International Centre of Insect Physiology and Ecology (icipe), Nairobi 00100, Kenya.
Biomed Res Int. 2013;2013:465213. doi: 10.1155/2013/465213. Epub 2013 Jul 9.
Virulence is the primary factor used for selection of entomopathogenic fungi (EPF) for development as biopesticides. To understand the genetic mechanisms underlying differences in virulence of fungal isolates on various arthropod pests, we compared the chitinase genes, chi2 and chi4, of 8 isolates of Metarhizium anisopliae. The clustering of the isolates showed various groups depending on their virulence. However, the analysis of their chitinase DNA sequences chi2 and chi4 did not reveal major divergences. Although their protein translates have been implicated in fungal virulence, the predicted protein structure of chi2 was identical for all isolates. Despite the critical role of chitin digestion in fungal infection, we conclude that chi2 and chi4 genes cannot serve as molecular markers to characterize observed variations in virulence among M. anisopliae isolates as previously suggested. Nevertheless, processes controlling the efficient upregulation of chitinase expression might be responsible for different virulence characteristics. Further studies using comparative "in vitro" chitin digestion techniques would be more appropriate to compare the quality and the quantity of chitinase production between fungal isolates.
毒力是选择昆虫病原真菌（EPF）开发为生物农药的主要因素。为了了解真菌分离物对各种节肢动物害虫毒力差异的遗传机制，我们比较了 8 株金龟子绿僵菌的几丁质酶基因 chi2 和 chi4。分离物的聚类显示出不同的组，这取决于它们的毒力。然而，对其几丁质酶 DNA 序列 chi2 和 chi4 的分析并没有揭示出主要的差异。尽管它们的蛋白质翻译已被牵连到真菌的毒力中，但 chi2 的预测蛋白质结构对于所有分离物都是相同的。尽管几丁质消化在真菌感染中起着关键作用，但我们得出结论，chi2 和 chi4 基因不能像以前所建议的那样作为分子标记来描述金龟子绿僵菌分离物中观察到的毒力变异。然而，控制几丁质酶表达高效上调的过程可能是导致不同毒力特征的原因。使用比较“体外”几丁质消化技术的进一步研究将更适合比较真菌分离物之间几丁质酶产生的质量和数量。
