<i>Sphaeropsis sapinea</i> Morphotypes Differ in Aggressiveness, but Both Infect Nonwounded Red or Jack Pines

Blodgett, J. T.; Stanosz, G. R.

doi:10.1094/pdis.1997.81.2.143

Cited by 69 publications

(61 citation statements)

References 12 publications

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“…The A morphotype seems to be dominant in all areas where disease has been reported. Pathogenic tests generally demonstrated a higher virulence for A and C than for B [21][22][23][24]214]. Several studies with vegetative compatibility groups and molecular markers showed a high genetic variability of S. sapinea morphotype A in some areas, e.g.…”

Section: Sphaeropsis Sapinea-pinusmentioning

confidence: 99%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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-This review synthesizes the available knowledge on drought-disease interactions in forest trees with a focus on (1) evidence and patterns of drought-disease interactions, (2) current understanding of processes and mechanisms, and (3) three well documented cases studies. The first part is based on the analysis of a database of slightly more than one hundred studies, obtained by keyword searches combining drought, diseases or pathogens, and forest trees. A large majority of published studies referred to a positive association between drought and disease, i.e. disease favoured by drought or drought and disease acting synergistically on tree health status, with a predominance of canker/dieback diseases, caused by pathogens like Botryosphaeria, Sphaeropsis, Cytospora and Biscognauxia (Hypoxylon). The type of disease-related variables (incidence vs. severity) and the intensity and timing of water stress were shown to be significant factors affecting the drought-infection interaction. Interactions with other abiotic stresses and species-specific and genetic effects, related to host or pathogen, have also been reported. Direct effects of drought on pathogens are generally negative, although most fungal pathogens exhibit an important plasticity and can grow at water potentials well below the minimum for growth of their host plants. Studies on indirect effects of drought on pathogens through other community interactions are still relatively scarce. Positive drought-infection effects can mostly be explained by indirect effects of drought on host physiology. The predisposition and the multiple stress hypotheses are presented, as well as recent developments in the study of the molecular basis of abiotic and biotic stress, and their interactions. Sphaeropsis sapinea on pines, Biscognauxia mediterranea on oaks and root pathogens in declines associated with drought provide illustrative examples, treated as case studies, of pathogens of current significance associated with drought. The conclusion highlights some knowledge gaps, e.g. the role of latent parasites and the shift to a pathogenic stage, or the genetics of some fungal groups. The need for prevention of pathogen dispersal, especially crucial in the case of latent pathogens, is emphasized. drought / water stress / pathogenic fungi / predisposition / forest trees Résumé -Interactions entre sécheresse et agents pathogènes chez les arbres forestiers. Cette revue synthétise les connaissances actuelles sur les interactions entre sécheresse et maladies chez les arbres forestiers, avec trois grandes parties : (1) description des types d'interaction ; (2) connaissances acquises sur les mécanismes impliqués ; (3) trois études de cas bien étudiées. La première partie est basée sur l'analyse d'une base de données d'une centaine d'études, sélectionnées par recherche sur mots clés. La plupart de ces études se rapportent à des maladies favorisées par la sécheresse ou à un effet synergique entre sécheresse et maladie sur l'état sanitaire des arbres, avec une prédominance de m...

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Section: Sphaeropsis Sapinea-pinusmentioning

confidence: 99%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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“…However, endophytic isolates of the ' B ' morphotype have been routinely recovered from cones of Mexican pines and have more recently been isolated in P. radiata cones from California (unpubl.). The ' B ' morphotype isolates are also less aggressive pathogens than those of the ' A ' morphotype (Blodgett & Stanosz 1997. Thus, the ' B ' morphotype is not only associated with disease, but can also be an endophyte in asymptomatic tissue.…”

Section: Origin Of Sphaeropsis Sapinea In the Southern Hemispherementioning

confidence: 99%

Comparison of genotypic diversity in native and introduced populations of Sphaeropsis sapinea isolated from Pinus radiata

Burgess

Wingfield

2001

Mycological Research

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“…In north central USA, D. pinea and D. scrobiculata coexist on Pinus banksiana (Palmer et al 1987, Palmer 1991, Blodgett & Stanosz 1997. P. radiata forms associations with D. pinea in exotic plantations but apparently only with D. scrobiculata in its native range.…”

Section: Discussionmentioning

confidence: 99%

“…This separation of cryptic species fits well with what is known of the biology of the two species. D. pinea is a virulent pathogen found throughout the world (Burgess & Wingfield 2002, Burgess, Wingfield & Wingfield 2004, whereas D. scrobiculata has a more limited range, principally the North-Central USA, and has low levels of pathogenicity (Palmer et al 1987, Blodgett & Stanosz 1997. Where their ranges overlap, the two morphotypes have been found to coexist on the same pine species and trees (Palmer et al 1987).…”

Section: Introductionmentioning

confidence: 99%

Geographic isolation of Diplodia scrobiculata and its association with native Pinus radiata

Burgess

Gordon

Wingfield³

et al. 2004

Mycological Research

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Diplodia pinea (syn. Sphaeropsis sapinea) is a well-known latent pathogen of Pinus spp. with a worldwide distribution. As such, this fungus is native where pines are endemic in the northern hemisphere and it has been introduced into all countries of the Southern Hemisphere where pines are exotic. The newly described D. scrobiculata (formerly known as the B morphotype of D. pinea) is thought to have a much more limited distribution. D. scrobiculata was first reported as an endophyte and weak pathogen of P. banksiana, where it was found to coexist with D. pinea. Diplodia scrobiculata is now known to have a much broader distribution in Northern America and Europe. In this study, seven Simple Sequence Repeat (SSR) markers were used to evaluate genetic diversity and gene flow between populations of D. scrobiculata. Results indicate a strong geographic isolation between populations of D. scrobiculata from different regions in North America, with unique alleles fixed in the different populations. The data fits the isolation by distance model indicating limited dispersal. Geographic isolation in combination with isolation by distance suggests prolonged reproductive isolation. Intensive collections of endophytes from native P. radiata in California have yielded only D. scrobiculata and not the significantly more pathogenic D. pinea. SSR analysis of three populations of D. scrobiculata from native P. radiata identified many shared alleles among the populations and moderate to high gene flow between them. The three Californian populations are distant and distinct from populations of D. scrobiculata from elsewhere. Under stress conditions, P. radiata is known to be very susceptible to D. pinea in plantations in the Southern Hemisphere. Native P. radiata is currently experiencing severe stress due to pitch canker caused by Fusarium circinatum. Such stress would provide ideal conditions for an associated outbreak of D. pinea. Thus, it is critical to prevent the movement of D. pinea into the last remaining native stands of P. radiata.

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Sphaeropsis sapinea Morphotypes Differ in Aggressiveness, but Both Infect Nonwounded Red or Jack Pines

Cited by 69 publications

References 12 publications

Interactive effects of drought and pathogens in forest trees

Interactive effects of drought and pathogens in forest trees

Comparison of genotypic diversity in native and introduced populations of Sphaeropsis sapinea isolated from Pinus radiata

Geographic isolation of Diplodia scrobiculata and its association with native Pinus radiata

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