Cutin deficiency in the tomato fruit cuticle consistently affects resistance to microbial infection and biomechanical properties, but not transpirational water loss |
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Authors: | Tal Isaacson Dylan K. Kosma Antonio J. Matas Gregory J. Buda Yonghua He Bingwu Yu Arika Pravitasari James D. Batteas Ruth E. Stark Matthew A. Jenks Jocelyn K. C. Rose |
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Affiliation: | Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA;, Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907 USA;, Departments of Chemistry, College of Staten Island and City College of New York, City University of New York Graduate Center and Institute for Macromolecular Assemblies, New York, NY 10031 USA;, Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA |
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Abstract: | Plant cuticles are broadly composed of two major components: polymeric cutin and a mixture of waxes, which infiltrate the cutin matrix and also accumulate on the surface, forming an epicuticular layer. Although cuticles are thought to play a number of important physiological roles, with the most important being to restrict water loss from aerial plant organs, the relative contributions of cutin and waxes to cuticle function are still not well understood. Tomato ( Solanum lycopersicum ) fruits provide an attractive experimental system to address this question as, unlike other model plants such as Arabidopsis, they have a relatively thick astomatous cuticle, providing a poreless uniform material that is easy to isolate and handle. We identified three tomato mutants, cutin deficient 1 ( cd1 ), cd2 and cd3 , the fruit cuticles of which have a dramatic (95–98%) reduction in cutin content and substantially altered, but distinctly different, architectures. This cutin deficiency resulted in an increase in cuticle surface stiffness, and in the proportions of both hydrophilic and multiply bonded polymeric constituents. Furthermore, our data suggested that there is no correlation between the amount of cutin and the permeability of the cuticle to water, but that cutin plays an important role in protecting tissues from microbial infection. The three cd mutations were mapped to different loci, and the cloning of CD2 revealed it to encode a homeodomain protein, which we propose acts as a key regulator of cutin biosynthesis in tomato fruit. |
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Keywords: | plant cuticle cutin tomato fruit transpiration plant–microbe interactions |
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