Gs. Gilbert et al., USE OF CLUSTER AND DISCRIMINANT ANALYSES TO COMPARE RHIZOSPHERE BACTERIAL COMMUNITIES FOLLOWING BIOLOGICAL PERTURBATION, Microbial ecology, 32(2), 1996, pp. 123-147
We present an approach to comparing the diversity and composition of b
acterial communities from different habitats and for identifying which
members of a community are most affected by an introduced bacterium.
We use this method to explore both previously published and new data f
rom field and growth chamber experiments in which we isolated heterotr
ophic bacteria from samples of root-free soil, roots of nontreated soy
bean seedlings, and from the roots of soybean seedlings grown from Bac
illus cereus UW85n1-treated seeds. We characterize bacterial isolates
for 40 physiological attributes, and grouped the isolates hierarchical
ly using two-stage density-linkage cluster analysis. Multivariate anal
ysis of variance and discriminant analysis of the relative frequencies
of the clusters in the soil and rhizosphere habitats were then used t
o determine whether there were differences among the bacterial communi
ties from the various habitats, and which of the clusters were most us
eful in discriminating among the communities. We used rarefied estimat
es of richness as a measure of community diversity in the various habi
tats. Introduction of UW85n1 affected the composition and/or diversity
of rhizosphere communities in three of four experiments.