Lupin and Arsenic: Research on soil decontamination by an exceptional
plant

Date:
August 24, 2021
Source:
University of Montreal
Summary:
Researchers have discovered a new chemical mechanism used by
roots of white lupin to clean up arsenic-contaminated soils,
such as those from mining operations.



FULL STORY ========================================================================== Pollution of soils with highly toxic arsenic is a worldwide problem
generating substantial risks to human health and the environment.


==========================================================================
In Canada, over 7000 sites contaminated with metals such as arsenic are considered 'highly concerning' by the government, with some past and
recent mining operations and wood preservative facilities having left
their mark on the environment by increasing soil arsenic levels by up
to 1000 times the maximum regulatory health limits.

One way in which arsenic contaminated soils could be rejuvenated is
to exploit natural mechanisms which have evolved in certain plants for contamination tolerance.

"The legume crop white lupin (L. albus) is one such arsenic tolerant
plant species being studied as for sustainable remediation," explains
Adrien Fre'mont, lead author of the study and a doctoral student in
biological sciences at the Universite' de Montre'al. "The mechanism
behind arsenic tolerance in white lupin is thought to be the release of
plant chemicals directly into soil by roots, but the nature of these
compounds is unknown and hard to study due to the complexity of these belowground interactions." Root chemicals an undiscovered country To
study this, the team developed nylon pouches which could be placed close
to roots in soil to capture exuded molecules without damaging the root
system. The complex mix of molecules collected from these pouches were
analysed using advanced (metabolomic) chemical profiling to identify
the compounds capable of binding metals produced by the Lupin plants in response to high concentrations of arsenic. Some of these metal-binding molecules, phytochelatins, are known to be used internally by plants
to deal with metal stress but have never before been captured as exuded
into polluted soils.

"We're really excited to see how matching new root-soil sampling
approaches with advanced metabolomic profiling can yield such unexpected discoveries," notes Fre'mont. "We know that plants can drastically
change soil properties and can transform or immobilise soil pollution,
but the chemistry underlying how they achieve this, and in particular
the makeup and function of root-exuded compounds, is still very much an undiscovered country." Plant roots directly altering polluted soils
The next steps of the research are to branch out into more detailed
analysis of the precise chemical reactions taking place at the root-soil interface, including exploration of different plant species, interactions
with microorganisms and the challenge of diverse soil pollution.

As Dr. Nicholas Brereton, University of Montreal and the study's senior
author, mentions: "It can be a real challenge to research the complex interactions going on belowground between plants and soil, but these
findings are rewarding in telling us that natural mechanisms have evolved
in plants to deal with this type of pollution. Although we're still
only just beginning to scratch below the surface of how these plant
root strategies work, as we learn more, we can potentially utilise
these natural processes to improve soil health and help to alleviate
some of the most persistent anthropogenic damage to our environment."
The research was supported by funding from the Natural Sciences and
Engineering Research Council of Canada, MITACS, Hydro-Que'bec and Natural Resources Canada Forest Innovation Program.

========================================================================== Story Source: Materials provided by University_of_Montreal. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Adrien Fre'mont, Eszter Sas, Mathieu Sarrazin, Emmanuel Gonzalez,
Jacques
Brisson, Fre'de'ric Emmanuel Pitre, Nicholas James Beresford
Brereton.

Phytochelatin and coumarin enrichment in root exudates of
arsenic‐treated white lupin. Plant, Cell & Environment,
2021; DOI: 10.1111/pce.14163 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210824135322.htm

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