Elucidating the role of SWEET13 in phloem loading of the C 4 grass Setaria viridis

2021 ◽  
Author(s):  
Lily Chen ◽  
Diep Ray Ganguly ◽  
Sarah Heckmatt Shafik ◽  
Maria Ermakova ◽  
Barry James Pogson ◽  
...  
Keyword(s):  
Phloem Loading ◽  
Setaria Viridis

An analysis of the role of the ShSUT1 sucrose transporter in sugarcane using RNAi suppression

2017 ◽  
Vol 44 (8) ◽  
pp. 795 ◽  
Author(s):  
Donna Glassop ◽  
Jiri Stiller ◽  
Graham D. Bonnett ◽  
Christopher P. L. Grof ◽  
Anne L. Rae
Keyword(s):  
Sucrose Concentration ◽  
Amplicon Sequencing ◽  
Phloem Loading ◽  
Gene Transcript ◽  
Direct Role ◽  
Rnai Technology ◽  
Transgenic Lines ◽  
Sucrose Mobilisation ◽  
And Storage

The role of ShSUT1 in sucrose mobilisation and storage in sugarcane was investigated by employing RNAi technology to reduce the expression of this gene. Transcript profiling in non-transformed plants showed an alignment between expression and sucrose concentration, with strongest expression in source leaves and increasing expression through the daylight period of a diurnal cycle. Five transgenic plant lines were produced with reduced ShSUT1 expression ranging from 52 to 92% lower than control plants. Differential suppression of ShSUT1 sequence variants in the highly polyploid sugarcane genome were also investigated. Amplicon sequencing of the ShSUT1 variants within the transgenic lines and controls showed no preferential suppression with only minor differences in the proportional expression of the variants. A range of altered sugar, fibre and moisture contents were measured in mature leaf and internode samples, but no phenotype was consistently exhibited by all five transgenic lines. Phenotypes observed indicate that ShSUT1 does not play a direct role in phloem loading. ShSUT1 is likely involved with retrieving sucrose from intercellular spaces for transport and storage.

Evidence for an essential role of the sucrose transporter in phloem loading and assimilate partitioning.

1994 ◽  
Vol 13 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J.W. Riesmeier ◽  
L. Willmitzer ◽  
W.B. Frommer
Keyword(s):  
Essential Role ◽  
Phloem Loading ◽  
Sucrose Transporter ◽  
Assimilate Partitioning

scholarly journals Importance of Poly-3-Hydroxybutyrate Metabolism to the Ability ofHerbaspirillum seropedicaeTo Promote Plant Growth

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Luis Paulo Silveira Alves ◽  
Fernanda Plucani do Amaral ◽  
Daewon Kim ◽  
Maritza Todo Bom ◽  
Manuel Piñero Gavídia ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Colonization ◽  
Normal Growth ◽  
Setaria Viridis ◽  
Low Oxygen ◽  
Herbaspirillum Seropedicae ◽  
Content Type ◽  
Stimulate Plant Growth ◽  
Microaerobic Conditions

ABSTRACTHerbaspirillum seropedicaeis an endophytic bacterium that establishes an association with a variety of plants, such as rice, corn, and sugarcane, and can significantly increase plant growth.H. seropedicaeproduces polyhydroxybutyrate (PHB), stored in the form of insoluble granules. Little information is available on the possible role of PHB in bacterial root colonization or in plant growth promotion. To investigate whether PHB is important for the association ofH. seropedicaewith plants, we inoculated roots ofSetaria viridiswithH. seropedicaestrain SmR1 and mutants defective in PHB production (ΔphaP1, ΔphaP1ΔphaP2, ΔphaC1, and ΔphaR) or mobilization (ΔphaZ1ΔphaZ2). The strains producing large amounts of PHB colonized roots, significantly increasing root area and the number of lateral roots compared to those of PHB-negative strains.H. seropedicaegrows under microaerobic conditions, which can be found in the rhizosphere. When grown under low-oxygen conditions, only the parental strain and ΔphaP2mutant exhibited normal growth. The lack of normal growth under low oxygen correlated with the inability to stimulate plant growth, although there was no effect on the level of root colonization. The data suggest that PHB is produced in the root rhizosphere and plays a role in maintaining normal metabolism under microaerobic conditions. To confirm this, we screened for green fluorescent protein (GFP) expression under the control of theH. seropedicaepromoters of the PHA synthase and PHA depolymerase genes in the rhizosphere. PHB synthesis is active on the root surface and later PHB depolymerase expression is activated.IMPORTANCEThe application of bacteria as plant growth promoters is a sustainable alternative to mitigate the use of chemical fertilization in agriculture, reducing negative economic and environmental impacts. Several plant growth-promoting bacteria synthesize and accumulate the intracellular polymer polyhydroxybutyrate (PHB). However, the role of PHB in plant-bacterium interactions is poorly understood. In this study, applying the C4 model grassSetaria viridisand several mutants in the PHB metabolism of the endophyteHerbaspirillum seropedicaeyielded new findings on the importance of PHB for bacterial colonization ofS. viridisroots. Taken together, the results show that deletion of genes involved in the synthesis and degradation of PHB reduced the ability of the bacteria to enhance plant growth but with little effect on overall root colonization. The data suggest that PHB metabolism likely plays an important role in supporting specific metabolic routes utilized by the bacteria to stimulate plant growth.

scholarly journals Multiple feedbacks between chloroplast and whole plant in the context of plant adaptation and acclimation to the environment

2014 ◽  
Vol 369 (1640) ◽  
pp. 20130244 ◽  
Author(s):  
Barbara Demmig-Adams ◽  
Jared J. Stewart ◽  
William W. Adams
Keyword(s):  
Plant Growth ◽  
Carbon Fixation ◽  
Photosynthetic Capacity ◽  
Growth Arrest ◽  
Phloem Loading ◽  
Energy Utilization ◽  
Carbon Export ◽  
Whole Plant ◽  
Source Sink

This review focuses on feedback pathways that serve to match plant energy acquisition with plant energy utilization, and thereby aid in the optimization of chloroplast and whole-plant function in a given environment. First, the role of source–sink signalling in adjusting photosynthetic capacity (light harvesting, photochemistry and carbon fixation) to meet whole-plant carbohydrate demand is briefly reviewed. Contrasting overall outcomes, i.e. increased plant growth versus plant growth arrest, are described and related to respective contrasting environments that either do or do not present opportunities for plant growth. Next, new insights into chloroplast-generated oxidative signals, and their modulation by specific components of the chloroplast's photoprotective network, are reviewed with respect to their ability to block foliar phloem-loading complexes, and, thereby, affect both plant growth and plant biotic defences. Lastly, carbon export capacity is described as a newly identified tuning point that has been subjected to the evolution of differential responses in plant varieties (ecotypes) and species from different geographical origins with contrasting environmental challenges.

scholarly journals Limited consequences for loss of RNA-directed DNA methylation in Setaria viridis domains rearranged methyltransferase (DRM) mutants

2022 ◽  
Author(s):  
Andrew C. Read ◽  
Trevor Weiss ◽  
Peter A. Crisp ◽  
Zhikai Liang ◽  
Jaclyn Noshay ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Transcriptional Repression ◽  
Regulation Of Gene Expression ◽  
Transcriptome Profiling ◽  
Setaria Viridis ◽  
Loss Of Function ◽  
Promoter Regions ◽  
Altered Expression ◽  
Genome Methylation

The Domains Rearranged Methyltransferases (DRMs) are crucial for RNA-directed DNA methylation (RdDM) in plant species. Setaria viridis is a model monocot species with a relatively compact genome that has limited transposable element content. CRISPR-based genome editing approaches were used to create loss-of-function alleles for the two putative functional DRM genes in S. viridis to probe the role of RdDM. The analysis of drm1ab double mutant plants revealed limited morphological consequences for the loss of RdDM. Whole-genome methylation profiling provided evidence for wide-spread loss of methylation in CHH sequence contexts, particularly in regions with high CHH methylation in wild-type plants. There is also evidence for locus-specific loss of CG and CHG methylation, even in some regions that lack CHH methylation. Transcriptome profiling identified a limited number of genes with altered expression in the drm1ab mutants. The majority of genes with elevated CHH methylation directly surrounding the transcription start site or in nearby promoter regions do not have altered expression in the drm1ab mutant even when this methylation is lost, suggesting limited regulation of gene expression by RdDM. Detailed analysis of the expression of transposable elements identified several transposons that are transcriptionally activated in drm1ab mutants. These transposons likely require active RdDM for maintenance of transcriptional repression.

scholarly journals Connecting Source with Sink: The Role of Arabidopsis AAP8 in Phloem Loading of Amino Acids

2016 ◽  
Vol 171 (1) ◽  
pp. 508-521 ◽  
Author(s):  
James P. Santiago ◽  
Mechthild Tegeder
Keyword(s):  
Amino Acids ◽  
Phloem Loading

The Role of the Stem in Phloem Loading of Minerals in Lupinus albus L. cv. Ultra

1980 ◽  
Vol 45 (3) ◽  
pp. 329-338 ◽  
Author(s):  
D. L. MCNEIL
Keyword(s):  
Lupinus Albus ◽  
Phloem Loading ◽  
Lupinus Albus L

scholarly journals Heritability and Functional Importance of the Setaria viridis Bacterial Seed Microbiome

2020 ◽  
Vol 4 (1) ◽  
pp. 40-52 ◽  
Author(s):  
Carolina Escobar Rodríguez ◽  
Livio Antonielli ◽  
Birgit Mitter ◽  
Friederike Trognitz ◽  
Angela Sessitsch
Keyword(s):  
Seed Vigor ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Setaria Viridis ◽  
Next Generation ◽  
Associated Bacteria ◽  
Seed Endophytes ◽  
External Sources ◽  
Rhizosphere Environment

Seed-associated bacteria represent an important reservoir of microorganisms passed onto progeny plants and have been postulated to be important for early plant development and early plant vigor. According to a few reports, some bacterial taxa seem to be transferred from seed to seed and some seed-associated microorganisms may derive from insect visits during flowering; however, the origin of seed endophytes is poorly understood. To better understand the origin, ecology, and functional role of seed bacterial endophytes, we planted Setaria viridis seeds over several generations in a sterile growth substrate. Seed microbiota of each generation were analyzed by next generation sequencing of 16S rRNA genes and seeds were characterized regarding to their germination and plant growth. Growing plants in a sterile (or highly depleted) substrate resulted in seed microbiota, which were largely less diverse and which had altered community composition, particularly at later generations, indicating that soil is an important reservoir of seed microbiota. Some taxa were inherited to the next generations seeds; however, different subsets of taxa were inherited in different seeds/seed batches and across different generations. This suggests that other factors than the host control the establishment of most seed endophytes and only few, e.g., obligate endophytes, might be consistently inherited. Furthermore, we observed a drastic decline in seed vigor and later generations were particularly affected. Overall, our results demonstrated that the supply of endophytes from external sources such as the soil/rhizosphere environment is highly important for the build-up of a healthy seed microbiome warranting early plant establishment and vigor of next generation plants.

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