Two new species of Diversispora (arbuscular mycorrhizal fungi; Glomeromycota) colonizing roots of endemic shrubs on nickel mine tailings in New-Caledonia

Abstract

Abstract Diversispora cerifera and Diversispora succinacia are new arbuscular mycorrhizal fungal species, that have been isolated and propagated from spores of rhizospheric soils of native vegetation that had naturally established from seeds on a nickel mine tailings test basin in New-Caledonia. Interestingly, these species were not recorded from ultramafic soils of maquis vegetation endemic to New-Caledonia surrounding the tailings basin. In greenhouse trap and single species cultures, fungi produced numerous spores, which were formed terminally or intercalary on subtending hyphae. Spores of D. cerifera are white yellow with a waxy appearance and spores of D. succinacia are translucent, amber in color. Spores of the two species are globose to subglobose. Spores of D. cerifera 70-100-120 µm in diameter and have three spore wall layers. Spores of D. succinacia 60–80 − 110 µm in diameter and have two spore wall layers. D. cerifera forms a monophyletic clade next to D. aurantia that has a subtending hyphal wall that is continuous with layers 1–3 of the spore wall. Instead, the hyphal wall for D. cerifera is continuous only with layers 1 and 2 of the spore wall. Morphologically and phylogenetically, D. succinacia is close to D. sabulosa and forms a monophyletic clade next to D. sabulosa that has smaller spores.