Occurrence and distribution of Gigaspora under Cryptostegia madagascariensis Bojer Ex Decne in Brazilian tropical seasonal dry forest

Abstract

The Brazilian tropical seasonal dry forest presents high abundance of arbuscular mycorrhizal fungal from Order Diversisporales, but the occurrence and distribution of Gigaspora species (Order Diversisporales) in invaded zones by exotic plant species in the Caatinga are not know yet. Here, we compare the occurrence and distribution of Gigaspora community in soils from invaded zone by the exotic plant species C. madagascariensis and soils from native zone by the native plant species M. tenuiflora from Brazilian tropical seasonal dry forest, Pombal, Paraiba, Brazil. We analysed and compared the number of spores and frequency of occurrence of Gigaspora species using 40 m transects and morphological analyses. In general, the most dominant Gigaspora species in the invaded zone was Gigaspora albida, whereas we did not find any dominance by Gigaspora species in the native zone. Differences in Gigaspora occurrence and distribution were associated with (1) the dominant plant species (C. madagascariensis vs. M. tenuiflora) that alter the occurrence and frequency of Gigaspora in field conditions from the Brazilian semiarid region, (2) the transition zone, where G. albida and G. margarita did not occur, and (3) specific plant-AMF pairing, where we identified G. gigantea as the most resilient AMF species occurring in all the studied sections into the 40 m transects. These results contribute to a deeper view about the Gigaspora occurrence and distribution in invaded and native zones of the Brazilian semiarid and open new perspective for ecological studies addressing specific AMF taxa and other exotic plant species in the Brazilian tropical seasonal dry forest.