Zhang Lili, Xu Pengjun, Xiao Haijun, Lu Yanhui, Liang Gemei, Zhang Yongjun, Wu Kongming
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
PLoS One. 2015 May 8;10(5):e0126391. doi: 10.1371/journal.pone.0126391. eCollection 2015.
Polygalacturonase (PG) is an enzyme in the salivary glands of piercing-sucking mirid bugs (Hemiptera: Miridae) that plays a key role in plant feeding and injury. By constructing a full-length cDNA library, we cloned and characterized 14 PG genes from the salivary glands of Apolygus lucorum, a pestiferous mirid bug in cotton, fruit trees and other crops in China. BLAST search analysis showed that the amino acid sequences deduced from transcripts of the PG genes were closely related to PGs from other mirid bugs. Phylogenetic analysis showed that the PGs of mirid bugs had six main branches, PG1-PG6 (Genbank accession numbers: KF881899~KF881912). We investigated the mRNA expression patterns of the A. lucorum PG genes using real-time PCR. All 14 PGs were expressed significantly higher in the salivary glands than in other tissues (head, thorax, abdomen, leg and wing). For eggs and nymphs, the expression levels of these PGs were much higher in the 5th instar stage than in the egg, and 1st and 3rd instar stages. The PG expression levels in 1-day-old adults were very low, and increased in 5, 20 and 30-day-old adults. Additionally, PG expression levels were generally similar between males and females. The possible physiological functions of PGs in A. lucorum were discussed.
多聚半乳糖醛酸酶（PG）是刺吸式盲蝽（半翅目：盲蝽科）唾液腺中的一种酶，在植物取食和造成损伤过程中起关键作用。通过构建全长cDNA文库，我们从绿盲蝽（一种危害棉花、果树及中国其他作物的盲蝽害虫）的唾液腺中克隆并鉴定了14个PG基因。BLAST搜索分析表明，PG基因转录本推导的氨基酸序列与其他盲蝽的PG密切相关。系统发育分析表明，盲蝽的PG有六个主要分支，即PG1 - PG6（Genbank登录号：KF881899~KF881912）。我们使用实时PCR研究了绿盲蝽PG基因的mRNA表达模式。所有14个PG在唾液腺中的表达均显著高于其他组织（头部、胸部、腹部、腿部和翅膀）。对于卵和若虫，这些PG在5龄期的表达水平远高于卵期、1龄期和3龄期。1日龄成虫的PG表达水平非常低，在5日龄、20日龄和30日龄成虫中表达增加。此外，PG在雌雄个体中的表达水平总体相似。文中还讨论了绿盲蝽中PG可能的生理功能。
