Plant and Environmental Sciences Department, New Mexico State University, 945 College Drive, Las Cruces, New Mexico, 88003, USA.
Department of Biology, San Diego State University, 5500 Campanile Drive, Mail Code 4614, San Diego, California, 92182, USA.
J Phycol. 2021 Jun;57(3):886-902. doi: 10.1111/jpy.13147. Epub 2021 Mar 23.
Cyanobacteria are crucial ecosystem components in dryland soils. Advances in describing α-level taxonomy are needed to understand what drives their abundance and distribution. We describe Trichotorquatus gen. nov. (Oculatellaceae, Synechococcales, Cyanobacteria) based on four new species isolated from dryland soils including the coastal sage scrub near San Diego, California (USA), the Mojave and Colorado Deserts with sites at Joshua Tree National Park and Mojave National Preserve, California (USA), and the Atacama Desert (Chile). The genus is morphologically characterized by having thin trichomes (<4.5 μm wide), cells both shorter and longer than wide, rarely occurring single and double false branching, necridia appearing singly or in rows, and sheaths with a distinctive collar-like fraying and widening mid-filament, the feature for which the genus is named. The genus is morphologically nearly identical with Leptolyngbya sensu stricto but is phylogenetically quite distant from that genus. It is consequently a cryptic genus that will likely be differentiated in future studies based on 16S rRNA sequence data. The type species, T. maritimus sp. nov. is morphologically distinct from the other three species, T. coquimbo sp. nov., T. andrei sp. nov. and T. ladouxae sp. nov. However, these latter three species are morphologically very close and are considered by the authors to be cryptic species. All species are separated phylogenetically based on sequence of the 16S-23S ITS region. Three distinct ribosomal operons were recovered from the genus, lending difficulty to recognizing further diversity in this morphologically cryptic genus.
蓝细菌是干旱土壤生态系统的重要组成部分。为了了解驱动其丰度和分布的因素,需要在描述 α 级分类方面取得进展。我们根据从包括加利福尼亚州圣地亚哥附近沿海莎草科灌丛、莫哈韦沙漠和科罗拉多沙漠(位于加利福尼亚州约书亚树国家公园和莫哈韦国家保护区)以及阿塔卡马沙漠(智利)的干旱土壤中分离出的四个新物种,描述了 Trichotorquatus 属(Oculatellaceae、Synechococcales、蓝细菌)。该属在形态上的特征是具有较窄的(<4.5μm 宽)纤毛、长短不一的细胞、很少发生单和双假分枝、营养繁殖体单独或成排出现、鞘上具有独特的领状磨损和中部变宽的特征,其名称也由此而来。该属在形态上与 Leptolyngbya 属(狭义)非常相似,但在系统发育上与该属相差甚远。因此,这是一个隐生属,在未来的研究中可能会根据 16S rRNA 序列数据进行区分。模式种 T. maritimus sp. nov. 在形态上与其他三个种(T. coquimbo sp. nov.、T. andrei sp. nov. 和 T. ladouxae sp. nov.)明显不同。然而,后三个种在形态上非常接近,被作者认为是隐生种。所有种在系统发育上是基于 16S-23S ITS 区的序列分开的。从该属中回收了三个不同的核糖体操纵子,这使得难以识别该形态上隐生属的进一步多样性。