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9 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

X-ray fluorescence and XANES spectroscopy revealed diverse potassium chemistries and colocalization with phosphorus in the ectomycorrhizal fungus Paxillus ammoniavirescens

Ectomycorrhizal (ECM) fungi play a major role in forest ecosystems and managed tree plantations. Particularly, they facilitate mineral weathering and nutrient transfer towards colonized roots. Among nutrients provided by these fungi, potassium (K) has been understudied compared to phosphorus (P) or nitrogen (N). The ECM fungus Paxillus ammoniavirescens is a generalist species that interacts with the root of many trees and can directly transfer K to them, including loblolly pine. However, the forms of K that ECM fungi can store is still unknown. Here, we used synchrotron potassium X-ray fluorescence (XRF) and K-edge X-ray Absorption Near Edge Structure (XANES) spectroscopy on P. ammoniavirescens growing in axenic conditions to investigate the K chemistries accumulating in the center and the edge of the mycelium. We observed that various K forms accumulated in different part of the mycelium, including K-nitrate (KNO 3 ), K-C-O compounds (such as K-tartrate K 2 (C 4 H 4 O 6 ) and K-oxalate (K 2 C 2 O 4 )), K-S and K-P compounds. Saprotrophic fungi have been shown to excrete carboxylic acids, which in turn play a role in soil mineral weathering. Our finding of several K counter-ions to carboxylic acids may suggest that, besides their direct transfer to colonized roots, K ions can also be involved in the production of compounds necessary for sourcing nutrients from their surrounding environment by ECM fungi. Additionally, this work reveals that XANES spectroscopy can be used to identify the various forms of K accumulating in biological systems.

Ectomycorrhizal symbiosis↗
DOE OSTI2020

Materials Data on K3P11 by Materials Project

K3P11 crystallizes in the orthorhombic Pbcn space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven P+0.27- atoms. There are a spread of K–P bond distances ranging from 3.34–3.63 Å. In the second K1+ site, K1+ is bonded to seven P+0.27- atoms to form KP7 pentagonal bipyramids that share corners with four equivalent PK2P3 square pyramids, corners with eight PKP3 tetrahedra, and corners with six PK3P2 trigonal bipyramids. There are a spread of K–P bond distances ranging from 3.36–3.61 Å. There are six inequivalent P+0.27- sites. In the first P+0.27- site, P+0.27- is bonded to two K1+ and three P+0.27- atoms to form distorted PK2P3 square pyramids that share corners with two equivalent KP7 pentagonal bipyramids, a cornercorner with one PK2P3 square pyramid, corners with five PKP3 tetrahedra, corners with nine PK3P2 trigonal bipyramids, and an edgeedge with one PK3P2 trigonal bipyramid. There are a spread of P–P bond distances ranging from 2.17–2.27 Å. In the second P+0.27- site, P+0.27- is bonded to three K1+ and two P+0.27- atoms to form distorted PK3P2 trigonal bipyramids that share a cornercorner with one KP7 pentagonal bipyramid, corners with four equivalent PK2P3 square pyramids, corners with seven PKP3 tetrahedra, corners with seven PK3P2 trigonal bipyramids, and edges with two PK2P3 trigonal bipyramids. The P–P bond length is 2.18 Å. In the third P+0.27- site, P+0.27- is bonded to one K1+ and three P+0.27- atoms to form PKP3 tetrahedra that share corners with three equivalent KP7 pentagonal bipyramids, corners with two equivalent PK2P3 square pyramids, corners with two PKP3 tetrahedra, and corners with seven PK3P2 trigonal bipyramids. There are one shorter (2.18 Å) and one longer (2.26 Å) P–P bond lengths. In the fourth P+0.27- site, P+0.27- is bonded to two equivalent K1+ and three P+0.27- atoms to form PK2P3 trigonal bipyramids that share corners with two equivalent KP7 pentagonal bipyramids, corners with four equivalent PK2P3 square pyramids, corners with four PKP3 tetrahedra, corners with seven PK3P2 trigonal bipyramids, and an edgeedge with one PK3P2 trigonal bipyramid. There are one shorter (2.23 Å) and one longer (2.27 Å) P–P bond lengths. In the fifth P+0.27- site, P+0.27- is bonded to three K1+ and two equivalent P+0.27- atoms to form PK3P2 trigonal bipyramids that share corners with two equivalent PK2P3 square pyramids, corners with six PKP3 tetrahedra, corners with ten PK3P2 trigonal bipyramids, and edges with two equivalent PK2P3 square pyramids. In the sixth P+0.27- site, P+0.27- is bonded to one K1+ and three P+0.27- atoms to form distorted PKP3 tetrahedra that share a cornercorner with one KP7 pentagonal bipyramid, corners with three equivalent PK2P3 square pyramids, corners with two PKP3 tetrahedra, and corners with seven PK3P2 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K4P3 by Materials Project

K4P3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six P+1.33- atoms. There are a spread of K–P bond distances ranging from 3.34–3.68 Å. In the second K1+ site, K1+ is bonded in a 7-coordinate geometry to seven P+1.33- atoms. There are a spread of K–P bond distances ranging from 3.32–3.50 Å. In the third K1+ site, K1+ is bonded in a square co-planar geometry to four equivalent P+1.33- atoms. All K–P bond lengths are 3.40 Å. There are two inequivalent P+1.33- sites. In the first P+1.33- site, P+1.33- is bonded in a 9-coordinate geometry to eight K1+ and one P+1.33- atom. The P–P bond length is 2.19 Å. In the second P+1.33- site, P+1.33- is bonded in a 9-coordinate geometry to seven K1+ and two equivalent P+1.33- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2P3 by Materials Project

K2P3 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to eight P+0.67- atoms to form a mixture of face, edge, and corner-sharing KP8 hexagonal bipyramids. There are a spread of K–P bond distances ranging from 3.46–3.53 Å. In the second K1+ site, K1+ is bonded in a 10-coordinate geometry to ten P+0.67- atoms. There are a spread of K–P bond distances ranging from 3.35–3.44 Å. There are two inequivalent P+0.67- sites. In the first P+0.67- site, P+0.67- is bonded in a 8-coordinate geometry to six K1+ and two equivalent P+0.67- atoms. Both P–P bond lengths are 2.17 Å. In the second P+0.67- site, P+0.67- is bonded in a 8-coordinate geometry to six K1+ and two P+0.67- atoms. The P–P bond length is 2.17 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KP by Materials Project

PK1 is Magnesium tetraboride-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 6-coordinate geometry to six P1- atoms. There are a spread of K–P bond distances ranging from 3.24–3.67 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to five P1- atoms. There are a spread of K–P bond distances ranging from 3.20–3.34 Å. There are two inequivalent P1- sites. In the first P1- site, P1- is bonded in a 7-coordinate geometry to five K1+ and two equivalent P1- atoms. There are one shorter (2.26 Å) and one longer (2.28 Å) P–P bond lengths. In the second P1- site, P1- is bonded in a 8-coordinate geometry to six K1+ and two equivalent P1- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2P3 by Materials Project

K2P3 crystallizes in the orthorhombic Fmmm space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to eight P+0.67- atoms to form a mixture of distorted edge, face, and corner-sharing KP8 hexagonal bipyramids. There are four shorter (3.47 Å) and four longer (3.51 Å) K–P bond lengths. In the second K1+ site, K1+ is bonded in a 10-coordinate geometry to ten P+0.67- atoms. There are a spread of K–P bond distances ranging from 3.36–3.46 Å. There are two inequivalent P+0.67- sites. In the first P+0.67- site, P+0.67- is bonded in a 8-coordinate geometry to six K1+ and two P+0.67- atoms. Both P–P bond lengths are 2.17 Å. In the second P+0.67- site, P+0.67- is bonded in a 8-coordinate geometry to six K1+ and two equivalent P+0.67- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KP by Materials Project

PK1 is Halite, Rock Salt structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K1+ is bonded to six equivalent P1- atoms to form a mixture of edge and corner-sharing KP6 octahedra. The corner-sharing octahedral tilt angles are 0°. All K–P bond lengths are 3.36 Å. P1- is bonded to six equivalent K1+ atoms to form a mixture of edge and corner-sharing PK6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KP15 by Materials Project

KP15 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one KP15 sheet oriented in the (0, 0, 1) direction. K1+ is bonded in a 6-coordinate geometry to six P+0.07- atoms. There are a spread of K–P bond distances ranging from 3.43–3.57 Å. There are fifteen inequivalent P+0.07- sites. In the first P+0.07- site, P+0.07- is bonded to one K1+ and three P+0.07- atoms to form corner-sharing PKP3 trigonal pyramids. There are a spread of P–P bond distances ranging from 2.20–2.24 Å. In the second P+0.07- site, P+0.07- is bonded in a distorted trigonal non-coplanar geometry to three P+0.07- atoms. There are a spread of P–P bond distances ranging from 2.20–2.25 Å. In the third P+0.07- site, P+0.07- is bonded in a distorted trigonal non-coplanar geometry to three P+0.07- atoms. The P–P bond length is 2.31 Å. In the fourth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. Both P–P bond lengths are 2.21 Å. In the fifth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. There are one shorter (2.24 Å) and one longer (2.26 Å) P–P bond lengths. In the sixth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. There are one shorter (2.20 Å) and one longer (2.23 Å) P–P bond lengths. In the seventh P+0.07- site, P+0.07- is bonded to one K1+ and three P+0.07- atoms to form distorted corner-sharing PKP3 tetrahedra. There are one shorter (2.23 Å) and one longer (2.31 Å) P–P bond lengths. In the eighth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. There are a spread of P–P bond distances ranging from 2.20–2.26 Å. In the ninth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. The P–P bond length is 2.24 Å. In the tenth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. The P–P bond length is 2.16 Å. In the eleventh P+0.07- site, P+0.07- is bonded to one K1+ and three P+0.07- atoms to form distorted corner-sharing PKP3 tetrahedra. In the twelfth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. In the thirteenth P+0.07- site, P+0.07- is bonded in a trigonal non-coplanar geometry to three P+0.07- atoms. The P–P bond length is 2.24 Å. In the fourteenth P+0.07- site, P+0.07- is bonded in a distorted rectangular see-saw-like geometry to two equivalent K1+ and two P+0.07- atoms. The P–P bond length is 2.16 Å. In the fifteenth P+0.07- site, P+0.07- is bonded to one K1+ and three P+0.07- atoms to form corner-sharing PKP3 trigonal pyramids.

36 MATERIALS SCIENCE↗