Rare earth elements detoxification mechanism in the hyperaccumulator Dicranopteris linearis: [silicon-pectin] matrix...

Area of Science:

• Plant Biology
• Environmental Science
• Biochemistry

Background:

• Dicranopteris linearis is a known hyperaccumulator of rare earth elements (REEs) and silicon (Si).
• Understanding how this plant copes with toxic REE levels is crucial for environmental remediation and resource recovery.

Purpose of the Study:

• To investigate the mechanisms by which D. linearis leaves tolerate excessive REE stress.
• To determine the role of silicon (Si) in mitigating REE toxicity in this hyperaccumulator species.

Main Methods:

• Exposure of D. linearis to lanthanum (La) stress, with and without Si supply.
• Analysis of plant biomass, cellular metabolism, gene expression (pectin-related), polysaccharide concentration, and enzyme activity.
• Characterization of Si-cell wall interactions and REE accumulation within cell wall components.

Main Results:

• Lanthanum stress reduced biomass but increased cell wall synthesis and modification metabolism.
• Silicon supply mitigated La-induced stress responses, including pectin-related gene expression and activity.
• Approximately 70% of leaf Si formed Si-O-C linkages within cell walls, enhancing REE retention.
• The Si-modified cell wall matrix significantly increased pectin-bound La accumulation (by 64%).

Conclusions:

• Silicon plays a vital role in REE detoxification in D. linearis by forming a [Si-pectin] matrix within cell walls.
• This mechanism enhances the plant's capacity to sequester toxic REEs, preventing cellular damage.
• Findings support the potential of D. linearis for phytotechnological applications, such as REE phytomining in contaminated environments.