Diversity of arbuscular mycorrhizal fungi associated withFlemingia vestitaBenth. ex Baker

Abstract

Diversity of arbuscular mycorrhizal fungi (AMF) was investigated from natural (MF) and cultivated sites (TF) of Flemingia vestita Benth. ex Baker. Samplings were done at monthly intervals for one crop cycle. Root samples were evaluated for AMF colonization. Trap cultures were also established with four different host plants (Oryza sativa L., Paspalum notatum Flüggé, Trifolium repens L. and Zea mays L.) using rhizosphere soils from natural and cultivated sites of F. vestita as the source of AMF inoculum. A total of 61 AMF species (51 from natural site and 46 from cultivated site) belonging to six genera (Acaulospora, Ambispora, Gigaspora, Glomus, Pacispora and Scutellospora) could be distinguished from F. vestita rhizosphere soil. 33 AMF species belonging to five genera (Acaulospora, Gigaspora, Glomus, Paraglomus and Scutellospora) were isolated from trap cultures (25 AMF species from trap plants with MF derived inoculum and 18 AMF species from trap plants with TF derived inoculum). Three additional AMF species were isolated in trap cultures that were not detected in field soils, indicating that trap culture allows development and sporulation of AMF species which otherwise were not recovered from field soil. Higher AMF diversity was observed in natural site than in cultivated site of F. vestita.

Arbuscular Mycorrhizal Fungi from Argentinean Highland Puna Soils Unveiled by Propagule Multiplication

“…This study showed that F. geosporus produced spores under the aforementioned multiplication conditions, which reinforces the importance of TC for spore production and the identification of this species in Puna soils. Therefore, F. geosporus was a cryptic AM species concerning Puna field samples but a generalist species in TC as it has been reported after different TC approaches were used in several environments [ 4 , 14 , 15 , 16 ]. In this study, trap culture allowed the development and sporulation of AMF species which otherwise could not have been recovered from field soil.…”

“…However, this morphospecies was not found in field soils from AC ( Table 1 ) or It ( Table 2 ). Generally, F. geosporus is a quickly sporulating species but its spore abundance, both from field soil and TC, varies depending on land use [ 13 ] and edaphic properties [ 14 ]. In general, some authors suggest that AMF yield spores after 10 weeks of TC multiplication, which is in accordance with the previous two months’ report for F. geosporus TC [ 13 , 15 ].…”

“…However, taking into account the different results obtained with the three TC strategies used for the It samples (no R. microaggregatum at the soil from ItM3-a2, see Table 2 ), it can be inferred that subsequent cultivation cycles with S. bicolor could inhibit R. microaggregatum sporulation. Furthermore, other studies showed that R. microaggregatum can be found in field sample soils, but that it cannot be recovered after 5 months of TC that included a single TPS per pot [ 14 ]. We therefore suggest that to achieve successful sporulation of R. microaggegatum , a TC strategy should include more than one TPS per TC cycle; several cycles of more than 5 months of cultivation, alternating TPS between cycles; and, in a third cycle, a TPS different from S. bicolor .…”

“…On the other hand, R. aggregatus ( Figure 2 a,b) was previously detected in It and AC soil samples [ 12 ], but it was not recovered from AC soils by TC in spite of being considered both a cryptic species for tropical areas [ 4 ] and a generalist species for field and meadow European soils [ 13 ] and Chinese mountains [ 15 ]. In these studies, R. aggregatus sporulation in TC was strongly influenced by TPS [ 14 ] and it only required an average of 4 months of multiplication [ 13 , 15 ]. Our results also reflect this trend in which the use of numerous TPS and a long cultivation period in TC (at least 13 months) promoted the sporulation of R. aggregatus .…”

“…This result deserves future study as S. sinuosa is a generalist AMF in Puna field soils [ 12 ]. Moreover, other studies show that, even though S. sinuosa is commonly found in field samples from tropical and Alpine environments [ 13 , 14 ], it could not be recovered by TC. Regardless, the application of TC strategies was successful in promoting S. sinuosa sporulation in Puna soils when the rest of the TPS were used.…”