Southern Insect Management Research Unit, USDA, Agricultural Research Service, Stoneville, MS 38776.
Biological Control of Insects Research Laboratory, USDA, Agricultural Research Service, 1503 S. Providence Road, Columbia, MO 65203.
J Insect Sci. 2021 May 1;21(3). doi: 10.1093/jisesa/ieab028.
Host plant preference of agricultural pests may shift throughout the growing season, allowing the pests to persist on wild hosts when crops are not available. Lygus Hahn (Hemiptera: Miridae) bugs are severe pests of cotton during flowering and fruiting stages, but can persist on alternative crops, or on weed species. Diversity of digestive enzymes produced by salivary glands and gut tissues play a pivotal role in an organism's ability to utilize various food sources. Polyphagous insects produce an array of enzymes that can process carbohydrates, lipids, and proteins. In this study, the digestive enzyme repertoire of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), was identified by high-throughput sequencing followed by cDNA cloning and sequencing. This study identified 87 digestive genes, including 30 polygalacturonases (PG), one β-galactosidase, three α-glucosidases, six β-glucosidases, 28 trypsin-like proteases, three serine proteases, one apyrase-like protease, one cysteine protease, 12 lipases, and two transcripts with low similarity to a xylanase A-like genes. RNA-Seq expression profiles of these digestive genes in adult tarnished plant bugs revealed that 57 and 12 genes were differentially expressed in the salivary gland and gut (≥5-fold, P ≤ 0.01), respectively. All polygalacturonase genes, most proteases, and two xylanase-like genes were differentially expressed in salivary glands, while most of the carbohydrate and lipid processing enzymes were differentially expressed in the gut. Seven of the proteases (KF208689, KF208697, KF208698, KF208699, KF208700, KF208701, and KF208702) were not detected in either the gut or salivary glands.
农业害虫对寄主植物的偏好可能会在整个生长季节发生变化，从而使害虫在作物不可用时能够在野生寄主上生存。棉盲蝽（半翅目：盲蝽科）在棉花开花和结果阶段是严重的害虫，但可以在替代作物或杂草物种上生存。唾液腺和肠道组织产生的消化酶的多样性在生物体利用各种食物源的能力中起着关键作用。多食性昆虫产生一系列可以处理碳水化合物、脂肪和蛋白质的酶。在这项研究中，通过高通量测序，然后进行 cDNA 克隆和测序，确定了玷污盲蝽（Lygus lineolaris（Palisot de Beauvois））的消化酶谱。这项研究鉴定了 87 种消化基因，包括 30 种多聚半乳糖醛酸酶（PG）、1 种β-半乳糖苷酶、3 种α-葡萄糖苷酶、6 种β-葡萄糖苷酶、28 种胰蛋白酶样蛋白酶、3 种丝氨酸蛋白酶、1 种类似 apyrase 的蛋白酶、1 种半胱氨酸蛋白酶、12 种脂肪酶和 2 种与木聚糖酶 A 样基因相似度较低的转录本。成年玷污盲蝽唾液腺和肠道中这些消化基因的 RNA-Seq 表达谱显示，分别有 57 和 12 个基因在唾液腺和肠道中差异表达（≥5 倍，P ≤ 0.01）。所有多聚半乳糖醛酸酶基因、大多数蛋白酶和 2 个木聚糖酶 A 样基因在唾液腺中差异表达，而大多数碳水化合物和脂质处理酶在肠道中差异表达。在肠道或唾液腺中均未检测到 7 种蛋白酶（KF208689、KF208697、KF208698、KF208699、KF208700、KF208701 和 KF208702）。
