Jing Luo1, Xiangyang Liu2, Lang Liu1, Poyao Zhang1, Longjia Chen1, Qiao Gao1, Weihua Ma1, Lizhen Chen3, Chaoliang Lei1. 1. Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. 2. College of Plant Protection, Huazhong Agricultural University, Zhenzhou 450002, China. 3. Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Beijing 100193, China. Electronic address: lzchen@mail.hzau.edu.cn.
Abstract
BACKGROUND: Adelphocoris suturalis Jakovlev is a major cotton pest in Southern China. Metathoracic scent glands (MTGs) produced pheromones that play an important role in survival and population propagation of this species, and also show great potential for pest control. Up to the present, there is little information that underlined the molecular basis of the pheromone biosynthesis of this bug. It is essential to clarify genes involved in the production of pheromone components, and also in the regulation of the variation of the blend ratio. RESULTS: We sequenced the transcriptome of metathoracic scent glands (MTGs) of A. suturalis. A total of 52 million 91-bp-long reads were obtained and assembled into 70,296 unigenes with a mean length of 691bp. Of these unigenes, a total of 26,744 (38%) unigenes showed significant similarity to known proteins in the NCBI database (E-value<10(-5)). Out of 26,744 hits, 9258 sequences were classified functionally into 25 COG categories, 16,473 unigenes were assigned to 242 KEGG pathways. Through blast searches of public database, a series of transcripts encoding proteins potentially related to the pheromone biosynthesis were selected, and the gene expression patterns were verified by qRT-PCR. The qRT-PCR results indicated that Asdelta9-DES, AsFAR, AsAOX, Ascarboxylesterase, AsNT-ES and AsATFs have a higher expression level in the period when female A. suturalis release sex pheromones. CONCLUSIONS: These data constitutes the first transcriptomic analysis exploring the repertoire of genes expressed in insect MTGs. We identified a large number of potential pheromone biosynthetic pathway genes. In this context, our study provides an invaluable resource for future exploration of molecular mechanisms of pheromone biosynthesis in A. suturalis, as well as other hemipteran species.
BACKGROUND:Adelphocoris suturalis Jakovlev is a major cotton pest in Southern China. Metathoracic scent glands (MTGs) produced pheromones that play an important role in survival and population propagation of this species, and also show great potential for pest control. Up to the present, there is little information that underlined the molecular basis of the pheromone biosynthesis of this bug. It is essential to clarify genes involved in the production of pheromone components, and also in the regulation of the variation of the blend ratio. RESULTS: We sequenced the transcriptome of metathoracic scent glands (MTGs) of A. suturalis. A total of 52 million 91-bp-long reads were obtained and assembled into 70,296 unigenes with a mean length of 691bp. Of these unigenes, a total of 26,744 (38%) unigenes showed significant similarity to known proteins in the NCBI database (E-value<10(-5)). Out of 26,744 hits, 9258 sequences were classified functionally into 25 COG categories, 16,473 unigenes were assigned to 242 KEGG pathways. Through blast searches of public database, a series of transcripts encoding proteins potentially related to the pheromone biosynthesis were selected, and the gene expression patterns were verified by qRT-PCR. The qRT-PCR results indicated that Asdelta9-DES, AsFAR, AsAOX, Ascarboxylesterase, AsNT-ES and AsATFs have a higher expression level in the period when female A. suturalis release sex pheromones. CONCLUSIONS: These data constitutes the first transcriptomic analysis exploring the repertoire of genes expressed in insect MTGs. We identified a large number of potential pheromone biosynthetic pathway genes. In this context, our study provides an invaluable resource for future exploration of molecular mechanisms of pheromone biosynthesis in A. suturalis, as well as other hemipteran species.