Conclusion
In
this study, for the first time, a functional sucrose-specific active
transporter, Ge SUT4, was identified that contributes to the
carbon flow in a fully mycoheterotrophy orchid,
G. elata. Localization of Ge SUT4 proteins on both the
plasma-membrane and tonoplast combined with physiological studies in
transgenic Arabidopsis indicate that this sucrose transporter imports
carbon from Armillaria fungal cells and also maintains
intracellular sucrose homeostasis. Even in the absence of photosynthesis
and a vascular translocation system, our studies demonstrate the
similarity in sucrose allocation mechanisms between the
mycoheterotrophic Gastrodia and autotropic plants, highlighting
the evolutionary importance of sucrose transporters in carbon
allocation.
Supplemental DataThe
following supplemental materials are available.
Figure
S1. Pictures of developing G. elata tubes.
Figure
S2. Phylogenetic tree of SUT transporters.
Figure
S3. Gene properties of Gastrodia GeSUT genes.
Figure
S4. Phylogenetic tree of genes involved in sucrose metabolism fromGastrodia.
Figure
S5. Transport activity of GeSUT4 to hexoses in yeast.
Figure
S6. The uptake activity of GeSUT4 to maltose.
Figure
S7. Localization of GeSUT4 expression.
Figure
S8. Leaf areas of transgenic Arabidopsis overexpressing GeSUT4.
Figure
S9. Roots growth of transgenic Arabidopsis overexpressing GeSUT4.