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

为了阐明一种病原菌Raffaelea quercivora的形态和分子特征的差异，从发生橡树大规模死亡的地区收集了21株真菌。另外用5株典型种真菌分离株进行性状比较。模式种的分生孢子大小为1.8-3.1×3.3-8.1 μm， 21株的分生孢子大小为1.4-5.4×3.0-10.3 μm。用于形态学表征的真菌分离株进一步应用于DNA分析，重点分析了内部转录间隔区（ITS）和核糖体DNA 28s区的D1/D2区。21株分离株在形态和分子特征上与模式种非常相似，表明它们与quercivora属同一种。我们在日本栎树大量死亡的损害点添加了114株推测为栎属真菌的真菌分离株。应用三种酶进行随机片段长度多态性（RFLP）分析。114种酶中78种的RFLP分析均成功，RFLP模式与模式种相同。上述结果表明，槲皮孢子虫是造成日本栎树大量死亡的病原菌，在日本受灾地区普遍存在。以4种壳斗科植物为研究对象，接种槲皮菌，探讨了影响壳斗科植物对槲皮菌敏感性的主要因素。接种真菌后，我们测量了变色轴向长度以及茎横截面上变色和不导电边材的面积。不同树种间的敏感性存在显著差异，横向变色面积的扩大与不导电边材面积的形成有很强的相关性。我们对和歌山地区采集的具有mycania保留的ambrosia beetles， Platypus querciorus进行了形态特征的测量。在和歌山县和京都县之间的种群中进行了quercivorus的交配试验。不同种群间的杂交交配虽然成功，但其繁殖率低于同一种群内的繁殖率。通过上述两地种群的交叉交配，进一步考察了成虫体型和虫廊形成对繁殖成功率的影响。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