Research

• Enhancing drought tolerance during shipping and retailing
  

• Understanding the molecular and biochemical regulation of senescence in plants
  

• Proteomic analysis of petal senescence

• Developing Molecular tools for Floriculture Crop Improvement
  

Enhancing drought tolerance during shipping and retailing

• Spray and drench applications of s-ABA, an abscisic acid biochemical (ConTego®) enhance drought tolerance in many crops.

• Applications can increase the shelf life of bedding plants that experience water stress during shipping or retailing.
  

• Some plant species, including viola, fuchsia, and pansy, develop leaf yellowing symptoms after re-watering that make them unmarketable.

• Leaf yellowing can be prevented by the application of BA + GA4+7 (Fascination®).

• S-ABA can be used on finished plants and plugs.
  

Above, Water was witheld from chrysanthemums and pansies for 5 days.

Understanding the molecular and biochemical regulation of senescence in plants

• The senescence or death of leaves, flowers and whole plants occurs naturally as part of the last stage of plant development, but it can also be accelerated by ethylene and environmental stress.
  

• We are interested in senescence because it reduces the postproduction quality and marketability of ornamental plants.
  

• Senescence is genetically controlled and the purpose of this program is to allow the plant to remobilize nutrients before a plant organ dies.

• The majority of the SAGs (Senescence Associated Genes) from petals encode enzymes involved in cellular catabolism (degradation).
  

• Nucleases and proteases that are up regulated during senescence function in the degradation of nucleic acids and proteins to allow for the remobilization of C, N and P.
  

• We are currently cloning genes involved in nutrient remobilization to understand how this process is controlled by ethylene, drought and nutrient stress.
  

• The expression of a high-affinity phosphate transporter (PhPT1) from petunia was found to correspond with P decreases during petal senescence.

Proteomic analysis of petal senescence

• Proteomics can be used to identify proteins involved in specific plant responses or developmental processes. 
  

• Proteins are separated by 2-dimensional electrophoresis (2-DE) and sequenced using mass spectroscopy. 
  

• The identification of proteins expressed in specific tissues under defined conditions provides us with a comprehensive understanding of the biochemical pathways regulating plant growth, development and responses to biotic and abiotic stresses.
  

• We have identified 133 proteins that are differentially regulated during petal senescence.
  

• The up regulated proteins are involved in defense and stress responses and macromolecule catabolism and remobilization.
  

• Gene expression patterns do not always match that of protein expression, providing evidence for the post-transcriptional regulation of senescence. 
  

Left, protein profile of petunia petals at 48 hours after flower opening (top,  nonsenscing flower) and 48 hours after pollination (bottom, senescing flower).

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Developing molecular tools for Floriculture Crop Improvement

DNA microarray technology

• Microarrays can be used to identify genes that control specific plant responses and developmental processes.

• This technology has given us the ability to investigate the expression of thousands of genes in one experiment.

•  Identifying genes within a particular tissue at a given developmental stage or following a specific treatment allows us to determine the metabolic processes occurring in the plant at that time.

• Genes identified through microarray experiments provide targets for gene manipulation of senescence and other important floriculture traits.

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