关于茭白黑粉菌的正名问题

茭白黑粉菌在文献中出现Yenia esculenta(P.Henn.)Liou及Ustilago esculenta P.Henn.两个名字。现经形态发生学的研究以明确新名字是否有效。此菌冬孢子没有休眠期,孢子成熟后在适宜的环境中即可萌发。萌发的最适pH值为6;最适温度为25％;不需要外界光的诱导,在黑暗条件下也能正常萌发;培养基中的营养成份对孢子萌发的速率有一定影响。冬孢子在不同的环境条件下,其萌发形态及方式都是稳定的:孢子萌发时产生有隔的担子或先菌丝(promycelium)。该先菌丝起初可以是无隔的,但生长到一定程度,便产生分隔,分隔多为2—4个。初生的先菌丝和小孢子是单核的,但成熟的先菌丝、小孢子及短菌丝细胞内均是双核的。可以认为,该菌的双核期在整个生活史中占有相当长的时间,它只有短暂的单核期。没有发现先菌丝、小孢子彼此之间或相互间融合的现象;未见到双核的融合及减数分裂过程。茭白黑粉菌在人工组合培养基上生成厚壁的孢子,较自然界中的冬孢子为大,但萌发方式则相同。最后作者等认为茭白黑粉菌仍应保留在Ustilago属中,而Yenia esculenta(P.Henn.)Liou的名字是无效的。     

菰黑粉菌科(Yeniaceae)的确认问题

菰黑粉菌科(Yeniaceae)是刘慎谔(1949)根据阎玫玉(1935)对菰黑粉菌(Yenia esculenta) 冬孢子**萌发方式的研究结果而建立的。但是20多年来,似还没有得到有关工作者的承认, 主要是由于黑粉菌冬孢子萌发方式受环境因素的影响很大,性状不太稳定的缘故。 为了确认 此科建立的必要性和合理性,在前人研究的基础上,对菰黑粉菌冬孢子的萌发方式和条件作了 进一步的研究。结果表明：菰黑粉菌冬孢子在形态上和生理上几乎同时成熟,孢子形成后便 可立即大量萌发。冬孢子的存活力较短暂,在室温下10个月完全丧失萌发力。 菰黑粉菌冬孢子在9-33℃下均能萌发,萌发的适温范围为24-30℃,30℃下8小时便 开始萌发。孢子在pH 2.0-11.0均能萌发,以pH3.5-7.0较好,最适pH为4.0-5.0。合 成培养基和植物性煎汁培养基有利于孢子的萌发,在动物性煎汁培养基和缺乏养料的蒸馏水 培养基上萌发较差。冬孢子在完全光照和完全黑暗下均能萌发。孢子萌发时对氧的需要量不 大,纯氧或过量的氧对萌发似有抑制作用。菰黑粉菌这种对萌发条件要求不严格的特性,表明 它具有广泛的适应性和顽强的生命力。这种特性是它在长期历史发展过程中所形成的,也是 长期人工选择和自然选择的结果。对这些生物学性状的了解,为在生产实践上争取茭白的丰 产奠定了理论基础。 温度、光照、氢离子浓度、营养条件和氧的供应,对菰黑粉菌冬孢子的萌发方式有一定的影 响,特别是对孢子原菌丝影响较大。但是对短的无隔担子原菌丝影响却不大,一般都没有引起 形态上的较大改变。刘慎谔(1949)根据这一性状所建立的菰黑粉菌属(Yenia)和菰黑粉菌科 (Yeniaceae),是有一定根据的,似应给予承认。 本文还对黑粉菌目的演化和分科问题进行了讨论。     

菰黑粉菌T-DNA突变体库的构建及分析

通过建立适用于菰黑粉菌Ustilago esculenta的农杆菌介导遗传转化(Agrobacterium tumefaciens-mediated transformation,ATMT)体系,构建菰黑粉菌T-DNA插入突变体库。针对性地筛选双核菌丝形成缺陷型转化子,并对T-DNA插入位点进行分析,为研究菰黑粉菌二态型转换的分子调控机理打下基础。以构建的菰黑粉菌自融合菌株TSP为出发菌株,以含有遗传霉素(G418)抗性基因(neo)的质粒为载体,通过ATMT构建菰黑粉菌T-DNA突变体库,并对诱导剂乙酰丁香酮(AS)浓度、转化的共培养时间、农杆菌浓度和菰黑粉菌芽孢子浓度等建库影响因素进行单因素条件试验,筛选最优条件;对继代培养的转化子基因组中的遗传霉素抗性基因进行PCR检测,验证转化子遗传稳定性;对突变体库中的转化子双核菌丝生长情况进行观察,测定其双核菌丝形成能力;对上述双核菌丝形成缺陷型转化子进行基因组重测序,分析其T-DNA插入位点。当遗传霉素浓度为75μg/mL时,菰黑粉菌的生长被完全抑制。当AS浓度为100μg/mL、共培养时间为24 h、孢子浓度为1×10⁵     

中国黑粉菌属和利罗黑粉菌属

黑粉菌属是Roussel 1806年建立的,全世界记载有三百余种,主要寄生于禾本科,是经济作物及牧草的重要致病菌·长期以来,对黑粉菌的邢子使用过各种名称,如厚垣孢子,冬孢子及黑粉孢子等.本文采用黑粉孢子以区别锈菌的冬孢子. 芳’(1979)在《中国真菌总汇》中列出黑粉菌属五十种及一个变型.作者经过显微结构和超显微结构的研究,承认其中二十九种为正确名称,八种及一变型为异名,顶黑粉菌(Ustilago acrearus Berk.)由于错拼而被废弃.埃地黑粉菌(Ustilago emodensis Berk.)被转移至利罗粉菌属(Liroa).另有十一种黑粉菌因缺少标本留待今后订正.自1979年以后,杨信东(1983)增加黑粉菌属二种我国新纪录,K.范基和郭林(1986)描述一新种,四种新纪录.在本文中,作者描述一新种:鸢尾蒜黑粉(Ustilago ixiolirii Guo L) ,孢子堆生在蒴果内,不开裂,黑色,粉末状.黑粉孢子球形,近球形,稀椭圆形, 12.5-21×10-21μm,黑褐色,壁厚1-1.Sμm,纹饰脑状.是迄今生在石蒜科植物上唯一黑粉菌的种,其它几种黑粉菌均属条黑粉菌属.本文增加七种我国新纪录.共计四十九种,寄生于六科四十四属植物,主要是禾本科和蓼科.这仅是黑粉菌属研究的初步报告,在全国范围内大量采集黑粉菌标本后,作者相信会有更多新种和我国新纪录被发现.利罗黑粉菌属(Liroa)是从黑粉菌属(Ustaligo)分出的,此属为单种属.     

黑粉菌属一新种及中国黑粉菌补遗VI

本文描述采自河北小五台山的黑粉菌一新种,即寄生在野青茅(Deyeuxia arundinacea(L.) Beauv)上的野青茅黑粉菌(Ustilago deyeuxiae L. Guo)。此种与网优黑粉菌(Ustilago scrobiculata Liro)近似,但野青茅黑粉菌网纹明显,网眼高。并报道三种黑粉菌中国新记录。1)酢浆草黑粉菌(Ustilago oxalidis Ellis&Tracy)寄生于醉浆草(Oxalis corniculata L.),此种是我国首次在酢浆草科(Oxalidaceae)植物上发现的黑粉菌。2)网状黑粉菌(Ustilago polygoni-alati Thirum. & Pavgi)寄生于尼泊尔萝(Polygonum nepalense Meisn.),作者对此种进行了订正研究。3)臭草条黑粉菌(Urocystis melicae (Lagerheim & Liro) Zundel)寄生于细叶臭草(Melica radula Fr.)。     

黑粉菌属的聚类分析

本文对我国黑粉菌属(Ustilago)51个样本,选取33个形态学和生物学编码性状进行了类平均法的系统聚类分析。根据聚类分析结果,建议将我国黑粉菌属分为3个表观群(Phenons);茭白黑粉菌目前以放在黑粉菌属内为妥;还认为 Ustilago ocrearum 是 Ustilagokoenigiae 的变种;Ustilago kusanoi 是 Ustilago minima 的变种;Us(?)ilago aoenoe 和 Usti-lago nuda 是两个不同种。     

中国黑粉菌补遗Ⅲ

本文报道我国黑粉菌三种新纪录。特氏楔孢黑粉菌(Thecaphora trailii Cooke)寄生于风毛菊(Saussurea japonica (Thunb.) DC.)花序中,孢子球由2-5(-8)个孢子组成,黑粉孢子10.5-22×8.5-15 Imo翠雀条黑粉菌(Urocystis delphinii Golovin)寄生于翠雀(Delphinium grandiflorum L.)的茎和叶柄上,孢子球由1-10个孢子组成,黑粉孢子12.5-18×10-15 μm,不育细胞5.5-12 μm。籣草黑粉菌(Ustilago echinata Schroeter)寄生于籣草(Phalaris arundinacea L.)的叶和叶鞘上,黑粉孢子12.5-19×10.5-16 μm,表面纹饰粗痰,部分联结为脊状或网状。     

茭白黑粉菌在茭白植株内形态发育的初步研究

茭白黑粉菌的菌丝体多年生,越冬期宿存于茭白地下茎中,翌年春天入侵由地下茎芽体形成的植株。菌丝具隔膜,分枝,细胞双核,在寄主细胞间隙并入侵细胞中生长,无吸器;受菌丝侵染的茭白地上茎薄壁细胞分裂增多,体积加大,并高度液泡化,使茎膨大。部分菌丝在茭白茎膨大后期菌丝壁胶化,原生质收缩成团,生成厚壁,形成冬孢子。     

金针菇粉孢子的生物学研究

采用单孢分离的方法分离培养金针菇粉孢子,对粉孢子的产生、萌发、核相及极性进行了研究。结果表明：单核菌丝和双核菌丝都产生粉孢子,粉孢子多呈圆柱或卵圆形,少数呈圆形或Y形。粉孢子很容易萌发,其芽管直径一般较粉孢子宽。单核菌丝产生单核的粉孢子,其极性与亲本菌丝相同;双核菌丝产生的粉孢子也为单核,未观察到双核或多核的粉孢子。双核菌丝产生的粉孢子一部分与组成双核体的一个亲本单核菌丝的交配型相同,另一部分与组成双核体的另一亲本单核菌丝有相同的交配型。     

金针菇粉孢子的生物学研究

采用单孢分离的方法分离培养金针菇粉孢子,对粉孢子的产生、萌发、核相及极性进行了研究。结果表明：单核菌丝和双核菌丝都产生粉孢子,粉孢子多呈圆柱或卵圆形,少数呈圆形或Ｙ形。粉孢子很容易萌发,其芽管直径一般较粉孢子宽。单核菌丝产生单核的粉孢子,其极性与亲本菌丝相同;双核菌丝产生的粉孢子也为单核,未观察到双核或多核的粉孢子。双核菌丝产生的粉孢子一部分与组成双核体的一个亲本单核菌丝的交配型相同。另一部分与组     

White rust of chrysanthemums

Teleutospores of Puccinia horiana Henn. germinate and discharge sporidia between 4 and 23 °C. At the optimum temperature of 17 °C sporidia discharge starts within 3 h. Maximum germination of the sporidia takes place within 2·5 h between o and 30 °C, there being no clear optimum. High humidity and a film of moisture appear to be necessary for germination of both teleutospores and sporidia. Sporidia can penetrate either leaf surface of chrysanthemum to cause infection between 4 and 24 1°C and within the optimum temperature range, 17–24 °C, effectively penetrate within 2 h. The sporidia are very sensitive to desiccation at below 90 % relative humidity. Methods are described, using leaf discs and whole plants, for screening chrysanthemum cultivars for susceptibility to white rust. Cultivars were placed in five classes ranging from susceptible to immune. Leaf discs of immune cultivars can be distinguished within 30 h by a brown discolouration at the point of inoculation. The early stages of development of the fungus in susceptible, resistant and immune hosts are described. The incubation period in susceptible plants is normally 7–10 days, teleutospores being formed a few days later. Leaves become less susceptible with age but the oldest leaves on 5-month-old plants could still be infected. The maximum survival time of teleutospores in the sori on detached leaves was 8 weeks but was considerably less under moist conditions or buried in soil. Low doses of a mancozeb with zineb fungicide controlled infection by preventing penetration rather than by inhibiting sporidial germination.     

Ultrastructure of primary sporidia of a wheat-bunt fungus,Tilletia caries,during ontogeny and mating

Summary Primary sporidia ofTilletia caries (DC.) Tul. are borne on denticles at the tips of promycelia. The promycelia contain many small vacuoles and mitochondria and numerous lipid bodies. As the primary sporidia develop, the promycelial cytoplasm passes into the nascent cells. Septa develop between the bases of mature sporidia and the tips of the denticles. Sporidia that abscise from the denticles commonly have prominent birth scars at their bases. The sporidia have very thin walls, few vacuoles, attenuated mitochondria, and numerous lipid bodies. Conjugation pegs are generally produced by both members of a conjugating pair of sporidia and there are bud scars where they emerge from the sporidia. The sporidial walls are apparently hydrolyzed during emergence of the pegs. Vesicles are sometimes present at the tips of the conjugation pegs and, before fusion, electron-dense accumulations are sometimes observed between the tips of adjacent pegs. The approaching conjugation pegs are precisely aligned prior to fusion, suggesting polar communication. The walls of the conjugation pegs fuse and then are hydrolyzed. Fused sporidia are relatively homogeneous in content. The nucleus in a sporidum is often close to the conjugation tube and occasionally is partly within the fusion tube.Cooperative investigations of the Oregon Agricultural Experiment Station, Brigham Young University, and Science and Education Administration-Agricultural Research, U.S. Department of Agriculture. Technical Paper No. 4,934 of the Oregon Agricultural Experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.     

The Development of an In Vitro Host-Pathogen System Consisting of Maize Seedling Segments Infected with Ustilago maydis

The nodal segments of 7-day-old seedlings of maize were inoculated with sporidia of Ustilago maydis. At different times after inoculation (day 0 to day 9), the nodal segments were explanted to tissue culture media containing Benomyl. On one of the media, segments explanted at day 1 or later responded with the formation of galls carrying roots. In such galls Ustilago could complete its life cycle and form teliospores. Explantation at day 0 never led to gall or teliospore formation. Thefindings are discussed with respect to the possible presence of mycoboethins.     

Release of secondary sporidia ofNeovossia indica from inoculated wheat spikes

Wheat-spikes inoculated withN. indica at the boot-leaf stage produced secondary sporidia when later incubated (intact/detached) under moist conditions in the laboratory. Sporidia were also released from inoculated spikes in the field where sporidial release exhibited diurnal periodicity. More sporidia were trapped between 5–6 o'clock than during the later parts of the day but no sporidia were trapped between 14–18 o'clock. However, they could be trapped at any time of the day from the detached spikes incubated under moist conditions in the laboratory. Sporidia trapped in different experiments were invariably of the allantoid type and they proved viable and infective. Maximum sporidia developed on the outer glumes of florets, and this observation was supported by scanning electron microcope studies. Sporidia developed at 15 and 20°C but not at 30°C. These findings indicated that repeated cycles of sporidial production in spikes provided more inoculum than expected from soil-borne teliospores ofN. indica.     

The life cycle of the smut fungus Moesziomyces penicillariae is adapted to the short-cycle of the host, Pennisetum glaucum

Moesziomyces penicillariae (Brefield) Vànky is a basidiomycete fungus responsible for smut disease on pearl millet, an important staple food in the sub-Sahelian zone. We revisited the life cycle of this fungus. Unlike other Ustilaginales, mating of sporidia was never observed and monoclonal cultures of monokaryotic sporidia were infectious in the absence of mating with compatible partner. These data argued for an atypical monokaryotic diploid cell cycle of M. penicillariae, where teliospores only form solopathogenic sporidia. After inoculation of monoclonal solopathogenic strains on spikelets, the fungus infects the ovaries and induces the folding of the micropilar lips, as observed during early pollination steps. The infected embryo then becomes disorganized and the fungus invades peripheral ovary tissues before sporulating. We evaluated the systemic growth abilities of the fungus. After root inoculation, mycelium was observed around and inside the roots. As argued by transmission electron microscopy (TEM) observations and polymerase chain reaction (PCR) detection using specific primers for M. penicillariae, the fungus can grow from roots to the caulinar meristems. In spite of this systemic growth, no sori were formed on the varieties of pearl millet tested after root inoculation. All together, these data suggest that the reduced life cycle of M. penicillariae – i.e. dispersal of ‘ready to infect’ solopathogenic sporidia, floral infection – is an adaptation to the aetiology of this disease to short-cycle pearl millet varieties from the sub-Sahel.     

Germination of Teliospores of Tilletia bardayana, the Causal Agent of Kernel Smut of Rice, in Relation to Some Physical Factors

Teliospores of Tilletia harclayana germinated equally well on the surface of 2 % water agar, soil extract agar and in cavities made in water agar. Maximum germination occurred at 29 °C under 12 h photoperiod with artificial daylight (cool fluorescent light). There was marked increase in germination when the teliospores in bunted grains were pre-treated for 30 min at 60 °C. Seventeen-week-old tehospores did not germinate while 73 week-old-tehospores showed retention of good germinability. Teliospores buried at 2 mm depth showed no germination whereas those at the moist surface germinated to produce sporidia. Implications of these results in the disease development are discussed.     

An unusual new <Emphasis Type="Italic">Phakopsora</Emphasis> from Tanzania

Phakopsora allophyli (Basidiomycota, Uredinales) is described on the basis of the type specimen of Uredo allophili Henn. on Allophylus sp. (Sapindaceae) from Tanzania. The species has paraphysate telia and teliospores with a single papillate germ pore. These features are unusual for members of the genus Phakopsora. The generic affiliation of the fungus with Phakopsora is discussed.     

A REINTERPRETATION OF THE ONTOGENY OF THE ASCOCARP OF SPECIES OF THE ERYSIPHACEAE

A study of four species of Erysiphaceae (Uncinula salicis, Podosphaera leucotricha, Erysiphe cichoracearum, and Microsphaera diffusa) revealed that the binucleate stages of the ascocarp are initiated in a similar manner to those of Diporotheca rhizophila Gordon & Shaw. The “appendages” developing on immature ascocarps are considered to be receptive hyphae. Appendages characteristic of mature ascocarps are produced much later. Lysis of certain centrum cells occurs, and asci are initiated from some of the remaining binucleate centrum cells. Resorption of centrum cells by the asci is supported by this investigation, corroborating Björling's earlier studies on Erysiphe graminis.