Defensive patterns of chestnut genotypes (Castanea spp.) against the gall wasp, Dryocosmus kuriphilus

Abstract

Plants draw from various genetically controlled defenses to protect against herbivores and pathogens. The efficacy of alternative defenses can vary with the biology and phylogeny of the enemy. Dryocosmus kuriphilus, an invasive gall maker native to China, has become one of the main pests of chestnut trees around the world. We studied genetic variation in resistance and susceptibility to D. kuriphilus within a replicated blocked planting of 12 chestnut genotypes established in Galicia, Spain in 2004. We found very high genetic variation in susceptibility to D. kuriphilus. We evaluated if the variation was due to host selection by the wasp, differential efficacy of inducible defenses in the trees, or variability in susceptibility of the plant to manipulation by the gallmaker. We assessed host selection by counting number of eggs laid by females in tree buds and comparing preferences with phytochemistry. We also measured inducible changes in phytochemistry within and around galls, gall physical characteristics, parasitism, and insect fitness. The effective defense mechanisms in resistant genotypes involved (1) hypersensitive reactions to eggs or neonates within buds and (2) early precise abscission of nascent galls from expanding leaves. Surprisingly, the genetic resistance to D. kuriphilus of the chestnut genotypes we tested was not related to phenols, terpenes, and primary nutrition.

The impact of the Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut tree growth may be mediated by site resources

“…Genetic analysis (identification of molecular markers) of two trees of each class, carried out by Functional Genomics and Sequencing Platform (RIAIDT) of the University of Santiago de Compostela, confirmed that the trees belong to different hybrid clones: "324" and "502" in "Esperante" and "324" and "HS" in "O Corgo." No galls were found in trees of clone "324, " which is known to be resistant to the gall wasp (Míguez-Soto et al, 2018;Castedo-Dorado et al, 2021;Lombardero et al, 2022), whereas galls were present in trees of both "502" and "HS" clones. In the remaining 14 plots, we found that the level of gall wasp attack varied across the trees.…”

“…This pest, commonly known as the Asian chestnut gall wasp, is native to China and can affect species of the genus Castanea and hybrid clones. Nevertheless, a wide range of variability among clones regarding the level of infestation by D. kuriphilus has been reported, suggesting a genotype-dependent variation in susceptibility (Sartor et al, 2015;Míguez-Soto et al, 2018;Castedo-Dorado et al, 2021;Lombardero et al, 2022). The same applies to the European populations of C. sativa, suggesting that the differences are due to specific features of individual trees within the populations (Bombi et al, 2018).…”

Effects of the Abandonment of Traditional Cultural Practices on Epiphytic Bryolichenic Communities in Chestnut Orchards in North-West Spain

“…Barr. together with the plague of chestnut gall wasp Dryocosmus kuriphilus Yasumatsu have caused great damage to these agroforestry systems [13,22]. Another threat is that of forest fires, which may increase in frequency, size, and intensity due to the increasing rates of biomass accumulation associated with land abandonment and to climate warming [23].…”

Identification of a Unique Genomic Region in Sweet Chestnut (Castanea sativa Mill.) That Controls Resistance to Asian Chestnut Gall Wasp Dryocosmus kuriphilus Yasumatsu

“…Variability in the intensity of ACGW attacks, up to resistance, was observed in the different species of chestnut [11][12][13]. Dini et al [14] and Lombardero et al [13] highlighted the defensive patterns of chestnut against ACGW and identified the hypersensitive reaction (HR) as a mechanism of resistance in resistant hybrid genotypes.…”