A wide range of genetic diversity in pear (Pyrus ussuriensis var. aromatica) genetic resources from Iwate, Japan revealed by SSR and chloroplast DNA markers
A wide range of genetic diversity in pear (Pyrus ussuriensis var. aromatica) genetic resources from Iwate, Japan revealed by SSR and chloroplast DNA markers
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DOI：
10.1007/s10722-006-9170-9
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发表时间：
2007-11-01
影响因子：
2
通讯作者：
Uematsu, Chiyomi
中科院分区：
文献类型：
--
作者：
Katayama, Hironori;Adachi, Shiho;Uematsu, Chiyomi
岩手山梨（Pyrus ussuriensis var.aromatica）是在日本野生生长的梨属物种之一。岩手山梨树的数量正在减少，因此迫切需要保护和评估。神户大学保存着从东北北部岩手县采集的 500 多种梨属物种，作为岩手山梨种质资源库。为了研究遗传多样性，对 86 个梨属个体（包括来自岩手县的 58 个品种）进行了从日本和欧洲梨开发的 5 个 SSR（简单序列重复）标记的检测。这些 SSR 基因座可以区分除 10 个无籽果实之外的所有岩手种质，并确定岩手山梨种质的遗传多样性。在 41 个等位基因中检测到高水平的变异，岩手种质在 5 个基因座上观察到的平均杂合度为 0.50。与当地梨品种“Iwatetanenashi”具有相同SSR基因型的无核种质被认为是通过嫁接进行无性繁殖的。在 UPGMA 表型图中，日本梨品种 (P.pyrifolia) 分为两组，其中包括一些岩手梨品种，包括无核品种。另外38份岩手县材料聚类不明确，这些材料与地理分布或形态特征之间没有明确的关系。等位基因频率显示，岩手梨品种在遗传上比日本梨品种更加多样化。大多数日本梨的叶绿体 DNA (cpDNA) 中 accD 和 psaI 基因之间的间隔区域存在 219 bp 的缺失，但其他梨属物种和两棵岩手山梨树则没有。岩手县种质中，79.3%具有缺失型cpDNA，其余为标准型cpDNA，无缺失。这些结果表明岩手县品种（包括日本梨品种）具有广泛的遗传多样性。 SSR 和 cpDNA 分析相结合，揭示了 Iwateyamanashi 的高度异质性，以及 Iwateyamanashi 及其与 P.pyrifolia 的杂交后代的共存。这些可能是前面描述的大范围连续形态变异的原因。
Iwateyamanashi (Pyrus ussuriensis var. aromatica) is one of the Pyrus species which grows wild in Japan. The number of Iwateyamanashi trees has been decreasing, so conservation and evaluation is urgently needed. Over 500 accessions of Pyrus species collected from Iwate in northern Tohoku region are maintained at Kobe University as an Iwateyamanashi germplasm collection. In order to investigate the genetic diversity, five SSR (simple sequence repeat) markers, developed from Japanese and European pear were examined for 86 Pyrus individuals including 58 accessions from Iwate. These SSR loci could discriminate between all the Iwate accessions except for 10 that bear seedless fruit, as well as determine the genetic diversity in Iwateyamanashi germplasms. High levels of variation were detected in 41 alleles and the mean observed heterozygosity across 5 loci was 0.50 for the Iwate accessions. Seedless accessions sharing identical SSR genotype with the local pear variety "Iwatetanenashi" were supposed to have been propagated vegetatively via grafting. In an UPGMA phenogram, Japanese pear varieties (P. pyrifolia) were clustered into two groups with some Iwate accessions including seedless ones. Another 38 Iwate accessions were not clustered clearly, and there was no clear relationship between these accessions and geographical distribution or morphological characters. Allele frequency revealed that the Iwate accessions were genetically more divergent than the Japanese pear varieties. Most Japanese pears possessed a 219 bp deletion at a spacer region between the accD and psaI genes in the chloroplast DNA (cpDNA), but other Pyrus species and two Iwateyamanashi trees did not. In the Iwate accessions, 79.3% had a deletion type cpDNA and others had a standard type cpDNA without deletion. These results are indicative of the wide range of genetic diversity in the Iwate accessions which include Japanese pear varieties. A combination of SSR and cpDNA analyses revealed high heterogeneity in Iwateyamanashi and coexistence of Iwateyamanashi and hybrid progeny with P. pyrifolia. These could be reasons for the wide range of continuous morphological variation described previously.