UR Gestion Durable des Sols, Laboratoire Géosciences, UFR Sciences de la Nature, Université Nangui Abrogoua, 02 BP 801, Abidjan 02, Côte d'Ivoire.
Laboratoire de Biotechnologie Végétale et Microbienne, UMRI 28 Sciences Agronomique et Génie Rural, Institut National Polytechnique Félix Houphouët-Boigny, Yamoussoukro, BP 1093, Côte d'Ivoire.
Mycorrhiza. 2023 Jul;33(4):257-275. doi: 10.1007/s00572-023-01113-9. Epub 2023 Jun 8.
Substantial areas of agricultural lands in Sub-Saharan Africa have been invaded by Chromolaena odorata (Asteraceae), but the consequences for arbuscular mycorrhiza fungi (AMF) remains poorly understood. This study explores changes in diverse AMF community attributes and soil available phosphorus following C. odorata invasion in forest and savanna fragments in Côte d'Ivoire (West Africa). Invaded-forest (COF) and savanna (COS) sites were compared to adjacent natural forest (FOR) and savanna (SAV) fragments, respectively. Physico-chemical variables and AMF spore density parameters were determined for soil samples from 0-20 cm depth. An 18S ribosomal RNA metabarcoding analysis of AMF communities was conducted. In addition, cowpea (Vigna unguiculata) was grown on soils collected from these sites under greenhouse conditions for determination of soil mycorrhizal infectivity. Noticeable changes in the composition of AMF communities in C. odorata relative to nearby forest and savanna non-invaded sites were observed. AMF-specific richness in COS (47 species) was lower than that in SAV (57 species) while it was higher in COF (68 species) than in FOR (63 species). COF and COS differed in AMF specific composition (Dissimilarity index = 50.6%). Chromolaena odorata invasions resulted in increased relative abundances of the genera Claroideoglomus and Glomus in COF, a decreased relative abundance of Paraglomus in COS and decreased relative abundances of Ambispora in both COF and COS. Total and healthy spore densities, cowpea root colonization intensity and soil available P were all higher in invaded sites than in natural ecosystems. Remarkably, although these values were different in FOR and SAV, they turned out to be similar in COF and COS (4.6 and 4.2 total spores g soil, 2.3 and 2.0 healthy spores g soil, and 52.6 and 51.6% root colonization, respectively) suggesting a C. odorata-specific effect. These findings indicate that soil mycorrhizal potential and phosphorus availability have improved following C. odorata invasion.
撒哈拉以南非洲地区的大片农业用地已被Chromolaena odorata（菊科）入侵，但人们对其对丛枝菌根真菌（AMF）的影响仍知之甚少。本研究探讨了科特迪瓦（西非）森林和稀树草原片段中 C. odorata 入侵后，不同 AMF 群落属性和土壤有效磷的变化。入侵森林（COF）和稀树草原（COS）与相邻的天然森林（FOR）和稀树草原（SAV）进行了比较。为了确定土壤样本的理化变量和 AMF 孢子密度参数，从 0-20cm 深度进行了土壤取样。对 AMF 群落进行了 18S 核糖体 RNA 宏条形码分析。此外，在温室条件下，用从这些地点采集的土壤种植豇豆（Vigna unguiculata），以确定土壤菌根感染力。与附近未受干扰的森林和稀树草原相比，在 C. odorata 中 AMF 群落的组成发生了明显变化。COS（47 种）中的 AMF 特有丰富度低于 SAV（57 种），而 COF（68 种）高于 FOR（63 种）。COF 和 COS 的 AMF 特有组成不同（不相似性指数=50.6%）。C. odorata 入侵导致 COF 中 Claroideoglomus 和 Glomus 的相对丰度增加，COS 中 Paraglomus 的相对丰度降低，COF 和 COS 中 Ambispora 的相对丰度降低。总孢子和健康孢子密度、豇豆根定殖强度和土壤有效磷均高于自然生态系统。值得注意的是，尽管 FOR 和 SAV 中的值不同，但 COF 和 COS 中的值却相似（总孢子分别为 4.6 和 4.2 个 g 土壤，健康孢子分别为 2.3 和 2.0 个 g 土壤，根定殖率分别为 52.6%和 51.6%），这表明 C. odorata 具有特异性效应。这些发现表明，C. odorata 入侵后，土壤菌根潜力和磷有效性得到了改善。
