From isolation to application: a case study of arbuscular mycorrhizal fungi of the Arabian Peninsula

Abstract

The vegetation in the Arabian Peninsula experiences drought, heat, soil salinity, and low fertility, mainly due to low phosphorus (P) availability. The beneficial mycorrhizal symbiosis between plants and arbuscular mycorrhizal fungi (AMF) is a key factor supporting plant growth under such environmental conditions. Therefore, AMF strains isolated from these soils might be useful as biotechnological tools for agriculture and revegetation practices in the region. Here we present a pioneering program to isolate, identify, and apply AMF isolated from rhizosphere soils of agricultural and natural habitats, namely date palm plantations and five native desert plants, respectively in the Southern Arabian Peninsula. We established taxonomically unique AMF species as single-spore cultures as part of an expanding collection of AMF strains adapted to arid ecosystems. Preliminary experiments were conducted to evaluate the abilities of these AMF strains to promote seedling growth of a main crop Phoenix dactylifera L. and a common plant Prosopis cineraria L. (Druce) in the Arabian Peninsula. The results showed that inoculation with certain AMF species enhanced the growth of both plants, highlighting the potential of these fungi as part of sustainable land use practices in this region.

Keywords: Date palm; Desert ecosystem; Mycorrhizal symbiosis; Native plants; Oman.

Fig. 1

Phylogenetic positions and morphology of the eight arbuscular mycorrhizal fungal (AMF) species recovered from the Arabian Peninsula. The simplified phylogenetic tree was inferred from the partial LSU rDNA region (628 dataset characters), and shows the positions of the isolated AMF species (shown in colored boldface). An image of each of the AMF species is associated with its phylogenetic position. Sequences were aligned in PAUP*4b10 (Swofford 2001) to other sequences from GenBank of species within the same genera. The phylogenetic tree was inferred using maximum likelihood criteria as implemented in PAUP*

Fig. 2

Effect of inoculation with arbuscular mycorrhizal fungi (AMF) on plant growth; (a) date palms grown as non-mycorrhizal control (left) and as mycorrhizal plants, inoculated with Diversispora aurantia (right); (b) Prosopis cineraria grown as non-mycorrhizal control (left) and as mycorrhizal plants, inoculated with Septoglomus africanum (right)

Fig. 3

Impact of inoculation with different arbuscular mycorrhizal fungal (AMF) species on (a) total leaf length and (b) the number of leaves of date palm seedlings. The consortium included all five AMF species: Diversispora aurantia, Septoglomus africanum, Claroideoglomus drummondii, Desertispora omaniana, and Pervetustus simplex. Different letters above bars indicate significant differences according to Tukey’s honest significant difference test (P ≤ 0.05). Data represent means ± standard error (n = 4–5)

Fig. 4

Impact of inoculation with different arbuscular mycorrhizal (AM) fungal species on the height of Prosopis cineraria seedlings 3 months after sowing compared with the growth of non-mycorrhizal controls: microbial wash (control 1), autoclaved inoculum carrier (control 2), microbial wash and autoclaved inoculum carrier (control 3), and negative control (control 4). In addition to inoculation with single AMF species, four consortia were used as inocula: consortium 1 (Pervetustus simplex strain C49 and C56), consortium 2 (Claroideoglomus drummondii and Desertispora omaniana), consortium 3 (Septoglomus africanum and De. omaniana), and consortium 4 (P. simplex strain C49, C. drummondii; S. africanum, and De. omaniana). Different letters above bars indicate significant differences according to Tukey’s honest significant difference test (P ≤ 0.05). Data represent means + SE (n = 3–13)