Molecular analyses of ambrosia beetles and its symbiotic fungi associated with mass mortalities of oak

为了弄清一种病原菌Raffaelea quincora在形态和分子特征上的差异，从栎树大规模死亡的地区采集了21个分离物。此外，还利用另外5个属于查询拟青霉模式种的真菌菌株对这些菌株的特征进行了比较。模式种的分生孢子大小为1.8~3.1×3.3~8.1μm，21个菌株的分生孢子大小为1.4~5.4×3.0~10.3μm。用于形态特征的真菌分离物被进一步用于DNA分析，重点是核糖体DNA 28S区的内部转录间隔区(ITS)和D1/D2区。从病区采集的21个分离物在形态和分子特征上与模式种的分离物非常相似，表明这些分离物与查询拟青霉相同。我们添加了从枯萎或死亡的…中获得的114个真菌分离物，这些分离物可能是查询拟青霉日本栎树大规模死亡的受害地点较多。用三种酶对它们进行随机片段长度多态性(RFLP)分析。在114种酶中，有78种酶的RFLP分析结果与模式种一致。通过对4种壳斗科植物的苗期接种研究，确定了影响栎树对该真菌敏感性的主要因素。接种真菌后，我们测量了变色的轴向长度以及变色和不导电的边材在茎横截面上的面积。不同树种的感病能力存在显著差异，即横向变色面积的扩大与形成的非导电边材面积的范围有很强的相关性。我们测量了和歌山县采集的文心虫的形态特征。对和歌山县与京都县之间的种群进行了交配试验。不同居群的交配虽然成功，但交配的繁殖率低于同一居群。我们进一步考察了成虫的身体大小和画廊的形成对繁殖成功的影响，通过以上两个县获得的种群之间的杂交。较少

To clarify the differences in morphological and molecular characteristics of a pathogenic fungus, Raffaelea quercivora, 21 isolates of the fungus were collected from areas where the mass mortality of oak trees has occurred. Additional 5 fungal isolates that were type species of R.quercivora were also used for comparison of the characters described among these isolates. The size of conidial spores was 1.8-3.1×3.3-8.1 μm for in the type species and 1.4-5.4×3.0-10.3 μm for the 21 isolates. The fungal isolates used for the morphological characterizations were further applied for DNA analyses focusing on both an internal transcribed spacer (ITS) region and a D1/D2 region in the 28s region of ribosomal DNA. The 21 isolates collected from the damage sites were quite similar in morphological and molecular traits with those of the type species suggesting that the isolates were identical to R.quercivora. We added 114 fungal isolates that supposed to be R.quercivora obtained from wilting or dead … More trees at damage sites of the mass mortality of oak trees in Japan. They were applied for random fragment length polymorphism (RFLP) analyses with three enzymes. Seventy-eight of 114 were successful for the RFLP analyses in all the enzymes, and the RFLP pattern was identical to that of the type species. These results indicate that R.quercivora is a pathogen of the mass mortality of oak trees and prevalent over damaged areas in Japan.We inoculated R.quercivora to the seedling of 4 Fagaceae species to determine the major factors associated with the susceptibility of the species to the fungus. After fungal inoculation, we measured the axial length of the discoloration and the areas of discolored and non-conducting sapwood on stem cross-sections. There were significant differences in the susceptibility among the tree species that was a strong correlation between the expansion of transverse discolored areas and the range of non-conductive sapwood areas formed.We measured morphological traits of ambrosia beetles, Platypus quercivorus that have mycangia retaining R.quercivora collected from Wakayama prefecture. The mating test of P.quercivorus was conducted for populations between Wakayama prefecture and Kyoto prefecture. Although the cross mating derived from the different populations were successful, the reproduction rate in the cross mating was lower than that within the same population. We further examined the effect of both the body size of adult beetles and the formation of galleries on reproduction successes by the cross mating between the populations obtained the two prefecture as above. Less