Monoterpene responses to interacting effects of drought stress and infection by the fungus Heterobasidion parviporum in two clones of Norway spruce (Picea abies)

Abstract

A B S T R A C TTo study simultaneous biotic and abiotic stress effects on monoterpene mediated defence response, four-year-old seedlings of two clones of Picea abies (c386: "relatively resistant" c386; c171: "relatively susceptible" clone 171) were inoculated with an isolate of rot fungus Heterobasidion parviporum and simultaneously subjected to a drought stress recovery cycle. Fungal growth into the wood was generally higher in well-watered (W) than in drought-stressed (D) plants. As predawn water potential decreased, gas exchange and maximal photochemical efficiency of PSII also declined. Water potential and chlorophyll fluorescence showed differences between clones in D plants, c386 being more tolerant than c171, while stomatal conductance and net photosynthesis differed between clones in W plants; c171 showing higher values than c386. A recovery of physiological functions was observed after re-watering. The clones showed different constitutive monoterpene profiles. The infection generally caused some extensive compositional changes in the relative contents of several monoterpenes and their enantiomers; also, sterile infection (wounded only samples) affected the relative proportions of monoterpenes, although to a lesser extent than reactions elicited by the fungus. The trend in monoterpene response to disease treatments was the same in D and W plants of both clones. In particular, higher proportion of δ-3-carene was found constitutively in c386 in comparison with c171; besides, infection with H. parviporum increased the relative contents of δ-3-carene in all the samples, even if proportions of this monoterpene in wounded plus inoculated tissues of c386 were significantly higher than cortical tissues from non-inoculated branches only in W seedlings 44 days after treatment.Although drought stress decreased the total absolute contents of monoterpenes, total monoterpene concentrations significantly increased in response to infection by H. parviporum.

Low Water Availability Increases Necrosis in Picea abies after Artificial Inoculation with Fungal Root Rot Pathogens Heterobasidion parviporum and Heterobasidion annosum

“…They observed increased pathogen growth in well-watered seedlings [33], which is in contrast to our results. However, the duration of water availability treatment (22 days) in Madmony et al [33] was much shorter than in this study (105 days). These results highlight the need for well-established inoculation studies for this pathosystem, when studying effects of abiotic disturbances.…”

“…This result is consistent with Linnakoski et al [2], who found that blue stain fungi E. polonica caused greater necrosis and mortality in P. abies seedlings with low water availability compared to those with high water availability. Madmony et al [33] inoculated H. parviporum into two-year-old branches of two different Norway spruce clonal ramets (4-year old) and subjected them to well-watered and drought environments. They observed increased pathogen growth in well-watered seedlings [33], which is in contrast to our results.…”

“…Madmony et al [33] inoculated H. parviporum into two-year-old branches of two different Norway spruce clonal ramets (4-year old) and subjected them to well-watered and drought environments. They observed increased pathogen growth in well-watered seedlings [33], which is in contrast to our results. However, the duration of water availability treatment (22 days) in Madmony et al [33] was much shorter than in this study (105 days).…”

Evaluation of potential genetic and chemical markers for Scots pine tolerance against Heterobasidion annosum infection

“…Availability of such markers will greatly facilitate screening for trees with high tolerance to root disease, while decreasing the required cost and labor. Since we collected tree samples before inoculation for terpene compounds and gene expression analysis, we emphasize that this work is distinct from other studies (Zamponi et al 2007;Madmony et al 2018) where samples were collected post-inoculation. When trees are wounded, the production of secondary metabolic compounds is induced, which interferes with the identification of trees that are naturally genetically resistant.…”

Efeito do estresse hídrico na composição química de brássicas e sua influência em Plutella xylostella (L., 1758) (Lep.: Plutellidae) e Trichogramma pretiosum Riley, 1879 (Hym.: Trichogrammatidae)

“…O composto terpinolene ou isoterpinene ou terpinolen ou alpha-terpinolene; 1,4(8)-pmenthadiene é um monoterpeno que em situações de estresse hídrico teve sua emissão diminuída e em tratamentos com estresse biótico ela foi aumentada em plantas de Picea abies (MADMONY et al, 2018). Neste trabalho foi encontrado terpinolene em plantas de couve e…”