Vetiver grass-microbe interactions for soil remediation

Vetiver grass (Chrysopogon zizaniodies) is a plant species with high economic and ecological values. In addition to being planted for essential oil production in over 70 countries, Vetiver was increasingly and successfully applied to soil erosion control, slope stabilization, and rehabilitation of degraded or contaminated lands. Vetiver can tolerate extreme climatic variations, including prolonged drought, flood, submergence, extreme temperature, high levels of salinity, sodicity, acidity, alkalinity, and a wide range of toxic metal(loid)s and organic contaminants. With a fast growth rate, high biomass, noninvasive impacts on local species, tolerance to pollution stress, and specific behavior of the roots, Vetiver is an ideal candidate for phytoremediation and restoration. It is crucial to understand whether the rhizospheric microbes associated with Vetiver play essential roles in stress tolerance. The principal objective of this article is to review the progress made so far in remediating contaminated sites using Vetiver, with emphasis on its interactions with soil microbes. Although little mechanistic information on Vetiver-microbe interactions in improving stress tolerance is available, this review extrapolates potential mechanisms by referring studies focus on plant stress tolerance and microbe-assisted adaptation.