Department of Entomology, Iowa State University, Ames, 50011, IA, USA.
Department of Entomology, Iowa State University, Ames, 50011, IA, USA.
Insect Biochem Mol Biol. 2018 Dec;103:36-45. doi: 10.1016/j.ibmb.2018.10.003. Epub 2018 Oct 21.
The phytophagous stink bug, Nezara viridula (L.) infests multiple plant species and impacts agricultural production worldwide. We analyzed the transcriptomes of N. viridula accessory salivary gland (ASG), principal salivary gland (PSG) and gut, with a focus on putative digestive proteases and nucleases that present a primary obstacle for the stability of protein- or nucleic acid-based stink bug control approaches. We performed high throughput Illumina sequencing followed by de novo transcriptome assemblies. We identified the sequences of 141 unique proteases and 134 nucleases from the N. viridula transcriptomes. Analysis of relative transcript abundance in conjunction with previously reported proteome data (Lomate and Bonning, 2016) supports high levels of serine protease expression in the salivary glands and high cysteine protease expression in the gut. Specifically, trypsin and chymotrypsin transcripts were abundant in the PSG, and cathepsin L-like cysteine protease transcripts were abundant in the gut. Nuclease transcript levels were generally lower than those of the proteases, the exception being abundant transcripts of ribonuclease-C20 in the PSG. The abundance of chymotrypsin, trypsin, and some carboxypeptidase transcripts suggests a significant role for the PSG in production of digestive enzymes. This result is at odds with the premise that the ASG produces watery saliva, which is high in enzymatic activity, while the PSG produces only sheath saliva. We have generated a comprehensive transcriptome sequence dataset from the digestive organs of N. viridula, identified major protease and nuclease genes and confirmed expression of the most abundant enzymes thereby providing greater insight into the digestive physiology of N. viridula.
植食性盲蝽，Nezara viridula（L.），侵害多种植物物种，并对全球农业生产造成影响。我们分析了 N. viridula 辅助唾液腺（ASG）、主唾液腺（PSG）和肠道的转录组，重点关注可能存在的消化蛋白酶和核酸酶，这些酶是蛋白质或基于核酸的盲蝽控制方法稳定性的主要障碍。我们进行了高通量 Illumina 测序，然后进行从头转录组组装。我们从 N. viridula 转录组中鉴定出 141 种独特蛋白酶和 134 种核酸酶的序列。相对转录丰度的分析结合先前报道的蛋白质组数据（Lomate 和 Bonning，2016）支持在唾液腺中高水平表达丝氨酸蛋白酶，在肠道中高水平表达半胱氨酸蛋白酶。具体来说，PSG 中丰富的胰蛋白酶和糜蛋白酶转录物，而肠中丰富的组织蛋白酶 L 样半胱氨酸蛋白酶转录物。核酸酶转录物水平通常低于蛋白酶，例外是 PSG 中丰富的核糖核酸酶-C20 转录物。糜蛋白酶、胰蛋白酶和一些羧肽酶转录物的丰度表明 PSG 在消化酶产生中起着重要作用。这一结果与 ASG 产生富含酶活性的稀薄唾液，而 PSG 仅产生鞘唾液的前提相矛盾。我们从 N. viridula 的消化器官中生成了一个全面的转录组序列数据集，鉴定了主要的蛋白酶和核酸酶基因，并证实了最丰富酶的表达，从而更深入地了解了 N. viridula 的消化生理学。
