• 
    

    
    

      99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看

      ?

      大腸埃希菌O127:H7植物組織內(nèi)生化研究概況

      2015-01-22 10:43:19楊黎汪海珍姚志遠(yuǎn)吳建軍
      關(guān)鍵詞:植物體埃希菌根際

      楊黎,汪海珍*,姚志遠(yuǎn),吳建軍

      (浙江大學(xué)環(huán)境與資源學(xué)院土水資源與環(huán)境研究所,浙江省亞熱帶土壤與植物營養(yǎng)重點(diǎn)開放實(shí)驗(yàn)室,杭州310058)

      大腸埃希菌O127:H7植物組織內(nèi)生化研究概況

      楊黎?,汪海珍?*,姚志遠(yuǎn),吳建軍

      (浙江大學(xué)環(huán)境與資源學(xué)院土水資源與環(huán)境研究所,浙江省亞熱帶土壤與植物營養(yǎng)重點(diǎn)開放實(shí)驗(yàn)室,杭州310058)

      人畜共患病原菌大腸埃希菌O157:H7是一種產(chǎn)志賀毒素的典型菌株,人體感染后會引起出血性腹瀉和腸炎,且可并發(fā)溶血性尿毒綜合征、血栓性血小板減少性紫癜等疾病,嚴(yán)重時(shí)可致人死亡.人畜糞肥攜帶的大腸埃希菌O157:H7等病原菌可通過污灌、徑流、農(nóng)田施用和昆蟲傳播等途徑進(jìn)入到土壤環(huán)境中,污染種植的水果和蔬菜,使其成為傳播大腸埃希菌O157:H7的重要媒介,對公眾健康構(gòu)成了嚴(yán)重威脅.大腸埃希菌O157:H7可從植物表面自身通道(如氣孔、皮孔和側(cè)根發(fā)生處等)或表面損傷(生物損傷或物理損傷等)等途徑進(jìn)入植物體內(nèi),隨宿主植物的細(xì)胞分化在植物體內(nèi)繁殖,與宿主植物構(gòu)成特殊的共生關(guān)系,但不形成特殊結(jié)構(gòu),也不引發(fā)植物體外觀形態(tài)改變.然而,大腸埃希菌O157:H7植物內(nèi)生化與植物體損傷程度、植物免疫系統(tǒng)及其模式識別受體(pattern recognition receptors,PRRs)、附生植物微生物群落和根際土壤微生物群落等因素之間存在復(fù)雜的交互作用.該文對大腸埃希菌O157:H7的污染來源、植物組織內(nèi)生化途徑及其影響因素等進(jìn)行了綜合的闡述,為深入了解人畜共患病原菌植物內(nèi)生化機(jī)制和污染風(fēng)險(xiǎn)提供參考,以便降低人畜共患病原菌對人類健康和環(huán)境安全的危害.

      大腸埃希菌O157:H7;植物;內(nèi)生化

      SummaryShiga toxin-producing Escherichia coli O157:H7,one of the most emergent foodborne pathogens,can cause illnesses ranging from diarrhea to hemorrhagic colitis and hemolytic-uremic syndrome.Escherichia coli O157:H7 is spread into the environment via fecal shedding or field application of farm effluent.The produce can be contaminated by E.coli O157:H7 through soil,feces,irrigation water,manure application,insects,or postharvest washing.Fresh produces,especially leafy greens that be consumed raw,are increasingly being recognized as the foremost transmitting vehicles.Many studies have shown that E.coli O157:H7 can internalize within a variety of tissue types.Although the internalized E.coli O157:H7 makes no difference to the normal growth of plants,it brings risks when people take in the unpasteurized fresh food.In this review,sources of contamination,main routes of internalization,interactions between internalized E.coli O157:H7 and the plant host as well as other microbeswere stated.

      The internalization of E.coli O157:H7 in fresh produce has been found to be associated with many routes including stomata,lenticels,sites of root emergence and sites of biological or physical damage.Because stomata are generally found in greater densities on the underside of leaves,greater internalization of E.coli O157:H7 on leaves would be likely on the abaxial side than on the adaxial side.Root uptake of E.coli O157:H7 and subsequent internalization has also been widely reported.Damaged leaves release more nutrients onto the leaf surface,which allow E.coli O157:H7 to grow and induce more E.coli O157:H7 to get into the leaves.Various factors including growth substrate,inoculums level,and plant species and cultivar,have shown to affect the level of internalization.

      Although there is no obvious change on the appearance of the plant,complicated interactions between internalized E.coli O157:H7 and the plant hosts have been discovered.Plant hosts have some pattern recognition receptors(PRRs)to recognize pathogen associated molecular patterns(PAMPs),and further activate plant immune response to limit the growth and spread of the pathogen.PAMPs contain flagellin,peptidoglycan,lipopolysaccharide,and other components which derived from pathogens.Studies have showed that elimination of these PAMPs leads to better growth of E.coli O157:H7 in the plant.Furthermore,phytopathogen can grow in the plant through secreting effector proteins to disturb the recognition of PAMPs by PRRs.Whether human pathogen currently carries the effector proteins is yet to be determined.Further research is needed to explain the mechanism of E.coli O157:H7 invasion and growth in the plant hosts.In addition,interactions between E.coli O157:H7 and the epiphytic microbes would affect the internalization of E.coli O157:H7.The metabolic products of the epiphytic microbes and the competition of nutrients between E.coli O157:H7 and the epiphytic microbes could limit the growth of E.coli O157:H7.On the other hand,some epiphytic microbes could produce available carbon sources to help E.coli O157:H7 grow and get into the plant hosts.

      In short,better understanding of the internalization of E.coli O157:H7 in plants and risks will be helpful in reducing the pathogenic infection to human.Further researches remain to be done in revealing the molecular and genetic details of the mechanisms that are involved to control the contamination of fresh produce by human pathogenic bacteria.

      微生物引起的食源性疾病是我國頭號食品安全問題,亦受到世界上其他國家的極大關(guān)注[1].其中,因畜禽糞便攜帶的人畜共患病原菌(如沙門菌、大腸埃希菌O157:H7等)污染農(nóng)產(chǎn)品而引發(fā)的食源性疾病及危害,目前受到了人們的特別關(guān)注.研究表明,人感染10個(gè)大腸埃希菌O157:H7活菌即可致病,導(dǎo)致患者出現(xiàn)劇烈腹痛,引起出血性結(jié)腸炎甚至溶血性尿毒綜合征[2].近年來,大腸埃希菌O157:H7在全球許多國家導(dǎo)致多起暴發(fā)流行,且引起的食源性疾病病死率較高,是國際公認(rèn)的食源性致病菌之一.其暴發(fā)主要與食用大腸埃希菌O157:H7污染的水果和蔬菜有關(guān),這些蔬菜涉及芽苗菜、菠菜、生菜、涼拌卷心菜、番茄、各種瓜類、蘋果汁、色拉等.大腸埃希菌O157:H7病原微生物可隨農(nóng)用污水、污泥或畜禽糞便等有機(jī)廢棄物的添加進(jìn)入土壤,并在土壤中存活,其存活時(shí)間可達(dá)數(shù)天乃至數(shù)百天[3-7],并可附著于生鮮農(nóng)產(chǎn)品表面或內(nèi)生化植物體內(nèi)造成污染[8-12].

      細(xì)菌植物內(nèi)生化是指細(xì)菌通過植物表面自身通道(如氣孔、皮孔和側(cè)根發(fā)生處等)或表面損傷(生物損傷或物理損傷等)各種途徑進(jìn)入到植物組織的細(xì)胞間和細(xì)胞內(nèi),隨植物的細(xì)胞分化而進(jìn)入中柱并在植物體內(nèi)繁殖,與植物構(gòu)成共生關(guān)系但不形成特殊結(jié)構(gòu)的一種現(xiàn)象[13-14].植物病原菌進(jìn)入植物體可使植物致病,受植物病原菌侵害的宿主植物在外觀上有別于正常植株[15],而人畜共患病原菌進(jìn)入植物體后植物無外觀表現(xiàn),不易被察覺.研究發(fā)現(xiàn),植物體可對內(nèi)生化的大腸埃希菌O157:H7形成保護(hù),表面殺菌劑難以將其消滅;大腸埃希菌O157:H7進(jìn)入植物體內(nèi)后,宿主植物體內(nèi)的某些物質(zhì)成分可作為病原菌生長所需的營養(yǎng)物質(zhì),但與此同時(shí),宿主植物也會分泌一系列物質(zhì)來抑制內(nèi)生化病原菌的繁殖與擴(kuò)散,營養(yǎng)物質(zhì)與抑菌物質(zhì)作用的差異則決定了病原菌的內(nèi)生化程度及其生長狀況[10].

      由于大腸埃希菌O157:H7致病的嚴(yán)重性,其在生鮮農(nóng)產(chǎn)品上內(nèi)生化的情況亦引起了國內(nèi)外研究者的重視.本文基于國內(nèi)外近年來的研究進(jìn)展,對大腸埃希菌O157:H7來源、植物內(nèi)生化途徑及其影響因素等進(jìn)行簡要綜述,為深入了解大腸埃希菌O157:H7植物內(nèi)生化機(jī)制和污染風(fēng)險(xiǎn)提供參考.

      1 植物體中大腸埃希菌O157:H7的來源

      大腸埃希菌O157:H7可通過多種途徑附著于植物表面,但植物表面溫度波動頻繁、溫差大、濕度低、營養(yǎng)物質(zhì)缺乏等因素都抑制了病原菌在植物體表的繁殖,這或許是迫使大腸埃希菌O157:H7進(jìn)入植物體的誘因之一[16].對于病原菌進(jìn)入植物體內(nèi)大致可歸為3種主要途徑:污水灌溉、糞肥施用和昆蟲傳播.

      1.1 污水灌溉

      大腸埃希菌O157:H7可在水中存活相當(dāng)長的時(shí)間,采用受病原菌污染的農(nóng)用水進(jìn)行灌溉,病原菌可隨水流動,附著于植物體表面,當(dāng)大腸埃希菌O157:H7隨水流動至植物體表通道或傷口時(shí)停留并伺機(jī)進(jìn)入植物體內(nèi)[17].有實(shí)驗(yàn)結(jié)果顯示,生菜種子播種前,將其浸泡于含有大腸埃希菌O157:H7的水中,經(jīng)過42 h的育苗培養(yǎng),在生菜幼苗根系表面和葉際表面均可檢測到大腸埃希菌O157:H7的存在[18].此時(shí),大腸埃希菌O157:H7雖未發(fā)生植物內(nèi)生化,但病原菌在植物體表的停留卻大大增加了病原菌進(jìn)入到植物體內(nèi)的風(fēng)險(xiǎn).Solomon等[19]用含有大腸埃希菌O157:H7的污水對生菜進(jìn)行灌溉(污水不接觸生菜地上部分),5 d后可在植物體內(nèi)檢測到病原菌的存在;而當(dāng)灌溉污水與植物體地上部分直接接觸時(shí),5 d后病原菌內(nèi)生化發(fā)生的概率明顯升高[20].將無病原菌污染的菠菜幼苗置于含有大腸埃希菌O157:H7的營養(yǎng)液中培養(yǎng),經(jīng)過7 d培養(yǎng)后,可在莖中檢測到大腸埃希菌O157:H7的存在[21].也有證據(jù)表明,生鮮農(nóng)產(chǎn)品在收割后清洗,植物體表面的病原菌極易隨水流動并通過主莖進(jìn)入植物體內(nèi)[22].

      1.2 糞肥施用

      畜禽糞便是優(yōu)質(zhì)的有機(jī)肥料,但大腸埃希菌O157:H7等病原菌的檢出率較高,畜禽糞便作為肥料或土壤改良劑施用是大腸埃希菌O157:H7污染農(nóng)產(chǎn)品的主要來源之一[2].我國雖無大型的大腸埃希菌O157:H7爆發(fā)流行,但隨糞肥的添加,大腸埃希菌O157:H7也被帶入土壤,為病原菌進(jìn)入植物體提供了途徑.與此同時(shí),糞肥中營養(yǎng)物質(zhì)更為豐富,使得土壤中大腸埃希菌O157:H7的存活時(shí)間更長[23],平均持續(xù)時(shí)間可達(dá)56 d以上[24].Ingham等[25]發(fā)現(xiàn),在粉質(zhì)黏壤土中添加未經(jīng)堆肥處理的牛糞,大腸埃希菌O157:H7的存活時(shí)間可達(dá)90 d以上,是對照組的兩倍.Solomon等[19]的實(shí)驗(yàn)結(jié)果也證明,施用含有大腸埃希菌O157:H7的糞肥后,可在生菜中檢測到病原菌的內(nèi)生化,且大腸埃希菌O157:H7可在植物體內(nèi)長距離移動,葉片中也檢出病原菌的存在.Looper等[26]用牛尾草做實(shí)驗(yàn),施用大腸埃希菌O157:H7污染的糞肥,4 d便可檢測到病原菌內(nèi)生化的現(xiàn)象.

      1.3 昆蟲傳播

      引起農(nóng)產(chǎn)品中大腸埃希菌O157:H7污染的來源還可能是一些昆蟲的媒介活動,其傳播范圍廣,且具有不定向性,從而增加了病原菌植物內(nèi)生化的傳播途徑和范圍[27].攜帶病原菌的昆蟲與植物體反復(fù)接觸以及植物體表面損傷共同作用,是導(dǎo)致蔬菜污染并引發(fā)食源性疾病的重要原因.Talley等[28]的研究結(jié)果表明,家蠅可以攜帶大腸埃希菌O157:H7,污染生長的菠菜和生菜.也有實(shí)驗(yàn)表明,果蠅唇瓣環(huán)溝處是大腸埃希菌O157:H7的主要聚集處,其攜帶病原菌時(shí)間可長于7 d;將攜帶大腸埃希菌O157:H7的果蠅與蘋果接觸,15 h后可在蘋果內(nèi)部檢測到大腸埃希菌O157:H7的存在;另外,雌性果蠅將產(chǎn)卵器插入植物表皮以下進(jìn)行產(chǎn)卵時(shí),可將大腸埃希菌O157:H7帶入蘋果中,增大了食用風(fēng)險(xiǎn)[29].

      2 大腸埃希菌O157:H7植物內(nèi)生化途徑

      細(xì)菌侵襲宿主細(xì)胞主要有2種機(jī)制[30]:一種是細(xì)菌配體與細(xì)胞相應(yīng)受體結(jié)合后,細(xì)菌被宿主細(xì)胞膜包裹而攝入,被稱為“拉鏈(zipper)”機(jī)制;另一種是細(xì)菌依賴TTSS(typeⅢsecretion/translocation systems)系統(tǒng)將效應(yīng)蛋白轉(zhuǎn)運(yùn)至宿主細(xì)胞,并通過“觸發(fā)(trigger)”機(jī)制誘導(dǎo)細(xì)菌進(jìn)入宿主細(xì)胞.這些效應(yīng)蛋白可誘導(dǎo)細(xì)胞骨架重排,導(dǎo)致“巨吞飲”,促使細(xì)菌入侵.但眾多研究結(jié)果表明,病原菌無法利用這種機(jī)制進(jìn)入植物體內(nèi),所以大多通過植物天然孔道和受損部位進(jìn)入植物體內(nèi)[31].

      氣孔作為葉片重要組成部分,其活動由其周邊的保衛(wèi)細(xì)胞調(diào)節(jié),在生理上具有重要的意義,是植物碳同化、呼吸、蒸騰等代謝作用中空氣和水蒸氣的通路,同樣也是植物地上部分病原菌最易入侵的天然通道[32].相關(guān)研究已證明,大腸埃希菌O157:H7可通過氣孔進(jìn)入生菜和菠菜植株中[33-35].Er i c k s on等[36]的研究發(fā)現(xiàn),在噴霧灌溉條件下大腸埃希菌O157:H7在葉片背面聚集更多,數(shù)量顯著高于葉片正面;在光照條件下葉片正面水分更易揮發(fā),溫度更高,不利于病原菌適應(yīng)環(huán)境.而陸生植物葉片氣孔多數(shù)分布在葉片背面,這也就相應(yīng)地為病原菌內(nèi)生化提供了條件.

      根系為植株提供物理支撐的同時(shí),也是營養(yǎng)吸收的主要來源,是植株必不可少的結(jié)構(gòu).根系隨植株的生長不斷向土壤延伸,與土壤直接接觸并產(chǎn)生表面磨損,使得病原菌更易進(jìn)入土壤根系.對比土壤栽種和營養(yǎng)液培養(yǎng)發(fā)現(xiàn),植物在土壤中栽培時(shí),大腸埃希菌O157:H7更易發(fā)生植物內(nèi)生化現(xiàn)象[21].通過顯微鏡觀察發(fā)現(xiàn),大腸埃希菌O157:H7通過侵入擬南芥根系的側(cè)根發(fā)生處從而進(jìn)入植物體[37].亦有相關(guān)實(shí)驗(yàn)證明,大腸埃希菌O157:H7可從污染土壤中進(jìn)入植物根部,再從植物內(nèi)部遷移至地上部分[19].另外,在離根軸表面數(shù)毫米之內(nèi)的根際微域土區(qū),植物根系不斷地分泌各種代謝產(chǎn)物,為微生物的生命活動提供了源源不斷的營養(yǎng)源[38].Ibekwe等[39]的實(shí)驗(yàn)發(fā)現(xiàn),在大腸埃希菌O157:H7污染的土壤中,根際土壤中的病原菌濃度顯著高于非根際土壤.

      同樣,大腸埃希菌O157:H7也可通過表皮損傷進(jìn)入植物體內(nèi),例如物理損傷和生物損傷.植物體表面損傷,甚至是肉眼不可見的損傷,也可為大腸埃希菌O157:H7的侵入和繁殖創(chuàng)造條件.有實(shí)驗(yàn)表明,在人為割傷或黃桿菌造成生物損傷的葉片上澆灌含有大腸埃希菌O157:H7的水后,10 d內(nèi)可持續(xù)檢測到植物體內(nèi)大腸埃希菌O157:H7的存在[40].也有研究者發(fā)現(xiàn),割傷部位會分泌出傷流液,其中的一些成分會為病原菌的生長提供營養(yǎng)物質(zhì),傷口部位也為病原菌進(jìn)入植物體內(nèi)開辟了通道.如大腸埃希菌O157:H7易附著在生菜葉[41]、蘋果[42]的割傷部位繁殖.

      3 大腸埃希菌O157:H7與宿主植物間的相互作用

      大腸埃希菌O157:H7進(jìn)入植物體后,宿主植物雖未表現(xiàn)出表觀的病變,但仍與病原菌在內(nèi)部發(fā)生相互作用,而這些相互作用的程度決定了大腸埃希菌O157:H7植物內(nèi)生化的程度.

      3.1 植物先天免疫反應(yīng)

      在植物與病原菌協(xié)同進(jìn)化過程中,也逐漸形成了一系列復(fù)雜高效的保護(hù)機(jī)制來抵御病原菌的侵染.宿主植物體內(nèi)存在一系列植物模式識別受體(pattern recognition receptors,PRRs)可識別病原菌鞭毛蛋白、肽聚糖、脂多糖等相關(guān)分子模式(pathogen associated molecular patterns,PAMPs),以迅速觸發(fā)基礎(chǔ)免疫,包括超敏反應(yīng)、活性氧爆發(fā)、植物抗毒素的產(chǎn)生以及一些抗病相關(guān)基因的表達(dá).此類防御反應(yīng)可以有效地抑制病原菌的生長和移動,控制病情[43-44].大腸埃希菌O1 5 7:H7具有許多病原菌相關(guān)分子模式,可被宿主植物先天免疫系統(tǒng)識別;有相關(guān)實(shí)驗(yàn)證明,消除這類病原菌相關(guān)分子模式可增加大腸埃希菌O157:H7植物內(nèi)生化的數(shù)量[45].

      3.2 效應(yīng)因子蛋白對植物先天免疫反應(yīng)的抑制

      研究發(fā)現(xiàn),植物病原菌可分泌特殊的效應(yīng)因子蛋白(effector proteins)進(jìn)入植物的細(xì)胞質(zhì)中與宿主蛋白發(fā)生作用,通過影響信號傳導(dǎo)來抑制植物模式識別受體(pattern recognition receptors,PRRs)對病原菌的識別,從而降低植物對外來侵入病原體的免疫作用,使得病原體在植物體內(nèi)大量積累[4647].而人畜共患病原菌是否存在這種機(jī)制抑制宿主植物的免疫效應(yīng)還有待更多實(shí)驗(yàn)來證明.但通過基因分析發(fā)現(xiàn),大腸埃希菌中多數(shù)與致病基因相關(guān)的編碼效應(yīng)因子蛋白的基因與植物病原菌中的基因相似,即可能會存在不同物種間基因的水平轉(zhuǎn)移,且人畜共患病原菌可適應(yīng)相當(dāng)廣范圍的宿主植物內(nèi)環(huán)境也可能與此有關(guān)[48].值得一提的是,人畜共患病原菌或可分泌效應(yīng)蛋白直接作用于宿主細(xì)胞,刺激宿主細(xì)胞合成糖轉(zhuǎn)運(yùn)蛋白,分泌單糖到質(zhì)外體空間,為病原菌的生長提供營養(yǎng)條件[49].

      3.3 效應(yīng)因子蛋白觸發(fā)的免疫反應(yīng)

      宿主植物細(xì)胞可對病原菌分泌的效應(yīng)因子蛋白進(jìn)行檢測,這種效應(yīng)觸發(fā)免疫力是宿主植物針對病原微生物效應(yīng)因子蛋白進(jìn)化出的反擊機(jī)制:通過直接或間接識別病原菌分泌的某些抗性效應(yīng)因子蛋白,在侵染位點(diǎn)啟動快速劇烈的防御應(yīng)答,來抑制病原菌植物內(nèi)生化[44,50].目前暫無相關(guān)實(shí)驗(yàn)數(shù)據(jù)表明這種宿主植物對病原菌效應(yīng)因子蛋白的識別作用在植物體與人畜共患病原菌間發(fā)生,但進(jìn)一步的研究也可能會選育出抗人畜共患病原菌的作物品種.

      4 大腸埃希菌O157:H7與其他微生物間的交互作用

      4.1 附生植物微生物群落

      大腸埃希菌O157:H7可進(jìn)入植物體內(nèi),附生植物微生物的存在同樣影響著大腸埃希菌O157:H7植物內(nèi)生化的程度和存活時(shí)間.人畜共患病原菌若要在植物表面或植物體內(nèi)寄居,必須與存在于植物表面或內(nèi)部的微生物群落進(jìn)行競爭.植物體的附生微生物和外來入侵的病原菌之間存在著對生存空間和營養(yǎng)物質(zhì)的爭奪,且附生微生物的代謝產(chǎn)物可抑制病原菌的內(nèi)生化與生長[16,51].如Lopez-Velasco等[52]的研究發(fā)現(xiàn),歐文菌對大腸埃希菌O157:H7生長的抑制不僅表現(xiàn)在對碳源的爭奪上,其代謝產(chǎn)物也可顯著抑制大腸埃希菌的生長速率.

      與此相反,附生植物微生物對大腸埃希菌O157:H7植物內(nèi)生化亦有促進(jìn)作用.存在于植物體內(nèi)的其他細(xì)菌或真菌具有分解細(xì)胞壁上聚合物的能力,大腸埃希菌O157:H7或可利用這些被分解后的小分子物質(zhì)完成自己的營養(yǎng)攝?。?1].同時(shí),植物病原菌會對植物體表面造成損傷,以傷口為中心的微環(huán)境恰好為大腸埃希菌O157:H7的繁殖提供了條件.另有研究發(fā)現(xiàn),大腸埃希菌O157:H7的植物內(nèi)生化有時(shí)是與其他一種或多種腸桿菌屬或假單胞菌屬的細(xì)菌共同侵入的結(jié)果,與附生微生物的共同侵入提高了病原菌侵入后的生長水平[50,53].

      4.2 根際土壤微生物群落

      根際環(huán)境土壤p H值、氧化還原電位、養(yǎng)分濃度和微生物活性的變化等均與土體土壤有明顯差異,根系分泌物則決定了根際微生物的種類和活性[38].根際微生物群落對病原菌植物內(nèi)生化影響較為復(fù)雜和多變,目前研究還較少.已發(fā)現(xiàn)的抑制大腸埃希菌O157:H7生長的細(xì)菌有假單胞菌、歐文菌、不動桿菌、微小桿菌和芽孢桿菌等[36].植物病原菌侵染根部可破壞細(xì)胞膜透性,使細(xì)胞內(nèi)化合物以擴(kuò)散方式釋放至根際[54].從營養(yǎng)物質(zhì)獲取層面上而言,這有益于大腸埃希菌O157:H7的營養(yǎng)物質(zhì)獲取.最新研究發(fā)現(xiàn),土壤中大腸埃希菌O157:H7的存活時(shí)間與微生物生物量碳和土壤氮含量間呈顯著正相關(guān),而與土壤綠彎菌的豐度呈顯著負(fù)相關(guān)[5].病原菌侵染根部將導(dǎo)致根的分泌作用加強(qiáng),根際周圍微生物種群數(shù)量增加,使得病原菌與根際微生物群落間的交互作用更為復(fù)雜[55].因此,更多的有關(guān)根系分泌物、土著微生物種類、土壤類型等因素對病原菌存活及進(jìn)入植物體的影響有待進(jìn)一步研究.

      5 前景與展望

      目前,無論是病原菌植物內(nèi)生化路徑跟蹤監(jiān)測水平,還是人們對內(nèi)生菌遺傳特性及內(nèi)生菌與宿主之間關(guān)系的了解來看,內(nèi)生菌相關(guān)研究都處于初級階段.特別是內(nèi)生菌與宿主關(guān)系方面,有許多值得深入探討的地方.比如內(nèi)生菌增強(qiáng)宿主生存的適應(yīng)性的相關(guān)機(jī)制,內(nèi)生菌與宿主交互過程等,均需要進(jìn)一步研究.大腸埃希菌O157:H7植物內(nèi)生化程度受土壤種類、病原菌濃度、植株種類和品種、植株生長水平等多種因素影響,近年來逐漸引起公眾的注意.更細(xì)致化地了解其內(nèi)生化機(jī)制將有助于對大腸埃希菌O157:H7植物內(nèi)生化的控制,從而減少人類食用生鮮農(nóng)產(chǎn)品的風(fēng)險(xiǎn),更加有效地預(yù)防大腸埃希菌O157:H7給人類造成的危害.

      (References):

      [1] 毛雪丹,胡俊峰,劉秀梅.微生物性食源性疾病流行病學(xué)負(fù)擔(dān)研究方法與應(yīng)用.中華預(yù)防醫(yī)學(xué)雜志,2010,44(6):546-549. Mao X D,Hu J F,Liu X M.Method and application of the epidemiological burden on foodborne diseases caused by microorganism.Chinese Journal of Preventive Medicine,2010,44(6):546-549.(in Chinese)

      [2] 王燕,謝貴林,杜琳.大腸桿菌O157:H7感染流行概況.微生物學(xué)免疫學(xué)進(jìn)展,2008,36(1):51-58.

      Wang Y,Xie G L,Du L.Review of infectious and epidemiological characteristics of Escherichia coli O157:H7. Progress in Microbiology and Immunology,2008,36(1):51-58.(in Chinese)

      [3] Zhang T X,Wang H Z,Wu L S,et al.Survival of Escherichia coli O157:H7 in soils from Jiangsu Province,China.PLoS ONE,2013,8(12):e81178.

      [4] Yao Z Y,Wei G,Wang H Z,et al.Survival of Escherichia coli O157:H7 in soils from vegetable fields with different cultivation patterns.Applied and Environmental Microbiology,2013,79(5):1755-1756.

      [5] Wang H Z,Ibekwe A M,Ma J C,et al.A glimpse of Escherichia coli O157:H7 survival in soils from eastern China.Science of the Total Environment,2014,476:49-56.

      [6] Franz E,Semenov A V,Termorshuizen A J,et al.Manureamended soil characteristics affecting the survival of E.coli O157:H7 in 36 Dutch soils.Environmental Microbiology,2008,10(2):313-327.

      [7] Patel J,Millner P,Nou X,et al.Persistence of enterohaemorrhagic and nonpathogenic E.coli on spinach leaves and in rhizosphere soil.Journal of AppliedMicrobiology,2010,108(5):1789-1796.

      [8] Berger C N,Sodha S V,Shaw R K,et al.Fresh fruit and vegetables as vehicles for the transmission of human pathogens.Environmental Microbiology,2010,12(9):2385-2397.

      [9] Gurtler J B,Douds Jr D D,Dirks B P,et al.Salmonella and Escherichia coli O157:H7 survival in soil and translocation into leeks(Allium porrum)as influenced by an arbuscular mycorrhizal fungus(Glomus intraradices).Applied and Environmental Microbiology,2013,79(6):1813-1820.

      [10] Marilyn C E,Jean L,Alison S P,et al.Preharvest internalization of Escherichia coli O157:H7 into lettuce leaves,as affected by insect and physical damage.Journal of Food Protection,2010,73(10):1809-1816.

      [11] Erickson M C,Webb C C,Davey L E,et al.Internalization and fate of Escherichia coli O157:H7 in leafy green phyllosphere tissue using various spray conditions.Journal of Food Protection,2014,77(5):713-721.

      [12] Schikora A,Carreri A,Charpentier E,et al.The dark side of the salad:Salmonella typhimurium overcomes the innate immune response of Arabidopsis thaliana and shows an Endo pathogenic lifestyle.PLoS ONE,2008,3(5):e2279.

      [13] 石晶盈,陳維信,劉愛媛.植物內(nèi)生菌及其防治植物病害的研究進(jìn)展.生態(tài)學(xué)報(bào),2006,26(7):2395-2401. Shi J Y,Chen W X,Liu A Y.Advances in the study of endophytes and their effects on control of plant disease.Acta Ecologica Sinica,2006,26(7):2395-2401.(in Chinese with English abstract)

      [14] 李阜棣,胡正嘉.微生物學(xué).北京:中國農(nóng)業(yè)出版社,2007:318-320. Li F D,Hu Z J.Microbiology.Beijing:China Agriculture Press,2007:318-320.(in Chinese)

      [15] 耿銳梅,張建萍,余柳青.植物病原菌毒素的種類、作用機(jī)理和應(yīng)用前景.浙江農(nóng)業(yè)學(xué)報(bào),2007,19(5):393-398. Geng R M,Zhang J P,Yu L Q.The kinds,action mechanism of pathotoxin and its application prospect.Acta Agriculturae Zhejiangensis,2007,19(5):393-398.(in Chinese with English abstract)

      [16] Liao C H,F(xiàn)ett W F.Analysis of native microflora and selection of strains antagonistic to human pathogens on fresh produce.Journal of Food Protection,2001,64(8):1110-1115.

      [17] Dev V J,Main M,Gould I.Waterborne outbreak of Escherichia coli O157.Journal of Applied Microbiology Symposium Supplement,2000,88(S1):124-132.

      [18] Warriner K,Ibrahim F,Dickinson M,et al.Interaction of Escherichia coli with growing salad spinach plants.Journal of Food Protection,2003,66(10):1790-1797.

      [19] Solomon E B,Yaron S,Matthews K R.Transmission of Escherichia coli O157:H7 from contaminated manure and irrigation water to lettuce plant tissue and its subsequent internalization.Applied and Environmental Microbiology, 2002,68(1):397-400.

      [20] Barker-Reid F,Harapas D,Engleitner S,et al.Persistence of Escherichia coli on injured iceberg lettuce in the field,overhead irrigated with contaminated water.Journal of Food Protection,2009,72(3):458-464.

      [21] Macarisin D,Patel J,Sharma V K.Role of curli and plant cultivation conditions on Escherichia coli O157:H7 internalization into spinach grown on hydroponics and in soil.International Journal of Food Microbiology,2014,173:48-53.

      [22] Penteado A L,Eblen B S,Miller A J.Evidence of Salmonella internalization into fresh mangos during simulated postharvest insect disinfestation procedures. Journal of Food Protection,2004,67(1):181-184.

      [23] Islam M,Doyle M P,Phatak S C,et al.Survival of Escherichia coli O157:H7 in soil and on carrots and onions grown in fields treated with contaminated manure composts or irrigation water.Food Microbiology,2005,22(1):63-70.

      [24] Johannessen G S,Bengtsson G B,Heier B T,et al. Potential uptake of Escherichia coli O157:H7 from organic manure into Crisphead lettuce.Applied and Environmental Microbiology,2005,71(5):2221-2225.

      [25] Ingham S C,Losinski J A,Andrews M P,et al.Escherichia coli contamination of vegetables grown in soils fertilized with non-composted bovine manure:Garden-scale studies. Applied and Environmental Microbiology,2004,70(11):6420-6427.

      [26] Looper M L,Edrington T S,Callaway T R,et al.Fate of Escherichia coli O157:H7 and Salmonella from contaminated manure slurry applied to soil surrounding tall fescue.Letters in Applied Microbiology,2009,48(5):513-516.

      [27] 徐正濤,周振濤,丁強(qiáng).贛榆縣常見蠅類攜帶病原菌及其耐藥狀況研究.醫(yī)學(xué)動物防制,2011,27(12):1082-1085. Xu Z T,Zhou Z T,Ding Q.Study on the pathogenic bacteria carries status of flies and antibiotic resistance of Ganyu. Chinese Journal of Pest Control,2011,27(12):1082-1085.(in Chinese with English abstract)

      [28] Talley J L,Wayadande A C,Wasala L P,et al.Association of Escherichia coli O157:H7 with filth flies(Muscidae and Calliphoridae)captured in leafy greens fields and experimental transmission of E.coli O157:H7 to spinach leaves by house flies(Diptera:Muscidae).Journal of Food Protection,2009,72(7):1547-1552.

      [29] Sela S,Nestel D,Pinto R,et al.Mediterranean fruit fly as a potential vector of bacterial pathogens.Applied and Environmental Microbiology,2005,71(7):4052-4056.

      [30] 王雪琴,周道國.沙門菌侵襲研究進(jìn)展.微生物與感染,2009,4(2):124-128. Wang X Q,Zhou D G.Research progress on the invasion of Salmonella typhimurium.Journal of Microbes and Infection,2009,4(2):124-128.(in Chinese)

      [31] Kroupitski Y,Golberg D,Belausov E,et al.Internalizationof Salmonella enterica in leaves is induced by light and involves chemotaxis and penetration through open stomata. Applied and Environmental Microbiology,2009,75(19):6076-6086.

      [32] Zeng W Q,Melotto M,He S Y.Plant stomata:A checkpoint of host immunity and pathogen virulence.Current Opinion in Biotechnology,2010,21(5):599-603.

      [33] Gomes C,Da Silva P,Moreira R G,et al.Understanding E.coli internalization in lettuce leaves for optimization of irradiation treatment.International Journal of Food Microbiology.2009,135(3):238-247.

      [34] Salda?a Z,Sánchez E,Xicohtencatl-Cortes J,et al.Surface structures involved in plant stomata and leaf colonization by Shiga-toxigenic Escherichia coli O157:H7.Frontiers in Microbiology,2011,119(2):1-9.

      [35] Xicohtencatl-Cortes J,Sanchez C E,Saldana Z,et al. Interaction of Escherichia coli O157:H7 with leafy green produce.Journal of Food Protection,2009,72(7):1531-1537.

      [36] Erickson M C,Webb C C,Diaz-Perez J C,et al.Surface and internalized Escherichia coli O157:H7 on field-grown spinach and lettuce treated with spray-contaminated irrigation water. Journal of Food Protection,2010,73(6):1023-1029.

      [37] Cooley M B,Miller W G,Mandrell R E.Colonization of Arabidopsis thaliana with Salmonella enterica and enterohemorrhagic Escherichia coli O157:H7 and competition by Enterobacter asburiae.Applied and Environmental Microbiology,2003,69(8):4915-4926.

      [38] 朱麗霞,章家恩,劉文高.根系分泌物與根際微生物相互作用研究綜述.生態(tài)環(huán)境,2003,12(1):102-105. Zhu L X,Zhang J E,Liu W G.Review of studies on interactions between root exudates and rhizospheric microorganism.Ecology and Environment,2003,12(1):102-105.(in Chinese)

      [39] Ibekwe A M,Watt P M,Shouse P J,et al.Fate of Escherichia coli O157:H7 in irrigation water on soils and plants as validated by culture method and real-time PCR. Canadian Journal of Microbiology,2004,50(12):1007-1014.

      [40] Aruscavage D,Miller S A,Ivey M L,et al.Survival and dissemination of Escherichia coli O157:H7 on physically and biologically damaged lettuce plants.Journal of Food Protection,2008,71(12):2384-2388.

      [41] Seo K H,F(xiàn)rank J F.Attachment of Escherichia coli O157:H7 to lettuce leaf surface and bacterial viability in response to chlorine treatment as demonstrated by using confocal scanning laser microscopy.Journal of Food Protection,1999,62(1):3-9.

      [42] Janisiewicz W J,Conway W S,Brown M W,et al.Fate of Escherichia coli O157:H7 on fresh-cut apple tissue and its potential for transmission by fruit flies.Applied and Environmental Microbiology,1999,65(1):1-5.

      [43] Ausubel F M.Are innate immune signaling pathways in plants and animals conserved?Nature Immunology,2005,6(10):973-979.

      [44] 陳英,譚碧玥,黃敏仁.植物天然免疫系統(tǒng)研究進(jìn)展.南京林業(yè)大學(xué)學(xué)報(bào):自然科學(xué)版,2012,36(1):129-136. Chen Y,Tan B Y,Huang M R.Recent advances in plant immune system.Journal of Nanjing Forestry University:Natural Science Edition,2012,36(1):129-136.(in Chinese with English abstract)

      [45] Iniguez A L,Dong Y,Carter H D,et al.Regulation of enteric endophytic bacterial colonization by plant defenses. Molecular Plant-Microbe Interactions,2005,18(2):169-178.

      [46] Wu Y,Wood M D,Tao Y,et al.Direct delivery of bacterial avirulence proteins into resistant Arabidopsis protoplasts leads to hypersensitive cell death.Plant Journal,2003,33(1):131-137.

      [47] Jones J D G,Dangl J L.The plant immune system.Nature,2006,444(7117):323-329.

      [48] Tobe T,Beatson S A,Taniguchi H,et al.An extensive repertoire of typeⅢsecretion effectors in Escherichia coli O157 and the role of lambdoid phages in their dissemination. Proceedings of the National Academy of Sciences,2006,103(40):14941-14946.

      [49] Chen L,Hou B,Lalonde S,et al.Sugar transporters for intercellular exchange and nutrition of pathogens.Nature,2010,468(7323):527-532.

      [50] Cooley M B,Chao D,Mandrell R E.Escherichia coli O157:H7 survival and growth on lettuce is altered by the presence of epiphytic bacteria.Journal of Food Protection,2006,69(10):2329-2335.

      [51] Brandl M T.Plant lesions promote the rapid multiplication of Escherichia coli O157:H7 on postharvest lettuce.Applied and Environmental Microbiology,2008,74(17):5285-5289.

      [52] Lopez-Velasco G,Tydings H A,Boyer R R,et al. Characterization of interactions between Escherichia coli O157:H7 with epiphytic bacteria in vitro and on spinach leaf surfaces.International Journal of Food Microbiology,2012,153(3):351-357.

      [53] Johnston M A,Harrison M A,Morrow R A.Microbial antagonists of Escherichia coli O157:H7 on fresh-cut lettuce and spinach.Journal of Food Protection,2009,72(7):1569-1575.

      [54] Martha C H,Gilberto C R,Xiong Z G,et al.Roles of root border cells in plant defense and regulation of rhizosphere microbial populations by extracellular DNA‘trapping’. Plant and Soil,2012,355(1/2):1-16.

      [55] Pawel B,Chian K,Paul S L.Not a peripheral issue:secretion in plant-microbe interactions.Current Opinion in Plant Biology,2010,13(4):378-387.

      Progress of researches on the internalization of Escherichia coli O127:H7 in plant tissues.Journal of
      Zhej iang University(Agric.&Li fe Sci.),2015,41(1):82-88

      Yang Li?,Wang Haizhen?*,Yao Zhiyuan,Wu Jianjun(Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition,Institute of Soil and Water Resource and Environmental Science,College of Environment &Resource Sciences,Zhejiang University,Hangzhou 310058,China)

      Escherichia coli O157:H7;plant;internalization

      X 171;R 378.2

      A

      10.3785/j.issn.1008-9209.2014.07.212

      國家自然科學(xué)基金資助項(xiàng)目(40971255).

      汪海珍,Tel:+86 571 88982063;E-mail:mywhz@163.com

      聯(lián)系方式:楊黎,E-mail:chengche0808@163.com;汪海珍,E-mail:mywhz@163.com.?為共同第一作者

      2014 07 21;接受日期(Accepted):2014 10 31;

      日期(Published online):2015 01 19 URL:http://www.cnki.net/kcms/detail/33.1247.S.20150119.1659.008.html

      猜你喜歡
      植物體埃希菌根際
      初中生物學(xué)概念系統(tǒng)化內(nèi)生的實(shí)踐
      根際微生物對植物與土壤交互調(diào)控的研究進(jìn)展
      高中生物穿膜問題的突破
      黃花蒿葉水提物對三七根際尖孢鐮刀菌生長的抑制作用
      植物體上的斐波那契數(shù)列
      促植物生長根際細(xì)菌HG28-5對黃瓜苗期生長及根際土壤微生態(tài)的影響
      中國蔬菜(2016年8期)2017-01-15 14:23:38
      植物體細(xì)胞雜交技術(shù)知識歸納及試題分析
      522例產(chǎn)ESBLs大腸埃希菌醫(yī)院感染的耐藥性和危險(xiǎn)因素分析
      產(chǎn)β-內(nèi)酰胺酶大腸埃希菌的臨床分布及耐藥性分析
      尿液大腸埃希菌和肺炎克雷伯菌I類整合子分布及結(jié)構(gòu)研究
      长乐市| 佛教| 清涧县| 雷山县| 湾仔区| 义乌市| 漳浦县| 田东县| 太仆寺旗| 德化县| 通州区| 泰和县| 九江县| 阿瓦提县| 枝江市| 弥渡县| 桑日县| 秦皇岛市| 吉水县| 深圳市| 灵璧县| 尖扎县| 哈巴河县| 子长县| 汶川县| 会同县| 仙桃市| 应城市| 大宁县| 梨树县| 罗江县| 祥云县| 本溪市| 元谋县| 黔西县| 文化| 普宁市| 镇江市| 怀集县| 都兰县| 瓦房店市|