中国霜霉的几个新种

本文描述了霜霉属(Peronospora)两个新种。即:寄生于唇形科植物香薷(Elsholtziapatrnia Garcke)上的香薷霜霉(Peronospora elsholtziae sp.nov.)和寄生于大花益母草(Leonurusmacranthus Maxim.)上的大花益母草霜霉(Peronospora leonuri sp.nov);单轴霉属(Plasmopara)一个新种,寄生于车前草科植物车前草(Plantago major L.)上的车前草单轴霉(Plasmoparaplantaginicola sp.nov.,);盘梗霉属(Bremia)一个新种,寄生于石竹科植物莫石竹(Moehringialateriflora L.)上的莫石竹盘梗霉(Bremia moehringiae sp.nov.).这四个新种均有拉丁文和中文描述。还分别讨论了新种与同科近似种之间的区别。     

霜霉一新种——大丁草盘梗霉

本文报道了寄生于菊科植物大丁草(Leibnitzia anandria)上的盘梗霉的一个新种——大丁草盘梗霉(Bremia leibnitziae sp. nov.)。它的形态特征与小孢盘梗霉(B. microspora)较为接近,但根据新种的孢囊梗分枝次数较多,且有时不规则,孢子囊体积较小,卵孢子容易形成以及寄主的差别等特点,可以将它们区别开。     

中国菊科植物上拟盘梗霉属的新种和新组合

拟盘梗霉属(Bremiella G.W.Wilson)霜霉,全世界已报道2个种。本文报道寄生于我国菊科植物上的1个新种及2个新组合。新种是寄生于茼蒿上的Bremiella multiformis Tao et Y.Qin sp.nov.。新组合是欧茼蒿上的Bremiella chrysanthemi-coronarii(Sawada)Tao comb.nov。及黄花蒿上的Bremiella artemisiae-annuae(Ling et M. C.Tai)Tao comb.nov.。对新种作了汉文及拉丁文描述,并附有形态图,还讨论了新种和新组合与近似种之间的区别。     

中国菊科植物上拟盘梗霉属的新种和新组合*

拟盘梗霉属(Bremiella G.W.Wilson)霜霉,全世界已报道2个种。本文报道寄生于我国菊科植物上的1个新种及2个新组合。新种是寄生于茼蒿上的Bremiella multiformis Tao et Y.Qin sp.nov.。新组合是欧茼蒿上的Bremiella chrysanthemi-coronarii(Sawada)Tao comb.nov。及黄花蒿上的Bremiella artemisiae-annuae(Ling et M. C.Tai)Tao comb.nov.。对新种作了汉文及拉丁文描述,并附有形态图,还讨论了新种和新组合与近似种之间的区别。     

中国霜霉一新种*

本文描述了霜霉属(Peronospora)一个新种,寄生于唇形科植物水棘针(Amethysteacaerulea L·)上的水棘针霜霉(Peronospora amethysteae Y.Li et Bai sp.nov.),有拉丁文和中文描述,并讨论了新种与同科植物上的相近种之间的区别。     

中国霜霉一新种

本文描述了霜霉属(Peronospora)一个新种,寄生于唇形科植物水棘针(Amethysteacaerulea L·)上的水棘针霜霉(Peronospora amethysteae Y.Li et Bai sp.nov.),有拉丁文和中文描述,并讨论了新种与同科植物上的相近种之间的区别。     

轴霜霉一新种——地榆轴霜霉

本文报道了采自我国新疆阿勒泰山寄生于蔷薇科(Rosaceae)植物地榆(Sanguisorba officinalis L.)上的轴霜霉新种——地榆轴霜霉(Plasmopara Sanguisorbae C.J.Li et al.sp.nov.)。轴霜霉寄生于蔷薇科植物上是首次报道。对该种的形态作了拉丁文和汉文描述,并附有特征图。     

盘梗霉属一新种——甜菜盘梗霉

本文报道了寄生于藜科(Chenopodiaccae)甜菜(Beta. Vulgaris L．)上的盘梗霉属一新种——甜菜盘梗霉(Bremia betae sp. Nov.)。对此新种作了汉文和拉丁文描述．     

中国拟盘梗霉分类的研究——Ⅱ.寄生在伞形科上的一个新种

本文报告在四川西部采集的寄生于繖形科植物水芹(Oenanthe javanica(B1.)DG.)和卵叶水芹(O.rosthornii Diels)上拟盘梗霉属的一个新种——水芹拟盘梗霉(Bremiellaoenantheae Tao et Y.Qin sp.nov.)。它与在捷克和罗马尼亚发现的,寄生在缴形科Berulaerecta上的Bremiella baudysii较为接近,但根据它们的孢子囊形态、大小、长宽比及萌发的方式等方面的差别,可以将它们区分开。对新种作了拉丁文及汉文描述,并附有形态图。     

中国单轴霉分类的研究——Ⅰ.寄生在唇形科和苋科植物上的新种

本文描述了单轴霉属(Plasmopara)霜霉菌的二个新种。它们是:寄生于唇形科植物香薷(Elsholtzia ciliata(Thunb.)Hyland)上的香薷单轴霉(Plasmopara elsholtziae spnov.)及苋科植物牛膝(Achyranthes bidentata Bl.)上的牛膝单轴霉(Plasmopara achyranthis sp. nov.)。牛膝单轴霉是本属真菌寄生于苋科植物的首次记录。上述二新种都有拉丁文及汉文描述,还分别讨论了新种与其同科或不同科寄主上的近似种之间的区别。     

Gonidial morphology and the specialization of Bremia lactucae Regel (Peronosporaceae) on hosts in the family Compositae

SKIDMORE, D. I. & INGRAM, D. S., 1985. Conidial morphology and the specialization of Bremia lactucae Regel (Peronosporaceae) on hosts in the family Compositae . Conidia of Bremia lactucae were collected from Lactuca saliva, Sonchus oleraceus, S. asper, Senecio vulgaris, S. bicolor subsp. cineraria, Cirsium arvense, Centaurea nigra and Picris hieracioides , from a wide distribution in the British Isles. There were no consistent differences between isolates taken from the different hosts in the lengths, breadths or length: breadth ratios of the conidia, the lengths of the conidiophores or the numbers of sterigmata per conidiophorc branch. Therefore, as there are no significant morphological differences between the isolates of Bremia lactucae from these hosts, the pathogen is classified upon host specialization. A review is presented of cross-infection studies in which isolates of B. lactucae had been inoculated on to a range of species of Compositae. On the basis of these investigations it is recommended that the term 'formae speciales' is used to denote host specialization of isolates within the species Bremia lactucae .     

盘霜霉一新种——岩参盘霜霉

本文报道了采自我国新疆天山西部寄生于菊科(Compositae)植物兰花岩参(Cicerbitaazurea (Ldb.) Beauv．)上的盘霜霉菌新种——岩参盘霜霉(Bremia cicerbitae C. J. Li et ZQ．Yuan sp. Nov．)。对该种的形态作了拉丁文和汉文描述,并附有特征图。模式标本保存于新疆农业大学真菌标本室(HMAAC 001154)。     

Pathogenic variation and sexual reproduction in Swedish populations of Bremia lactucae

Summary The host-pathogen interaction between lettuce (Lactuca sativa) and downy mildew (Bremia lactucae) is mainly differential and the resistance so far utilized in the host is vertical. As in many other obligate parasites, the introduction of cultivars with new vertical resistance has exerted a strong selection pressure on the pathogen resulting in significant changes in virulence frequencies and in the establishment of races with new combinations of virulence. Genetic diversity in pathogen populations may arise through mutation and gene flow, and new virulence genotypes may then be established through parasexuality and sexual recombination. In Swedish populations of Bremia lactucae, the pattern of variation in the parasite agrees well with that which might be expected in a diploid, outcrossing organism with frequent sexual reproduction. This is supported by: two or more isolates, different in virulence and mating type, may occur together on the same lettuce leaf; zygotes (oospores) are formed in all populations investigated and the frequency varies from 22% to 98%; oospores germinate rather frequently under suitable conditions. To breed for resistance in dynamic host-pathogen systems such as this one is difficult and the program should preferably be based on race-non-specific resistance.     

Evidence for high degrees of specialisation, evolutionary diversity, and morphological distinctiveness in the genus Bremia

Bremia lactucae is one of the most important pathogens in lettuce production. Recent molecular?studies revealed considerable genetic variation in this species complex. However, only few accessions from the same host have been examined for most species and no study investigating the morphological distinctiveness of phylogenetic lineages of Bremia has so far been reported. Thus it is believed that morphological species delimitation in Bremia is not feasible. In the present study, multiple accessions of neglected species, which had been described decades ago, but have not been widely accepted, were investigated, considering both multi-gene phylogenies and morphological characters. All previously described species from host genera other than Lactuca investigated, Bremia microspora, Bremia ovata, Bremia saussureae, and Bremia sonchicola, could be confirmed as distinct, host-specific entities. Also, morphological characteristics of their conidiophores and conidia allowed delimitation of these species. Therefore, not only the wide species concept to merge all Bremia species on the Asteraceae under B. lactucae is inappropriate but also their delimitation on the basis of morphological characters seems feasible. In addition, it has been shown that Bremia elliptica is phylogenetically distinct from the other species infecting the genus Lactuca, B. lactucae. It is therefore concluded that B. lactucae is most likely limited to Lactuca sativa and closely-related species, and that most species of Bremia are highly host specific. This finding might stimulate the search for durable resistance genes in genera closely related to the genus Lactuca and in divergent species of the genus itself.     

中国叉丝壳属分类研究——Ⅴ.忍冬科上的新种和已知种

本文报道寄生于我国忍冬科植物上的叉丝壳属白粉菌5个种:双盾叉丝壳Microsphacra dipeltae Yu et Lai sp. nov., 二郎山叉丝壳M. erlangshanensis Yu sp. nov.,忍冬叉丝壳M. lonicerae(DC.)Winter,万布叉丝壳M. van-brunctiana Gerard和荚蒾叉丝壳M.viburni(Duby)Blumer,前二者为新种;对新种作了汉文和拉丁文描述,并附有形态图。每一个种都列有寄主种类和国内外分布,并讨论了它们与邻近种之间的区别。     

Recognition of lettuce downy mildew effector BLR38 in Lactuca serriola LS102 requires two unlinked loci

Plant-pathogenic oomycetes secrete effector proteins to suppress host immune responses. Resistance proteins may recognize effectors and activate immunity, which is often associated with a hypersensitive response (HR). Transient expression of effectors in plant germplasm and screening for HR has proven to be a powerful tool in the identification of new resistance genes. In this study, 14 effectors from the lettuce downy mildew Bremia lactucae race Bl:24 were screened for HR induction in over 150 lettuce accessions. Three effectors—BLN06, BLR38 and BLR40—were recognized in specific lettuce lines. The recognition of effector BLR38 in Lactuca serriola LS102 did not co-segregate with resistance against race Bl:24, but was linked to resistance against multiple other B. lactucae races. Two unlinked loci are both required for effector recognition and are located near known major resistance clusters. Gene dosage affects the intensity of the BLR38-triggered HR, but is of minor importance for disease resistance.     

茎点霉和叶点霉两属的新种及国内新记录种

本文对采自东北地区的115份茎点霉(Phoma)和叶点霉(Phyllosticta)的标本进行分类研究,有新种2个和国内新记录种9个。新种是木瓜生叶点霉(Phyllosticta chaenomelesicola L.Yu et Bai)和草玉铃生叶点霉(Phyllosticta convallaricola L.Yu et Bai)。新种有拉丁文和汉文描述及图。对新记录种作了简要介绍。模式标本保存于沈阳农业大学植保系真菌标本室(HMSAU)。     

中国单轴霉分类的研究Ⅱ.寄生在伞形科上的新种和已知种

本文报道在我国伞形科植物上寄生的4种单轴霉(Plasmopara)。其中寄生于鸭儿芹(Cryptotaenia japonic Hassk)上的鸭儿芹单轴霉(Plasmopara cryptotaeniae sp.nov.)和寄生于水芹[Oenanthe javanica(BI.)DC.]及卵叶水芹(O.rosthornii Diels)上的水芹单轴霉(Plasmopara oenantheae sp.nov.)是2个新种。寄生于变豆菜(Sanicula chinensis Bunge)上的变豆菜单轴霉(Plasmopara saniculae Traian et O.savulescu)是亚洲的新记录种。