菝葜上一锈菌新种

本文描述了采自海南省的光叶菝葜Smilax corbularia Kunth var.woodii(Merr.)T.Koyama上的膨孢柄锈菌Puccinia oedospora J.Y.Zhuang sp.nov.此菌的夏孢子大小38—50×35—42μm,壁分两层,内层肉桂褐色,厚2—2.5μm,外层无色膨大,厚达5—13μm,顶部两端具明显帽状突起;冬孢子大小30—48×20—30μm,双胞,壁亦分两层,内层淡黄褐色或污黄色,极薄,外层近无色,厚2—3μm。就孢壁结构而言,此菌酷似分布中、南美寄生于紫葳科和马鞭草科植物上的饰柄锈菌属Prospodium的种。但其冬孢子壁光滑,柄无饰物,其寄主属单子叶植物的百合科(或菝葜科),故暂把它置于柄锈菌属中。     

垂头菊柄锈菌新种

本文报告了盘花垂头菊Cremanthodium discoideum Maxim.上的一锈菌新种——垂头菊柄锈菌Puccinia cremanthodii J.Y.Zhuang et S.X.Wei。模式标本采自青海省,保藏在中国科学院微生物研究所真菌标本室。本种主要特征是:冬孢子椭圆形或近倒卵形,两端圆,中部略缢缩,32—48×19—32μm,孢壁肉桂褐色至粟褐色,2—3.5μm厚,连同孔帽约5μm厚,有不规则的网状皱纹,柄达100μm长,易破碎。垂头菊属植物上未曾记载过有锈菌,本种为首次报道。垂头菊属是喜马拉雅和青藏高原的特有属,分布高海拔地带,推测此菌可能为青藏高原所特有。     

柄锈属二新种

本文描述了柄锈属的二个新种,一种是寄生在金线草(Antenoron filiforme(Thunb.)Roberty et Vautier](蓼科)上的金线草柄锈(Puccinia antenori J.Y.Zhuang et Wang sp.nov.),模式标本采自福建省浦城;另一种是寄生在花锚(Halenia sp.)(龙胆科)上的波壁柄锈(Puccinia undulitunicata J.Y.Zhuang et Wang sp.nov.),模式标本采自四川省炉霍与甘孜之间的锣锅梁子。金线草柄锈的夏孢子堆均匀密布于叶背面,褐色粉末状;夏孢子亚球形、倒卵形或椭圆形,18—35×17—23μm,壁厚1—2μm,淡黄褐色,有刺,芽孔2个,生在腰部附近。冬孢子堆颜色较深;冬孢子棍棒形或椭圆形,隔膜处不缢缩或稍缢缩,25—45×13—23μm, 顶壁厚3.5—5μm,肉桂褐色,光滑;上部细胞芽孔顶生,下部细胞芽孔生于隔膜附近。本种近似韦氏蓼柄锈(Puccinia polygoni-weyrichii T.Miyake),但其夏孢子壁厚度均匀,冬孢子顶壁增厚,而后者夏孢子顶壁增厚(5—7μm),冬孢子壁厚度均匀(2—2.5μm)。波壁柄锈的冬孢子堆在叶两面散生,黑褐色或黑色粉末状。夏孢子在冬孢子堆中混杂,近球形或宽椭圆形,22—25×18—23μm,壁厚2—2.5μm,密生小刺,暗褐色,有3—5个散生的芽孔。冬孢子椭圆形或倒卵形,隔膜处不缢缩,25—40×20—25μm,壁波状起伏,厚度不均匀(1.5—2.5μm),栗褐色;上部细胞芽孔顶生,下部细胞芽孔近基生或基生。本种由于冬孢子壁呈波状起伏而不同于龙胆科植物上的其他已知的柄锈。     

青藏高原东缘的锈菌资料IV.悬钩子上一个类似柄锈菌的新锈菌

本文报告采自四川西部九寨沟自然保护区菰帽悬钩子(Rubus pileatus Focke)上的一个锈菌新种。标本上仅见冬孢子堆,冬孢子双胞,类似柄锈菌的冬孢子。由于未见性子器,属的地位尚难确定。然而,此菌的冬孢子堆外观酷似悬钩子植物上特有的单种属阿氏锈菌属(Arthuriomyces)。镜下观察测得孢子大小为40-55(-65) × 22-28 μm,孢壁厚度为3-4.5 μm,有细皱纹,每个细胞各具一芽孔。从芽孔数及位置看符合阿氏锈菌属的特征,因而将此菌暂隶于此属,命名为悬钩子生阿氏锈菌(Arthuriomyces rubicola sp. nov.)     

青藏高原东缘的锈菌资料Ⅱ.裸堆串孢锈菌属在我国的首次记录

裸堆串孢锈菌属以冬孢子单孢串生为主要特征,孢子堆裸露缺包被,外观酷似柄锈属的孢子堆。此属已知7种。寄生于菊科,大戟科和荨麻科植物,6种分布美洲,1种分布东亚.本文报告亚洲仅知的一种,即寄生于宽叶孢麻Urtica laetevirens Maxim.的川息尔堆串孢锈菌Baeodromus tranzschelii Azbukina,标本采自四川九寨沟(岷山).     

牛紏吴茱萸柄锈菌新种

本文描述了采自海南省琼中县牛紏吴茱萸Evodia trichotoma (Lour.) Pierre(芸香科)上的柄锈菌一新种——Puccinia evodiae-trichotomae J. -y. Zhuang。本种与巴布亚一新几内亚产的吴茱萸Evodia sp.上的另一种柄锈菌Puccinia evodiae Cumm.略近似,但冬孢子堆裸露呈垫状,而后者则深埋于病瘿中。冬孢子形状与大小和后者相仿,然而少数孢子可长达60μm,顶壁有时略增厚,颜色很浅或近几色。镜下可见一些孢子已萌发,推测可能属无眠冬孢型。芸香科植物上的柄锈菌目前仅知10种,本种特征与它们均不相同,故鉴定为新种。本新种模式标本保藏在中国科学院微生物研究所真菌标本室。     

中国块菌属一新种

本文描述了块菌属(Tuber)的一个新种,巨孢块菌(Tuber gigantosporum)。这一新种1989年采于四川省会东县。它的子囊孢子特殊大,一般105—115×75μm,最大可达120×80μm,小者亦可达80×55μm。而块菌属已知种的子囊孢子的大小一般在21—52×15—38μm范围内,最大也不超过90×60μm。仅此一点已使其明显区别于该属任何已知种。此外,该种孢子壁异常厚,可达14μm,有三层,也是别于其它块菌已知种的重要特征。该块菌生于地下,与云南松有共生关系。模式标本保存在中国科学院沈阳应用生态所植物标本室(IFS)。     

油杉叶锈研究

油杉叶锈寄生在油杉叶上,作者研究了此菌的模式标本、同引模式标本和后来在模式地区采得的标本;并和柱锈属、金锈属、鞘锈属、栅锈属等11属锈菌作了比较研究。证明这种锈菌冬孢子堆为带状或扁平柱状,无细胞组织垫座,无被;冬孢子可互相撕离而不破裂,孢壁薄而无色,无柄。这些性状说明它不同于柱锈而近于金锈属。因此作者将其转归金锈属,改定为Chrysomyxa keteleeriae(Tai)Wang et Peterson新组合,(基础异名Cronartium keteleeriae Tai)。这种锈菌与其它生在云杉、铁杉叶上的4种短生金锈属锈菌一样,冬孢子堆都生在针叶上,窄带状到扁平柱状或圆形有短柄,鲜桔色或桔红色。虽然油杉叶锈冬孢子堆高达 6mm,但这只是同一属内的种间差别,也象Coleosporium crowellii Cumm。与同属内其它种的区别一样,属于种间的差别。云南粗杉金锈的冬孢子可以从10—20细胞组成的有柄孢子分离产生,正如鞘柄锈冬孢子的互相分离产生一样。冷杉金锈,特别是变形金锈的冬孢子的产生方式也是这样。生在同种油杉寄主枝上的Peridermium kunmingense Jen和油杉叶锈有无关系,需在接种试验后才能肯定。从寄主与寄主菌共同进化关系看,这种锈菌的寄主——油杉在分类系统上与金锈属寄主——云杉、铁杉等属近缘,传统分类学家多认为它同冷杉、银杉、黄杉等属同归冷杉亚科。但也有学者认为油杉有许多原始性状,与冷杉亚科无关。作者在油杉上发现金锈可能支持了传统植物分类系统。     

异孢耳霉的分离和鉴定

本文报道了1987年冬季在南平地区分离的一个腐生耳霉新纪录——异孢耳霉(Conidiobolus incongruus),分生孢子梗无色,不分叉,6—10×50—130μm,分生孢子无色,多数球形,少数亚球形至椭圆形,13—33×16—35μm,易萌发,多数形成菌丝体,少数可形成次生分生孢子或三生分生孢子,弹射在水琼脂上的分生孢子常能迅速产生小分生孢子。接合孢子球形,淡黄色,光滑,直径18—29μm,壁厚2.5—5μm。     

丛枝菌根真菌的三个我国新记录种

象牙白球囊霉(图1~3)Glomus eburneum Kennedy,Stutz&Morton,Mycologia,91(6):1083~1093,1999.孢子透明-象牙白色,圆形,近圆形,直径35~120μm,或不规则形,35~60×100~120μm。孢壁2层,第一层无色透明,厚1~2μm,老孢子中该层壁易缺失。第二层壁,层状透明,厚1.0~2.5μm,压碎孢子该层壁易皱缩而与第一层壁分开。连孢菌丝无色透明,宽2~5μm,内含物油状。连孢菌丝有隔包住内含物,Melzer’s试剂中孢子无染色反应。标本号:B1,B4,B7,B10,Z2,Z3,Z6,Z9,Z10,Z12,N3,N6,N9,N11。从莱阳农学院长期定位试验田玉米和小麦根际土壤中分离得到。海得拉…     

Carotenoid pigments in rust fungi: Extraction,separation, quantification and characterisation

Diseases caused by rust fungi represent critical constraints to global plant production. A characteristic feature of rust pathogens is the striking pigments they produce in one or more spore forms, which give them a rusty appearance. Here, we review the literature published to date on the extraction, separation, quantification and characterisation of carotenoid pigments in rust fungi. These pigments are thought to protect rust fungi against UV radiation and oxidative stress, and possibly act as virulence factors. The yellow-orange colour of some rust species is due to carotenoid pigments. Four carotenoids have been found in rust fungi: phytoene, lycopene, γ-carotene and β-carotene, but their relative contributions to biological functions are largely unknown. Different pre-processes and storage of spore materials, as well as different extraction processes, have been applied in a wide range of investigations on rust spore pigments. We find that the value of the current literature on rust carotenoids for taxonomic diagnostics in understanding the evolution of pigment biosynthesis and in assessing their role in pathogenesis is limited. Re-investigation of rust carotenoid composition using modern analytical technologies is therefore critical to further these fields of research. Our review includes detailed guidance on choice of techniques for rust carotenoid experimental analyses.     

Genetics of durable resistance to leaf rust and stripe rust of an Indian wheat cultivar HD2009

The Indian bread wheat cultivar HD2009 has maintained its partial resistance to leaf rust and stripe rust in India since its release in 1976. To examine the nature, number and mode of inheritance of its genes for partial leaf rust and stripe rust resistance, this cultivar was crossed with cultivar WL711, which is susceptible to leaf rust and stripe rust. The F1, F2, F3 and F5 generations from this cross were assessed separately for adult plant disease severity under artificial epidemic of race 77-5 of leaf rust and race 46S119 of stripe rust. Segregation for rust reaction in the F2, F3 and F5 generations indicated that resistance to each of these rust diseases is based on 2 genes, each with additive effects. Although the leaf rust resistance of HD2009 is similar in expression to that conferred by the gene Lr34, but unlike the wheats carrying this gene, cultivar HD2009 did not show leaf tip necrosis, a morphological marker believed to be tightly linked to the leaf rust resistance gene Lr34. Thus, the non-hypersensitive resistance of HD2009 was ascribed to genes other than Lr34.     

锈寄生菌的分布及其林间发生规律的研究

锈寄生菌主要分布于辽宁省的本溪、抚顺和丹东地区,对其在林间发生规律的研究结果表明,锈寄生菌孢子飞散高峰时出现在零点和12点;一年内孢子飞散时期为6月中旬至9月下旬,8月下旬为飞散高峰期。孢子飞散量受控于气象因子,特别与降雨量关系密切,锈寄生菌的潜育期为1个月左右。落叶松褐锈病的发生程度随着锈寄生菌寄生率的逐年增加而减轻,表明锈寄生菌对落叶松褐锈病有一定的控制作用。     

Undescribed wheat gene for partial leaf rust and stripe rust resistance from Thatcher derivatives RL6058 and 90RN249 carryingLr34

Inheritance of partial leaf rust and stripe rust resistance of a Thatcher wheat 90RN2491, earlier reported to carry two doses of the gene pairLr34-Yr18 and the reference line RL6058 (6*Thatcher/PI58548) for theLr34-Yr18 gene pair was studied against predominant and highly virulent Indian races. Thatcher derivatives 90RN2491 and RL6058 were intercrossed as well as crossed with the leaf rust and stripe rust susceptible Indian cultivar WL711. The F₁, F₂ and F₃ generations from these crosses were assessed for rust severity against leaf rust race 77-5 and stripe rust race 46S119. The F₂ and F₃ generations from the crosses of RL6058 and 90RN2491 with WL711, segregated 15 resistant : 1 susceptible (F₂) and 7 homozygous resistant : 8 segregating : 1 homozygous susceptible (F₃) ratios, respectively, both for leaf rust and stripe rust severity. Therefore, partial resistance against each of the leaf rust and stripe rust races in both RL6058 and 90RN2491 is ascribed to two independently inherited dominant genes. One of the two genes for leaf rust and stripe rust resistance in 90RN2491 and RL6058 isLr34 and the linked geneYr18, respectively. The second leaf rust resistance gene in both the Thatcher lines segregated independently of stripe rust resistance. Therefore, it is notLr34 and it remains unidentified.     

中国野生鸭茅种质资源锈病抗性研究

鸭茅是一种著名的温带牧草,容易感染锈病。本研究从植株感病率、感病严重度、病情指数和反应指数4方面对国内37份鸭茅种质资源(野生资源35份)进行锈病的病情调查及抗病性研究。研究初步揭示了鸭茅锈病的发病规律,研究结果显示02-106、02-107、90-130、02-115等4份材料对鸭茅锈病具有较好抗性,可作为育种材料进一步深入研究。     

Genetic studies of leaf and stem rust resistance in six accessions of Triticum turgidum var. dicoccoides.

Six accessions of Triticum turgidum var. dicoccoides L. (4x, AABB) of diverse origin were tested with 10 races of leaf rust (Puccinia recondita f.sp. tritici Rob. ex Desm.) and 10 races of stem rust (P. graminis f.sp. tritici Eriks. &Henn.). Their infection type patterns were all different from those of lines carrying the Lr or Sr genes on the A or B genome chromosomes with the same races. The unique reaction patterns are probably controlled by genes for leaf rust or stem rust resistance that have not been previously identified. The six dicoccoides accessions were crossed with leaf rust susceptible RL6089 durum wheat and stem rust susceptible 'Kubanka' durum wheat to determine the inheritance of resistance. They were also crossed in diallel to see whether they carried common genes. Seedlings of F1, F2, and BC1F2 generations from the crosses of the dicoccoides accessions with RL6089 were tested with leaf rust race 15 and those from the crosses with 'Kubanka' were tested with stem rust race 15B-1. The F2 populations from the diallel crosses were tested with both races. The data from the crosses with the susceptible durum wheats showed that resistance to leaf rust race 15 and stem rust race 15B-1 in each of the six dicoccoides accessions is conferred by a single dominant or partially dominant gene. In the diallel crosses, the dominance of resistance appeared to be affected by different genetic backgrounds. With one exception, the accessions carry different resistance genes: CI7181 and PI 197483 carry a common gene for resistance to leaf rust race 15. Thus, wild emmer wheat has considerable genetic diversity for rust resistance and is a promising source of new rust resistance genes for cultivated wheats.     

TECHNICAL ADVANCE: Transformation of the flax rust fungus,Melampsora lini: selection via silencing of an avirulence gene

Rust fungi cause devastating diseases on many important food crops, with a damaging stem rust epidemic currently affecting wheat production in Africa and the Middle East. These parasitic fungi propagate exclusively on plants, precluding the use of many biotechnological tools available for other culturable fungi. In particular the lack of a stable transformation system has been an impediment to the genetic manipulation required for molecular analysis of rust pathogenicity. We have developed an Agrobacterium‐mediated genetic transformation procedure for the model flax rust fungus Melampsora lini, which infects flax (Linum usitatissimum). Selection of transgenic rust lines is based on silencing of AvrL567, which encodes a rust effector protein that is recognised by the flax L6 immune receptor. The non‐transgenic rust line is unable to infect flax plants expressing L6, while silenced transgenic lines are virulent on these plants, providing an effective selection system. This directly confirms that the cloned AvrL567 gene is responsible for flax rust virulence phenotypes, and demonstrates the utility of this system to probe rust gene function.     

Inheritance of leaf rust and stem rust resistance in 'Roblin' wheat.

The Canadian common wheat (Triticum aestivum L.) cultivar 'Roblin' is resistant to both leaf rust (Puccinia recondita Rob. ex. Desm.) and stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. and E. Henn.). To study the genetics of this resistance, 'Roblin' was crossed with 'Thatcher', a leaf rust susceptible cultivar, and RL6071, a stem rust susceptible line. A set of F6 random lines was developed from each cross. The random lines and the parents were grown in a field rust nursery artificially inoculated with a mixture of P. recondita and P. graminis isolates and scored for rust reaction. The same material was tested with specific races of leaf rust and stem rust. These data indicated that 'Roblin' has Lr1, Lr10, Lr13, and Lr34 for resistance to P. recondita and Sr5, Sr9b, Sr11, and possibly Sr7a and Sr12 for resistance to P. graminis. In a 'Thatcher' background, the presence of Lr34 contributes to improve stem rust resistance, which appears also to occur in 'Roblin'.     

Induction of Systemic Acquired Resistance in Pea against Rust (Uromyces pisi) by Exogenous Application of Biotic and Abiotic Inducers

Pea breeding for rust resistance is hampered by the little resistance available in pea. In an attempt to validate alternative control methods, we evaluated the potential of systemic acquired resistance for rust control in pea by biotic and abiotic inducers. Challenge with a virulent or with an avirulent rust isolate prior to pea rust inoculation did not induce resistance either locally or systemically. Exogenous application of salicylic acid in the range 5–10 m m prior to rust inoculation did not protect against rust locally, but reduced rust infection systemically in first upper leaf node although not in the upper ones. Some phytotoxicity was observed at 10 m m . Exogenous application of benzothiadiazole in the range 1–10 m m provided locally a 30–40% reduction in infection frequency. At least 5 m m was needed to reduce rust infection systemically in first upper leaf, and 10 m m in upper ones. Exogenous application of dl -3-amino- n -butyric acid (BABA) provided locally a 45–58% reduction in infection frequency, while systemically a 33–58 and 49–58% reduction of rust symptoms was achieved on leaves at second and third nodes respectively. BABA application was not associated with symptoms of phytotoxicity.     

Comparison of the Wheat Brown and Yellow Rusts for Monocyclic Sporulation and Infection Processes, and their Polycyclic Consequences

Sporulation capacity and infection efficiency of wheat brown and yellow rusts were measured daily in favourable controlled conditions. Monocyclic sporulation capacity for a single lesion of yellow rust was 9 times greater than for an isolated lesion of brown rust, and 40 times greater than for a lesion of brown rust at medium infection density. Infection efficiency fluctuated and reached about 40 % for brown rust but remained under 5% for yellow rust. For both fungi, sporulation capacity and infection efficiency compensated for each other, but their product, the daily multiplication factor, was greater for yellow rust than for brown rust. Progeny/parent ratio was 3 times greater for yellow rust. Effect of daily multiplication factor variations on epidemic progress was simulated using a simple matrix model. Increase in number of lesions was faster in brown rust than in yellow rust because of a latent period shorter by 2 days. Semi-systemic growth of yellow rust fungus reduced, however, the difference between both fungi when sporulating surface was calculated.