Department of Entomology and the Nematology and Chemistry units, Plant Protection Institute; Agricultural Research Organization (ARO), the Volcani Center, Rishon Le Zion, Israel.
The Robert H. Smith Faculty of Agriculture, Food & Environment the Hebrew University of Jerusalem, Rehovot, Israel.
Sci Rep. 2020 Jun 29;10(1):10500. doi: 10.1038/s41598-020-67097-0.
Entomopathogenic nematodes are effective biocontrol agents against arthropod pests. However, their efficacy is limited due to sensitivity to environmental extremes. The objective of the present study was to establish a foundation of genetic-based selection tools for beneficial traits of heat and desiccation tolerance in entomopathogenic nematodes. Screening of natural populations enabled us to create a diverse genetic and phenotypic pool. Gene expression patterns and genomic variation were studied in natural isolates. Heterorhabditis isolates were phenotyped by heat- and desiccation-stress bioassays to determine their survival rates compared to a commercial line. Transcriptomic study was carried out for the commercial line, a high heat-tolerant strain, and for the natural, low heat-tolerant isolate. The results revealed a higher number of upregulated vs. downregulated transcripts in both isolates vs. their respective controls. Functional annotation of the differentially expressed transcripts revealed several known stress-related genes and pathways uniquely expressed. Genome sequencing of isolates with varied degrees of stress tolerance indicated variation among the isolates regardless of their phenotypic characterization. The obtained data lays the groundwork for future studies aimed at identifying genes and molecular markers as genetic selection tools for enhancement of entomopathogenic nematodes ability to withstand environmental stress conditions.
昆虫病原线虫是防治节肢动物害虫的有效生物防治剂。然而，由于它们对环境极端条件的敏感性，其效果受到限制。本研究的目的是为昆虫病原线虫的耐热和耐旱性等有益特性建立基于遗传的选择工具的基础。对自然种群的筛选使我们能够创建一个多样化的遗传和表型库。对天然分离物进行了基因表达模式和基因组变异研究。通过热和干燥胁迫生物测定对 Heterorhabditis 分离物进行表型分析，以确定与商业品系相比的存活率。对商业品系、高耐热菌株和天然低耐热分离物进行了转录组研究。结果表明，与各自的对照相比，两个分离物中上调的转录本数量高于下调的转录本数量。差异表达转录本的功能注释揭示了一些独特表达的已知与应激相关的基因和途径。对具有不同程度应激耐受性的分离物进行的基因组测序表明，无论其表型特征如何，分离物之间存在差异。获得的数据为未来的研究奠定了基础，旨在确定基因和分子标记作为遗传选择工具，以增强昆虫病原线虫耐受环境应激条件的能力。
