Data from: Gene expression differences between western redcedar seedlings resistant and susceptible to cedar leaf blight

Western redcedar (T. plicata) is an important Cupressaceae both at
economic and cultural levels in the Pacific Northwest of North America. In
adult trees, the species produces one of the most weathering-resistant
heartwoods among conifers, making it one of the preferred species for
outdoor applications. However, young T. plicata plants are susceptible to
infection with cedar leaf blight (D. thujina), an important foliar
pathogen that can be devastating in nurseries and small-spaced
plantations. Despite that, variability in the resistance against D.
thujina in T. plicata has been documented, and such a variability can be
used to breed T. plicata for resistance against the pathogen. This
investigation aimed to discern the phenotypic and gene expression
differences between resistant and susceptible T. plicata seedlings to shed
light on the potential constitutive resistance mechanisms against cedar
leaf blight in western redcedar. The study consisted of two parts. First,
the histological differences between four resistant and four susceptible
families that were never infected with the pathogen were investigated. And
second, the differences between one resistant and one susceptible family
that were infected and not infected with the pathogen were analyzed at the
chemical (C, N, mineral nutrients, lignin, fiber, starch, and terpenes)
and gene expression (RNA-Seq) levels. The histological part showed that T.
plicata seedlings resistant to D. thujina had constitutively thicker
cuticles and lower stomata densities than susceptible plants. The chemical
analyses revealed that, regardless of their infection status, resistant
plants had higher foliar concentrations of sabinene and α-thujene, and
higher levels of expression of transcripts that code for leucine-rich
repeat receptor-like protein kinases and for bark storage proteins. In
conclusion, the data collected in this study shows that constitutive
differences at the phenotypic (histological and chemical) and gene
expression level exist between T. plicata seedlings susceptible and
resistant to D. thujina. Such differences have potential use for
marker-assisted selection and breeding for resistance against cedar leaf
blight in western redcedar in the future.