scholarly journals Expression of a NGATHA1 Gene from Medicago truncatula Delays Flowering Time and Enhances Stress Tolerance

2020 ◽  
Vol 21 (7) ◽  
pp. 2384
Author(s):  
Tao Guo ◽  
Shumin Wang ◽  
Yinruizhi Li ◽  
Jianbo Yuan ◽  
Lixin Xu ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Stress Tolerance ◽  
Flowering Time ◽  
Medicago Truncatula ◽  
Transgenic Arabidopsis ◽  
Hormone Synthesis ◽  
Cis Acting ◽  
Plant Expression Vector ◽  
Lateral Organ ◽  
Delayed Flowering

Shoot branching is one of the most variable determinants of crop yield, and the signaling pathways of plant branches have become a hot research topic. As an important transcription factor in the B3 family, NGATHA1 (NGA1), plays an important role in regulating plant lateral organ development and hormone synthesis and transport, but few studies of the role of this gene in the regulation of plant growth and stress tolerance have been reported. In this study, the NGA1 gene was isolated from Medicago truncatula (Mt) and its function was characterized. The cis-acting elements upstream of the 5′ end of MtNGA1 and the expression pattern of MtNGA1 were analyzed, and the results indicated that the gene may act as a regulator of stress resistance. A plant expression vector was constructed and transgenic Arabidopsis plants were obtained. Transgenic Arabidopsis showed delayed flowering time and reduced branching phenotypes. Genes involved in the regulation of branching and flowering were differentially expressed in transgenic plants compared with wild-type plants. Furthermore, transgenic plants demonstrated strong tolerances to salt- and mannitol-induced stresses, which may be due to the upregulated expression of NCED3 (NINE-CIS-EPOXYCAROTENOID DIOXYGENASE 3) by the MtNGA1 gene. These results provide useful information for the exploration and genetic modification use of MtNGA1 in the future.

scholarly journals Overexpression of AtAHL20 causes delayed flowering in Arabidopsis via repression of  FT expression

2020 ◽  
Author(s):  
Reuben Tayengwa ◽  
Pushpa Sharma-Koirala ◽  
Courtney F. Pierce ◽  
Breanna E Werner ◽  
Michael M Neff
Keyword(s):  
Drought Stress ◽  
Transgenic Plants ◽  
Gene Family ◽  
Stress Tolerance ◽  
Flowering Time ◽  
Camelina Sativa ◽  
Negative Regulator ◽  
Wild Type ◽  
Late Flowering ◽  
Drought Stress Tolerance

Abstract Background The 29-member Arabidopsis AHL gene family is classified into three main classes based on nucleotide and protein sequence evolutionary differences. These differences include the presence or absence of introns, type and/or number of conserved AT-hook and PPC domains. AHL gene family members are divided into two phylogenetic clades, Clade-A and Clade-B. A majority of the 29 members remain functionally uncharacterized. Furthermore, the biological significance of the DNA and peptide sequence diversity, observed in the conserved motifs and domains found in the different AHL types, is a subject area that remains largely unexplored. Results Transgenic plants overexpressing AtAHL20 flowered later than the wild type. Transcript accumulation analyses showed that 35S:AtAHL20 plants contained reduced FT, TSF, AGL8 and SPL3 mRNA levels. Similarly, overexpression of AtAHL20’s orthologue in Camelina sativa, Arabidopsis’ closely related Brassicaceae family member species, conferred a late-flowering phenotype via suppression of CsFT expression. In addition, 35S:AtAHL20 seedlings exhibited suppressed hypocotyl length and enhanced water stress tolerance. However, overexpression of an aberrant AtAHL20 gene harboring a missense mutation in the AT-hook domain’s highly conserved R-G-R core motif abolished the late-flowering phenotype. Data from targeted yeast-two-hybrid assays showed that AtAHL20 interacted with itself and several other Clade-A Type-I AHLs which have been previously implicated in flowering-time regulation: AtAHL22, AtAHL27 and AtAHL29. Conclusion We showed via gain-function analysis that AtAHL20 is a negative regulator of FT expression, as well as other downstream flowering time regulating genes. A similar outcome in Camelina sativa transgenic plants overexpressing CsAHL20 suggest that this is a conserved function. Additionally, overexpression of AtAHL20 resulted in shorter hypocotyls and enhanced drought stress tolerance compared to wild-type plants. Our results demonstrate that AtAHL20 is a negative regulator of transition to flowering and hypocotyl elongation, but a positive regulator of drought stress tolerance.

Overexpression of the mango MiCO gene delayed flowering time in transgenic Arabidopsis

2020 ◽  
Vol 143 (1) ◽  
pp. 219-228
Author(s):  
Yuan Liu ◽  
Cong Luo ◽  
Xiu-Juan Zhang ◽  
Xin-Xi Lu ◽  
Hai-Xia Yu ◽  
...  
Keyword(s):  
Flowering Time ◽  
Transgenic Arabidopsis ◽  
Delayed Flowering

scholarly journals The Candidate Photoperiod Gene MtFE Promotes Growth and Flowering in Medicago truncatula

2021 ◽  
Vol 12 ◽  
Author(s):  
Geoffrey Thomson ◽  
Lulu Zhang ◽  
Jiangqi Wen ◽  
Kirankumar S. Mysore ◽  
Joanna Putterill
Keyword(s):  
Flowering Time ◽  
Medicago Truncatula ◽  
Wild Type ◽  
Transport Pathway ◽  
Knock Out ◽  
Nuclear Factor Y ◽  
Winter Annual ◽  
Flowering Locus ◽  
Delayed Flowering ◽  
Two Hybrid

Flowering time influences the yield and productivity of legume crops. Medicago truncatula is a reference temperate legume that, like the winter annual Arabidopsis thaliana, shows accelerated flowering in response to vernalization (extended cold) and long-day (LD) photoperiods (VLD). However, unlike A. thaliana, M. truncatula appears to lack functional homologs of core flowering time regulators CONSTANS (CO) and FLOWERING LOCUS C (FLC) which act upstream of the mobile florigen FLOWERING LOCUS T (FT). Medicago truncatula has three LD-induced FT-like genes (MtFTa1, MtFTb1, and MtFTb2) with MtFTa1 promoting M. truncatula flowering in response to VLD. Another photoperiodic regulator in A. thaliana, FE, acts to induce FT expression. It also regulates the FT transport pathway and is required for phloem development. Our study identifies a M. truncatula FE homolog Medtr6g444980 (MtFE) which complements the late flowering fe-1 mutant when expressed from the phloem-specific SUCROSE-PROTON SYMPORTER 2 (SUC2) promoter. Analysis of two M. truncatula Tnt1 insertional mutants indicate that MtFE promotes flowering in LD and VLD and growth in all conditions tested. Expression of MtFTa1, MtFTb1, and MtFTb2 are reduced in Mtfe mutant (NF5076), correlating with its delayed flowering. The NF5076 mutant plants are much smaller than wild type indicating that MtFE is important for normal plant growth. The second mutant (NF18291) displays seedling lethality, like strong fe mutants. We searched for mutants in MtFTb1 and MtFTb2 identifying a Mtftb2 knock out Tnt1 mutant (NF20803). However, it did not flower significantly later than wild type. Previously, yeast-two-hybrid assays (Y2H) suggested that Arabidopsis FE interacted with CO and NUCLEAR FACTOR-Y (NF-Y)-like proteins to regulate FT. We found that MtFE interacts with CO and also M. truncatula NF-Y-like proteins in Y2H experiments. Our study indicates that despite the apparent absence of a functional MtCO-like gene, M. truncatula FE likely influences photoperiodic FT expression and flowering time in M. truncatula via a partially conserved mechanism with A. thaliana.

scholarly journals Degradation of trinitrotoluene by transgenic nitroreductase in Arabidopsis plants

2018 ◽  
Vol 64 (No. 8) ◽  
pp. 379-385 ◽  
Author(s):  
Zhu Bo ◽  
Han Hongjuan ◽  
Fu Xiaoyan ◽  
Li Zhenjun ◽  
Gao Jianjie ◽  
...  
Keyword(s):  
Transgenic Plants ◽  
Transgenic Arabidopsis ◽  
Environmental Pollutant ◽  
Specific Rate ◽  
Wild Type Plant ◽  
Wild Type ◽  
Fresh Weight ◽  
Human Carcinogen ◽  
Specific Rate Constant ◽  
Nitroreductase Activity

The explosive 2,4,6-trinitrotoluene (TNT) is a highly toxic and persistent environmental pollutant. TNT is toxic to many organisms, it is known to be a potential human carcinogen, and is persistent in the environment. This study presents a system of phytoremediation by Arabidopsis plants developed on the basis of overexpression of NAD(P)H-flavin nitroreductase (NFSB) from the Sulfurimonas denitrificans DSM1251. The resulting transgenic Arabidopsis plants demonstrated significantly enhanced TNT tolerance and a strikingly higher capacity to remove TNT from their media. The highest specific rate constant of TNT disappearance rate was 1.219 and 2.297 mL/g fresh weight/h for wild type and transgenic plants, respectively. Meanwhile, the nitroreductase activity in transgenic plant was higher than wild type plant. All this indicates that transgenic plants show significantly enhanced tolerances to TNT; transgenic plants also exhibit strikingly higher capabilities of removing TNT from their media and high efficiencies of transformation.

scholarly journals Potential transceptor AtNRT1.13 modulates shoot architecture and flowering time in a nitrate-dependent manner

2021 ◽  
Author(s):  
Hui-Yu Chen ◽  
Shan-Hua Lin ◽  
Ling-Hsin Cheng ◽  
Jeng-Jong Wu ◽  
Yi-Chen Lin ◽  
...  
Keyword(s):  
Flowering Time ◽  
Nitrate Transport ◽  
Dependent Manner ◽  
Transport Activity ◽  
Node Number ◽  
Shoot Architecture ◽  
Glucuronidase Reporter ◽  
Uptake Activity ◽  
Delayed Flowering ◽  
Severe Growth

Abstract Compared with root development regulated by external nutrients, less is known about how internal nutrients are monitored to control plasticity of shoot development. In this study, we characterize an Arabidopsis thaliana transceptor, NRT1.13 (NPF4.4), of the NRT1/PTR/NPF family. Different from most NRT1 transporters, NRT1.13 does not have the conserved proline residue between transmembrane domains 10 and 11; an essential residue for nitrate transport activity in CHL1/NRT1.1/NPF6.3. As expected, when expressed in oocytes, NRT1.13 showed no nitrate transport activity. However, when Ser 487 at the corresponding position was converted back to proline, NRT1.13 S487P regained nitrate uptake activity, suggesting that wild-type NRT1.13 cannot transport nitrate but can bind it. Subcellular localization and β-glucuronidase reporter analyses indicated that NRT1.13 is a plasma membrane protein expressed at the parenchyma cells next to xylem in the petioles and the stem nodes. When plants were grown with a normal concentration of nitrate, nrt1.13 showed no severe growth phenotype. However, when grown under low-nitrate conditions, nrt1.13 showed delayed flowering, increased node number, retarded branch outgrowth, and reduced lateral nitrate allocation to nodes. Our results suggest that NRT1.13 is required for low-nitrate acclimation and that internal nitrate is monitored near the xylem by NRT1.13 to regulate shoot architecture and flowering time.

scholarly journals Overexpression of Cotton a DTX/MATE Gene Enhances Drought, Salt, and Cold Stress Tolerance in Transgenic Arabidopsis

2019 ◽  
Vol 10 ◽  
Author(s):  
Pu Lu ◽  
Richard Odongo Magwanga ◽  
Joy Nyangasi Kirungu ◽  
Yangguang Hu ◽  
Qi Dong ◽  
...  
Keyword(s):  
Cold Stress ◽  
Stress Tolerance ◽  
Transgenic Arabidopsis

scholarly journals A Composite Analysis of Flowering Time Regulation in Lettuce

2021 ◽  
Vol 12 ◽  
Author(s):  
Rongkui Han ◽  
Maria José Truco ◽  
Dean O. Lavelle ◽  
Richard W. Michelmore
Keyword(s):  
Flowering Time ◽  
Crop Production ◽  
Phenotypic Diversity ◽  
Model Organism ◽  
Leafy Vegetables ◽  
Vegetable Crops ◽  
Comprehensive Overview ◽  
Molecular Studies ◽  
Functional Inference ◽  
Delayed Flowering

Plants undergo profound physiological changes when transitioning from vegetative to reproductive growth. These changes affect crop production, as in the case of leafy vegetables. Lettuce is one of the most valuable leafy vegetable crops in the world. Past genetic studies have identified multiple quantitative trait loci (QTLs) that affect the timing of the floral transition in lettuce. Extensive functional molecular studies in the model organism Arabidopsis provide the opportunity to transfer knowledge to lettuce to explore the mechanisms through which genetic variations translate into changes in flowering time. In this review, we integrated results from past genetic and molecular studies for flowering time in lettuce with orthology and functional inference from Arabidopsis. This summarizes the basis for all known genetic variation underlying the phenotypic diversity of flowering time in lettuce and how the genetics of flowering time in lettuce projects onto the established pathways controlling flowering time in plants. This comprehensive overview reveals patterns across experiments as well as areas in need of further study. Our review also represents a resource for developing cultivars with delayed flowering time.

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