Xiao C L, Rogers J D, Kim Y K, Liu Q
Department of Plant Pathology, Washington State University, Tree Fruit Research and Extension Center 1100 North Western Avenue, Wenatchee, Washington 98801, USA.
Mycologia. 2005 Mar-Apr;97(2):464-73. doi: 10.3852/mycologia.97.2.464.
A new species of Phacidiopycnis associated with pome fruits is described. The fungus causes fruit rot on apples during storage and is associated with a twig dieback and canker disease of crabapple trees and dead twigs of pear trees. To characterize the biology of the fungus and compare it with Ph. piri, the type species of the genus, effects of nine media and light on mycelial growth and pycnidial production, mycelial growth in response to temperature and mode of conidial germination in response to nutrient were determined. Apple-juice agar, pear-juice agar, prune-juice agar, potato-dextrose agar (PDA) and malt-extract agar, Czapek-Dox agar and oatmeal agar (OMA) favored mycelial growth. Cornmeal agar (CMA) did not favor mycelial growth. Light effect on pycnidial formation was medium dependent. Abundant pycnidia with mature conidia formed in 14 d old PDA and OMA cultures at 20 C, regardless of light, whereas none or very few pycnidia formed on other media in the dark. Fluorescent light stimulated formation of pycnidia except on CMA. The fungus grew at -3-25 C, with optimum growth at 15-20 C. Conidia germinated either by forming germ tubes or less often by budding. Budding of conidia occurred in 1 and 10% pear-juice solutions but not in 100% pear-juice solution. Six isolates of Ph. washingtonensis from different species of pome fruits had identical ITS sequences. The sizes of the ITS region were the same for both Ph. washingtonensis and Ph. piri, and four polymorphic nucleotide sites were found in the ITS region between Ph. washingtonensis and Ph. piri. The similarity in ITS sequences between these two taxa is confirmatory evidence for the erection of the new species of Phacidiopycnis associated with pome fruits we describe here.
描述了一种与仁果类果实相关的新种盾壳霉。该真菌在苹果贮藏期间引起果实腐烂，并与海棠树的枝条枯死和溃疡病以及梨树的枯枝有关。为了表征该真菌的生物学特性并将其与该属的模式种梨盾壳霉进行比较，测定了9种培养基和光照对菌丝生长和分生孢子器产生的影响、菌丝对温度的响应生长以及分生孢子对营养物质的萌发方式。苹果汁琼脂、梨汁琼脂、李子汁琼脂、马铃薯葡萄糖琼脂（PDA）、麦芽提取物琼脂、查氏琼脂和燕麦片琼脂有利于菌丝生长。玉米粉琼脂（CMA）不利于菌丝生长。光照对分生孢子器形成的影响取决于培养基。无论光照如何，在20℃下培养14天的PDA和OMA培养基上形成了大量带有成熟分生孢子的分生孢子器，而在黑暗中其他培养基上没有或很少形成分生孢子器。除CMA外，荧光灯刺激分生孢子器的形成。该真菌在-3-25℃下生长，最适生长温度为15-20℃。分生孢子通过形成芽管萌发，较少通过出芽萌发。分生孢子在1%和10%的梨汁溶液中出芽，但不在100%的梨汁溶液中出芽。从不同仁果类果实物种中分离出的6株华盛顿盾壳霉具有相同的ITS序列。华盛顿盾壳霉和梨盾壳霉的ITS区域大小相同，在华盛顿盾壳霉和梨盾壳霉之间的ITS区域发现了4个多态性核苷酸位点。这两个分类单元之间ITS序列的相似性是我们在此描述的与仁果类果实相关的新种盾壳霉建立的确证证据。
