Milne, R.J. and Byrt, C.S. and Patrick, J.W and Grof, C.P. (2013) Are sucrose transporter expression profiles linked with patterns of biomass partitioning in Sorghum phenotypes? Frontiers in Plant Science.
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Abstract
Sorghum bicolor is a genetically diverse C4 monocotyledonous species, encompassing varieties capable of producing high grain yields as well as sweet types which accumulate soluble sugars (predominantly sucrose) within their stems to high concentrations. Sucrose produced in leaves (sources) enters the phloem and is transported to regions of growth and storage (sinks). It is likely that sucrose transporter (SUT) proteins play pivotal roles in phloem loading and the delivery of sucrose to growth and storage sinks in all Sorghum ecotypes. Six SUTs are present in the published Sorghum genome, based on the BTx623 grain cultivar. Homologues of these SUTs were cloned and sequenced from the sweet cultivar Rio, and compared with the publically available genome information. SbSUT5 possessed nine amino acid sequence differences between the two varieties. Two of the remaining five SUTs exhibited single variations in their amino acid sequences (SbSUT1 and SbSUT2) whilst the rest shared identical sequences. Complementation of a mutant Saccharomyces yeast strain (SEY6210), unable to grow upon sucrose as the sole carbon source, demonstrated that the Sorghum SUTs were capable of transporting sucrose. SbSUT1, SbSUT4 and SbSUT6 were highly expressed in mature leaf tissues and hence could contribute to phloem loading. In contrast, SbSUT2 and SbSUT5 were expressed most strongly in sinks consistent with a functional role of facilitating sucrose import into stem storage pools and developing inflorescences.
| Item Type: | Article |
|---|---|
| Additional Information: | We thank the Australian Research Council (ARC) for financial support under ARC’s Linkage Projects funding scheme (Project Number LP0883808). |
| Uncontrolled Keywords: | expression profiling, Sorghum, source-sink pathway, sucrose transporters, sucrose storage |
| Author Affiliation: | School of Environmental and Life Sciences, Australia |
| Subjects: | Crop Improvement |
| Divisions: | Sorghum |
| Depositing User: | Mr Balakrishna Garadasu |
| Date Deposited: | 25 Jun 2013 10:54 |
| Last Modified: | 25 Jun 2013 10:54 |
| Official URL: | http://www.frontiersin.org/Plant_Physiology/10.338... |
| URI: | http://eprints.icrisat.ac.in/id/eprint/10737 |
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