Kwon D H, Kwon H K, Kim D H, Yang C Y
Research Institute of Agriculture and Life Science, Seoul National University,Seoul 08826,Republic of Korea.
Horticultural and Herbal Crop Environment Division,National Institute of Horticultural and Herbal Science, Rural Development Administration,Jeollabuk-do 55365,Republic of Korea.
Bull Entomol Res. 2018 Apr;108(2):241-252. doi: 10.1017/S0007485317000694. Epub 2017 Jul 31.
Rapid determination of the larval species composition and understanding of their genetic structure is important to establish the appropriate management system for multiple species infesting in fruits. We established accurate and rapid diagnostic methods based on multiplex polymerase chain reaction (PCR) diagnostic techniques to discriminate the three major lepidopteran species in orchard, Carposina sasakii, Grapholita dimorpha, and Grapholita molesta. Each species was identified by amplifying species-specific PCR products (375 bp for C. sasakii, 125 and 234 bp for G. dimorpha, and 125 bp for G. molesta). Based on species composition analysis from six types of infested fruits, G. dimorpha constituted the highest proportion (47.8%), followed by 35.2 and 13.5% for G. molesta and C. sasakii, respectively. Interestingly, high prevalence was found in G. dimorpha and G. molesta for plum and peach, respectively. Based on genetic diversity analysis, the three insect species exhibited moderate or high haplotype diversity and low nucleotide diversity, ranging from 0.319 to 0.699 and 0.0006 to 0.0045, respectively. Demographic expansion was not detected according to either a neutrality test or mismatch distribution analysis. Moreover, no significant genetic structure corresponding to province, host plant, fruit type, or collection period was observed. These results suggest that the population of each species would have high dispersal ability following fruit-generating periods via intrinsic host adaptation ability regardless of the spatial and temporal conditions. Determination of larval composition on fruit is valuable for establishing appropriate management systems that take the species into consideration; additionally, population genetic approaches can be utilized to understand the effects of environmental factors (province, host fruit, fruit type, etc.) on population structures.
快速确定幼虫的物种组成并了解其遗传结构，对于建立针对多种侵害水果的物种的适当管理系统至关重要。我们基于多重聚合酶链反应（PCR）诊断技术建立了准确、快速的诊断方法，以区分果园中的三种主要鳞翅目物种，即桃小食心虫、梨小食心虫和苹小食心虫。通过扩增物种特异性PCR产物来鉴定每个物种（桃小食心虫为375 bp，梨小食心虫为125和234 bp，苹小食心虫为125 bp）。基于对六种受侵染水果的物种组成分析，梨小食心虫占比最高（47.8%），其次是苹小食心虫和桃小食心虫，分别为35.2%和13.5%。有趣的是，梨小食心虫在李子中、苹小食心虫在桃子中感染率较高。基于遗传多样性分析，这三种昆虫物种表现出中等或高单倍型多样性和低核苷酸多样性，范围分别为0.319至0.699和0.0006至0.0045。无论是中性检验还是错配分布分析，均未检测到种群扩张。此外，未观察到与省份、寄主植物、果实类型或采集时期相对应的显著遗传结构。这些结果表明，每个物种的种群在果实生成期后，无论空间和时间条件如何，通过内在的寄主适应能力都具有较高的扩散能力。确定水果上的幼虫组成对于建立考虑物种因素的适当管理系统很有价值；此外，种群遗传学方法可用于了解环境因素（省份、寄主果实、果实类型等）对种群结构的影响。
