Vitale A, Polizzi G
Dipartimento di Scienze e Tecnologie Fitosanitarie, University of Catania, Via S. Sofia 100, 95123 Catania, Italy.
Plant Dis. 2007 Mar;91(3):328. doi: 10.1094/PDIS-91-3-0328A.
Leaf spots, stem lesions, crown rot, and root rot, caused by heterothallic fungus Cylindrocladium pauciramosum C.L. Schoch & Crous,, on young plants in a nursery represent an important problem in many representative ornamental plant-growing areas of Italy since the disease was first reported in 1993 (2). Symptoms observed during surveys in Italy from 1993 to 2005 were attributed solely to the asexual stage, and the teleomorph (Calonectria pauciramosa C.L. Schoch & Crous) was never found. In October 2005, orange-to-red brown fungal fruiting bodies pertaining to the genus Calonectria were observed in belowground regions and at the soil line on collar and stem tissues of seedlings of the mastic tree (Pistacia lentiscus L., Anacardiaceae) affected by damping off in two nurseries of eastern Sicily. The sexual structures were solitary or in groups, orange-to-red brown, subglobose to ovoid. On the basis of 50 microscopic observations of leaf tissues, they ranged from 180 to 280 μm in diameter and from 270 to 400 μm high. In the presence of adequate moisture, ascospores were discharged from mature perithecia in visible, viscous, and white droplets. Asci containing eight ascospores were clavate and tapering to a long thin stalk. Fusoid ascospores were hyaline and guttulate with rounded ends, slightly curved, 1-septate, not or slightly constricted at the septum, and measured 33 to 39 μm long and 6 to 8 μm wide. However, measurements show that perithecia, asci, and ascospores also fall within the range described by Schoch et al. (3). Single ascospore cultures did not produce perithecia. On the basis of these descriptions and the ability of single-ascospore cultures to mate with two Italian (DISTEF-G87 and DISTEF-G128) and two South African (STE-U 971 and STE-U 1670) selected tester strains of Cylindrocladium pauciramosum (2), the perithecia were identified as C. pauciramosa. To our knowledge, this is the first natural occurrence of the perfect stage of Cylindrocladium pauciramosum in Italy. The presence of the teleomorph is very important because it represents a second means of spread after conidia. Furthermore, the occurrence of the teleomorph also could lead to a 1:1 mating type ratio. In this case, lower percentages of hermaphrodites should be expected (1,4). References: (1) G. Polizzi et al. J. Plant Pathol. 80:262, 1998. (2) G. Polizzi and P. W. Crous. Eur. J. Plant Pathol. 105:413, 1999. (3) C. L. Schoch et al. Mycologia 91:286, 1999. (4) C. L. Schoch et al. Plant Dis. 85:941, 2001.
由异宗配合真菌少枝柱盘孢菌（Cylindrocladium pauciramosum C.L. Schoch & Crous）引起的叶斑病、茎部病斑、根颈腐烂和根腐病，对意大利许多典型观赏植物种植区的苗圃中的幼苗来说是一个重要问题，自1993年首次报道该病以来一直如此（2）。1993年至2005年在意大利调查期间观察到的症状仅归因于无性阶段，从未发现有性阶段（少枝卡氏腔菌（Calonectria pauciramosa C.L. Schoch & Crous））。2005年10月，在西西里岛东部两个苗圃中受猝倒病影响的乳香黄连木（Pistacia lentiscus L.，漆树科）幼苗的地下区域以及茎基部和茎组织的土壤线处，观察到了属于卡氏腔菌属的橙红色至红棕色真菌子实体。这些有性结构单个或成群出现，橙红色至红棕色，近球形至卵形。基于对叶片组织的50次显微镜观察，它们的直径为180至280μm，高为270至400μm。在有足够湿度的情况下，子囊孢子从成熟的子囊壳中以可见的、粘性的白色液滴形式释放出来。含有八个子囊孢子的子囊呈棒状，向细长的柄部逐渐变细。梭形子囊孢子无色透明，具油滴，两端圆形，稍弯曲，具1个隔膜，在隔膜处不缢缩或稍缢缩，长33至39μm，宽6至8μm。然而，测量结果表明，子囊壳、子囊和子囊孢子也在Schoch等人（3）描述的范围内。单孢子培养物未产生子囊壳。基于这些描述以及单孢子培养物与两种意大利（DISTEF - G87和DISTEF - G128）和两种南非（STE - U 971和STE - U 1670）选定的少枝柱盘孢菌测试菌株交配的能力（2），这些子囊壳被鉴定为少枝柱盘孢菌。据我们所知，这是少枝柱盘孢菌在意大利首次自然出现有性阶段。有性阶段的存在非常重要，因为它代表了分生孢子之后的第二种传播方式。此外，有性阶段的出现也可能导致1:1的交配型比例。在这种情况下，预计雌雄同体的比例会更低（1,4）。参考文献：（1）G. Polizzi等人，《植物病理学杂志》80:262，1998年。（2）G. Polizzi和P.W. Crous，《欧洲植物病理学杂志》105:413，1999年。（3）C.L. Schoch等人，《真菌学》91:286，1999年。（4）C.L. Schoch等人，《植物病害》85:941，2001年。
