A total of 15 AMF species associated with tamarind (Tamarindus indica) crop soils were identified and are listed with their abundances in Table 2. Of the species found, 53% belonged to the Glomeraceae family, 20% to the Acaulosporaceae, and 13% to the Diversisporaceae. In terms of genus-level diversity, Glomus was the most abundant, representing 33% of the identified species, followed by Acaulospora, Diversispora, and Rhizophagus, each accounting for 13% of the total species (Figure 1). The average percentage of colonized trees was of 50%, and regarding the observed structures in the microscope’s visual field, 39% were found with hyphae, 31% with arbuscules and 14% with vesicles (Figure 2). On the other hand, the present investigation found that in the roots of T. indica evaluated, there were other structures corresponding to dark septate endophytes, which are also part of the rhizosphere.

Table 2

Figure 1

Figure 2

Bourou et al. (2010) documented to AMF colonization ranging from 3.9 to 11% of the roots of T. indica trees, with higher colonization rates in trees established on soils under poor conditions and subjected to drought. In the present study, the colonization percentage found was significantly greater (50%) than that reported by Arcos (2015), who also assessed trees from the same region as those evaluated in this study and found 12% of colonization. Some authors report that differences in the colonization percentage may be influenced by a series of environmental and functional factors such as host, regional location, temperatures, rain and the availability of nutrients to soils (Smith and Read 2008). It is possible that the tamarind crops particular conditions in this case, such as medium phosphorous content, limited availability of water, high competence with unwanted plants and the absence of other farming practices, set out an environment in which some AMF are adapted to tolerate stress conditions, in the sense suggested by Chagnon et al. (2013). Different mechanisms have been proposed to explain physiological, molecular and morphological changes in symbiotic plants when overcoming the effects of water stress. These mechanisms explain how the plants survive and maintain vigorous growth under the aforementioned conditions (Abdelmalik et al. 2020; Cheng et al. 2021). Jiménez (2019) demonstrated that tamarind seedlings inoculated with Glomus commercial had a greater amount of dry matter in roots and aerial parts than non-inoculated seedlings, as well as a faster recovery when seedlings were attacked by leaf-cutting ants.

In this study, a higher percentage of the genus Glomus associated with tamarind was found, while Arcos (2015) found a higher presence of Acaulospora. These two genera are abundant in tropical soil (Peña-Venegas et al. 2007; Cofré et al. 2019). Additionally, they contain species that have been reported to be associated with plants exposed to episodes of drought (Lenoir et al. 2016; Bahadur et al. 2019).

Tamarindus indica is a species that establishes symbiotic connections with a great variety of AM fungi, specifically those from the genera Glomus and Acaulospora in the tropical dry forest of Western Antioquia. The percentage of AMF colonization highlights its importance to tamarind plants in an environment prone to recurring drought. Future research could focus on defining mycorrhizal dependence, exploring its interaction with nitrifying bacteria and confirming the species identity through molecular techniques.

The authors express that they do not have any conflict of interest.