Department of Entomology, Purdue University, West Lafayette, IN 47907, USA.
Insect Mol Biol. 2013 Apr;22(2):155-71. doi: 10.1111/imb.12011. Epub 2013 Jan 7.
Termites are highly eusocial insects that thrive on recalcitrant materials like wood and soil and thus play important roles in global carbon recycling and also in damaging wooden structures. Termites, such as Reticulitermes flavipes (Rhinotermitidae), owe their success to their ability to extract nutrients from lignocellulose (a major component of wood) with the help of gut-dwelling symbionts. With the aim to gain new insights into this enzymatic process we provided R. flavipes with a complex lignocellulose (wood) or pure cellulose (paper) diet and followed the resulting differential gene expression on a custom oligonucleotide-microarray platform. We identified a set of expressed sequence tags (ESTs) with differential abundance between the two diet treatments and demonstrated the source (host/symbiont) of these genes, providing novel information on termite nutritional symbiosis. Our results reveal: (1) the majority of responsive wood- and paper-abundant ESTs are from host and symbionts, respectively; (2) distinct pathways are associated with lignocellulose and cellulose feeding in both host and symbionts; and (3) sets of diet-responsive ESTs encode putative digestive and wood-related detoxification enzymes. Thus, this study illuminates the dynamics of termite nutritional symbiosis and reveals a pool of genes as potential targets for termite control and functional studies of termite-symbiont interactions.
白蚁是高度真社会性的昆虫，以木质素和土壤等难处理的物质为食，因此在全球碳循环中发挥着重要作用，同时也对木质结构造成破坏。白蚁，如台湾乳白蚁（Rhinotermitidae），之所以成功，是因为它们能够在肠道共生体的帮助下从木质纤维素（木材的主要成分）中提取营养物质。为了深入了解这一酶促过程，我们用复杂的木质纤维素（木材）或纯纤维素（纸）饲料喂养 R. flavipes，并在定制的寡核苷酸微阵列平台上跟踪由此产生的差异基因表达。我们在两种饲料处理之间鉴定了一组具有差异丰度的表达序列标签（EST），并证明了这些基因的来源（宿主/共生体），为白蚁营养共生提供了新的信息。我们的研究结果揭示：（1）大多数对木材和纸张有反应的 EST 来自宿主和共生体；（2）木质纤维素和纤维素喂养在宿主和共生体中分别与不同的途径相关联；（3）一组对饮食有反应的 EST 编码潜在的消化和与木材相关的解毒酶。因此，本研究阐明了白蚁营养共生的动态，并揭示了一组作为白蚁控制和白蚁-共生体相互作用功能研究的潜在靶标基因。
