Bock Clive H, Frusso Enrique, Zoppolo Roberto, Ortiz Edson R, Shiller Jason, Charlton Nikki D, Young Carolyn A, Randall Jennifer J
United States Department of Agriculture-Agriculture Research Service, Southeastern Fruit and Tree Nut Research Lab, 21 Dunbar Road, Byron, GA 31008, U.S.A.
Instituto de Recursos Biológicos, INTA Castelar, Las Cabañas y De Los Reseros s.n., (1686) Hurlingham, Buenos Aires, Argentina.
Phytopathology. 2022 Oct;112(10):2224-2235. doi: 10.1094/PHYTO-01-22-0031-R. Epub 2022 Sep 26.
Scab, caused by the plant-pathogenic fungus , is a major disease of pecan in South America, resulting in loss of quantity and quality of nut yield. Characteristics of the populations of in South America are unknown. We used microsatellites to describe the genetic diversity and population structure of in South America, and determined the mating type status of the pathogen. The four hierarchically sampled orchard populations from Argentina (AR), Brazil (BRC and BRS), and Uruguay (UR) had moderate to high genotypic and gene diversity. There was evidence of population differentiation ( = 0.196) but the correlation between geographic distance and genetic distance was not statistically significant. Genetic differentiation was minimal between the UR, BRC, and BRS populations, and these populations were more clearly differentiated from the AR population. The and mating types occurred in all four orchards and their frequencies did not deviate from the 1:1 ratio expected under random mating; however, multilocus linkage equilibrium was rejected in three of the four populations. The population genetics of South American populations of has many similarities to the population genetics of previously described in the United States. Characterizing the populations genetics and reproductive systems of are important to establish the evolutionary potential of the pathogen and, thus, its adaptability-and can provide a basis for informed approaches to utilizing available host resistance and determining phytosanitary needs.
由植物病原真菌引起的疮痂病是南美洲山核桃的一种主要病害，会导致坚果产量的数量和质量下降。南美洲该病原菌群体的特征尚不清楚。我们使用微卫星来描述南美洲该病原菌的遗传多样性和群体结构，并确定该病原菌的交配型状态。来自阿根廷（AR）、巴西（BRC和BRS）和乌拉圭（UR）的四个分层采样果园群体具有中度到高度的基因型和基因多样性。有群体分化的证据（Fst = 0.196），但地理距离与遗传距离之间的相关性无统计学意义。UR、BRC和BRS群体之间的遗传分化最小，这些群体与AR群体的分化更明显。两种交配型在所有四个果园中都有出现，其频率未偏离随机交配预期的1:1比例；然而，四个群体中有三个群体拒绝了多位点连锁平衡。南美洲该病原菌群体的群体遗传学与之前在美国描述的该病原菌的群体遗传学有许多相似之处。表征该病原菌的群体遗传学和生殖系统对于确定该病原菌的进化潜力，进而确定其适应性很重要，并且可以为利用现有寄主抗性和确定植物检疫需求的明智方法提供基础。
