Warming Scenarios and Phytophthora cinnamomi Infection in Chestnut (Castanea sativa Mill.)

Abstract

The main threats to chestnut in Europe are climate change and emerging pathogens. Although many works have separately addressed the impacts on chestnut of elevated temperatures and Phytophthora cinnamomi Rands (Pc) infection, none have studied their combined effect. The objectives of this work were to describe the physiology, secondary metabolism and survival of 6-month-old C. sativa seedlings after plants were exposed to ambient temperature, high ambient temperature and heat wave events, and subsequent infection by Pc. Ten days after the warming scenarios, the biochemistry of plant leaves and roots was quantified and the recovery effect assessed. Plant growth and root biomass under high ambient temperature were significantly higher than in plants under ambient temperature and heat wave event. Seven secondary metabolite compounds in leaves and three in roots were altered significantly with temperature. Phenolic compounds typically decreased in response to increased temperature, whereas ellagic acid in roots was significantly more abundant in plants exposed to ambient and high ambient temperature than in plants subjected to heat waves. At recovery, leaf procyanidin and catechin remained downregulated in plants exposed to high ambient temperature. Mortality by Pc was fastest and highest in plants exposed to ambient temperature and lowest in plants under high ambient temperature. Changes in the secondary metabolite profile of plants in response to Pc were dependent on the warming scenarios plants were exposed to, with five compounds in leaves and three in roots showing a significant ‘warming scenario’ × ‘Pc’ interaction. The group of trees that best survived Pc infection was characterised by increased quercetin 3-O-glucuronide, 3-feruloylquinic acid, gallic acid ethyl ester and ellagic acid. To the best of our knowledge, this is the first study addressing the combined effects of global warming and Pc infection in chestnut.

Potassium Phosphonate Induces Resistance in Sweet Chestnut against Ink Disease Caused by Phytophthora Species

“…This is consistent with the optimum temperature for pathogen growth in vitro, which is shown to be around 27 °C [ 49 ]. In a scenario of climate change, with an expected rise in the mean temperature in the following decades [ 69 ], the spread and impact of P. cinnamomi on chestnut stands will most likely increase in Mediterranean areas [ 70 , 71 ]. In contrast, the aggressiveness of P .…”

“…This work also highlights the potential for some species to become serious pathogens on sweet chestnut in Mediterranean regions under the current climate change scenario. Climate change, in particular a rise in mean temperatures, extreme precipitation regimes, and severe droughts, could intensify ink disease incidences and further destabilize chestnut stands [ 71 , 76 ]. In the absence of alternative methods to control Phytophthora disease in forests, trunk injection with K-phosphonate remains a valid solution to mitigate the emergence of P. cinnamomi and, overall, reduce the impact of ink disease in chestnut stands.…”

Different Approaches to establish soil health and to combat Phytophthora cinnamomi

“…Previous studies on various species have shown that stress induced by different abiotic and biotic factors can modify the composition of phenolic compounds such as fl avonoids and tannins in different anatomical parts of plants [45]. These secondary metabolites exhibit high antimicrobial activity, are strong inhibitors of digestive proteases, and accumulate mainly in the leaves, stems, and roots of trees [46,47].…”

“…With regard to trees of the genus Quercus, some authors have described the content of phenolic compounds under different abiotic conditions, such as cold and drought [48]. Regarding the response to P. cinnamomi, studies have been conducted on the variations of these compounds in chestnut and their dependence on the temperature of the environment [45].…”

An improved method to study Phytophthora cinnamomi Rands zoospores interactions with host

“…Compounded by factors linked to global warming, such as environmental shifts, P. cinnamomi incidence is on the rise [ 1 , 5 – 10 ]. Extreme drying and warming temperatures are unfavorable conditions for Phytophthora species and other related subspecies [ 1 , 9 , 11 – 14 ]. To confront this growing threat, new research methodologies are imperative.…”