González M S, Rondón A
Instituto Nacional de Investigaciones Agrícolas, Centro Nacional de Investigaciones Agropecuarias, Apdo. Postal 4653, Maracay 2101, Venezuela.
Plant Dis. 2005 Jul;89(7):773. doi: 10.1094/PD-89-0773C.
During August 2003, guava fruit (Psidium guajava L.) cv. Red Dominicana from Cojedes state in Venezuela showed circular, purple-to-brown lesions (0.5 to 1.0 cm) that spread over all surfaces and became black and shrunken on severely affected fruit. Symptomatic tissues were plated aseptically on potato dextrose agar (PDA). Colonies that were initially gray and turned black with age were consistently isolated. The fungus was characterized by dense, submerged, brown-to-black mycelium with septate hyphae. Ascocarps were perithecial, abundant, granulose, subglobose to cylindric obpyriform, solitary or aggregated, mostly unilocular with prominent long necks; ascocarp walls were stromatic, composed of several layers of cells, thick walled, and deeply pigmented on the outside. Asci were subclavate to cylindrical, stipitate, 44 to 84 × 7 to 9 μm, and eight-spored; asci walls were thick and bitunicate. Ascospores were unicellular, hyaline, guttulate, fusiform ellipsoid, widest in the mid-region with rounded ends and gelatinous plugs, and 12 to 17 × 4.5 μm. Conidiomata were pycnidial, intermixed among ascocarps, variable in shape, dark brown, solitary or aggregated, ostiolate, and with long necks up to 1 mm. Pycnidial walls were pseudoparenchymatic, multicellular, and composed of many layers of brown compressed cells. Conidiogenous cells were hyaline, subglobose to cylindrical, and smooth, and holoblastic. Conidia were hyaline, unicellular, obovate, 6 to 12 (7.5) × 5 to 8 μm, slightly truncate at the bases, rounded at apices, guttulate, and provided a gelatinous envelope and apical appendage. Appendages were hyaline, tubular, smooth, and 3.0 to 4.5 × 0.5 μm. The fungus is homothallic because single ascospores and single conidia developed ascigerous states. The ascigerous state was identified as Guignardia psidii (1) and the anamorph as Phyllosticta psidiicola (1,2). Pathogenicity tests were conducted on detached fruits inoculated with monosporic cultures. Pathogenesis and symptom development only occurred when a mixture of mycelium, ascospores, and conidia was used as inoculum. The fungus was reisolated from symptomatic fruit tissues. To our knowledge, this is the first report of Guignardia psidii, an ascigerous state of Phyllosticta psidiicola from guava fruits in Venezuela. References: (1) B. A. Ullasa and R. D. Rawal. Curr. Sci. 53:435, 1984. (2) H. A. van der Aa. Page 95 in: No. 5, Stud. Mycol., 1973.
2003年8月期间，来自委内瑞拉科赫德斯州的番石榴（Psidium guajava L.）品种“红多米尼加”果实上出现圆形、由紫色至棕色的病斑（直径0.5至1.0厘米），这些病斑蔓延至果实整个表面，严重受害的果实会变黑并萎缩。将有症状的组织无菌接种到马铃薯葡萄糖琼脂（PDA）培养基上。最初呈灰色、随时间变黑的菌落被持续分离出来。该真菌的特征为具有密集、埋生、棕色至黑色的菌丝体以及有隔膜的菌丝。子囊果为子囊壳，数量众多，颗粒状，近球形至圆柱形倒梨形，单个或聚集，多数单腔且有突出的长颈；子囊果壁为子座状，由多层细胞组成，壁厚，外部颜色深。子囊呈近棒形至圆柱形，有柄，44至84×7至9微米，含8个孢子；子囊壁厚且为双层壁。子囊孢子单细胞，透明，具油滴，梭形椭圆形，中部最宽，两端圆形，有胶状塞，大小为12至17×4.5微米。分生孢子器为分生孢子盘，与子囊果混生，形状多样，深褐色，单个或聚集，有孔口，颈部长达1毫米。分生孢子盘壁为拟薄壁组织，多细胞，由多层棕色压缩细胞组成。产孢细胞透明，近球形至圆柱形，表面光滑，全壁芽生。分生孢子透明，单细胞，倒卵形，6至12（7.5）×5至8微米，基部略截形，顶端圆形，具油滴，有胶状包被和顶端附属物。附属物透明，管状，光滑，3.0至4.5×0.5微米。该真菌为同宗配合，因为单个子囊孢子和单个分生孢子都能发育出产囊体状态。产囊体状态被鉴定为番石榴球座菌（1），无性型为番石榴叶点霉（1,2）。用单孢培养物对接种离体果实进行致病性测试。仅当使用菌丝体、子囊孢子和分生孢子混合物作为接种物时才会发生致病作用和症状发展。从有症状的果实组织中再次分离出该真菌。据我们所知，这是委内瑞拉番石榴果实上首次报道番石榴球座菌，它是番石榴叶点霉的产囊体状态。参考文献：（1）B. A. Ullasa和R. D. Rawal。《当代科学》53:435，1984年。（2）H. A. van der Aa。载于：《真菌研究》第5期，第95页，1973年。
