During feeding on Solanum dulcamara, the gall mite Eriophyes cladophthirus perforated the walls of the epidermal cells; the epidermal cells reacted by forming callose around the feeding punctures. Within the first hour of mite activity important cytological changes occurred in the injured cells, especially in the nuclei-which enlarged and appeared optically empty. At the same time, affinity for specific fluorescent DNA-binding reagents was gradually lost. The surrounding cells later differentiated into nutritive cells on which the mites then fed. Similar nuclear and DNA alterations were also seen in punctured nutritive cells. Chitosan, a polymer of β-1,4-linked glucosamine residues, with a strong affinity for DNA, was histochemically detectable within punctured cells and was clearly visible in the nuclei within one hour. These results suggest that chitosan, transmitted by the mite, might cause DNA changes in punctured cells, and might play a major role in plant-mite interactions. © 1989.
Bronner, R., Westphal, E., & Dreger, F. (1989). Chitosan, a component of the compatible interaction between Solanum dulcamara L. and the gall mite Eriophyes cladophthirus Nal. Physiological and Molecular Plant Pathology, 34(2), 117–130. https://doi.org/10.1016/0885-5765(89)90020-9