Root exudation the ecological driver of hydrocarbon rhizoremediation

Rhizoremediation is a bioremediation technique whereby microbial degradation of organiccontaminants occurs in the rhizosphere. It is considered to be an effective and affordable “greentechnology” for remediating soils contaminated with petroleum hydrocarbons. Root exudation ofa wide variety of compounds (organic, amino and fatty acids, carbohydrates, vitamins, nucleotides,phenolic compounds, polysaccharides and proteins) provide better nutrient uptake for the rhizospheremicrobiome. It is thought to be one of the predominant drivers of microbial communities in therhizosphere and is therefore a potential key factor behind enhanced hydrocarbon biodegradation. Manyof the genes responsible for bacterial adaptation in contaminated soil and the plant rhizosphere arecarried by conjugative plasmids and transferred among bacteria. Because root exudates can stimulategene transfer, conjugation in the rhizosphere is higher than in bulk soil. A better understanding ofthese phenomena could thus inform the development of techniques to manipulate the rhizospheremicrobiome in ways that improve hydrocarbon bioremediation.