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.
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 ; Department of Microbiology and Plant Pathology, University of Pretoria Pretoria, 0002, South Africa.
Ecol Evol. 2014 Sep;4(17):3444-55. doi: 10.1002/ece3.1149. Epub 2014 Aug 21.
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.
Knoxdaviesia proteae 是一种特定于开普花卉王国标志性植物 Protea repens 花部结构的真菌，由为这些花授粉的甲虫上携带的螨虫传播。虽然已经确定了 K. proteae 的载体，但对其分布模式知之甚少。从当前和以前的花期采集了 P. repens 带种子的果序，并从中分离和培养了 K. proteae 个体。使用 12 个针对该物种的微卫星标记来确定 K. proteae 分离株的基因型。遗传多样性指数显示，来自两个不同果序年龄类别的 K. proteae 分离株之间具有高度相似性。该种群的杂合度较高（0.74±0.04），并遇到了异常高的基因型多样性（G = 97.87%）。由于果序年龄类之间（Nm = 47.83）和 P. repens 树之间（Nm = 2.96）存在大量移徙者，种群分化可以忽略不计。简约分析揭示了相互关联的基因型，表明存在重组和同形现象，连锁不平衡指数证实了 K. proteae 中存在普遍的异交（[Formula: see text] = 0.0067；P = 0.132）。该种群的高多样性和混合交配可能是由于经常发生基因流和异交生殖策略所致。来自单个 P. repens 树的个体之间缺乏遗传凝聚力表明，K. proteae 的传播并非主要通过螨虫在短距离内发生，而是甲虫的长距离传播在这些有趣真菌的生物学中起着重要作用。
