Stroma-forming endophyte Epichloë glyceriae provides wound-inducible herbivore resistance to its grass host

Fungal endophyte-grass associations are diverse and complex. Some endophytes (e.g. Neotyphodium spp.) reproduce asexually by growing vegetatively into host seeds and many of these vertically-transmitted endophytes form mutualisms with their hosts by providing high levels of alkaloids, such as lolines, that reduce herbivore performance. Additionally, Neotyphodium coenophialum provides wound-inducible herbivore resistance through increased production of lolines. Neotyphodium likely evolved from Epichloë spp. which are sexually reproducing endophytes that are transmitted horizontally to the next host generation through production of stromata (fruiting bodies), which sterilize host grasses. We asked if wound-inducible resistance like that in N . coenophialum also occurs in the ancestral, sexually reproducing Epichloë glyceriae , which infects Glyceria striata . Host grasses were damaged by fall armyworm caterpillars, artificially cut, or left undamaged. An aphid bioassay tested the plant's toxicity to herbivores, expression of lolc (a gene in the loline biosynthesis pathway) was quantified using real-time RT-PCR, and loline concentration was quantified using gas chromatography and mass spectrometry. Artificially-damaged plants supported fewer live aphids, had greater lolc mRNA expression, and greater loline concentration than undamaged plants. Herbivore-damaged plants supported intermediate performance by aphids, low lolc mRNA expression, and minimal loline concentration. Our study is the first to demonstrate sexual endophytes can produce lolines following wounding. This suggests wound-induced responses are ancestral within the Epichloë / Neotyphodium clade and reveals a trait of grass endophytes that may have predisposed them for the evolution of defensive mutualisms with their hosts.     

Variation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradients

Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra , F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifer tarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km² area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara , was, on average, 12% (local scale) and 37% (regional scale). In F. rubra , infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina , an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara . These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species.     

禾草内生真菌的遗传多样性及其共生关系

 近百年的禾草内生真菌研究历经了由浅入深的过程,从最初的家畜中毒事件认识到是一种共生内生真菌存在的缘故,到如今利用分子生物学技术揭示其共生机制,人类发现这类植物内生真菌并非想象中的对生态系统无足轻重。Epichloë及其无性型Neotyphodium与禾本科植物是系统发生的互利共生关系,尤其是Neotyphodium可提高宿主抵抗环境胁迫的能力和抵御动物的取食,增强植物的竞争力。禾草内生真菌有3种生活史：有性生活史、无性生活史和兼性生活史,后者表明真菌在不同的宿主及环境下既能营有性生殖也可营无性繁殖,是一种更灵活而有效的生活史对策。对内生真菌分子系统学、生活史以及与宿主禾草协同进化的研究发现,Neotyphodium起源于禾草致病真菌Epichloë的某些种,或是Epichloë与Neotyphodium的种间杂交后代。植物和内生真菌各异的生活史策略,真菌的种间杂交,两者的协同进化亦或种群间基因流的差异,都促成了共生体多样化的基因组合（Genetic combination ）,也是其共生关系多样化的根源。内生真菌对宿主的有益作用只在特定基因型真菌、宿主和一定环境条件下才起作用,自然生态系统的共生关系要比农业系统复杂得多,是一个从互利共生至寄生关系的连续系统。未来对于更多共生体的遗传背景和基因与环境相互作用的阐明将有助于对禾草内生真菌共生关系本质更加深入的认识。     

Taxonomy, diversity and origins of symbiotic endophytes of Achnatherum sibiricum in the Inner Mongolia Steppe of China

We sampled five Achnatherum sibiricum populations and documented the distribution and abundance of endophytes. In total, 438 fungal isolates were obtained. They were classified into 11 morphotypes based on growth rate and morphological characters including colonial morphology, the production of conidiogenous cells, conidial size and dimension on potato dextrose agar medium. Both tub2 and actG sequences identified only a single product in all representative isolates from three dominant morphotypes. All sequences fell in the same main clade, including Neotyphodium gansuense and Neotyphodium gansuense var. inebrians from another Achnatherum species in North China, Achnatherum inebrians , and Neotyphodium guerinii from European grasses Melica ciliate and Melica transsilvanica . Based on both morphological and phylogenetic analyses, isolates in morphotype I were described as representing a novel Neotyphodium species, Neotyphodium sibiricum sp. nov. Isolates in both morphotype II and III were identified as representing N. gansuense . Both tub2 and actG sequences suggested that N. sibiricum and N. guerinii were probably derived from a common Epichloë ancestor.     

禾草内生真菌对其它微生物的影响研究进展

禾草内生真菌在宿主植物的茎叶等地上组织中普遍存在,不仅能够提高禾草对生物与非生物逆境的抗性,而且能够对周围环境中的不同微生物类群产生影响。主要总结了禾草Neotyphodium/Epichlo内生真菌对病原真菌、丛枝菌根真菌和土壤微生物的影响及其作用机理。发现禾草内生真菌普遍存在对病原真菌的抑制作用,而对丛枝菌根真菌存在不对称的竞争作用,且因种类而异。禾草内生真菌对土壤微生物群落的作用则会随着土壤类型和时间等外界因素发生变化。禾草内生真菌对不同类群微生物的影响机制主要包括:通过生态位竞争、抑菌物质分泌、诱导抗病性等对病原真菌造成影响;通过根系化学物质释放、营养元素调节、侵染条件差异等对丛枝菌根真菌造成影响;通过根际沉积物和凋落物等对土壤微生物群落造成影响。禾草内生真菌产生的生物碱能提高宿主植物对包括昆虫在内草食动物采食的抗性,影响病原菌的侵入、定殖和扩展;根组织分泌物中包含次生代谢产物能够抑制菌根真菌、土传病原真菌及其它土壤微生物的侵染与群落组成;也可能通过次生代谢物影响禾草的其它抗性。因此,禾草内生真菌在植物-微生物系统中的作用应该给予更多的关注和深入研究。     

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     

Geographic distribution patterns of vertically transmitted endophytes in two native grasses in Argentina

The incidence of epichloid endophytes in populations of wild grasses is usually variable, and the knowledge about distribution patterns and how environmental factors affect such an incidence is limited. Here we performed a broad scale survey data to study whether the distribution patterns and the incidence of vertically-transmitted endophytes in populations of two native grasses from South-America, Poa lanuginosa Poir. and Poa bonariensis (Lam.) Kunth., are associated with environmental characteristics. We also characterized the endophytes from different populations to establish if the genotype of the endophytes is also correlated with environmental variables. The incidence of endophytes ranged from 0 to 100 % in both host species. In P. lanuginosa, endophytes were only found in populations on sandy coastal dunes and their incidence was positively associated with winter regime rainfall and soil water availability in the growing season. In P. bonariensis, endophytes were only found in populations in xerophytic forests and their incidence was highly associated with plant community. The distributions of infested populations suggested that the endophytes are not found in those areas with the most favorable or most stressing growth conditions accordingly to climatic or edaphical characteristics. Only the vertically transmitted hybrid endophyte species Neotyphodium tembladerae was detected in both host species. Under the hypothesis of vertical transmission, these results suggested that the endophyte should have been lost in endophyte free populations but is maintained in populations established in environments presenting moderate stress as salinity or short drought periods.     

禾本科植物内生真菌资源及其物种多样性

植物内生真菌是当代微生物资源研究的一个热门话题,对禾本科植物内生真菌资源研究进行了总结。与冷季型禾本科植物共生的麦角菌科epichlo内生真菌是目前的研究重点,包括偶尔在宿主植物体表形成子座的Epichlo属真菌和几乎完全不形成症状的Neotyphodium属真菌。具体介绍该真菌类群的物种多样性及其地理分布多样性,概括了它们在全球各大区域的分布特征。对近年来中国迅速发展的epichlo内生真菌的研究作了总结,最后展望了国际国内epichlo内生真菌资源探索的发展方向。特别指出:冷季型禾本科植物内生真菌在南美洲和亚洲,暖季型禾本科植物内生真菌在热带亚热带地区的研究还相对薄弱,值得今后继续加强探索和挖掘。     

内蒙古中东部草原羽茅内生真菌的遗传多样性

该文从形态学和基因水平上对内蒙古中东部草原4个羽茅(Achnatherum sibiricum)种群所含的27个内生真菌(Neotyphodium)菌株的遗传多样性进行了研究,结果表明羽茅内生真菌在形态学和基因水平上均表现出较高的遗传多样性。在PDA培养基上,根据菌落颜色、质地、生长速率和分生孢子外观等特征,可分为4个形态型;西乌旗、霍林郭勒和定位站3个种群所含的内生真菌菌落具有相似的生长特性和外观,而羊草(Leymus chinensis)样地种群无论从菌落外观和质地的多样性,还是遗传多样性指数均高于其它3个样地。用20个随机引物对这27株内生真菌基因组DNA进行RAPD分析,共检测到463个位点,其中461个为多态位点,多态位点百分率达99.6%,特有位点93个,占20.1%。Nei基因多样性指数h和Shannon多样性指数I分别为 0.238 0和0.387 0;多数菌株间的遗传一致度较低而遗传距离较大,在DNA水平上存在较显著的遗传变异。基于Nei无偏遗传距离和UPGMA法的聚类分析结果将27株内生真菌分为7组,并且与形态型的划分基本一致,RAPD分析方法提高了内生真菌类群划分的可靠性。     

内生真菌对草坪植物病原真菌抑制作用的比较

分别从野生牧草羽茅(Achnatherum sibiricum (L.) Keng)、栽培种高羊茅(Festuca arundinacea Schreb.)(品种Millennium)、栽培种黑麦草(Lolium perenne L.) (品种Justus)中分离出内生真菌Neotyphodium sp.、N. coenophialum和N. lolli,通过体外培养法比较了这3种内生真菌对草坪植物病原真菌的抑制作用.结果表明,从羽茅中分离的内生真菌Neotyphodium sp.在两菌相交前对所有供试的病原真菌都有一定的抑制作用,其中对枝孢霉属(Cladosporium sp.)、弯孢霉属(Curvularia sp.)和拟茎点属(Phomopsis sp.)病原真菌的抑制效果尤为显著,对峙培养3d后的抑菌率分别达70.1%、52.3%和30.9%,营养竞争作用、重寄生作用是其主要的拮抗机制;从高羊茅中分离的内生真菌N. coenophialum对枝孢霉属病原真菌存在一定的抑制作用;而从黑麦草中分离的内生真菌N. lolli与病原真菌对峙培养时,病原真菌菌落慢慢侵占整个营养空间,内生真菌停止生长并逐渐褐变死亡.体外培养结果说明Neotyphodium sp.对供试病原真菌的拮抗效果优于N. coenophialum和N. lolli,由此推测Neotyphodium sp.与宿主植物羽茅的共生可能有利于宿主植物抵抗病原真菌的侵扰.     

Epichloë fungal endophytes and the formation of synthetic symbioses in Hordeeae (=Triticeae) grasses

This review examines two classes of organism that live in symbiosis; grasses, and fungi. Specifically it deals with grasses of the tribe Hordeeae (formerly Triticeae) of the subfamily Poöideae and the Epichloë fungi of family Clavicipitaceae. Epichloë endophytes, particularly asexual forms, have important roles in pastoral agricultural systems in the Americas, Australia, and New Zealand. Selected strains add value to some grass-based forage systems by providing both biotic and abiotic stress resistance. The importance of cereal grasses such as wheat, barley, rye, and oats to human and animal nutrition and indeed to the foundation and maintenance of human civilization is well documented. Both organism classes, Epichloë endophytes and cereal grasses, are of great importance in their own contexts. Here, we seek to review these two classes of organism and examine the possibility of bringing them together in symbiosis with the ultimate goal of improving cereal production systems.     

Widespread occurrence of Neotyphodium-like endophyte in populations of Bromus tomentellus Boiss. in Iran

Neotyphodium species occur as endophytic fungi in cool-season grasses around the world. The beneficial aspects of grass-Neotyphodium associations have provoked researchers to look for a novel association in plant species where this symbiotum has not been reported. We surveyed Russian bromegrass (Bromus tomentellus Boiss.) accessions from a germplasm collection for the presence of Neotyphodium spp. fungi and determined levels of endophyte infection in B. tomentellus populations in native rangelands of Iran. Among 50 collected accessions, symbiotic fungi were detected in 45 accessions without any symptoms of choke disease on host plants. In culture medium, fast-growing endophytes appeared from seeds after 7-14 days. Plants grown from seed collections were 80-100% infected. Based on morphological characteristics and PCR analysis, we concluded that this fungus is a member of the Neotyphodium group of endophytic fungi. Lack of apparent toxicity to grazing animals suggests a place for endophyte-infected B. tomentellus in rangeland renovation, providing this infected grass exhibits increased tolerance to abiotic stresses.     

Origin, divergence, and phylogeny of epichloe endophytes of native Argentine grasses

The epichlo? endophytes are systemic, constitutive, and often vertically transmitted fungal symbionts of grass species in subfamily Po?ideae. Prior studies indicate that several asexual epichlo? endophytes (Neotyphodium species) have evolved directly from sexual (Epichlo?) species, whereas others evolved by hybridization between two or more endophyte species. In this paper, we investigate the phylogenies of 27 Neotyphodium spp. isolates from 10 native grass species (in 4 tribes) in 22 populations throughout Argentina. Relationships among these fungi and a worldwide collection of epichlo? endophytes were estimated by phylogenetic analysis of sequences from variable portions (mainly introns) of genes for beta-tubulin (tub2) and translation elongation factor 1-alpha (tef1). Most of the Argentine endophyte isolates were interspecific hybrids of Epichlo? festucae and E. typhina. Only one isolate was a hybrid of a different ancestry, and three isolates were apparently non-hybrid endophytes. These results indicate that interspecific hybridization, which promotes genetic variation, was common during the evolution of the endophytes of Argentine grasses.     

Fungal endophyte–grass symbioses are rare in the California floristic province and other regions with Mediterranean-influenced climates

Research on agronomic grasses has shown that Class 1 fungal endophytes (Neotyphodium/Epichloë; Clavicipitaceae) can have profound effects on host plant fitness. However, in natural systems, even basic ecological knowledge of most endophyte symbioses is lacking. Here, I describe the distribution and abundance of endophytes across 36 native (or naturalized) grasses in a previously unsurveyed region, the California Floristic Province. Symbiosis was generally low: 8.33 % of species and 18.75 % of genera hosted endophytes. I then compared the proportions of symbiotic species and genera found in California and other Mediterranean regions to the proportions found in non-Mediterranean regions. Surveys of Mediterranean-influenced regions showed significantly lower proportions of species (～66 % lower) and genera (～65 % lower) hosting endophyte than surveys of non-Mediterranean regions. This pattern suggests that selection in Mediterranean climates may not favor endophyte symbioses.     

Intraspecific competition of endophyte infected vs uninfected plants of two woodland grass species

Grass endophytes (Clavicipitaceae, Ascomycota) are generally considered to be mutualists which increase the host's fitness. Infected plants are often more persistent and competitive than uninfected plants, influencing population dynamics and plant community diversity. However, most of this empirical evidence is based on studies focusing on agronomically important grass species such as tall fescue or perennial ryegrass and their implications for livestock and man-made habitats. Recent studies indicate that endophyte-plant associations may be more variable, ranging from parasitic to mutualistic. In the present study, we investigated the influence of endophyte infection on two wild woodland grasses, which are naturally infected with distinct fungal endophytes: Brachypodium sylvaticum with Epichloë sylvatica and Bromus benekenii with Epichloë bromicola . An intraspecific competition experiment was conducted over two growing seasons in the greenhouse and in an experimental garden. At first harvest (after 12 weeks growing), endophyte infection had a significant negative effect on above ground dry matter yield (DMY) of B. sylvaticum , but a significant positive effect on DMY of Br. benekenii under competition. The same differential effects on DMY and on total seed number were also observed at final harvest (after 62 weeks growing). Results from Br. benekenii were consistent with our hypothesis of increased competitive abilities of infected plants in nature which could explain the high infection rate observed in natural populations. In contrast, this explanation does not hold true for B. sylvaticum , and other factors such as increased herbivore and pathogen resistance together with frequent horizontal transmission may be responsible for the very high incidence of this association in nature. Our results confirm previous predictions that beneficial effects of endophyte infection in wild grasses can vary for different grass species, even in comparable habitats.     

Endophytes of native grasses from South America: Biodiversity and ecology

We review and present preliminary results of studies on cool-season grass endophytes native to South America. These fungi have been studied only in Argentina, where they have been detected in 36 native grass species. The hybrid Neotyphodium tembladerae is present in an extremely wide host range found in diverse environmental conditions, but some other endophytes seem to be strictly associated with one host species in a particular environment. In host species that inhabit different environments, the incidence of endophytes is highly variable among populations and in most of the cases is clearly associated with environmental conditions. In these native grasses, Neotyphodium presents a mutualistic behaviour, conferring enhanced growth, promoting the symbiosis with arbuscular mycorrhizal fungi, and inhibiting growth of pathogenic fungi. In native forage grasses, preliminary analyses indicate that some Argentinian endophytes can produce lolines but are unlikely to produce lolitrem B or ergot alkaloids.     

Development and characterization of EST-derived simple sequence repeat (SSR) markers for pasture grass endophytes.

Fungal endophytes of the genus Neotyphodium are common in temperate pasture grass species and confer both beneficial and deleterious agronomic characteristics to their hosts. The aim of this study was to develop molecular markers based on simple sequence repeat (SSR) loci for the identification and assessment of genetic diversity among Neotyphodium endophytes in grasses. Expressed sequence tags (ESTs) from both Neptyphodium coenophialum and Neotyphodium lolii were examined, and unique SSR loci were identified in 9.7% of the N. coenophialum sequences and 6.3% of the N. lolii sequences. A variety of SSRs were present, although perfect trinucleotide repeat arrays were the most common. Primers were designed to 50 SSR loci from N. coenophialum and 57 SSR loci from N. lolii and were evaluated using 20 Neotyphodium and Epichlo? isolates. A high proportion of the N. coenophialum and N. lolii primers produced amplification products from the majority of isolates and most of these primers detected genetic variation. SSR markers from both N. coenophialum and N. lolii detected high levels of polymorphism between Neotyphodium and Epichlo? species, and low levels of polymorphism within N. coenophialum and N. lolii. SSR markers may be used in appropriate combinations to discriminate between species. Comparison with amplified fragment length polymorphism (AFLP) data demonstrated that the SSR markers were informative for the assessment of genetic variation within and between endophyte species. These markers may be used to identify endophyte taxa and to evaluate intraspecific population diversity, which may be correlated with variation for endophyte-derived agronomic traits.     

Interactions among fungal endophytes,grasses and herbivores

The interaction between two species often depends on the presence or absence of a third species. One widespread three-species interaction involves fungal endophytes infecting grasses and the herbivores that feed upon them. The endophytes are allied with the fungal family Clavicipitaceae and grow systemically in intercellular spaces in above-ground plant tissues including seeds. Like relatedClaviceps species, the endophytes produce a variety of alkaloids that make the host plants toxic or distasteful to herbivores. A large number of grass species are infected, especially cool-season grasses in temperate areas. Field and laboratory studies have shown that herbivores avoid infected plants in choice trials and suffer increased mortality and decreased growth on infected grasses in feeding experiments. Resistance to herbivores may provide a selective advantage to infected plants in competitive interactions with noninfected plants. Recent studies have shown that differential herbivory can reverse competitive hierarchies among plant species. Both endophyte-infected and noninfected tall fescue grass (Festuca arundinacea) are outcompeted by orchardgrass (Dactylis glomerata) in the absence of insect herbivory. However, when herbivores are present infected tall fescue outcompetes orchardgrass. These results suggest that the frequency of infection in grass species and grassland communities will increase over time. Several studies are reviewed illustrating increases in infection frequency within grass populations subject to herbivore pressure. Endophytic fungi may be important regulators of plant-herbivore interactions and so indirectly affect the structure and dynamics of plant communities.     

Do foliar endophytes affect grass litter decomposition? A microcosm approach using Lolium multiflorum

Symbiotic infection with fungal endophytes has been shown to decrease herbivory in several temperate grasses. We tested the hypothesis that foliar endophytes of grasses may also affect below-ground processes upon their host death, by altering the litter quality for detritivores or the microenvironment for decomposition. Microcosm–litterbag experiments were used to assess decay rates for litter produced by endophyte ( Neotyphodium sp.) infected vs uninfected Lolium multiflorum plants, and to examine endophyte-mediated effects of prior site occupants on current litter decomposition. We found that litter from endophyte-infected L. multiflorum decomposed more slowly than litter from endophyte-free conspecifics and from a naturally uninfected grass, Bromus unioloides . Furthermore, the endophyte–grass association modified the decomposition environment, so that B. unioloides litter decomposed faster when placed underneath a thick layer of endophyte-free L. multiflorum litter. Litter decay rates increased with the amount of root debris remaining in situ from the previous season, but were not affected by the infection status of prior site occupants. The lower decomposability of litter from infected L. multiflorum plants persisted across a range of microenvironments, as determined by different amounts of above-ground litter and soil moisture conditions. Endophyte infection tended to reduce the N content of decaying litter; however, litter N and C/N ratio mainly accounted for interspecific differences in decomposition. Our results imply that fungal endophytes not only can affect herbivory food chains, but also soil organisms and the ecosystem processes they regulate. This study suggests a novel role for symbiotic foliar endophytes in linking above-ground and below-ground sub-systems.     

Endophytic fungal beta-1,6-glucanase expression in the infected host grass

Mutualistic fungal endophytes infect many grass species and often confer benefits to the hosts such as reduced herbivory by insects and animals. The physiological interactions between the endophytes and their hosts have not been well characterized. Fungal-secreted proteins are likely to be important components of the interaction. In the interaction between Poa ampla and the endophyte Neotyphodium sp., a fungal beta-1,6-glucanase is secreted into the apoplast, and activity of the enzyme is detectable in endophyte-infected plants. Sequence analysis indicates the beta-1,6-glucanase is homologous to enzymes secreted by the mycoparasitic fungi Trichoderma harzianum and Trichoderma virens. DNA gel-blot analysis indicated the beta-1,6-glucanase was encoded by a single gene. As a secreted protein, the beta-1,6-glucanase may have a nutritional role for the fungus. In culture, beta-1,6-glucanase activity was induced in the presence of beta-1,6-glucans. From RNA gel blots, similar beta-1,6-glucanases were expressed in tall fescue (Festuca arundinacea Schreb.) and Chewings fescue (Festuca rubra L. subsp. fallax [Thuill] Nyman) infected with the endophyte species Neotyphodium coenophialum and Epichlo? festucae, respectively.