Temporal variation in airborne spore concentration of <i>Chrysomyxa rhododendri</i>: correlation with weather conditions and consequences for Norway spruce infection

Ganthaler, Andrea; Mayr, Stefan

doi:10.1111/efp.12190

Cited by 17 publications

(14 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Missing needles were estimated according to the number of empty needle bases and by using a discrete scale with 10% intervals. Monitoring over several years is important, as the percentage of infected needles is influenced by local spore densities and weather conditions during the infection period (Ganthaler and Mayr, 2015 ). Consequently, the mean infection degree of several years is expected to represent the general susceptibility of the tree to infection by C. rhododendri and was used for correlation analyses with compounds concentrations.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, previous studies underlined the relevance of seasonal variations and infection-induced changes in the accumulation of individual foliar phenolic compounds. This variability is of particular importance for C. rhododendri infections, as the pathogen infects only the new sprouting needles in early summer (Ganthaler and Mayr, 2015 ) and can spread only within a single infected needle. In addition, previous studies indicate different accumulation patterns of flavonoids and stilbenes during needle development in spruce (Strack et al, 1989 ; Slimestad and Hostettmann, 1996 ; Slimestad, 1998 ), but studies on continuous seasonal courses are missing.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Foliar Phenolic Compounds in Norway Spruce with Varying Susceptibility to Chrysomyxa rhododendri: Analyses of Seasonal and Infection-Induced Accumulation Patterns

et al. 2017

View full text Add to dashboard Cite

Secondary phenolic metabolites are involved in plant responses to various biotic stress factors, and are apparently important for the defense against fungal pathogens. In this study, we investigated their role in defense against the rust Chrysomyxa rhododendri in Norway spruce. The fungal pathogen undergoes a seasonal lifecycle with host shift; after overwintering in rhododendron shrubs, it attacks the sprouting current-year spruce needles and causes needle fall in autumn. Repeated infections lead to reduced timber yield and severe problems with rejuvenation in subalpine Norway spruce forests. Trees with varying susceptibility to infection by C. rhododendri were selected and foliar phenolic composition was assessed using UHPLC-MS. We report on seasonal accumulation patterns and infection-related changes in the concentrations of 16 metabolites, including flavonoids, stilbenes, simple phenylpropanoids and the precursor shikimic acid, and their correlation with the infection degree of the tree. We found significant variation in the phenolic profiles during needle development: flavonoids were predominant in the first weeks after sprouting, whereas stilbenes, picein and shikimic acid increased during the first year. Following infection, several flavonoids and resveratrol increased up to 1.8 fold in concentration, whereas picein and shikimic acid were reduced by about 70 and 60%, respectively. The constitutive and early stage infection-induced concentrations of kaempferol, quercetin and taxifolin as well as the late stage infection-induced concentrations of stilbenes and picein were negatively correlated with infection degree. We conclude that a combination of constitutive and inducible accumulation of phenolic compounds is associated with the lower susceptibility of individual trees to C. rhododendri. The potentially fungicidal flavonoid aglycones may limit hyphal growth and prevent development of infection symptoms, and high levels of stilbenes may impede the infection of older needles. The presented results underline a highly compound-specific seasonal accumulation and defense response of Norway spruce and may facilitate the selection of promising trees for breeding programs.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Foliar Phenolic Compounds in Norway Spruce with Varying Susceptibility to Chrysomyxa rhododendri: Analyses of Seasonal and Infection-Induced Accumulation Patterns

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Image analysis can enhance the ability to distinguish between genotypes with different levels of susceptibility and is highly useful for investigating quantitative genetics of disease resistance (Xie et al ., ). Moreover, imaging techniques represent an innovative methodology to analyse the distribution of disease symptoms within forest stands and individual crowns, as well as potential links with topography, orientation, slope and climate parameters (Ganthaler & Mayr, ).…”

Section: Discussionmentioning

confidence: 99%

“…However, visual estimation is always subject to an individual's experience and reduces the repeatability (Bock et al ., ). For analyses on seedlings or individual branches, this problem was solved by counting needles with and without disease symptoms to determine the exact percentage of needles affected (Ganthaler & Mayr, ). This time‐consuming and laborious approach was the only option to obtain an exact quantification of symptom development, but limited the number of samples and was not applicable to whole trees.…”

Section: Introductionmentioning

confidence: 99%

Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce

2018

Self Cite

View full text Add to dashboard Cite

High elevation spruce forests of the European Alps are frequently infected by the needle rust Chrysomyxa rhododendri, a pathogen causing remarkable defoliation, reduced tree growth and limited rejuvenation. Exact quantification of the disease severity on different spatial scales is crucial for monitoring, management and resistance breeding activities. Based on the distinct yellow discolouration of attacked needles, it was investigated whether image analysis of digital photographs can be used to quantify disease severity and to improve phenotyping compared to conventional assessment in terms of time, effort and application range. The developed protocol for preprocessing and analysis of digital RGB images enabled identification of disease symptoms and healthy needle areas on images obtained in ground surveys (total number of analysed images n = 62) and by the use of a semiprofessional quadcopter (n = 13). Obtained disease severities correlated linearly with results obtained by manual counting of healthy and diseased needles for all approaches, including images of individual branches with natural background (R 2 = 0.87) and with black background (R 2 = 0.95), juvenile plants (R 2 = 0.94), and top views and side views of entire tree crowns of adult trees (R 2 = 0.98 and 0.88, respectively). Results underline that a well‐defined signal related to needle bladder rust symptoms of Norway spruce can be extracted from images recorded by standard digital cameras and using drones. The presented protocol enables precise and time‐efficient quantification of disease symptoms caused by C. rhododendri and provides several advantages compared to conventional assessment by manual counting or visual estimations.

show abstract

“…2 and 9) with the lowest pathogen spread increased the accumulation of TPC in the roots two month after inoculation. Ganthaler and Mayr [66] revealed the seasonal variation and infection-induced changes in the accumulation of phenolic compounds. A study of Norway spruce resistant to Chrysomyxa rhododendri indicated that constitutive and early stage infection-induced concentrations of some phenolics strongly correlated with susceptibility and also reflected the levels of the tree's resistance [67].…”

Section: Infection-induced Phenolic Responsementioning

confidence: 99%

The Resistance of Scots Pine (Pinus sylvestris L.) Half-sib Families to Heterobasidion annosum

Marčiulynas

Sirgedaitė-Šėžienė

Žemaitis

et al. 2019

Forests

View full text Add to dashboard Cite

This study observed the genotypic variation among Scots pine (Pinus sylvestris L.) half-sib families’ susceptibility to Heterobasidion annosum. Scots pine susceptibility was tested in 12 half-sib families by inoculating them with four different H. annosum strains. At two, six, and ten months after the inoculations, the susceptibility indicators (incidence rate, pathogen spread, and mortality rate) were compared and the total phenolic compounds (TPC) in the inoculated and control groups determined using the Folin–Ciocalteu method. Among half-sib families, significant differences were found for seedling mortality (range: 1.3%–21.2%); however, the differences in incidence rate (range: 54%–77%) and pathogen spread (range: 24–53 mm) were not significant. The incidence rate among half-sib families correlated positively and significantly (r = 0.72, p < 0.05) with the mortality rate, while the pathogen spread correlated negatively with mortality, although the correlation was not significant (r = −0.29, p > 0.05). The TPC comparison with susceptibility indicators showed that the half-sib families with lower susceptibility were characterized by the ability to increase TPC after inoculation compared to the control group. This tendency was most apparent in stems and roots six and two months after inoculation, respectively. Correlation analyses revealed that higher TPC in stems six months after inoculation determined a lower incidence rate (r = −0.32, p < 0.05), while higher Change in concentration of total phenolic compounds (TPCΔ) indicated a lower pathogen spread (r = −0.60, p < 0.05). The lowest incidence of the pathogen was determined in half-sib families with the highest TPCΔ in the roots two months after inoculation. The lower susceptibility of Scots pine half-sib families is based on a combination of enhanced constitutive and inducible phenolic defense mechanisms. The data may facilitate the selection of Scots pine half-sib families with low susceptibility for breeding programs and forest management strategies.

show abstract

Temporal variation in airborne spore concentration of Chrysomyxa rhododendri: correlation with weather conditions and consequences for Norway spruce infection

Cited by 17 publications

References 25 publications

Foliar Phenolic Compounds in Norway Spruce with Varying Susceptibility to Chrysomyxa rhododendri: Analyses of Seasonal and Infection-Induced Accumulation Patterns

Foliar Phenolic Compounds in Norway Spruce with Varying Susceptibility to Chrysomyxa rhododendri: Analyses of Seasonal and Infection-Induced Accumulation Patterns

Using image analysis for quantitative assessment of needle bladder rust disease of Norway spruce

The Resistance of Scots Pine (Pinus sylvestris L.) Half-sib Families to Heterobasidion annosum

Contact Info

Product

Resources

About