齊小浪 杜娟 李尚偉 黃海
摘要:昆蟲抗菌肽是昆蟲體液免疫產(chǎn)生的天然免疫因子,受Toll信號(hào)通路和IMD信號(hào)通路的調(diào)控。Toll信號(hào)通路主要是昆蟲細(xì)胞對(duì)革蘭氏陽(yáng)性菌和真菌的免疫應(yīng)答,而IMD信號(hào)通路主要參與細(xì)胞對(duì)革蘭氏陰性菌的免疫反應(yīng)。Toll和IMD信號(hào)通路中存在多種調(diào)節(jié)免疫反應(yīng)的正、負(fù)反饋信號(hào)因子。兩條信號(hào)通路都始于信號(hào)通路上游的模式識(shí)別受體識(shí)別病原微生物表面的病原相關(guān)分子模式,經(jīng)過信號(hào)因子級(jí)聯(lián)反應(yīng)傳遞信號(hào),于信號(hào)通路下游轉(zhuǎn)錄因子進(jìn)入細(xì)胞核,激活體液免疫相關(guān)基因的表達(dá)。
關(guān)鍵詞:病原相關(guān)分子模式;模式識(shí)別受體;信號(hào)級(jí)聯(lián);轉(zhuǎn)錄因子
中圖分類號(hào):Q963
文獻(xiàn)標(biāo)識(shí)碼:A
文章編號(hào):1008-0457(2022)02-0044-007
國(guó)際DOI編碼:10.15958/j.cnki.sdnyswxb.2022.02.007
抗菌肽(antibacterial peptide,ABP)又稱抗微生物肽( antimicrobial peptides,AMPs ) 或肽抗生素(peptide antibiotics),現(xiàn)多用AMPs一詞??咕膹V泛存在于脊椎動(dòng)物和無脊椎動(dòng)物、植物以及細(xì)菌和真菌中,是大多數(shù)生物對(duì)抗病原體入侵的天然防御屏障。這些相對(duì)較小( 分子量< 10 kDa ) 的陽(yáng)離子兩親活性多肽,長(zhǎng)度、序列和結(jié)構(gòu)可變,理化性質(zhì)穩(wěn)定、水溶性好、 熱穩(wěn)定,對(duì)革蘭氏陽(yáng)性菌(Gram-positive,G+)、革蘭氏陰性菌 (Gram-negative,G-)、真菌、病毒、原生動(dòng)物及癌細(xì)胞具有廣譜活性 [1-2]。截止2020年7月,美國(guó)內(nèi)布拉斯加大學(xué)醫(yī)學(xué)中心的抗菌肽數(shù)據(jù)庫(kù)(http://aps.unmc.edu/AP/)收錄了來自6個(gè)界的共計(jì)3236個(gè)抗菌肽,其中358個(gè)來自細(xì)菌,5個(gè)來自古生菌,8個(gè)來自原生生物,20個(gè)來自真菌,360個(gè)來自植物,還有2401個(gè)來自動(dòng)物(包括一些合成肽)。
多細(xì)胞生物常遇到病原生物的侵染,盡管昆蟲缺乏經(jīng)典意義上的適應(yīng)性免疫系統(tǒng),但人們?cè)缫颜J(rèn)識(shí)到,它們也擁有強(qiáng)大的抗感染手段。昆蟲作為地球上最繁盛的生物種群,僅僅依靠先天免疫反應(yīng)來抵抗病原微生物感染。昆蟲的先天免疫主要有血細(xì)胞介導(dǎo)的細(xì)胞免疫和脂肪體介導(dǎo)的體液免疫。昆蟲體液免疫反應(yīng)主要為刺激脂肪體產(chǎn)生細(xì)胞外分子(如抗菌肽)和級(jí)聯(lián)酚氧化酶源激活系統(tǒng)發(fā)生黑化反應(yīng)。昆蟲體液免疫主要由Toll、IMD (immune deficiency)、JNK(c-Jun N-terminal kinase)和JAK-STAT (Janus kinase/signal transducers and activators of transcription)信號(hào)通路調(diào)節(jié),研究顯示誘導(dǎo)細(xì)胞外分子產(chǎn)生的關(guān)鍵轉(zhuǎn)錄因子主要集中在Toll和IMD信號(hào)通路,而JNK通路與發(fā)育、代謝調(diào)節(jié)及應(yīng)激反應(yīng)有關(guān),JAK/STAT通路主要參與細(xì)胞分化、存活和增殖過程[3-4]。即昆蟲抗菌肽基因的表達(dá)由Toll和IMD (immune deficiency) 信號(hào)通路調(diào)節(jié),兩條信號(hào)通路均激活NF-κB 轉(zhuǎn)錄因子,啟動(dòng)AMP 和其他效應(yīng)分子基因的表達(dá)[5]。Toll信號(hào)通路介導(dǎo)和調(diào)控由G+菌和真菌引起的昆蟲體內(nèi)免疫反應(yīng)[6-7];而IMD信號(hào)通路介導(dǎo)和調(diào)控由G-菌引起的體內(nèi)免疫反應(yīng)[8-9]。
先天免疫系統(tǒng)由模式識(shí)別分子(受體)介導(dǎo),該分子識(shí)別病原體中存在但宿主中不存在的保守分子模式(配體),例如G-菌的脂多糖( LPS )、G+菌的脂磷壁酸、G+和G-菌的肽聚糖( PGN )、真菌的β-1,3-葡聚糖(β-1,3-glucan)以及細(xì)菌和病毒的DNA和RNA。配體識(shí)別后,模式識(shí)別分子激活或調(diào)節(jié)各種免疫反應(yīng),包括脊椎動(dòng)物的獲得性免疫也是如此[10]。在Toll和IMD信號(hào)通路中,信號(hào)分子的傳遞分別降解細(xì)胞質(zhì)中的Cactus和Relish,釋放出的轉(zhuǎn)錄因子作用于靶標(biāo)基因位點(diǎn),繼而調(diào)節(jié)抗菌肽基因的表達(dá)[11-12]。本文綜述體液免疫的Toll和IMD信號(hào)通路中的關(guān)鍵調(diào)控信號(hào)分子以及這兩條通路如何調(diào)控昆蟲抗菌肽基因的表達(dá)。
1模式識(shí)別受體
模式識(shí)別受體 (pattern recognition receptor,PRR)是指存在于固有免疫細(xì)胞表面的一類能夠直接識(shí)別病原相關(guān)分子模式(pathogen associated molecular pattern,PAMP)[13]的受體分子。PRR由胚系基因編碼,組成性表達(dá),能引起快速應(yīng)答和識(shí)別各種病原體。PRR具有調(diào)理、活化補(bǔ)體、吞噬、啟動(dòng)細(xì)胞信號(hào)轉(zhuǎn)導(dǎo)和誘導(dǎo)細(xì)胞凋亡等生物學(xué)功能。與Toll和IMD信號(hào)通路相關(guān)的PAMP主要有LPS、DAP-type PGN(二氨基庚二酸型肽聚糖)、Lys-type PGN(賴氨酸型肽聚糖)和β-1,3-glucan。昆蟲細(xì)胞中與這兩條通路相關(guān)的PRR主要包括肽聚糖識(shí)別蛋白(peptidoglycan recongnition protein,PGRP)、革蘭氏陰性菌結(jié)合蛋白(Gram negative binding protein,GNBP)和Spatzle蛋白。
1.1肽聚糖識(shí)別蛋白
PGRP是一類存在于大多數(shù)動(dòng)物體內(nèi)的模式識(shí)別蛋白,從昆蟲到哺乳動(dòng)物高度保守,包含一個(gè)C-端PGRP結(jié)構(gòu)域,約有165個(gè)氨基酸殘基。根據(jù)其結(jié)構(gòu),肽聚糖識(shí)別蛋白分為長(zhǎng)型(PGRP-L)和短型(PGRP-S),短型具有信號(hào)肽,均為分泌型胞外蛋白;長(zhǎng)型可以是胞內(nèi)、胞外或跨膜蛋白。一些酶促PGRP (例如PGRP-LB、PGRP-SC和PGRP-SB) 能從多糖鏈上去除肽,將肽聚糖切割成非免疫刺激片段。PGRP要么通過肽聚糖調(diào)節(jié)免疫反應(yīng),要么作為殺菌分子。相反,非酶促PGRP (例如PGRP-LC、PGRP-LE和PGRP-SA )無酶活性,但保留了結(jié)合肽聚糖的能力。非酶促PGRP通常作為PRR起作用,介導(dǎo)依賴于微生物配體的下游信號(hào)活化。果蠅有19個(gè)PGRP基因,編碼13種已知蛋白質(zhì),它們執(zhí)行多種防御功能[14]。果蠅PGRP-SD是跨膜受體PGRP-LC上游所需的分泌型模式識(shí)別受體,通過促進(jìn)肽聚糖重新定位到細(xì)胞表面來增強(qiáng)IMD信號(hào)通路的激活信號(hào)[15]。PGRP-LC是一種跨膜受體,通過胞外PGRP結(jié)構(gòu)域結(jié)合PGN,并通過激活I(lǐng)MD所需的胞內(nèi)結(jié)構(gòu)域與IMD相互作用[16],促進(jìn)果蠅Relish蛋白復(fù)合體的加工和核定位。果蠅PGRP-SA和PGRP-SD用于激活Toll信號(hào)通路。PGRP-SA存在于血淋巴中,與G+菌肽聚糖結(jié)合后能夠和PGRP-SD以及GNBP1共同作用于Spatzle前體激活酶,剪切后的Spatzle可激活Toll通路,生產(chǎn)抗菌肽殺死細(xì)菌。
1.2G-菌結(jié)合蛋白
GNBP是昆蟲體內(nèi)對(duì)入侵病菌具有識(shí)別和結(jié)合能力的一種模式識(shí)別蛋白,是激活Toll通路上的一種結(jié)合蛋白,與細(xì)菌β-1,3-葡聚糖酶具有序列同源性[17]。Lee等[18]在1996年首次從家蠶(Bombyx mori)血淋巴中分離出一種可以結(jié)合G-細(xì)胞壁的蛋白GNBP。GNBP蛋白可以糖基化,這是參與細(xì)胞—細(xì)胞粘附或識(shí)別的共同特征。果蠅有3種不同的GNBP,GNBP1和GNBP2通過與PGRP-SA相互作用,參與激活抗G+菌感染的Toll信號(hào)通路,而GNBP3參與抗真菌感染免疫反應(yīng)[19]。
1.3Spatzle蛋白
Spatzle是一種存在于血淋巴中的胞外細(xì)胞因子樣蛋白[20]。細(xì)胞合成和分泌出來的Spatzle蛋白是無活性的二聚體前體(pro-Spatzle),由一個(gè)25 kDa的前結(jié)構(gòu)域和一個(gè)14 kDa的C-端半胱氨酸結(jié)構(gòu)域(C-106)組成。Toll通過其配體Spatzle的酶切形式激活。pro-Spatzle通過絲氨酸蛋白酶Easter介導(dǎo)的蛋白水解切割產(chǎn)生Spatzle,在胚胎背軸形成過程中,Spatzle被母體提供的Easter切割。而在感染后,Spatzle加工酶激活Spatzle。Spatzle的雙重激活是通過兩種相似但不同的絲氨酸蛋白酶的時(shí)空差異表達(dá)來實(shí)現(xiàn)的。絲氨酸蛋白酶形成許多肽酶,參與消化、凝血、受精、免疫反應(yīng)和胚胎發(fā)育等生命活動(dòng)過程。在蛋白水解級(jí)聯(lián)時(shí),它們可以介導(dǎo)對(duì)生理或外來刺激的快速局部反應(yīng),其中兩個(gè)級(jí)聯(lián)反應(yīng)切割Spatzle從而激活Toll受體[21-22]。
2Toll和IMD信號(hào)通路中的信號(hào)分子
Toll信號(hào)通路包括Grass(Gram-positive specific serine protease)、SPE(Spatzle processing enzyme)、Spatzle、ModSP(modulator serine proteases)、SPE(Spatzle processing enzyme)Toll、MyD88(myeloid differentiation factor 88)、Tube、Pelle、Cactus和Dorsal/DIF(differentiation-inducing factor)等信號(hào)分子。IMD信號(hào)通路包括IMD、FADD(fas-associated death domain)、DREDD(death-related ced-3/Nedd2-like protein)、TAK1、TAB2(TAK binding 2)、IKK和Relish等信號(hào)分子。
2.1Toll通路中的信號(hào)分子
昆蟲Toll受體是一類I型跨膜蛋白,可分為胞外區(qū)、跨膜區(qū)和胞內(nèi)區(qū)3部分。其胞外區(qū)具有亮氨酸重復(fù)基序,胞內(nèi)區(qū)保守序列與白細(xì)胞介素-1受體的胞內(nèi)區(qū)保守序列高度同源,被稱為Toll白細(xì)胞介素1受體 (Toll IL-1 receptor,TIR) 結(jié)構(gòu)域。Toll的上游配體是具有活性的Spatzle,而它又通過其TIR結(jié)構(gòu)域招募下游信號(hào)分子MyD88[23-24]。昆蟲Toll受體作為先天免疫系統(tǒng)的一個(gè)重要成員,主要是將胞外識(shí)別蛋白探測(cè)到的危險(xiǎn)信號(hào)傳遞到胞內(nèi),從而激活昆蟲的先天免疫應(yīng)答。
Grass(Gram-positive specific serine protease)是Toll信號(hào)通路上游中一種具有發(fā)夾結(jié)構(gòu)的絲氨酸蛋白酶,SPE(spatzle processing enzyme)是一種Spatzle加工酶,髓樣分化蛋白(myeloid differentiation protein 88,MyD88)具有3個(gè)主要結(jié)構(gòu)域:死亡結(jié)構(gòu)域(death domain,DD)、中間結(jié)構(gòu)域和Toll白細(xì)胞介素1受體結(jié)構(gòu)域。N-端的死亡結(jié)構(gòu)域通過同型蛋白互作與白介素1受體相關(guān)激酶(IL-1 receptor-associated kinase,IRAK)家族成員相聯(lián)系;C-端TIR與其他包含該結(jié)構(gòu)域的蛋白相互作用[25]。Tube蛋白的N-端含有死亡結(jié)構(gòu)域,C-端結(jié)構(gòu)域包含5個(gè)重復(fù)的由8個(gè)氨基酸殘基組成的基序。Pelle是一種絲氨酸/蘇氨酸蛋白激酶,包含一個(gè)C-端的催化域和一個(gè)N-端的調(diào)節(jié)域,此結(jié)構(gòu)域含有類似Tube那樣的死亡結(jié)構(gòu)域。Tube直接與Pelle相互作用,它們形成一個(gè)蛋白復(fù)合物而發(fā)揮作用[26]。Cactus與哺乳動(dòng)物的κB抑制蛋白 (inhibitor of kappa B,IκB) 同源,包括酸性反式激活結(jié)構(gòu)域(acidic transactivate domain,ATAD)、錨蛋白重復(fù)結(jié)構(gòu)域(ankyrin repeats)和脯氨酸/谷氨酸/絲氨酸/蘇氨酸結(jié)構(gòu)域(proline/glutamic acid/serine/threonine domain,PESTD)[27]。Dorsal/DIF (dorsal-related immunity factor) 屬于核轉(zhuǎn)錄因子NF-κB/Rel蛋白,被Cactus維持在細(xì)胞質(zhì)內(nèi),Cactus磷酸化后導(dǎo)致其降解,釋放Dorsal/DIF,從細(xì)胞質(zhì)移位到核內(nèi),啟動(dòng)抗菌肽基因表達(dá)[28-29]。
2.2IMD通路中的信號(hào)分子
IMD基因控制果蠅的免疫防御,IMD受體蛋白作為受體近端接頭起著中心作用,直接與PGRP-LC或PGRP-LE受體以及FADD相互作用。介導(dǎo)G-的免疫反應(yīng),編碼一種類似于哺乳動(dòng)物RIP (receptor interacting protein)蛋白的死亡結(jié)構(gòu)域,IMD蛋白在激活NF-κB和細(xì)胞凋亡中發(fā)揮作用[30]。IMD信號(hào)傳遞的主要結(jié)果不是細(xì)胞因子,而是抗菌肽的產(chǎn)生[31]。FADD是一種含死亡結(jié)構(gòu)域的銜接蛋白,與Fas的死亡結(jié)構(gòu)域相互作用并引發(fā)細(xì)胞凋亡,故名Fas相關(guān)死亡域蛋白[32]。DREDD是一種與細(xì)胞凋亡相關(guān)的蛋白酶,是IMD信號(hào)通路中必不可少的酶,轉(zhuǎn)錄因子Relish的激活依賴于DREDD[33]。TAK1 (transforming growth factor β-activated kinase 1)是絲裂原活化蛋白激酶(mitogen-activated protein kinase,MAPK)家族成員,它是一種必不可少的中間調(diào)節(jié)物,將來自受體復(fù)合物的上游信號(hào)傳遞到下游的MAPKs或NF-κB[34]。IKK (IκB kinase) 復(fù)合物由2個(gè)催化亞基 (IKK1和IKK2) 和1個(gè)調(diào)節(jié)亞基 (IKKγ)組成。IκB被IKK復(fù)合物磷酸化后就發(fā)生降解,引起NF-κB家族轉(zhuǎn)錄因子釋放和活化。Relish是一種類似于哺乳動(dòng)物p100和p105的NF-κB前體蛋白,與pl00或pl05加工不同,Relish由蛋白內(nèi)切酶激活,然后轉(zhuǎn)移到細(xì)胞核中,在細(xì)胞核中驅(qū)動(dòng)高水平的( 100倍或更多) 抗菌肽基因表達(dá)。Relish為一個(gè)二組分蛋白,具有IκB蛋白家族特征,由N端的Rel同源結(jié)構(gòu)域 (RHD)和C端的Ankyrin重復(fù)結(jié)構(gòu)域組成,在未被激活的細(xì)胞中,Relish在細(xì)胞質(zhì)中被IκB樣IKK結(jié)構(gòu)域所抑制。當(dāng)IMD信號(hào)通路被激活時(shí),Relish被切割使得N端的RHD傳遞到細(xì)胞核中激活抗菌肽基因表達(dá),而C端的Ankyrin重復(fù)結(jié)構(gòu)域仍然留在細(xì)胞質(zhì)中,在果蠅中IKK復(fù)合物控制Relish的切割和激活[35]。
3Toll信號(hào)通路
G+或真菌誘導(dǎo)Toll信號(hào)通路,激活體液免疫,誘導(dǎo)抗菌肽基因表達(dá)。Toll信號(hào)通路如圖1所示,當(dāng)昆蟲受到G+和真菌的侵染時(shí),Toll信號(hào)通路的PGRP和GNBP與病原體相關(guān)分子結(jié)合會(huì)觸發(fā)淋巴液中涉及三種不同的絲氨酸蛋白酶酶原的一系列酶解反應(yīng),三步蛋白水解級(jí)聯(lián)導(dǎo)致Spatzle的成熟[36]。作為配體的成熟Spatzle會(huì)結(jié)合到Toll受體膜遠(yuǎn)端LRR結(jié)構(gòu)域的凹面上激活Toll受體,被激活后的Toll受體通過結(jié)構(gòu)域與MyD88/Tube/Pelle三聚體作用,使得Pelle被磷酸化并從三聚體中分離出來,將信號(hào)傳遞給下游的核抑制劑Cactus,隨后Cactus被泛素化和磷酸化后降解,釋放轉(zhuǎn)錄因子Dorsal/DIF進(jìn)入細(xì)胞核中靶標(biāo)基因的啟動(dòng)子區(qū)域并與RNA酶結(jié)合形成多聚體,啟動(dòng)天蠶素(cecropin)、防衛(wèi)素(defensible)和梅氏抗菌肽(metchnikowin)等抗菌基因的表達(dá)[37]。
4IMD信號(hào)通路
革蘭氏陰性菌誘導(dǎo)IMD信號(hào)通路,激活體液免疫,誘導(dǎo)抗菌肽基因表達(dá)。IMD信號(hào)通路如圖2所示,當(dāng)昆蟲受到G-的侵染時(shí),宿主細(xì)胞膜上的PGRP-LC受體和胞內(nèi)PGRP-LE受體都能與DAP型PGN特異性結(jié)合,多聚化并激活銜接蛋白IMD。隨后激活I(lǐng)MD信號(hào)通路的2個(gè)下游分支(Relish分支、JNK分支)。被激活的IMD蛋白通過同型死亡效應(yīng)結(jié)構(gòu)域( death effector domain,DED )與FADD連接并招募DREDD裂解轉(zhuǎn)錄因子Relish C端的Ankyrin重復(fù)結(jié)構(gòu)域。同時(shí),DREDD會(huì)裂解暴露IMD蛋白N端的IAP 蛋白結(jié)合基序( IAP-binding motif,IBM ),在泛素酶的作用下與聚泛素鏈K63綴合。隨后調(diào)控TAB2的泛素結(jié)合結(jié)構(gòu)域激活TAK1,TAK1激活依賴于IKK裂解的Relish磷酸化和活化。隨后被活化Relish N端的RHD/轉(zhuǎn)錄因子轉(zhuǎn)移到靶標(biāo)基因的啟動(dòng)子區(qū)域與RNA酶結(jié)合形成多聚體,啟動(dòng)抗菌物質(zhì)基因的轉(zhuǎn)錄和表達(dá)。另一方面,IMD受體蛋白基因的表達(dá)和調(diào)節(jié)早期免疫反應(yīng)(傷口愈合和黑化)的JNK分支都受Relish和TAK1等信號(hào)因子的負(fù)反饋調(diào)節(jié)[38-39]。
5 總結(jié)與展望
近年來的研究已明確了Toll和IMD在昆蟲發(fā)育和免疫方面的重要作用,Toll信號(hào)通路介導(dǎo)和調(diào)控由G+菌和真菌引起的昆蟲體內(nèi)免疫反應(yīng),而IMD信號(hào)通路介導(dǎo)和調(diào)控由G-菌引起的體內(nèi)免疫反應(yīng),但在分子層面研究免疫基因功能和調(diào)控機(jī)制尚不完全清楚[8-9]。解決這些問題對(duì)理解體液免疫相關(guān)基因快速且穩(wěn)定誘導(dǎo)的潛在分子機(jī)制和NF-κB介導(dǎo)的防御反應(yīng)(包括免疫激活和生理適應(yīng)這兩個(gè)方面)具有極其重要的意義。
隨著轉(zhuǎn)錄組學(xué)、基因組學(xué)、蛋白組學(xué)、RNAi及基因編輯技術(shù)等生物學(xué)技術(shù)的迅速發(fā)展,現(xiàn)已發(fā)現(xiàn)并鑒定了大量昆蟲免疫信號(hào)通路中的相關(guān)基因及調(diào)控因子[40]。目前關(guān)于Toll和IMD信號(hào)通路的研究主要集中在模式生物果蠅中,對(duì)于其他資源昆蟲及有害昆蟲的研究相對(duì)較少。對(duì)其他昆蟲內(nèi)的Toll和IMD信號(hào)通路功能和調(diào)節(jié)機(jī)制的深入研究可以為尋找新的害蟲防治方法提供新的途徑。此外,昆蟲的Toll和IMD信號(hào)通路分別與哺乳動(dòng)物的 TLR(Toll-like receptor)和TNFR(tumor necrosis factor receptor)信號(hào)通路同源[41]。深入研究昆蟲天然免疫的分子機(jī)制,可為炎癥性疾病、感染性疾病和癌癥等人類疾病的預(yù)防及治療提供參考。
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Research Progress of Insect Toll and IMD Signal Pathways
Qi Xiaolang,Du Juan,Li Shangwei*,Huang Hai
(Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions,Institute of Entomology,Guizhou University,Guiyang,Guizhou 550025,China)
Abstract:Insect antimicrobial peptides are innate immune factors produced by insect humoral immunity,which are regulated by Toll and IMD signaling pathways.Toll signaling pathway is mainly involved in the immune response of insect cells to Gram-positive bacteria and fungi,while IMD signaling pathway is mainly involved in the immune response of cells to Gram-negative bacteria.There are many positive and negative feedback signal factors regulating immune response in Toll and IMD signaling pathways.Both signaling pathways begin with pattern recognition receptors that recognize pathogen-associated molecular patterns on the surface of pathogenic microorganisms,and then signals are transmitted through a signal cascade.At the downstream of the signaling pathways,transcription factors enter the nucleus to activate the expression of humoral immunity-related genes.
Keywords:pathogen-associated molecular patterns;pattern recognition receptor;signal cascade;transcription factor
收稿日期:2021-08-19
修回日期:2021-12-25
基金項(xiàng)目:國(guó)家自然科學(xué)基金項(xiàng)目(31560610)
通訊作者:李尚偉(1965—),男,博士,教授,主要從事昆蟲分子生物學(xué)與生物防治研究,E-mail:swlii@163.com.
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