<i>Septoglomus mexicanum</i>, a new species of arbuscular mycorrhizal fungi from semiarid regions in Mexico

<i>Septoglomus mexicanum</i> is here described as a new species of arbuscular mycorrhizal fungi (AMF; Glomeromycota) based on morphological and phylogenetic analyses. It was isolated from rhizospheric soil of two endemic Mexican legumes: <i>Prosopis laevigata</i> and <i>Mimosa luisana</i>, which grow in semiarid regions of central Mexico. <i>Septoglomus mexicanum</i> is characterized by forming globose spores of (154.5–)202.8(–228.9) µm diam and a spore wall consisting of four layers (SWL1–SWL4): outer wall layer (SWL1) hyaline, evanescent, (1.7–)3.2(–4.3) µm thick; SWL2 laminate and smooth, orange to reddish orange, (3.1–)4.5(–6.1) µm thick; SWL3 laminate, smooth, reddish orange to reddish brown, (4.1–)5.1(–5.7) µm thick; and SWL4 hyaline, semiflexible, (0.93–)1.2(–1.4) µm thick. None of the spore wall layers stain with Melzer’s reagent. The subtending hypha has a color from yellowish to golden and presents a septum on spore base. <i>Septoglomus mexicanum</i> can be distinguished from all other <i>Septoglomus</i> species by spore size and color, by spore wall structure (four layers), and by color change of the subtending hypha. Phylogenetic analysis based on the AMF extended DNA barcode covering a 1.5-kb fragment of the small subunit (SSU), internal transcribed spacer region (ITS1-5.8S-ITS2), and the large subunit (LSU) of rRNA genes places <i>S. mexicanum</i> in the genus <i>Septoglomus</i>, separated from other described <i>Septoglomus</i> species, especially <i>S. turnauae</i>, with whom it could be confused morphologically. All available sequences in public databases suggest that this new fungal species has not yet been previously detected. Thus, there are currently 149 Glomeromycota species registered in Mexico, representing 47.4% of the known species worldwide.本研究通过形态学与系统发育分析，将墨西哥隔孢囊霉（Septoglomus mexicanum）确立为球囊霉门（Glomeromycota）丛枝菌根真菌（arbuscular mycorrhizal fungi, AMF）的一个新物种。该菌株分离自墨西哥两种特有豆科植物光叶牧豆树（Prosopis laevigata）与路易萨含羞草（Mimosa luisana）的根际土壤，这些植物生长于墨西哥中部半干旱区域。墨西哥隔孢囊霉的典型特征为形成球状孢子，孢子直径为(154.5–)202.8(–228.9) μm，孢子壁共四层（SWL1–SWL4）：外层壁（SWL1）呈透明状、易脱落，厚度为(1.7–)3.2(–4.3) μm；SWL2为层状结构且表面光滑，颜色介于橙色至红橙色之间，厚度为(3.1–)4.5(–6.1) μm；SWL3同样为层状光滑结构，颜色从红橙色过渡至红棕色，厚度为(4.1–)5.1(–5.7) μm；SWL4呈透明状、半柔韧，厚度为(0.93–)1.2(–1.4) μm。所有孢子壁层均不与梅尔泽试剂（Melzer’s reagent）发生染色反应。支撑菌丝的颜色为淡黄色至金黄色，且在孢子基部具隔膜。墨西哥隔孢囊霉可通过孢子尺寸与颜色、孢子壁结构（四层结构）以及支撑菌丝的颜色变化，与所有其他隔孢囊霉属（Septoglomus）物种相区分。基于覆盖核糖体RNA基因小亚基（small subunit, SSU）1.5 kb片段、内转录间隔区（internal transcribed spacer region, ITS1-5.8S-ITS2）以及大亚基（large subunit, LSU）的AMF扩展DNA条形码开展的系统发育分析显示，墨西哥隔孢囊霉隶属于隔孢囊霉属，与其他已发表的隔孢囊霉属物种形成独立分支，其中在形态上最易与其混淆的是S. turnauae。公共数据库中所有可用序列均表明，该真菌新种此前未被检测到。目前墨西哥已记录的球囊霉门物种共计149种，占全球已知球囊霉门物种总数的47.4%。

搜集汇总

背景与挑战

背景概述

该数据集描述了一种新发现的丛枝菌根真菌物种Septoglomus mexicanum，基于形态学和系统发育分析，从墨西哥半干旱地区两种豆科植物的根际土壤中分离得出。数据集提供了详细的孢子特征（如大小和四层孢子壁结构）和系统发育位置，并指出墨西哥已知Glomeromycota物种数量占全球的47.4%，突出了其在真菌多样性研究中的重要性。