The review of literature also suggests that bacterial collections
from drought-prone areas performed better in increasing plants’
tolerance to drought stress than those that were isolated from
areas that do not experience drought. However, this relation,
drawn from a few studies, needs to be validated in more cases.
While there have been suggestions for this, it is not clear if higher
percentages of PGPR isolated from dry environments will confer
drought tolerance compared to collections of PGPR from “normal”
agricultural fields. Overall, there is a continuing need to screen
collections of PGPR for drought tolerance from diverse environments.