SWEET7C Antibody

What is SWEET7C and what role does it play in rice biology?

SWEET7C (Uniprot: Q2QWX8) is a member of the SWEET (Sugars Will Eventually be Exported Transporters) family in Oryza sativa subsp. japonica. Similar to other SWEET proteins, it likely functions as a sugar transporter involved in various physiological processes. The SWEET family proteins are notably implicated in disease susceptibility, particularly to bacterial pathogens like Xanthomonas oryzae pv. oryzae (Xoo). Research indicates that some SWEET genes, particularly SWEET14, are targeted by TAL effectors (Transcription Activator-Like effectors) from pathogens to induce susceptibility . SWEET7C specifically may have evolved roles distinct from but related to other characterized members of this family. Understanding SWEET7C requires contextualizing it within the broader SWEET family framework while exploring its unique properties and expression patterns.

What are the basic specifications of commercially available SWEET7C Antibodies?

The SWEET7C Antibody (example Product Code: CSB-PA652425XA01OFG) is a polyclonal antibody raised in rabbits against recombinant Oryza sativa subsp. japonica SWEET7C protein . This research-grade reagent is typically provided in liquid form, suspended in a preservative buffer containing 0.03% Proclin 300, 50% Glycerol, and 0.01M PBS at pH 7.4 . The antibody is purified using antigen affinity methods and is designated for research applications only, not for diagnostic or therapeutic use . When handling SWEET7C Antibody, researchers should note its species reactivity is specific to Oryza sativa subsp. japonica, with validated applications including ELISA and Western blotting . Proper storage at -20°C or -80°C is essential, with repeated freeze-thaw cycles being detrimental to antibody performance.

What are the validated applications for SWEET7C Antibody in rice research?

SWEET7C Antibody has been validated primarily for ELISA and Western blot applications in rice research . When designing experiments, researchers should consider these validated applications as primary approaches, while exploratory applications may require additional optimization. For Western blotting, the antibody enables detection of native SWEET7C protein in rice tissue extracts, allowing researchers to monitor expression levels across different tissues, developmental stages, or in response to biotic/abiotic stresses. ELISA applications provide quantitative measurement of SWEET7C protein, useful for comparative studies.

While not explicitly validated in the provided information, experienced researchers might cautiously explore additional applications common to polyclonal antibodies, such as:

• Immunohistochemistry (IHC) for tissue localization studies

• Immunoprecipitation (IP) for protein-protein interaction studies

• Chromatin immunoprecipitation (ChIP) for studying protein-DNA interactions

Each exploratory application requires thorough validation, including appropriate positive and negative controls. When reporting novel applications, researchers should document detailed validation procedures alongside experimental results to establish methodological reliability.

What are the recommended protocols for protein extraction when studying SWEET7C?

Effective protein extraction is critical for successful SWEET7C detection. SWEET transporters are membrane-associated proteins, requiring extraction protocols that efficiently solubilize membrane components while preserving protein integrity. A recommended extraction protocol includes:

• Tissue homogenization in ice-cold extraction buffer containing:

  • 50 mM Tris-HCl (pH 7.5)

  • 150 mM NaCl

  • 1% Triton X-100 or 1% NP-40

  • 0.5% sodium deoxycholate

  • 1 mM EDTA

  • Protease inhibitor cocktail (fresh)

• Incubation with gentle agitation at 4°C for 30-60 minutes to facilitate membrane protein solubilization

• Centrifugation at 14,000 × g for 15 minutes at 4°C to remove insoluble debris

• Careful collection of the supernatant containing solubilized proteins

• Protein quantification using Bradford or BCA assay

Researchers should be aware that membrane proteins like SWEET transporters often require detergent optimization. If initial extraction yields are low, consider testing alternative detergents such as CHAPS, digitonin, or DDM, which may better preserve SWEET7C structure and epitope accessibility. Additionally, incorporating a membrane fractionation step prior to detergent solubilization can enrich for membrane-associated proteins, potentially improving detection sensitivity.

What are the optimal conditions for Western blot analysis using SWEET7C Antibody?

For optimal Western blot results with SWEET7C Antibody, researchers should implement the following protocol:

• Sample preparation:

  • Use 20-50 μg of total protein per lane

  • Mix with Laemmli buffer containing 5% β-mercaptoethanol

  • Heat at 70°C for 10 minutes (avoid boiling, which may cause membrane protein aggregation)

• Gel electrophoresis:

  • Use 10-12% SDS-PAGE gels

  • Include molecular weight markers spanning 20-100 kDa range

• Transfer conditions:

  • Wet transfer to PVDF membrane (preferred over nitrocellulose for membrane proteins)

  • Transfer at 100V for 60-90 minutes in cold transfer buffer containing 20% methanol

• Blocking:

  • Block with 5% non-fat dry milk in TBST (TBS + 0.1% Tween-20) for 1 hour at room temperature

• Primary antibody incubation:

  • Dilute SWEET7C Antibody 1:500 to 1:2000 in blocking buffer

  • Incubate overnight at 4°C with gentle agitation

• Washing:

  • Wash 4 times with TBST, 5 minutes each

• Secondary antibody incubation:

  • Use HRP-conjugated anti-rabbit IgG at 1:5000 dilution

  • Incubate for 1 hour at room temperature

• Detection:

  • Develop using enhanced chemiluminescence (ECL) substrate

  • Expose to film or image using a digital imaging system

Always include appropriate controls in Western blot experiments:

• Positive control (if available, tissue known to express SWEET7C)

• Negative control (tissue known not to express SWEET7C)

• Loading control (anti-actin or anti-GAPDH antibody)

The expected molecular weight for SWEET7C should be verified against manufacturer specifications, as post-translational modifications may affect migration patterns.

How should ELISA protocols be optimized for SWEET7C detection?

For quantitative analysis of SWEET7C protein using ELISA, researchers should consider the following optimized protocol:

• Plate preparation:

  • Coat high-binding 96-well plates with capture antibody (2-5 μg/ml) in carbonate buffer (pH 9.6)

  • Incubate overnight at 4°C

• Blocking:

  • Block with 3% BSA in PBST (PBS + 0.05% Tween-20) for 2 hours at room temperature

• Sample preparation:

  • Prepare protein extracts as described in section 2.2

  • Dilute samples in sample diluent (1% BSA in PBST)

  • Include a standard curve if quantitative comparison is required

• Sample incubation:

  • Add 100 μl of diluted samples to wells

  • Incubate for 2 hours at room temperature with gentle shaking

• Detection antibody:

  • Use SWEET7C Antibody at 1:1000 dilution in antibody diluent (1% BSA in PBST)

  • Incubate for 2 hours at room temperature

• Secondary antibody:

  • Use HRP-conjugated anti-rabbit IgG (1:5000)

  • Incubate for 1 hour at room temperature

• Substrate reaction:

  • Add TMB substrate solution

  • Stop reaction with 2N H₂SO₄ after appropriate color development

• Measurement:

  • Read absorbance at 450 nm with 570 nm reference wavelength

For sandwich ELISA formats, researchers may need to use a different antibody recognizing a separate epitope on SWEET7C. When reporting ELISA results, include details on assay sensitivity (limit of detection), specificity (cross-reactivity testing), and precision (intra- and inter-assay coefficients of variation).

How can SWEET7C Antibody be used to investigate the role of SWEET7C in pathogen response?

SWEET7C Antibody can be instrumental in exploring the potential role of SWEET7C in pathogen response mechanisms, particularly in the context of bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo). Research on related SWEET proteins suggests these transporters play critical roles in disease susceptibility . To investigate SWEET7C's role, researchers can implement the following approaches:

• Expression profiling during infection:

  • Collect rice tissue samples at different time points post-inoculation with Xoo

  • Perform Western blots using SWEET7C Antibody to track protein expression changes

  • Correlate protein levels with disease progression and bacterial population

• Comparative analysis with known susceptibility genes:

  • Design experiments comparing SWEET7C expression with SWEET14 expression during infection

  • SWEET14 is a known susceptibility gene targeted by TAL effectors AvrXa7 and PthXo3

  • Determine if SWEET7C shows similar induction patterns or distinct regulation

• Localization studies:

  • Use SWEET7C Antibody for immunohistochemistry to examine protein localization before and during infection

  • Determine if bacterial infection alters subcellular distribution of SWEET7C

• Co-immunoprecipitation experiments:

  • Use SWEET7C Antibody to pull down protein complexes

  • Identify potential interacting partners that might modulate SWEET7C function during infection

• Genetic studies combined with protein analysis:

  • Compare SWEET7C protein levels in resistant versus susceptible rice varieties

  • Determine if resistance genes like Xa7 affect SWEET7C expression patterns

When conducting these studies, researchers should be aware that the Xa7 resistance gene in rice provides protection against pathogen exploitation of SWEET14 . Similar mechanisms might exist for SWEET7C, warranting investigation into potential protective R genes that may have evolved to guard against SWEET7C-targeting pathogens.

What experimental design considerations are essential for studying SWEET7C expression across different rice tissues?

Comprehensive study of SWEET7C expression across rice tissues requires careful experimental design consideration:

• Tissue selection and sampling strategy:

  • Include diverse tissues: roots, stems, leaves (young/mature), panicles, seeds

  • Sample at multiple developmental stages (seedling, vegetative, reproductive)

  • Consider diurnal variation by sampling at consistent times

• Technical considerations for protein extraction:

  • Optimize extraction protocols for each tissue type (fiber-rich tissues like stems require modified extraction)

  • Normalize protein loading based on total protein rather than housekeeping genes, which may vary across tissues

  • Include tissue-specific extraction controls

• Experimental controls:

  • Positive control: Include tissues known to express SWEET transporters

  • Negative control: Include appropriate negative controls (if available)

  • Technical replicates: Perform at least three technical replicates

  • Biological replicates: Use multiple plants for each tissue type

• Quantification methodology:

  • Use digital imaging systems with appropriate dynamic range

  • Implement software-based quantification with background subtraction

  • Normalize SWEET7C signal to total protein (measured by stain-free technology or loading controls)

• Data presentation:

  • Present quantified expression data in tabular format including statistical analysis

  • Include representative Western blot images showing SWEET7C detection across tissue types

*Note: The above table is a representative example and should be populated with actual experimental data.

This comprehensive tissue expression profile can provide insights into SWEET7C's physiological roles and help guide further functional studies.

How can researchers investigate potential interactions between SWEET7C and pathogen effector proteins?

Investigating interactions between SWEET7C and pathogen effector proteins requires sophisticated approaches combining immunological, biochemical, and molecular techniques:

• Co-immunoprecipitation (Co-IP) studies:

  • Use SWEET7C Antibody to immunoprecipitate protein complexes from infected rice tissues

  • Perform reverse Co-IP using antibodies against suspected effector proteins

  • Analyze precipitated complexes by mass spectrometry to identify interacting partners

• Yeast two-hybrid (Y2H) screening:

  • Use SWEET7C as bait to screen against a library of pathogen effector proteins

  • Validate positive interactions with complementary methods like Co-IP

  • Map interaction domains through truncation or mutation analysis

• Bimolecular Fluorescence Complementation (BiFC):

  • Create fusion constructs of SWEET7C and candidate effector proteins with split fluorescent protein fragments

  • Express in plant cells to visualize potential interactions in vivo

  • Document subcellular localization of interaction complexes

• Surface Plasmon Resonance (SPR) or microscale thermophoresis:

  • Purify SWEET7C protein (potentially using the antibody for purification verification)

  • Measure direct binding kinetics with purified effector proteins

  • Determine binding affinity constants for different effector-SWEET7C pairs

• Chromatin Immunoprecipitation (ChIP) analysis:

  • Investigate if TAL effectors (like those targeting SWEET14) bind to SWEET7C promoter regions

  • Compare binding patterns with those observed for known susceptibility genes

Research on related SWEET genes has shown that TAL effectors like AvrXa7 and PthXo3 target the promoter of SWEET14 to induce expression and promote disease susceptibility . Researchers should investigate whether similar mechanisms apply to SWEET7C, examining its promoter for potential effector binding elements (EBEs) similar to those found in SWEET14.

What methodological approaches can distinguish between normal physiological functions of SWEET7C and its role during pathogen infection?

Distinguishing between SWEET7C's normal physiological functions and its potential role during pathogen infection requires multi-faceted experimental approaches:

• Temporal expression profiling:

  • Track SWEET7C protein levels across developmental stages using the antibody

  • Compare with expression patterns during pathogen infection

  • Identify divergent expression patterns that may indicate distinct regulatory mechanisms

• Subcellular localization studies:

  • Use immunohistochemistry with SWEET7C Antibody to track protein localization

  • Compare localization patterns in healthy versus infected tissues

  • Determine if pathogen infection causes redistribution of SWEET7C

• Transport activity assays:

  • Develop functional assays to measure SWEET7C transport activity

  • Compare substrate specificity and transport rates in normal versus infected conditions

  • Determine if pathogen effectors directly modify SWEET7C transport function

• Genetic approaches:

  • Create SWEET7C knockout or RNAi lines to assess developmental phenotypes

  • Challenge these lines with pathogens to assess disease susceptibility

  • Complement with SWEET7C variants that cannot be induced by pathogens

• Transcriptional regulation analysis:

  • Examine SWEET7C promoter for elements responsive to developmental signals

  • Compare with potential pathogen-responsive elements

  • Use reporter constructs to dissect these distinct regulatory mechanisms

• Interactome comparison:

  • Use SWEET7C Antibody for Co-IP followed by mass spectrometry

  • Compare SWEET7C interaction partners in healthy versus infected tissues

  • Identify infection-specific protein associations

This comprehensive approach can reveal how pathogens may co-opt normal SWEET7C functions or induce pathological changes in its activity, similar to how Xanthomonas exploits SWEET14 functions through TAL effector-mediated upregulation .

What are common challenges when using SWEET7C Antibody and how can they be addressed?

Researchers working with SWEET7C Antibody may encounter several technical challenges. The following troubleshooting guide addresses common issues and provides practical solutions:

• Weak or absent signal in Western blots:

  • Increase antibody concentration (try 1:500 instead of 1:1000)

  • Extend primary antibody incubation time to overnight at 4°C

  • Optimize protein extraction protocol for membrane proteins

  • Use fresh antibody aliquots to avoid freeze-thaw degradation

  • Increase protein loading (50-75 μg per lane)

  • Try alternative blocking agents (5% BSA instead of milk)

• High background or non-specific binding:

  • Increase washing steps (5-6 washes for 10 minutes each)

  • Decrease primary antibody concentration

  • Pre-adsorb antibody with non-specific proteins

  • Use higher stringency wash buffers (increase Tween-20 to 0.2%)

  • Optimize blocking conditions (try 5% BSA instead of milk)

• Multiple bands in Western blot:

  • Determine if bands represent different isoforms, post-translational modifications, or degradation products

  • Run appropriate controls (knockout tissue if available)

  • Use more stringent washing conditions

  • Perform peptide competition assay to identify specific bands

• Inconsistent results between experiments:

  • Standardize protein extraction protocols

  • Use consistent antibody lots when possible

  • Implement quantitative loading controls

  • Standardize incubation times and temperatures

  • Document all experimental conditions meticulously

• Poor reproducibility in ELISA:

  • Standardize plate washing procedures

  • Ensure consistent reagent preparation

  • Use calibrated pipettes for all liquid handling

  • Prepare fresh buffers for each experiment

  • Include internal reference standards

By systematically addressing these challenges, researchers can establish reliable protocols for SWEET7C detection, enabling consistent and reproducible results across experiments.

How should researchers validate SWEET7C Antibody specificity in their experimental systems?

Rigorous validation of SWEET7C Antibody specificity is essential for generating reliable research data. Researchers should implement the following validation approaches:

• Peptide competition assay:

  • Pre-incubate SWEET7C Antibody with excess immunizing peptide

  • Run parallel Western blots with blocked and unblocked antibody

  • Specific bands should disappear in the blocked antibody lane

• Genetic controls:

  • If available, use SWEET7C knockout or knockdown tissues as negative controls

  • Use tissues with known SWEET7C overexpression as positive controls

  • Compare band patterns and intensities across these genetic controls

• Cross-reactivity testing:

  • Test the antibody against recombinant proteins of other SWEET family members

  • Determine if the antibody recognizes closely related SWEET proteins

  • Document any cross-reactivity to inform experimental interpretations

• Mass spectrometry validation:

  • Perform immunoprecipitation with SWEET7C Antibody

  • Analyze precipitated proteins by mass spectrometry

  • Confirm SWEET7C presence and identify any co-precipitating proteins

• Antibody specificity table:

  • Create a comprehensive validation table documenting all specificity tests

  • Include results from multiple validation approaches

  • Update the table as new validation data becomes available

*Note: The above table is a template to be completed with actual experimental data.

Thorough validation not only ensures research quality but also helps identify potential limitations of the antibody that should be considered during experimental design and data interpretation.

How does research on SWEET7C connect to broader studies of plant immunity and disease resistance?

SWEET7C research connects to broader plant immunity studies through several important conceptual frameworks:

• Guard hypothesis in plant immunity:
  The relationship between SWEET transporters and disease resistance exemplifies the "guard hypothesis" in plant immunity. Similar to how the Xa7 resistance gene guards SWEET14 from pathogen exploitation , undiscovered resistance genes may protect SWEET7C. The guard hypothesis proposes that R proteins "guard" susceptibility factors, triggering immunity when pathogens attempt to manipulate these factors. SWEET7C research provides an opportunity to explore this fundamental concept in a potentially novel context.

• Evolutionary arms race between hosts and pathogens:
  SWEET transporters represent a fascinating example of the evolutionary arms race between plants and pathogens. Pathogens evolve effectors to manipulate SWEET genes for nutritional gain, while plants evolve R genes to detect this manipulation. Studying SWEET7C could reveal whether it has been subject to similar evolutionary pressures as SWEET14, potentially uncovering distinct adaptation strategies in the SWEET family.

• Trade-offs between development and immunity:
  SWEET transporters play essential roles in plant development but are exploited during pathogen infection. This dual functionality exemplifies the trade-offs plants face between normal physiology and disease resistance. SWEET7C research could reveal how plants balance these competing demands, potentially identifying unique regulatory mechanisms that minimize vulnerability while maintaining essential functions.

• Transcriptional reprogramming during immune responses:
  Research on SWEET14 has shown how TAL effectors reprogram host transcription to induce susceptibility . Studying whether SWEET7C undergoes similar transcriptional manipulation could provide insights into the mechanisms and specificity of pathogen-induced transcriptional reprogramming, a central concept in plant immunity research.

By situating SWEET7C research within these broader conceptual frameworks, researchers can make significant contributions to fundamental understanding of plant-pathogen interactions while advancing knowledge of specific rice disease resistance mechanisms.

What emerging technologies might enhance future research on SWEET7C function?

Several emerging technologies show particular promise for advancing SWEET7C research:

• CRISPR/Cas9 gene editing for functional genomics:

  • Create precise SWEET7C knockout lines to assess loss-of-function phenotypes

  • Generate epitope-tagged SWEET7C variants for improved detection

  • Edit promoter elements to investigate transcriptional regulation

  • Develop base editing approaches to modify specific amino acids and assess functional consequences

• Single-cell proteomics:

  • Analyze SWEET7C expression at single-cell resolution across tissues

  • Identify cell type-specific expression patterns not detectable in bulk tissue analysis

  • Reveal potential heterogeneity in SWEET7C expression during infection

• Cryo-electron microscopy (Cryo-EM):

  • Determine SWEET7C protein structure at near-atomic resolution

  • Visualize conformational changes during transport cycle

  • Identify potential binding sites for regulatory proteins or pathogen effectors

• Advanced imaging technologies:

  • Super-resolution microscopy to visualize SWEET7C localization with nanometer precision

  • Live-cell imaging to track SWEET7C dynamics during infection

  • Correlative light and electron microscopy to link protein localization with ultrastructural features

• Metabolic flux analysis:

  • Trace sugar movement in plants with altered SWEET7C expression

  • Quantify changes in metabolic flux during pathogen infection

  • Connect SWEET7C activity to whole-plant carbon partitioning

• Multi-omics integration:

  • Combine proteomics, transcriptomics, and metabolomics data

  • Create comprehensive models of SWEET7C function in health and disease

  • Identify regulatory networks controlling SWEET7C expression and activity

These emerging technologies can address current knowledge gaps and provide unprecedented insights into SWEET7C function at molecular, cellular, and whole-plant levels.