小菜蛾清道夫受体基因家族鉴定与生物信息学分析

Genome-wide Identification and Bioinformatics Analysis of Scavenger Receptor Gene Family in Plutella xylostella

【目的】小菜蛾(Plutella xylostella)对化学杀虫性抗药性逐年上升,使RNAi(RNA interference)农药广受关注。小菜蛾清道夫受体(Scavenger receptor,SR)在细胞免疫中表现出吞噬和清除病原体的能力,使其成为RNAi农药的备选靶标基因。为确定小菜蛾SR基因相关靶标,鉴定分析了小菜蛾SR基因家族成员信息。【方法】基于全基因组数据,对小菜蛾SR基因家族的理化性质、跨膜结构、系统发育进化、蛋白质二三级结构预测、蛋白保守基序、磷酸化位点预测等内容进行分析。【结果】小菜蛾SR基因家族有12个CD36蛋白序列,具有相似的理化性质和功能结构,均含有多个亲水性和疏水性区域及2个跨膜螺旋区,蛋白质二、三级结构的主要特征为无规则卷曲,磷酸化位点中丝氨酸含量最高。小菜蛾与家蚕(Bombyx mori)、冈比亚按蚊(Anopheles gambiae)、黑腹果蝇(Drosophila melanogaster)、烟草天蛾(Manduca sexta)、赤拟谷盗(Tribolium castaneum)等6个物种共包含117条CD36蛋白序列,这些序列在进化树上分成5个分支,具有相似结构的基因聚为同一支,进化保守性强。小菜蛾CD36px4、CD36px5具有更复杂的三级结构,且motif19、motif20两个基序只存在于CD36px4,推测其在物种进化中发挥某些特异功能,CD36px4磷酸化位点数量多达143个,可能与凋亡细胞的吞噬和清除功能表达有关。【结论】鉴定分析到12个小菜蛾SR蛋白均为跨膜型蛋白,且含有丰富的磷酸化位点,预测其可参与细胞内外物质传输、信号传递及能量代谢等机体活动,具有介导细胞凋亡、吞噬和清除凋亡细胞的功能,可作为RNAi农药的备选靶标,为小菜蛾RNAi农药靶标的筛选提供重要依据。

【Objective】The resistance of Plutella xylostella to chemical insecticides is increasing year by year,which makes RNAi(RNA interference)pesticides widely concerned.The P.xylostella SR have phagocytic and pathogen-clearing abilities in cellular immunity,rendering them a promising target for RNAi pesticides.This study explores alternative targets for such pesticides by investigating the SR gene family in P.xylostella.【Method】Based on the P.xylostella genome,we comprehensively analyzed the physicochemical properties,transmembrane structure,phylogenetic evolution,secondary and tertiary structure prediction,conserved protein motifs and phosphorylation site prediction of SR gene family.【Result】The SR gene family of P.xylostella has 12 CD36 protein sequences with similar physicochemical properties and functional structures,all of which contain multiple hydrophilic and hydrophobic regions as well as two transmembrane helical regions.Their secondary and tertiary structures feature irregular coiling with the highest serine content in the phosphorylation site.A total of six species,including P.xylostella,Bombyx mori,Anopheles gambiae,Drosophila melanogaster,Manduca sexta and Tribolium castaneum contained 117 CD36 protein sequences that were classified into five distinct branches on the evolutionary tree.Genes with similar structures were grouped together within the same branch,indicating a high conservation throughout evolution.CD36px4 and CD36px5 exhibit more intricate tertiary structures.The motif 19 and motif 20 are exclusive to CD36px4,suggesting their potential involvement in species evolution.With a staggering 143 phosphorylation sites,CD36px4 may play a crucial role in the phagocytosis and clearance of apoptotic cells.【Conclusion】The 12 SRs identified are transmembrane proteins with abundant phosphorylation sites,predicted to participate in various physiological processes such as intracellular and extracellular material transport,signal transduction,energy metabolism,and apoptosis regulation.They also possess the functions of mediating phagocytosis and clearance of cellular debris.These receptors represent a promising target for RNAi-based pesticides.The results have provided a crucial foundation for the screening of RNAi pesticide targets.