Kretzer Annette M, Dunham Susie, Molina Randy, Spatafora Joseph W
SUNY College of Environmental Science and Forestry, Faculty of Environmental and Forest Biology, 1 Forestry Drive, Syracuse, NY 13210, USA.
Mol Ecol. 2005 Jul;14(8):2259-68. doi: 10.1111/j.1365-294X.2005.02547.x.
We have collected sporocarps and tuberculate ectomycorrhizae of both Rhizopogon vinicolor and Rhizopogon vesiculosus from three 50 x 100 m plots located at Mary's Peak in the Oregon Coast Range (USA); linear map distances between plots ranged from c. 1 km to c. 5.5 km. Six and seven previously developed microsatellite markers were used to map the approximate size and distribution of R. vinicolor and R. vesiculosus genets, respectively. Genetic structure within plots was analysed using spatial autocorrelation analyses. No significant clustering of similar genotypes was detected in either species when redundant samples from the same genets were culled from the data sets. In contrast, strong clustering was detected in R. vesiculosus when all samples were analysed, but not in R. vinicolor. These results demonstrate that isolation by distance does not occur in either species at the intraplot sampling scale and that clonal propagation (vegetative growth) is significantly more prevalent in R. vesiculosus than in R. vinicolor. Significant genetic differentiation was detected between some of the plots and appeared greater in the more clonal species R. vesiculosus with Phi(ST) values ranging from 0.010 to 0.078*** than in R. vinicolor with Phi(ST) values ranging from -0.002 to 0.022** (*P < 0.05, **P < 0.01, ***P < 0.001). When tested against the null hypothesis of no relationship between individuals, parentage analysis detected seven likely parent/offspring pairs in R. vinicolor and four in R. vesiculosus (alpha = 0.001). Of these 11 possible parent/offspring pairs, only two R. vinicolor pairs were still supported as parent/offspring when tested against the alternative hypothesis of being full siblings (alpha = 0.05). In the latter two cases, parent and offspring were located at approximately 45 m and 28 m from each other. Challenges to parentage analysis in ectomycorrhizal fungi are discussed.
我们从美国俄勒冈海岸山脉玛丽峰的三个50×100米的样地中采集了酒红须腹菌（Rhizopogon vinicolor）和泡囊须腹菌（Rhizopogon vesiculosus）的子实体和具瘤外生菌根；样地之间的直线地图距离约为1公里至约5.5公里。分别使用六个和七个先前开发的微卫星标记来绘制酒红须腹菌和泡囊须腹菌遗传个体的大致大小和分布。利用空间自相关分析来分析样地内的遗传结构。当从数据集中剔除来自同一遗传个体的冗余样本后，在这两个物种中均未检测到相似基因型的显著聚类。相比之下，当分析所有样本时，在泡囊须腹菌中检测到强烈聚类，但在酒红须腹菌中未检测到。这些结果表明，在样地内采样尺度上，这两个物种均未出现距离隔离现象，并且克隆繁殖（营养生长）在泡囊须腹菌中比在酒红须腹菌中更为普遍。在一些样地之间检测到显著的遗传分化，并且在克隆性更强的泡囊须腹菌中似乎更为明显，其Phi(ST)值范围为0.010至0.078***，而酒红须腹菌的Phi(ST)值范围为 -0.002至0.022**（*P < 0.05，**P < 0.01，***P < 0.001）。在针对个体之间无关系的零假设进行检验时，亲权分析在酒红须腹菌中检测到七个可能的亲子对，在泡囊须腹菌中检测到四个（α = 0.001）。在这11个可能的亲子对中，当针对全同胞的备择假设进行检验时（α = 0.05），只有两个酒红须腹菌亲子对仍被支持为亲子对。在后两种情况下，亲本和子代彼此相距约45米和28米。讨论了外生菌根真菌亲权分析面临的挑战。
