Exocarp Properties and Transcriptomic Analysis of Cucumber Cucumis sativus Fruit Expressing Age-Related Resistance to Phytophthora capsiciReport as inadecuate




Exocarp Properties and Transcriptomic Analysis of Cucumber Cucumis sativus Fruit Expressing Age-Related Resistance to Phytophthora capsici - Download this document for free, or read online. Document in PDF available to download.

Very young cucumber Cucumis sativus fruit are highly susceptible to infection by the oomycete pathogen, Phytophthora capsici. As the fruit complete exponential growth, at approximately 10–12 days post pollination dpp, they transition to resistance. The development of age-related resistance ARR is increasingly recognized as an important defense against pathogens, however, underlying mechanisms are largely unknown. Peel sections from cucumber fruit harvested at 8 dpp susceptible and 16 dpp resistant showed equivalent responses to inoculation as did whole fruit, indicating that the fruit surface plays an important role in defense against P. capsici. Exocarp from 16 dpp fruit had thicker cuticles, and methanolic extracts of peel tissue inhibited growth of P. capsici in vitro, suggesting physical or chemical components to the ARR. Transcripts specifically expressed in the peel vs. pericarp showed functional differentiation. Transcripts predominantly expressed in the peel were consistent with fruit surface associated functions including photosynthesis, cuticle production, response to the environment, and defense. Peel-specific transcripts that exhibited increased expression in 16 dpp fruit relative to 8 dpp fruit, were highly enriched P<0.0001 for response to stress, signal transduction, and extracellular and transport functions. Specific transcripts included genes associated with potential physical barriers i.e., cuticle, chemical defenses flavonoid biosynthesis, oxidative stress, penetration defense, and molecular pattern MAMP-triggered or effector-triggered R-gene mediated pathways. The developmentally regulated changes in gene expression between peels from susceptible- and resistant- age fruits suggest programming for increased defense as the organ reaches full size.



Author: Kaori Ando, Kevin M. Carr, Marivi Colle, Ben N. Mansfeld, Rebecca Grumet

Source: http://plos.srce.hr/



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