TY  - JOUR
AU  - Hüdig, Meike
AU  - Tronconi, Marcos A
AU  - Zubimendi, Juan P
AU  - Sage, Tammy L
AU  - Poschmann, Gereon
AU  - Bickel, David
AU  - Gohlke, Holger
AU  - Maurino, Veronica G
TI  - Respiratory and C4-photosynthetic NAD-malic enzyme coexist in bundle sheath cell mitochondria and evolved via association of differentially adapted subunits
JO  - The plant cell
VL  - 34
IS  - 1
SN  - 1040-4651
CY  - Rockville, Md.
PB  - Soc.
M1  - FZJ-2021-04289
SP  - 597–615
PY  - 2022
AB  - In plant mitochondria, nicotinamide adenine dinucleotide phosphate (NAD)-malic enzyme (NAD-ME) has a housekeeping function in malate respiration. In different plant lineages, NAD-ME was independently co-opted in C4 photosynthesis. In the C4 Cleome species Gynandropsis gynandra and Cleome angustifolia, all NAD-ME genes (NAD-MEα, NAD-MEβ1, and NAD-MEβ2) were affected by C4 evolution and are expressed at higher levels than their orthologs in the C3 species Tarenaya hassleriana. In Tarenaya hassleriana, the NAD-ME housekeeping function is performed by two heteromers, NAD-MEα/β1 and NAD-MEα/β2, with similar biochemical properties. In both C4 species, this role is restricted to NAD-MEα/β2. In the C4 species, NAD-MEα/β1 is exclusively present in the leaves, where it accounts for most of the enzymatic activity. GgNAD-MEα/β1 exhibits high catalytic efficiency and is differentially activated by the C4 intermediate aspartate, confirming its role as the C4-decarboxylase. During C4 evolution, NAD-MEβ1 lost its catalytic activity; its contribution to the enzymatic activity results from a stabilizing effect on the associated α-subunit and the adquisition of regulatory properties. We conclude that in bundle sheath cell mitochondria of C4 species, the functions of NAD-ME as C4 photosynthetic decarboxylase and as a housekeeping enzyme coexist and are performed by isoforms that combine the same α subunit with differentially adapted β subunits.
LB  - PUB:(DE-HGF)16
C6  - pmid:34734993
UR  - <Go to ISI:>//WOS:000745840600036
DO  - DOI:10.1093/plcell/koab265
UR  - https://juser.fz-juelich.de/record/902470
ER  -