茶籽象ATP合成酶基因在不同海拔选择压力下的遗传分化及结构变异

【目的】基于不同地区茶籽象线粒体ATP合成酶基因遗传分化及结构变异,研究环境压力尤其是海拔对茶籽象不同地理种群遗传多样性及系统发育关系的影响,探讨ATP合成酶基因在适应环境压力中碱基及氨基酸序列结构变化规律,为茶籽象防控提供理论依据。【方法】采集不同地理海拔油茶产区的茶籽象种群,设计ATP合成酶基因特异性引物,PCR扩增获取ATP基因,基于ATP基因应用相关分析软件分析碱基序列遗传多样性及系统发育关系,分析氨基酸序列结构差异及氨基酸使用频率。【结果】获得32个单倍型(NCBI: MH560360—MH560391),其中存在5个共享单倍型,包含个体数2~36不等;茶籽象各地理种群遗传多样性分化无明显规律(核酸多样性π为0.000 86 ~ 0.048 03),茶籽象种群扩张不明显(Tajima’s D < 0,P > 0.05;Fu’s Fs > 0);依据地理海拔,茶籽象种群可显著聚为低海拔和高海拔2个分支,2个分支间受到显著的环境正选择(选择系数:高海拔ω=1.65,低海拔ω=2.26,LRTP<0.001),分化明显( F st =0.374,P < 0.001);低海拔分支 ATPSTBX]8STBZ]编码解氨基酸序列(36个保守位点)较高海拔分支(27个保守位点)更为保守,且高海拔分支酸性氨基酸使用率较高,这可能与昆虫为适应高海拔而增加蛋白稳定性、提高氧结合效率以及氧化呼吸效率有关。【结论】茶籽象种群ATP合成酶基因分化程度不高,但存在对海拔明显的适应性进化。

Genetic Differentiation and Structural Variation of ATP Synthase Gene of Curculio chinensis (Coleptera: Curculionidae) under Selection Pressure at Different Altitudes

【Objective】 The camellia weevil,Curculio chinensis (Coleoptera:Curculionidae),is a host-specific parasite of camellia seeds and has caused huge economic losses in China.Despite its economic impact,the genetic diversity is rarely understood.In this study,based on the genetic differentiation and structural variation of mitochondrial ATP synthase gene of C.chinensis in different regions,the influence of environmental selection pressure,especially the geographical altitude,on the genetic diversity and the phylogenetic structure of different geographical populations of C.chinensis was studied,and the changes of bases as well as their amino acid sequence structure of ATP synthase gene in adapting to environmental pressure were discussed,which is important to provide theoretical basis for establishing a control strategy of this pest.【Method】 The populations of camellia weevil at different geographical altitudes were collected from the main oil-tea production areas.The specific primers of ATP synthase gene were designed and the ATP synthase gene was amplified by PCR.Genetic diversity and phylogenetic structure were estimated based on ATP gene sequences,and the structural differences of amino acids sequences and frequency were moreover analyzed.【Result】 Genetic diversity and the phylogenetic structure of C.chinensis were inferred using the sequences of ATP synthase gene among different geographical populations.Thirty-two haplotypes (NCBI:MH560360-MH560391) in 119 individuals from all the sample regions in China were obtained.There was no obvious regularity in the genetic diversity differentiation of various geographical populations of camellia weevil (Nucleotide diversity π:0.000 86-0.048 03).The population expansion of camellia weevil was not significant (Tajima’s D <0,P >0.05;Fu’s Fs>0).Based on the geographical altitudes,all the samples of camellia weevil can significantly divided into two branches (F st =0.374,P <0.001) under different selection pressures (Choice index:ω high altitude = 1.65,ω low altitude = 2.26,LRT P <0.001).STBX]ATP8STBZ] gene in the samples of low altitude branch (36 conservative sites) was more conservative compared to that in high altitude branch (27 conservative sites),and acidic amino acid utilization rate in high altitude branch was higher than that in low altitude branch,which might be related to the increase of protein stability,oxygen binding efficiency and oxidative respiratory efficiency of insects to adapt to high altitude.【Conclusion】 The differentiation degree of ATP synthase gene in C.chinensis populations is low,but there is significant adaptation evolution to geographical altitude.