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Panmixia defines the genetic diversity of a unique arthropod-dispersed fungus specific to Protea flowers.

Aylward J, Dreyer LL, Steenkamp ET, Wingfield MJ, Roets F - Ecol Evol (2014)

Bottom Line: Population differentiation was negligible, owing to the numerous migrants between the infructescence age classes (N m = 47.83) and between P. repens trees (N m = 2.96).The high diversity and panmixia in this population is likely a result of regular gene flow and an outcrossing reproductive strategy.The lack of genetic cohesion between individuals from a single P. repens tree suggests that K. proteae dispersal does not primarily occur over short distances via mites as hypothesized, but rather that long-distance dispersal by beetles plays an important part in the biology of these intriguing fungi.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Zoology, Stellenbosch University Private Bag X1, Matieland, 7602, South Africa ; Department of Science and Technology (DST)/National Research Foundation (NRF) Centre of Excellence in Tree Health Biotechnology (CTHB), University of Pretoria Pretoria, 0002, South Africa.

ABSTRACT
Knoxdaviesia proteae, a fungus specific to the floral structures of the iconic Cape Floral Kingdom plant, Protea repens, is dispersed by mites phoretic on beetles that pollinate these flowers. Although the vectors of K. proteae have been identified, little is known regarding its patterns of distribution. Seed bearing infructescences of P. repens were sampled from current and previous flowering seasons, from which K. proteae individuals were isolated and cultured. The genotypes of K. proteae isolates were determined using 12 microsatellite markers specific to this species. Genetic diversity indices showed a high level of similarity between K. proteae isolates from the two different infructescence age classes. The heterozygosity of the population was high (0.74 ± 0.04), and exceptional genotypic diversity was encountered (Ĝ = 97.87%). Population differentiation was negligible, owing to the numerous migrants between the infructescence age classes (N m = 47.83) and between P. repens trees (N m = 2.96). Parsimony analysis revealed interconnected genotypes, indicative of recombination and homoplasies, and the index of linkage disequilibrium confirmed that outcrossing is prevalent in K. proteae ([Formula: see text] = 0.0067; P = 0.132). The high diversity and panmixia in this population is likely a result of regular gene flow and an outcrossing reproductive strategy. The lack of genetic cohesion between individuals from a single P. repens tree suggests that K. proteae dispersal does not primarily occur over short distances via mites as hypothesized, but rather that long-distance dispersal by beetles plays an important part in the biology of these intriguing fungi.

No MeSH data available.


Related in: MedlinePlus

Overview of Protea repens and its fungal associate, Knoxdaviesia proteae. (A) Protea repens tree with light pink inflorescences in bloom, (B) cream inflorescence and infructescence (seed head) of P. repens, (C) Knoxdaviesia proteae sexual structures with visible spore droplets (arrow) on P. repens flowers. Scale bar = 1 cm.
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fig01: Overview of Protea repens and its fungal associate, Knoxdaviesia proteae. (A) Protea repens tree with light pink inflorescences in bloom, (B) cream inflorescence and infructescence (seed head) of P. repens, (C) Knoxdaviesia proteae sexual structures with visible spore droplets (arrow) on P. repens flowers. Scale bar = 1 cm.

Mentions: The manner in which Knoxdaviesia species are moved between Protea infructescences is poorly understood. In the Protea–ophiostomatoid fungus symbiosis, mites appear to be the primary vectors of fungal spores and beetles are believed to act as secondary vectors (Roets et al. 2007, 2009a, 2011b). Roets et al. (2009a) found that the small mite vectors easily move vertically between infructescences on the same Protea plant in search of new and moist environments. These authors also found that the mites are phoretic on beetles associated with Protea species and proposed that lateral movement to infructescences of other plants is facilitated by beetles carrying the mites (Roets et al. 2009a). Two arthropod vectors are, therefore, involved in the dispersal of Protea-associated ophiostomatoid fungi, probably acting as short- and long-distance dispersal agents, respectively. Because of the sticky spore droplets produced by these fungi (Fig.1) and their enclosed niche, dispersal via abiotic agents, such as air and water, is unlikely to occur.


Panmixia defines the genetic diversity of a unique arthropod-dispersed fungus specific to Protea flowers.

Aylward J, Dreyer LL, Steenkamp ET, Wingfield MJ, Roets F - Ecol Evol (2014)

Overview of Protea repens and its fungal associate, Knoxdaviesia proteae. (A) Protea repens tree with light pink inflorescences in bloom, (B) cream inflorescence and infructescence (seed head) of P. repens, (C) Knoxdaviesia proteae sexual structures with visible spore droplets (arrow) on P. repens flowers. Scale bar = 1 cm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228618&req=5

fig01: Overview of Protea repens and its fungal associate, Knoxdaviesia proteae. (A) Protea repens tree with light pink inflorescences in bloom, (B) cream inflorescence and infructescence (seed head) of P. repens, (C) Knoxdaviesia proteae sexual structures with visible spore droplets (arrow) on P. repens flowers. Scale bar = 1 cm.
Mentions: The manner in which Knoxdaviesia species are moved between Protea infructescences is poorly understood. In the Protea–ophiostomatoid fungus symbiosis, mites appear to be the primary vectors of fungal spores and beetles are believed to act as secondary vectors (Roets et al. 2007, 2009a, 2011b). Roets et al. (2009a) found that the small mite vectors easily move vertically between infructescences on the same Protea plant in search of new and moist environments. These authors also found that the mites are phoretic on beetles associated with Protea species and proposed that lateral movement to infructescences of other plants is facilitated by beetles carrying the mites (Roets et al. 2009a). Two arthropod vectors are, therefore, involved in the dispersal of Protea-associated ophiostomatoid fungi, probably acting as short- and long-distance dispersal agents, respectively. Because of the sticky spore droplets produced by these fungi (Fig.1) and their enclosed niche, dispersal via abiotic agents, such as air and water, is unlikely to occur.

Bottom Line: Population differentiation was negligible, owing to the numerous migrants between the infructescence age classes (N m = 47.83) and between P. repens trees (N m = 2.96).The high diversity and panmixia in this population is likely a result of regular gene flow and an outcrossing reproductive strategy.The lack of genetic cohesion between individuals from a single P. repens tree suggests that K. proteae dispersal does not primarily occur over short distances via mites as hypothesized, but rather that long-distance dispersal by beetles plays an important part in the biology of these intriguing fungi.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Zoology, Stellenbosch University Private Bag X1, Matieland, 7602, South Africa ; Department of Science and Technology (DST)/National Research Foundation (NRF) Centre of Excellence in Tree Health Biotechnology (CTHB), University of Pretoria Pretoria, 0002, South Africa.

ABSTRACT
Knoxdaviesia proteae, a fungus specific to the floral structures of the iconic Cape Floral Kingdom plant, Protea repens, is dispersed by mites phoretic on beetles that pollinate these flowers. Although the vectors of K. proteae have been identified, little is known regarding its patterns of distribution. Seed bearing infructescences of P. repens were sampled from current and previous flowering seasons, from which K. proteae individuals were isolated and cultured. The genotypes of K. proteae isolates were determined using 12 microsatellite markers specific to this species. Genetic diversity indices showed a high level of similarity between K. proteae isolates from the two different infructescence age classes. The heterozygosity of the population was high (0.74 ± 0.04), and exceptional genotypic diversity was encountered (Ĝ = 97.87%). Population differentiation was negligible, owing to the numerous migrants between the infructescence age classes (N m = 47.83) and between P. repens trees (N m = 2.96). Parsimony analysis revealed interconnected genotypes, indicative of recombination and homoplasies, and the index of linkage disequilibrium confirmed that outcrossing is prevalent in K. proteae ([Formula: see text] = 0.0067; P = 0.132). The high diversity and panmixia in this population is likely a result of regular gene flow and an outcrossing reproductive strategy. The lack of genetic cohesion between individuals from a single P. repens tree suggests that K. proteae dispersal does not primarily occur over short distances via mites as hypothesized, but rather that long-distance dispersal by beetles plays an important part in the biology of these intriguing fungi.

No MeSH data available.


Related in: MedlinePlus