ABSTRACT

Morphological studies suggest that the major pathogen causing basal stem rot of oil palm in Papua New Guinea and Solomon Islands is Ganoderma boninense. This study presents the first evidence for conspecificity of G. boninense from four countries where basal stem rot is prevalent. Seventy-three dikaryotic isolates of Ganoderma boninense from Indonesia, Malaysia, Papua New Guinea, and Solomon Islands were studied via mating tests, analyses of nuc internal transcribed spacer ITS1-5.8S-ITS2 sequences, and microsatellite genotyping. Sequence similarity in the ITS1-5.8S-ITS2 region was >99%, and all exotic isolates successfully mated with Papua New Guinea tester strains. Transfer of nuclei during mating was also confirmed via microsatellite markers for the first time in this species. Four microsatellite primers were used to generate evidence for 33 alleles in the four populations. All isolates studied had unique genetic fingerprints but alleles were also shared, suggesting gene flow. Heterozygosities were lower than expected in Indonesian and Papua New Guinea populations, consistent with the possibility of localized inbreeding.

摘要

形态学研究表明，引起巴布亚新几内亚和所罗门群岛油棕茎基部腐烂的主要病原体是灵芝。本研究提供了来自四个基部茎腐病流行的国家的G. boninense同种特异性的第一个证据。七十三株灵芝双核分离株通过交配测试、分析 nuc 内部转录间隔区 ITS1-5.8S-ITS2 序列和微卫星基因分型对来自印度尼西亚、马来西亚、巴布亚新几内亚和所罗门群岛的 ITS1-5.8S-ITS2 区域的序列相似性 > 99%，所有外来分离株都成功与巴布亚新几内亚测试菌株交配。在该物种中，也首次通过微卫星标记证实了交配过程中的细胞核转移。四个微卫星引物用于生成四个种群中 33 个等位基因的证据。研究的所有分离株都有独特的遗传指纹，但等位基因也是共享的，这表明基因流动。印度尼西亚和巴布亚新几内亚种群的杂合度低于预期，与局部近交的可能性一致。