植物内生菌及其防治植物病害的研究进展

综述了植物内生菌及其防治植物病害的研究进展.植物内生菌分布广,种类多,几乎存在于所有目前已研究过的陆生及水生植物中,目前全世界至少已在80个属290多种禾本科植物中发现有内生真菌,在各种农作物及经济作物中发现的内生细菌已超过120种.感染内生菌的植物宿主往往具有生长快速、抗逆境、抗病害、抗动物危害等优势,比未感染内生菌的植株更具生存竞争力.植物内生菌的防病机理主要表现在通过产生抗生素类,水解酶类,植物生长调节剂和生物碱类物质,与病原菌竞争营养物质,增强宿主植物的抵抗力以及诱导植物产生系统抗性等途径抑制病原菌生长.另外,对植物内生真菌和内生细菌的分离、筛选和检测方法;利用植物内生菌控制植物病害的途径如人工接种内生菌,利用内生菌代谢产生的抗生素以及将内生菌作为基因工程的载体菌等进行了综述.同时,对植物内生菌作为生物防治因子未来发展前景及存在的问题进行了讨论.利用植物内生菌作为生物防治因子进行大田防病,需要考虑它的病理学、生态学和形态学等方面的影响.     

植物内生菌研究及其科学意义

植物内生菌是近三十年来在国内外迅速受到关注的微生物类群,研究的角度不同,概念也比较混乱。本文就植物内生菌研究及其科学意义进行了综述和讨论。植物内生菌在国外广受关注,始于禾本科植物内生真菌以及林木内生真菌的特殊作用。产紫杉醇的红豆杉内生真菌被报道后,植物内生菌研究在生理活性物质领域开始暴发式的增加。通过对一年生草本植物、多年生草本植物、木本植物和藤本植物各部位的内生微生物的比较和分析,总结了植物内生菌的一些共性和特殊性,指出了植物内生菌研究的一些发展趋势。本文探讨植物内生菌对地球上的微生物物种总量的贡献。提出"植物体在自然界的实际生存状态实际上是微生物和植物的状态"的观点,导出植物育种实际上是"植物和微生物的共生体的培育"的观点。还讨论了植物内生菌对生态学、生物学、微生物的进化和物种形成、内生菌/宿主的联合代谢、以及植物保护学、畜牧兽医学、林学等领域的意义和影响。本文认为,植物内生菌研究打开了微生物资源的一个新局面,将在多个领域中产生更广泛的影响。植物内生菌研究的真正意义不仅在于其生态独特性,更在于微生物在宿主体内和宿主植物的协同作用及协同作用所产生的新功能和新物质。     

管叶槽舌兰新鲜及硅胶干燥根样内生菌多样性研究

管叶槽舌兰(Holcoglossum kimballianum)是一种珍稀濒危兰科植物,其野生种群亟需保护。内生菌对兰科植物的生长发育至关重要,为评估管叶槽舌兰内生菌的多样性、分析采样方式对其内生菌的影响,该文采用高通量测序技术对迁地保育状态下新鲜与硅胶干燥的管叶槽舌兰根内生菌进行研究。结果表明:(1)新鲜及干燥管叶槽舌兰根内生菌物种组成明显不同,管叶槽舌兰内生真菌注释到6门46科51属,内生细菌注释到15门105科178属; 干燥后管叶槽舌兰根内生真菌注释到6门88科116属,内生细菌注释到21门154科336属。(2)迁地保育状态的管叶槽舌兰根样内生菌具有丰富的多样性,并且内生细菌群落丰富度和多样性远比内生真菌群落高; 经硅胶干燥后,内生真菌α多样性指数升高、β多样性指数降低,而内生细菌的α多样性指数降低、β多样性指数则升高。(3)差异显著性真菌黄盖小脆柄菇(Psathyrella candolleana)和刺盘孢属(Colletotrichum)的C. tofieldiae只存在于新鲜根样中,新鲜管叶槽舌兰差异显著性细菌是马赛菌属(Massilia),干燥根样中差异显著性细菌类群包括拜叶林克氏菌科(Beijerinckiaceae)、黄色杆菌科(Xanthobacteraceae)及慢生根瘤菌属(Bradyrhizobium)。(4)共发生网络分析显示,经干燥后管叶槽舌兰根样内生菌群落中占互作主导地位的优势物种和互作模式都发生了改变。综上认为,不同采样处理会影响管叶槽舌兰根内生菌的群落结构,在研究兰科植物根样内生菌时宜使用新鲜的根样。该研究结果为管叶槽舌兰野生种群保护及人工栽培提供了内生菌数据基础,也为兰科植物内生微生物采样方法提供了参考。     

植物内生放线菌的分离方法

植物内生放线菌是一类大有开发潜力的微生物资源。目前使用的分离条件和技术尚不完善,容易被外源菌和内生真菌、细菌污染,因此内生放线菌尤其是稀有内生放线菌的选择性分离技术至少是今后一段时间研究的重点。介绍了植物内生放线菌选择性分离方法并提出值得研究的问题。     

植物内生菌是有待深入开发的资源宝库

植物内生菌是指那些在其生活史的一定阶段或者全部阶段生活于健康植物各种组织和器官内部的真菌或者细菌,被感染的宿主植物(至少是暂时)不表现出外在症状。在长期的协同进化过程中,大部分植物内生菌都与植物形成了互惠互利的关系,在从宿主那里获得稳定的生活环境的同时,可增强或赋予宿主抗病、抗干旱、固氮等能力,或通过其代谢产物促进植物的生长;有些内生菌还被发现能够产生与宿主相同或相似的活性物质。因此对植物内生菌的研究从20     

植物内生细菌对植物健康的作用

植物内生菌是一个多样性十分丰富的微生物类群,存在于没有外在感染症状的健康植物组织内,并与宿主植物协同进化.随着研究领域的不断拓宽和研究方法的不断更新,植物内生菌与植物健康的关系以及应用逐渐成为研究热点.本文主要综述了内生细菌的多样性、进入植物组织内的机制以及内生细菌的主要功能及应用,提出了现阶段内生菌研究存在的问题,并展望了内生菌研究的前景.     

药用植物青蒿不同种类的内生菌抑菌活性分析

为了研究青蒿不同种类的内生菌抑制细菌和抑制真菌的活性,该研究采用组织块法和研磨法从青蒿的根、茎、叶中分离内生细菌、放线菌和真菌,以大肠埃希菌(Escherichia coli)(CICC 23657)、枯草芽孢杆菌(Bacillus subtilis)(CICC 10275)、金黄色葡萄球菌(Staphylococcus aureus)(CICC 10384)、黑曲霉(Aspergillus niger)(CICC 2487)、酿酒酵母(Saccharomyces cerevisiae)(CICC 33032)为指示菌,采用琼脂块法和双层平板法检测内生菌的抑菌活性。结果表明:(1)从青蒿植株中共分离到76株内生菌,其中内生细菌19株、内生放线菌34株、内生真菌23株。从分离部位来看,56株来自于茎段、17株来自于根段、3株来自叶片。(2)内生细菌中抑菌活性菌株占总菌株的比例最高,为95%,内生放线菌和内生真菌中抑菌活性菌株的比例分别为41%、35%。(3)内生细菌的抗菌谱较广;虽然内生放线菌的抗菌谱较窄,但其中高抗菌株较多,尤其对酿酒酵母的抑菌效果好。综上结果显示,药用植物青蒿中存在着丰富的有抑菌活性的内生菌,且不同种类的内生菌抑菌活性不同。     

植物内生放线菌的分离方法*

植物内生放线菌是一类大有开发潜力的微生物资源。目前使用的分离条件和技术尚不完善,容易被外源菌和内生真菌、细菌污染,因此内生放线菌尤其是稀有内生放线菌的选择性分离技术至少是今后一段时间研究的重点。介绍了植物内生放线菌选择性分离方法并提出值得研究的问题。     

中国种子植物内生真菌资源及菌植协同进化

综述了中国种子植物内生真菌资源研究概况,比较了裸子植物和被子植物内生真菌种类,它们都具有肉座菌目(Hypocreales),粪壳菌目(Sordariales),散囊菌目(Eurotiales),毛霉目(Mucorales)及不产孢类(Myceliasterilia)内生真菌。裸子植物内生真菌涉及52个属,既包括高等的子囊菌和担子菌,也包括低等的卵菌(Oomycetes)和接合菌(Zygomycetes)类。被子植物涉及60个属,主要为高等的子囊菌(Ascomycetes)和担子菌(Basidiomycetes),低等的卵菌和接合菌报道很少。双子叶植物涉及40个属,单子叶植物内生真菌涉及30个属,两类被子植物所报道的内生真菌只有11个属相同。裸子植物与双子叶植物内生真菌相似程度较高,都具有炭角菌目(Xylariales)、格孢腔菌目(Pleosporales)、柔膜菌目(Helotiales)和白粉菌目(Erysiphales),刺盘孢菌属(Colletotrichum)、拟茎点霉属(Phomopsis)、枝孢霉属(Cladosporium)、地霉属(Geotrichum)等内真菌,共20个属相同。各类种子植物具有自己独特的一些内生真菌。还对植物与其内生真菌的协同进化关系进行了分析。     

药用植物内生真菌研究进展

药用植物内生真菌具有抗肿瘤、抗菌、抗病毒、抗氧化等活性,能够产生植物生长素、细胞激动素、赤霉素等促植物生长物质促进植物生长,从而使研究药用植物内生真菌成为寻找新型拮抗菌、抗肿瘤、抗氧化活性药物的重要资源。本文对药用植物内生真菌的多样性、分离鉴定、产生的次生代谢产物及其功能等做一综述。     

禾草-内生真菌共生体在草地农业系统中的作用

综述了国内外近年对禾草 -内生真菌 (N eotyphodium)的研究进展。全世界现已报道 14种禾草内生真菌 ,与 2 3个属的禾草形成共生体 ,我国已在 13属 2 5种天然草地禾草中发现内生真菌 ,其中发草属 (Descampsia)、大麦属 (H ord eum)和赖草属(L eymus)以往在国际文献中未曾报道。内生真菌在禾草体内产生的生物碱 ,致使采食带菌禾草的马、牛、羊、鹿等家畜产生中毒症状 ,每年给美国、新西兰等国造成的经济损失达 6.4亿美元之多 ,对其毒理研究取得了进展。已发现我国醉马草 (Achnatheruminebrians)对家畜的毒性与内生真菌的侵染有关。内生真菌侵染增加可使禾草对 42种害虫的抗性 ,并可增加对某些线虫和病害的抗性。与不带菌禾草相比 ,带菌禾草的另一特点是抗逆性强 ,牧草产量高。国际在该领域的研究主要集中在多年生黑麦草(L olium p erenne)和高羊茅 (Festuca arundinacea)。我国的研究发现 ,带菌布顿大麦草 (H ordeum bodg anii)和圆柱披碱草(Elymus cylind ricus)的牧草产量分别增加 3 3 .3 %和 2 78.8% ,分孽数分别增加 13 6.8%和 84.5%。目前 ,国际研究的重点包括大规模开展内生真菌生物学与生态学特性的研究 ,创造不含对家畜有害毒素的有益禾草 -内生真菌共生体 ,培育带内生真菌的草坪草品种 ,培育抗毒     

The community of needle endophytes reflects the current physiological state of Norway spruce

This study investigated fungal endophytes in the needles of Norway spruce (Picea abies) cuttings in relation to host tree growth. We also determined the prevalence of endophytes in needles incubated for six months. The cuttings originated from clonal origins showing slow- and fast-growth in long-term field trials but the heritable differences in growth rate were not yet detected among the studied cutting. Endophytes were isolated from surface-sterilized needles with culture-free DNA techniques. No significant differences were observed between endophyte communities of slow- and fast-growing clonal origins. However, the endophyte community correlated with the current growth rate of cuttings suggesting that endophytes reflect short- rather than long-term performance of a host. The concentration of condensed tannins was similar in slow- and fast-growing clonal origins but it showed a negative relationship with endophyte species richness, implying that these secondary compounds may play an important role in spruce tolerance against fungal infections. More than a third of endophyte species were detected in both fresh and decomposing needles, indicating that many needle endophytes are facultative saprotrophs. Several potentially pathogenic fungal species were also found within the community of saprotrophic endophytes.     

An endophyte‐rich diet increases ant predation on a specialist herbivorous insect

1. All plants form symbioses with microfungi, known as endophytes, which live within plant tissues. Numerous studies have documented endophyte–herbivore antagonism in grass systems, but plant–endophyte–insect interactions are highly variable for forbs and woody plants. 2. The net effect of endophytes on insect herbivory may be modified by their interactions with higher trophic levels, such as predators. Including these multitrophic dynamics may explain some of the variability among endophyte studies of non‐grass plants, which are currently based exclusively on bitrophic studies. 3. The abundance of natural foliar endophytes in a Neotropical vine was manipulated and beetles were fed high or low endophyte diets. Experimental assays assessed whether dietary endophyte load affected beetle growth, leaf consumption, and susceptibility to ant predation. 4. Beetles feeding on high‐ versus low‐endophyte plants had almost identical growth and leaf consumption rates. 5. In a field bioassay, however, it was discovered that feeding on an endophyte‐rich diet increased a beetle's odds of capture by predatory ants nine‐fold. 6. Endophytes could thus provide an indirect, enemy‐mediated form of plant defence that operates even against specialist herbivores. We argue that a multitrophic approach is necessary to untangle the potentially diverse types of endophyte defence among plants.     

Consequences of simultaneous interactions of fungal endophytes and arbuscular mycorrhizal fungi with a shared host grass

Plants simultaneously associate with multiple microbial symbionts throughout their lifetimes. To address the question of whether the effects of simultaneous symbionts are contingent on the specific identities, we conducted a greenhouse experiment manipulating the presence and identities of arbuscular mycorrhizal fungi (AMF) and fungal endophytes on the shared host grass Elymus hystrix. Each plant host was inoculated with one of two AMF species having varying effects on host growth, or a sterile soil control. Further, we used naturally occurring endophyte‐infected (E+) and uninfected (E–) individuals from two populations of the endophyte Epichloë elymi that varied in their interaction with E. hystrix. We then measured responses of plants, AMF, and fungal endophytes. Overall, we found that the combined effects of AMF and fungal endophytes on plant growth were additive, reflecting the mutualistic quality of each symbiont independently interacting with host plants. However, fungal endophyte infection differentially altered hyphal colonization of the two AMF species and the identity of the coinfecting AMF species affected fungal endophyte fitness traits. The results of this study demonstrate that the outcome of interspecific symbiotic interactions varies with partner identity such that the effects of simultaneous symbioses can not be generalized.     

Do the costs and benefits of fungal endophyte symbiosis vary with light availability?

? Here, we examined whether fungal endophytes modulated host plant responses to light availability. First, we conducted a literature review to evaluate whether natural frequencies of endophyte symbiosis in grasses from shaded habitats were higher than frequencies in grasses occupying more diverse light environments. Then, in a glasshouse experiment, we assessed how four levels of light and the presence of endophyte symbioses affected the growth of six grass species. ? In our literature survey, endophytes were more commonly present in grasses restricted to shaded habitats than in grasses from diverse light environments. ? In the glasshouse, endophyte symbioses did not mediate plant growth in response to light availability. However, in the host grass, Agrostis perennans, symbiotic plants produced 53% more inflorescences than nonsymbiotic plants at the highest level of shade. In addition, under high shade, symbiotic Poa autumnalis invested more in specific leaf area than symbiont-free plants. Finally, shade increased the density of the endophyte in leaf tissues across all six grass species. ? Our results highlight the potential for symbiosis to alter the plasticity of host physiological traits, demonstrate a novel benefit of endophyte symbiosis under shade stress for one host species, and show a positive association between shade-restricted grass species and fungal endophytes.     

Genetic diversity in epichloid endophytes of Hordelymus europaeus suggests repeated host jumps and interspecific hybridizations

Epichloid fungal endophytes (Epichloë and Neotyphodium spp.) are excellent model systems for studying speciation processes because of their variable life history traits that are linked to host grass fitness. Presumed jumps to new hosts and subsequent somatic hybridizations appear to be common among epichloid endophytes resulting in increased genetic variation upon which selection can act and speciation be initiated. In this study, we explored the endophyte diversity of a rare European native woodland grass species, Hordelymus europaeus, along a latitudinal transect covering the entire distribution range of H. europaeus. From 28 populations in six countries, isolates were sampled and molecularly characterized. Based on the sequences of tubB and tefA, six distinct epichloid taxa (interspecific hybrid or cryptic haploid species) were found, of which four were novel and two have been previously reported from this host. Of the novel endophytes, two were presumed to be interspecific hybrids and two of nonhybrid origin. While previously known endophytes of H. europaeus are seed‐born and strictly asexual, one of the novel nonhybrid endophytes found in the glacial refugium of the Apennine peninsula reproduced sexually in cultured plants. This is the first case of a seed‐borne, but sexually reproducing endophyte of this host. We discuss the origin, and possible ancestral species, of the six epichloid taxa using phylogenetic analyses. Repeated host jumps and somatic hybridizations characterize the diversity of the endophytes. To date, no other grass species is known to host a larger diversity of endophytes than H. europaeus.     

Endophytic fungal communities in woody perennials of three tropical forest types of the Western Ghats,southern India

Fungal endophytes of tropical trees are expected to be exceptionally species rich as a consequence of high tree diversity in the tropics and the purported host restriction among the endophytes. Based on this premise, endophytes have been regarded as a focal group for estimating fungal numbers because their possible hyperdiverse nature would reflect significantly global fungal diversity. We present our consolidated ten-year work on 75 dicotyledonous tree hosts belonging to 33 families and growing in three different types of tropical forests of the NBR in the Western Ghats, southern India. We conclude that endophyte diversity in these forests is limited due to loose host affiliations among endophytes. Some endophytes have a wide host range and colonize taxonomically disparate hosts suggesting adaptations in them to counter a variety of defense chemicals in their hosts. Furthermore, such polyphagous endophytes dominate the endophyte assemblages of different tree hosts. Individual leaves may be densely colonized but only by a few endophyte species. It appears that the environment (the type of forest in this case) has a larger role in determining the endophyte assemblage of a plant host than the taxonomy of the host plant. Thus, different tropical plant communities have to be studied for their endophyte diversity to test the generalization that endophytes are hyperdiverse in the tropics, estimate their true species richness, and use them as a predictor group for more accurate assessment of global fungal diversity.     

内生真菌对植物生长发育及抗逆性的影响

本文从内生真菌的涵义和基本生物学特征出发,对国内外近二十年来关于内生真菌与植物关系的研究情况作了综述,主要包括内生真菌的检测、鉴定和转染,内生真菌对植物生长发育与抗逆性的影响,以及内生真菌在农业及其他相关领域的应用前景。文中提及作者近期开展的关于内生真菌对黑麦草抗旱性影响的研究课题及其初步进展。     

内生真菌对植物生长发育及抗逆性的影响

本文从内生真菌的涵义和基本生物学特征出发,以国内外近二十年来关于内生真菌与植物关系的研究情况作了综述。主要包括内生真菌的检测、鉴定和转染,内生真菌对植物生长发育与抗逆性的影响,以及内生真菌在农业及其他相关领域的应用前景。文中提及作者近期开展的关于内生真菌对黑麦草抗旱性影响的研究课题及其初步进展。     

The effects of Epichloë endophytes on the growth and competitiveness of Achnatherum sibiricum are mediated by soil microbe diversity

季节性干旱驱动亚热带森林的碳积累 本研究旨在表明处于南亚热带的鼎湖山生物圈保护区的干旱频率和强度正在增加,并说明季节性干旱对亚热带森林碳积累的影响。这是为了应对全球气候变化导致的干旱加剧所带来的威胁开展的一项研究。我们使干旱指数(标准化降水指数、标准降水蒸散发指数、降水距平百分率及自校准帕尔默干旱指数)准确确定干旱期和降水量增加期。此后,将2003至2014年(12年)监测采集的实测涡动通量和土壤含水量数据在干旱期和湿润期之间进行比较,以确定干旱对生态系统碳积累的影响。在本研究所选择的12年期间,干旱的发生时间约占比20%,最强干旱事件和严重程度发生于2012至2013年。研究期间的年平均降水量和气温分别为1404.57 ± 43.2 mm和22.65 ± 0.1 °C,与30年记录(1990–2020)相比较,年降水量减少量可达523 mm,而气温则增加了2.55 °C。与全球针对大多数森林生态系统研究所发表的数据呈相反趋势,处于中国南亚热带区域的鼎湖山生物圈保护区在60%的干旱期内所监测的森林生态系统记录到显著的碳积累趋势,说明季节性干旱驱动了森林的碳积累。