The diversity of arbuscular mycorrhizal fungi amplified from grapevine roots (Vitis viniferaL.) in Oregon vineyards is seasonally stable and influenced by soil and vine age

Abstract

The diversity of arbuscular mycorrhizal fungi (AMF) in 10 Oregon vineyards was assessed by examining spores in soil and amplifying mycorrhizal DNA from roots. Seventeen spore morphotypes were found in soil, including seven species in the Acaulosporaceae. Eighteen phylotypes were amplified from grape roots with AM1 and NS31 primers, and clones were dominated by Glomus spp. (> 99%). A few clones (< 1%) representing a single phylotype within Gigasporaceae, and a single clone within Archaeosporaceae were amplified from roots with AM1-NS31 primers. A separate experiment employing known proportions of grape roots colonized by Glomus intraradices or by Gigaspora rosea showed that fungi within Gigasporaceae might be underrepresented in clone abundance when Glomus spp. co-occur in roots. No clones representing fungi within the Acaulosporaceae were amplified from vineyards, although specific fungi within Acaulosporaceae were shown to colonize Pinot noir roots in sterilized soil and were amplified from these roots. Four Glomus phylotypes, including G. intraradices, were found in roots from all 10 vineyards, and these fungi accounted for 81% of clones. AMF phylotypes amplified from roots did not change during the growing season, although six phylotypes varied with soil type. The presence of three phylotypes was affected by vineyard age, and phylotype richness appeared to decline as vineyard age increased beyond 20 y. PCA analysis supported the hypothesis that the AMF community is different in red-hill soils than in valley soils and indicated certain phylotypes might be associated with lower soil and vine nutrient status. However, the changes in the AMF community in grape roots across vineyards were subtle because most root samples were dominated by the same three or four phylotypes. A separate analysis using primers to amplify AMF from the Archeasporaceae/Paraglomeraceae showed most root samples also were colonized by at least one Paraglomus or Archaeospora phylotype.

Soil Characteristics Driving Arbuscular Mycorrhizal Fungal Communities in Semiarid Mediterranean Soils

“…There is no doubt that soil type has a role in the AMF distribution (10,34,35,40,(77)(78)(79)(80), and our work also demonstrated that soil type is a major factor driving AMF assemblages, after elimination of the host factor and other environmental variables not related to soil characteristics. Although individual soil characteristics have been reported to play important roles in AMF community structure and composition (7,11,13,40,42,78,(81)(82)(83), very limited data sets regarding soil characteristics were used in these studies, and the relative incidences of each soil property determined after complete soil characterization have not been reported previously.…”

Local Adaptation to Soil Hypoxia Determines the Structure of an Arbuscular Mycorrhizal Fungal Community in Roots from Natural CO2Springs

“…Both dominant phylotypes are present in the two mofettes, which are separated by 40 m. The evolutionary history of the two dominant taxa cannot be inferred from these data, but it is highly unlikely that the same lineages have evolved independently, so dispersal between the mofettes is the likely explanation. Data from other, more-distant mofette areas will be required to determine the extent of dispersal limitation, if any, although the presence of similar phylotypes in samples from the United States (35) suggests the possibility of long-range dispersal. The fact that the two dominant phylotypes are sister taxa also supports adaptation and local dispersal as an explanation for the pattern observed at this locality.…”

Arbuscular mycorrhiza symbiosis in viticulture: a review

“…3). Indeed, in the vineyard, AMF communities are highly influenced by the soil characteristics but also to a smaller extent by the host plant development stage (Schreiner and Mihara 2009;Balestrini et al 2010). Moreover, although AMF from grape roots mainly belong to the Glomerales group, members of the Diversisporales are mainly found in sandy vineyard soils (Balestrini et al 2010).…”

“…Schreiner and Mihara (2009) mainly detected sequences of phylotypes assigned to the Glomeraceae family in a set of ten vineyards in Oregon (USA). Among them was only one known species, nowadays classified as Rhizophagus irregularis, as well as very few Claroideoglomeraceae and Gigasporaceae sequences.…”