Sclerophyllous structural and chemical traits of mite‐induced galls on Crinodendron patagua (Elaeocarpaceae) leaves
L. M. Guedes, L. Rodríguez‐Cerda, N. Aguilera, E. Grandón, F. R. Valeriano, J. F. de Lima, J. F. P. de Oliveira, B. G. FerreiraAbstract
Sclerophyllous plants present a suite of traits, including small, leathery leaves with thick cuticles, dense trichomes and sclerified tissues, which are often accompanied by high levels of secondary metabolites. Although these features are generally associated with protection and defence, they do not necessarily deter gall‐inducing organisms. In fact, some gall inducers may exploit the structural and chemical complexity of sclerophyllous tissues to develop protective and nutrient‐rich microhabitats. This appears to be the case for eriophyid mites (Acari: Eriophyidae) that induce galls on the leaves of
Crinodendron patagua
Mol. (Elaeocarpaceae), a sclerophyllous species endemic to Chile and characteristic of coastal Mediterranean forests. We hypothesized that these mites exploit and enhance the morphoanatomical and chemical traits of
C. patagua
sclerophyllous leaves to induce the formation of galls that function as protective, nutrient‐enriched microhabitats in the stressful Mediterranean‐type climate of central Chile.
Anatomical, cytohistometric, histochemical and spectrophotometric analyses were performed on galled and non‐galled leaves to evaluate changes in anatomical structure, primary metabolites (proteins and reducing sugars) and secondary metabolites (polyphenols). The results revealed that mites induce anatomical changes that favour progeny development, including hypotrophy and thinning of adaxial epidermal cell walls rich in cellulose and hemicellulose and the accumulation of proteins and reducing sugars in these nutritive cells. In parallel, lignified trichomes redifferentiated at the opening of the gall, abaxial epidermal cells exhibited hypertrophy and thickened walls, and the polyphenol content increased in gall tissues. Some sclerophyllous characteristics were intensified, whereas others remained unchanged.
Gall development in
C. patagua
selectively reprograms structural and biochemical traits to meet the nutritional and protective needs of eriophyid mites, partially supporting our original hypothesis.