D-Amino Acids Are Exuded by Arabidopsis thaliana Roots to the Rhizosphere

作者：Hener Claudia; Hummel Sabine; Suarez Juan; Stahl Mark; Kolukisaoglu Uner^*

来源：International Journal of Molecular Sciences, 2018, 19(4): 1109.

DOI：10.3390/ijms19041109

• D-amino acids
• chiral LC-MS
• root exudation
• plant-rhizosphere interactions
• molecular transport

Proteinogenic L-amino acids (L-AAs) are essential in all kingdoms as building blocks of proteins. Their D-enantiomers are also known to fulfill important functions in microbes, fungi, and animals, but information about these molecules in plants is still sparse. Previously, it was shown that D-amino acids (D-AAs) are taken up and utilized by plants, but their ways to reduce excessive amounts of them still remained unclear. Analyses of plant D-AA content after D-Ala and D-Glu feeding opened the question if exudation of D-AAs into the rhizosphere takes place and plays a role in the reduction of D-AA content in plants. The exudation of D-Ala and D-Glu could be confirmed by amino acid analyses of growth media from plants treated with these D-AAs. Further tests revealed that other D-AAs were also secreted. Nevertheless, treatments with D-Ala and D-Glu showed that plants are still able to reduce their contents within the plant without exudation. Further exudation experiments with transport inhibitors revealed that D-AA root exudation is rather passive and comparable to the secretion of L-AAs. Altogether, these observations argued against a dominant role of exudation in the regulation of plant D-AA content, but may influence the composition of the rhizosphere.

• 出版日期2018-4