Stafford-Banks Candice A, Rotenberg Dorith, Johnson Brian R, Whitfield Anna E, Ullman Diane E
Department of Plant Pathology, University of California Davis, Davis, California, United States of America.
Department of Plant Pathology, Kansas State University, Manhattan, Kansas, United States of America.
PLoS One. 2014 Apr 15;9(4):e94447. doi: 10.1371/journal.pone.0094447. eCollection 2014.
Saliva is known to play a crucial role in insect feeding behavior and virus transmission. Currently, little is known about the salivary glands and saliva of thrips, despite the fact that Frankliniella occidentalis (Pergande) (the western flower thrips) is a serious pest due to its destructive feeding, wide host range, and transmission of tospoviruses. As a first step towards characterizing thrips salivary gland functions, we sequenced the transcriptome of the primary salivary glands of F. occidentalis using short read sequencing (Illumina) technology. A de novo-assembled transcriptome revealed 31,392 high quality contigs with an average size of 605 bp. A total of 12,166 contigs had significant BLASTx or tBLASTx hits (E≤1.0E-6) to known proteins, whereas a high percentage (61.24%) of contigs had no apparent protein or nucleotide hits. Comparison of the F. occidentalis salivary gland transcriptome (sialotranscriptome) against a published F. occidentalis full body transcriptome assembled from Roche-454 reads revealed several contigs with putative annotations associated with salivary gland functions. KEGG pathway analysis of the sialotranscriptome revealed that the majority (18 out of the top 20 predicted KEGG pathways) of the salivary gland contig sequences match proteins involved in metabolism. We identified several genes likely to be involved in detoxification and inhibition of plant defense responses including aldehyde dehydrogenase, metalloprotease, glucose oxidase, glucose dehydrogenase, and regucalcin. We also identified several genes that may play a role in the extra-oral digestion of plant structural tissues including β-glucosidase and pectin lyase; and the extra-oral digestion of sugars, including α-amylase, maltase, sucrase, and α-glucosidase. This is the first analysis of a sialotranscriptome for any Thysanopteran species and it provides a foundational tool to further our understanding of how thrips interact with their plant hosts and the viruses they transmit.
众所周知，唾液在昆虫取食行为和病毒传播中起着至关重要的作用。目前，尽管西花蓟马（Frankliniella occidentalis (Pergande)）因其具有破坏性的取食、广泛的寄主范围和番茄斑萎病毒属病毒的传播而成为一种严重害虫，但对蓟马唾液腺和唾液的了解却很少。作为表征蓟马唾液腺功能的第一步，我们使用短读测序（Illumina）技术对西花蓟马主要唾液腺的转录组进行了测序。一个从头组装的转录组揭示了31392个高质量重叠群，平均大小为605 bp。共有12166个重叠群与已知蛋白质有显著的BLASTx或tBLASTx匹配（E≤1.0E-6），而高比例（61.24%）的重叠群没有明显的蛋白质或核苷酸匹配。将西花蓟马唾液腺转录组（唾液转录组）与从Roche-454读数组装的已发表的西花蓟马全身转录组进行比较，发现了几个具有与唾液腺功能相关的推定注释的重叠群。唾液转录组的KEGG通路分析表明，大多数（前20个预测的KEGG通路中的18个）唾液腺重叠群序列与参与代谢的蛋白质匹配。我们鉴定了几个可能参与解毒和抑制植物防御反应的基因，包括醛脱氢酶、金属蛋白酶、葡萄糖氧化酶、葡萄糖脱氢酶和钙网蛋白。我们还鉴定了几个可能在植物结构组织的口外消化中起作用的基因，包括β-葡萄糖苷酶和果胶裂解酶；以及糖类的口外消化相关基因，包括α-淀粉酶、麦芽糖酶、蔗糖酶和α-葡萄糖苷酶。这是对任何缨翅目物种唾液转录组的首次分析，它提供了一个基础工具，以进一步加深我们对蓟马如何与其植物寄主以及它们传播的病毒相互作用的理解。
