Biotic stress responses and oxidative defense mechanisms of Pinus brutia against pine processionary moth infestations

Defense mechanisms were studied for Pinus brutia, a cornerstone Turkish forest tree, against pine processionary moth damage by Thaumetopoea pityocampa (Den. & Schiff.) and Thaumetopoea wilkinsoni Tams 1926 moth species. This research addressed the significance of Pinus brutia in afforestation and breeding. The expression of enzymatic antioxidants (SOD, POD, CAT, APX) and photosynthetic pigments (chlorophylls and carotenoids) at a clonal level in response to insect damage was assessed. Approximately 84 needle samples from 28 Pinus brutia clones from the Antalya Düzlerçamı Brutian Pine Seed Orchard were studied. Samples were collected in February and August 2021 to capture responses during key insect activity periods. These samples were then analyzed for pigment concentrations and antioxidant activities. Statistical analysis revealed that sampling period and clone significantly affected chlorophyll and carotenoid levels. The POD and SOD activities were primarily influenced by the sampling period. However, CAT activity was affected by the number of insect pouches, the period, and the clone. APX activity was significantly impacted by both pouch number and sampling period. These findings offer insights into how seasonal changes and genetic variations modulate P. brutia clones’ defense mechanisms against pine processionary moth infestations, informing future forest management.