de Wet Juanita, Wingfield Michael J, Coutinho Teresa A, Wingfield Brenda D
Tree Pathology Co-operative Programme (TPCP), Department of Microbiology and Plant Pathology.
Department of Genetics, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, 0002, SOUTH AFRICA.
Plant Dis. 2000 Feb;84(2):151-156. doi: 10.1094/PDIS.2000.84.2.151.
Post-hail-associated dieback of Pinus patula and P. radiata trees, induced by Sphaeropsis sapinea (=Diplodia pinea), is a common and important disease in commercial pine plantations. Two morphotypes, A and B, have been described for this fungus based on differences in cultural characteristics, conidial morphology, and virulence among isolates from the north central United States. The existence of the two described morphotypes was later verified through the use of random amplified polymorphic DNA (RAPD) analyses, and the morphotypes were designated as the A and B RAPD marker groups. The objective of this study was to characterize a set of S. sapinea isolates from South Africa, Indonesia, and Mexico using RAPD analysis and DNA sequencing of the internal transcribed spacer (ITS) region of the ribosomal DNA operon. Sizes of conidia and culture morphology were, furthermore, used to compare the three groups of S. sapinea isolates that emerged from the RAPD analysis. Two of the RAPD groups included isolates from the United States, representing the A and B morphotypes, while the third RAPD group accommodated Indonesian and one Mexican isolate. ITS sequences of all the S. sapinea isolates were highly homologous and resolved only the A and B RAPD groups. The ITS sequences of the isolates in the third RAPD group were the same as those of the A RAPD group. Conidia of isolates representing the A and B morphotypes were approximately the same size, but those of the third RAPD group were significantly longer. RAPD analysis enabled us to identify a third group of S. sapinea that is different from the well-recognized A and B groups. Isolates in this third RAPD group also have a distinct morphological characteristic and thus represent a third discrete morphological group, which we refer to as the C morphotype of S. sapinea.
由松球壳孢菌（=松色二孢菌）引起的辐射松和展叶松雹灾后衰退，是商业松树林中一种常见且重要的病害。基于来自美国中北部的分离株在培养特征、分生孢子形态和毒力方面的差异，已描述了该真菌的两种形态型，即A和B。后来通过随机扩增多态性DNA（RAPD）分析证实了所描述的两种形态型的存在，并将这些形态型指定为A和B RAPD标记组。本研究的目的是使用RAPD分析以及核糖体DNA操纵子内部转录间隔区（ITS）区域的DNA测序，对来自南非、印度尼西亚和墨西哥的一组松球壳孢菌分离株进行特征描述。此外，还利用分生孢子大小和培养形态对RAPD分析中出现的三组松球壳孢菌分离株进行比较。其中两个RAPD组包括来自美国的分离株，代表A和B形态型，而第三个RAPD组包含印度尼西亚和一个墨西哥分离株。所有松球壳孢菌分离株的ITS序列高度同源，仅分辨出A和B RAPD组。第三个RAPD组中分离株的ITS序列与A RAPD组的相同。代表A和B形态型的分离株的分生孢子大小大致相同，但第三个RAPD组的分生孢子明显更长。RAPD分析使我们能够识别出与公认的A和B组不同的第三组松球壳孢菌。这个第三个RAPD组中的分离株也具有独特的形态特征，因此代表了第三个离散的形态组，我们将其称为松球壳孢菌的C形态型。
