Viaud M, Couteaudier Y, Riba G
Station de Recherches de Lutte Biologique, Institut National de la Recherche Agronomique, Guyancourt, France.
Appl Environ Microbiol. 1998 Jan;64(1):88-93. doi: 10.1128/AEM.64.1.88-93.1998.
Protoplast fusion of diauxotrophic mutants of a Beauveria bassiana entomopathogenic strain (Bb28) and a Beauveria sulfurescens toxinogenic strain (Bs2) produced hybrids which were significantly different from the parents in pathogenicity. Some of the hybrids were hypervirulent and killed insects more quickly than the Bb28 strain, probably because these hybrids had acquired the toxic activity of the Bs2 strain. By using six nuclear genes and a telomeric fingerprint probe, the molecular structures of the hybrids were studied. The results demonstrated the occurrence of parasexual events. Hybrids appeared to be diploid or aneuploid, with portions of the genome being heterozygous. A mitochondrial molecular marker indicated homoplasmy of the hybrids and inheritance of mitochondria from strain Bs2 or Bb28. The pathogenicities and the ploidies of the hybrids remained stable after passage through the host insect, showing that somatic hybridization provides an attractive method for the genetic improvement of biocontrol efficiency in the genus Beauveria.
球孢白僵菌昆虫病原菌株（Bb28）的双营养缺陷型突变体与硫黄白僵菌产毒素菌株（Bs2）进行原生质体融合，产生的杂种在致病性方面与亲本有显著差异。一些杂种具有高毒力，比Bb28菌株更快地杀死昆虫，这可能是因为这些杂种获得了Bs2菌株的毒性活性。通过使用六个核基因和一个端粒指纹探针，研究了杂种的分子结构。结果证明了准性生殖事件的发生。杂种似乎是二倍体或非整倍体，基因组的部分区域是杂合的。一个线粒体分子标记表明杂种的同质性以及线粒体从Bs2菌株或Bb28菌株的遗传。杂种通过宿主昆虫传代后，其致病性和倍性保持稳定，表明体细胞杂交为球孢白僵菌属生物防治效率的遗传改良提供了一种有吸引力的方法。
