PS5 (Fig. 4m) showed the same colonization pattern, while Novosphingobium sp.
TR4 (Fig. 4i) showed less GUS staining at the root tip than other bacterial strains. In the root hairs zone, Burkholderia sp.
SS5 (Fig. 4b) and Sphingomonas sp. PS5 (Fig. 4n) obviously showed higher GUS activity than Klebsiella sp. SS2 (Fig. 4f)
and Novosphingobium sp. TR4 (Fig. 4j).