Biodiversity of Trichoderma species of healthy and Fusarium wilt-infected banana rhizosphere soils in Tenerife (Canary Islands, Spain)

Banana ( ) is the most important crop in the Canary Islands (38.9% of the total cultivated area). The main pathogen affecting this crop is the soil fungal f. sp. subtropical race 4 ( -STR4), for which there is no effective control method under field conditions. Therefore, the use of native biological control agents may be an effective and sustainable alternative. This study aims to: (i) investigate the diversity and distribution of species in the rhizosphere of different banana agroecosystems affected by -STR4 in Tenerife (the island with the greatest bioclimatic diversity and cultivated area), (ii) develop and preserve a culture collection of native species, and (iii) evaluate the influence of soil chemical properties on the community. A total of 131 isolates were obtained from 84 soil samples collected from 14 farms located in different agroecosystems on the northern (cooler and wetter) and southern (warmer and drier) slopes of Tenerife. Ten species, including , and , and two putative novel species, named . aff. and . aff. , were identified based on the sequences. (35.89% relative abundance) and aff. (27.48%) were the most abundant and dominant species on both slopes, while other species were observed only on one slope (north or south). Biodiversity indices (Margalef, Shannon, Simpson, and Pielou) showed that species diversity and evenness were highest in the healthy soils of the northern slope. The Spearman analysis showed significant correlations between species and soil chemistry parameters (mainly with phosphorus and soil pH). To the best of our knowledge, six species are reported for the first time in the Canary Islands ( ) and in the rhizosphere of banana soils ( , ). This study provides essential information on the diversity/distribution of native species for the benefit of future applications in the control of -STR4.