Effect of Huntiella decorticans and drought on Nothofagus dombeyi seedlings

MASERA, PABLO; PILDAIN, MARÍA BELÉN; AQUINO, MARIANO; DE ERRASTI, ANDRÉS; DALLA SALDA, GUILLERMINA; RAJCHENBERG, MARIO; URRETAVIZCAYA, MARÍA FLORENCIA

AoB PLANTS

Oxford University Press

Año: 2023 vol. 15

In the temperate forests of Patagonia, Argentina, Nothofagus dombeyi, commonly known as Coihue, has shown sensitivity to intensedrought events, leading to mortality. Studies have been conducted on Coihue decline and mortality using a variety of approaches, including therole of extreme heat waves and drought, pests and pathogens, particularly the fungus Huntiella decorticans. This work aimed to evaluate survival,vitality, necrosis extension and growth response of inoculated and non-inoculated Coihue seedlings from different provenances exposed todifferent soil moisture levels. To achieve this goal, 96 Coihue seedlings from 2 different provenances were assigned to 8 different experimentaltreatments. Treatments were composed of the presence or absence of H. decorticans and different soil moisture content conditions, dry, wetand the exposure to dry condition at different times of the experiment. Both dry conditions and H. decorticans had negative effects on the survivaland growth rate of Coihue. The combination of both factors resulted in 100 % mortality, regardless of the plants’ geographical provenances.Mortality began to be observed 3 months after pathogen inoculation, during the warmest month. Necrosis extension produced by the pathogenwas similar for most of the inoculated treatments. The treatment under wet condition during the experiment but subjected to dry condition inthe previous growing season presented lower necrosis extension (8.4 ± 3.2 %), than the other treatments. The radial increase was also affectedby the treatments and geographical provenance, being those plants exposed to dry conditions which grew less (0.19 ± 0.21 mm). This study enhancesour understanding of the plant–pathogen interaction. According to our results, Coihue may become more susceptible to mortality, whenH. decorticans and water deficit conditions act synergistically.