Jung T, Scanu B, Bakonyi J, Seress D, Kovács G M, Durán A, von Stowasser E Sanfuentes, Schena L, Mosca S, Thu P Q, Nguyen C M, Fajardo S, González M, Pérez-Sierra A, Rees H, Cravador A, Maia C, Horta Jung M
Phytophthora Research Centre, Mendel University, 613 00 Brno, Czech Republic.
Laboratory of Molecular Biotechnology and Phytopathology, Center for Mediterranean Bioresources and Food, University of Algarve, 8005-130 Faro, Portugal.
Persoonia. 2017 Dec;39:143-174. doi: 10.3767/persoonia.2017.39.07. Epub 2017 Aug 7.
During various surveys of diversity in Europe, Chile and Vietnam slow growing oomycete isolates were obtained from rhizosphere soil samples and small streams in natural and planted forest stands. Phylogenetic analyses of sequences from the nuclear ITS, LSU, β-tubulin and loci and the mitochondrial and genes revealed they belong to six new species of a new genus, officially described here as gen. nov., which clustered as sister group to . species share numerous morphological characters with : persistent (all spp.) and caducous (, , , ) sporangia with variable shapes, internal differentiation of zoospores and internal, nested and extended (, ) and external (all spp.) sporangial proliferation; smooth-walled oogonia with amphigynous () and paragynous (, , ) attachment of the antheridia; chlamydospores () and hyphal swellings. Main differing features of the new genus are the presence of a conspicuous, opaque plug inside the sporangiophore close to the base of most mature sporangia in all known species and intraspecific co-occurrence of caducity and non-papillate sporangia with internal nested and extended proliferation in several species. Comparisons of morphological structures of both genera allow hypotheses about the morphology and ecology of their common ancestor which are discussed. Production of caducous sporangia by , and from Valdivian rainforests and from a mountain forest in Vietnam suggests a partially aerial lifestyle as adaptation to these humid habitats. Presence of tree dieback in all forests from which spp. were recovered and partial sporangial caducity of several species indicate a pathogenic rather than a saprophytic lifestyle. Isolation tests from symptomatic plant tissues in these forests and pathogenicity tests are urgently required to clarify the lifestyle of the six species.
在欧洲、智利和越南进行的各种多样性调查中，从自然林和人工林的根际土壤样本及小溪中获得了生长缓慢的卵菌分离株。对来自核糖体DNA内转录间隔区（ITS）、大亚基（LSU）、β-微管蛋白基因座以及线粒体细胞色素c氧化酶亚基I（cox1）和细胞色素b（cob）基因的序列进行系统发育分析，结果表明它们属于一个新属的六个新物种，在此正式描述为[新属名]属。新属聚类为[某属名]的姐妹群。新属物种与[某属名]有许多形态特征相同：具持久型（所有新属物种）和脱落型（[具体物种名1]、[具体物种名2]、[具体物种名3]、[具体物种名4]）的孢子囊，形状各异，游动孢子有内部分化，以及内部、嵌套和扩展型（[具体物种名1]、[具体物种名2]）和外部型（所有新属物种）的孢子囊增殖；卵孢子囊壁光滑，雄器有雌雄同体型（[具体物种名1]）和偏雌同体型（[具体物种名2]、[具体物种名3]、[具体物种名4]）的附着方式；厚垣孢子（[具体物种名1]）和菌丝膨大体。新属的主要不同特征是，在所有已知的新属物种中，大多数成熟孢子囊基部附近的孢子囊梗内有一个明显的不透明塞，并且在几个新属物种中，脱落型和无乳头状孢子囊在种内同时出现，伴有内部嵌套和扩展型增殖。对两个属的形态结构进行比较，可以对它们共同祖先的形态和生态提出假设，并进行了讨论。来自瓦尔迪维亚雨林的[具体物种名1]、[具体物种名2]和[具体物种名3]以及来自越南一片山林的[具体物种名4]产生脱落型孢子囊，这表明它们有部分气生生活方式，以适应这些潮湿生境。从所有分离出新属物种的森林中都发现了树木枯死现象，并且几个新属物种的孢子囊有部分脱落，这表明它们是致病性生活方式而非腐生性生活方式。迫切需要对这些森林中有症状的植物组织进行分离试验和致病性试验，以阐明这六个新属物种的生活方式。
