Relationship between genotype and soil environment during colonization of poplar roots by mycorrhizal and endophytic fungi

Abstract

Poplars are among the few tree genera that can develop both ectomycorrhizal (ECM) and arbuscular (AM) associations; however, variable ratios of ECM/AM in dual mycorrhizal colonizations were observed in the roots of a variety of poplar species and hybrids. The objective of our study was to analyze the effect of internal and external factors on growth and dual AM and ECM colonization of poplar roots in three 12-15-year-old common gardens in Poland. We also analyzed the abundance of nonmycorrhizal fungal endophytes in the poplar roots. The Populus clones comprised black poplars (Populus deltoides and P. deltoides x Populus nigra), balsam poplars (Populus maximowiczii x Populus trichocarpa), and a hybrid of black and balsam poplars (P. deltoides x P. trichocarpa). Of the three sites that we studied, one was located in the vicinity of a copper smelter, where soil was contaminated with copper and lead. Poplar root tip abundance, mycorrhizal colonization, and soil fungi biomass were lower at this heavily polluted site. The total mycorrhizal colonization and the ratio of ECM and AM colonization differed among the study sites and according to soil depth. The influence of Populus genotype was significantly pronounced only within the individual study sites. The contribution of nonmycorrhizal fungal endophytes differed among the poplar clones and was higher at the polluted site than at the sites free of pollution. Our results indicate that poplar fine root abundance and AM and ECM symbiosis are influenced by environmental conditions. Further studies of different site conditions are required to characterize the utility of poplars for purposes such as the phytoremediation of polluted sites.

New mutualistic fungal endophytes isolated from poplar roots display high metal tolerance

“…Similar colonisation rates were reported for several poplar clones from contaminated soils, although higher ECM colonisation rates are often reported (Khasa et al 2002;Gehring et al 2006;Karliński et al 2010). However, those data were derived from studies with older trees, and poplar preferentially associates with AM species during the first years of growth.…”

Biomass and Volume Yield in Mature Hybrid Poplar Plantations on Temperate Abandoned Farmland

“…Several endophytic bacteria from poplars can promote the growth of their host plant by providing N-fixation, growth regulators or by preventing the growth or activity of plant pathogens [62,63]. Poplar growth can also be promoted by the colonization of fungal endophytes, but also ectomycorrhizal and arbuscular mycorrhizal fungi [64]. The effects of those symbiotic associations have been found to be strongly influenced by poplar genotypes, as well as environmental conditions [64,65].…”

Ectomycorrhizal fungal community associated with autochthonous white poplar from Serbia

“…Poplars in plantations and natural stands regularly form dual associations with ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi (Karlinski et al 2010) that are known to prefer different soil depths (Neville et al 2002). While AM community has rarely attracted the interest of researchers, several prominent ECM species are thoroughly studied in poplars, in particular in white poplar (Populus alba L.), including the most expensive white truffle (Tuber magnatum Pico - Angelini & Granetti 1995).…”