act through a complex genetic pathway that has been studied extensively in annual plants such as Arabidopsis. Perennial trees are characterised by a juvenile non-flowering phase lasting several years followed by an adult phase in which there is repeated cycling between vegetative and reproductive growth. The genetic control of flowering time is potentially more complex in perennials than in annuals and is less understood. Here, we examine the control of flowering in Eucalyptus globulus subsp. globulus, an important forestry species in temperate parts of the world. The E. globulus subsp. globulus homologues of two important flowering genes FLOWERING LOCUS T (FT) and LEAFY (LFY) were isolated and quantitative RT-PCR was used to measure their expression over a 2-year period. The expression of the homologue of FT in E. globulus subsp. globulus leaves was associated with the annual transition from vegetative to reproductive growth (i.e. flower bud initiation). Expression of the LFY homologue was associated with early flower bud development. In a comparison of FT and LFY expression patterns in two clones each of an early and late anthesis genotype, no association between the expression of these genes and the timing of anthesis was shown. Taken together, this indicates that FT and LFY could form part of the flower initiation pathway in Eucalyptus but do not regulate the observed differences in anthesis time.

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