Abstract
Plants exude a wide variety of compounds into the rhizosphere,
modulating soil functioning and diversity. The number of studies
investigating exudation has exponentially increased over the past
decades. Yet, the high inter-study variability of the results is slowing
down our understanding of the root-soil interactions. Such variability
is partly due to the absence of harmonized methodologies to collect and
characterize exudation. Here, we discuss how various experimental
aspects influence exudation profiles by performing a literature review,
and we suggest best practices for different experimental setups. We
discuss state-of-the art of spatially resolved exudate collection,
collection in controlled vs field conditions, and plant growth setups
ranging from hydroponics to soil. We highlight the importance of
preparing experimental blanks, in situ vs ex situ exudate
collection, various collection media and timing of collection, exudate
storage and processing, and analytical considerations. We summarize best
practices for experimental setup and reporting of parameters in an
easily accessible table format to facilitate discussion of best
practices in the field. An increased standardization in the field
together with the systematic studies suggested will improve our
knowledge on how plant exudation shapes interactions with organisms in
soil.