S5-11
Protein Polymorphism in Starch Granules of Storage Roots of Cassava
Clones with Different Genetic Backgrounds
Gomes
A.P.G, T.L. Rocha and L.J.C.B. Carvalho
EMBRAPA-Genetic Resources and Biotechnology,
CP 02372, CEP 70770-900 Sain Parque Rural, Brazilia, Brazil carvalho@cenargen.embrapa.br
The proportion of
amylose to amylopectine in starch granule has been proved to be
dependent on the gene that codes for granule bound starch synthase (GBSS). Amylopectine structure has also been reported to be related
to starch granule bound proteins of unknown enzymatic functions.
Novel cassava clones with storage roots (SR) that accumulate
different proportions of amylose:amylopectine have been isolated in our
laboratory. In this
communication we use these novel cassava clones to further understand
the genetics of this starch diversity structure in the SR of cassava.
Protein extracts from purified starch granules are being analyzed
by SDS-PAGE, 2-DE gels, computer assisted (GELLAB-IIa software)
analysis, MALDI-TOF protein characterization and protein sequencing.
SDS-PAGE results indicated several single protein bands present
in the CAS36 clones series that is not present in the commercial clones.
Protein size varied from 100 to 40kDa molecular mass.
The 2-DE gel analysis confirm this polymorphism and revealed the
presence of proteins with pI varying from 4.6 to 6.8.
Further protein characterization are underway to isolate the
genes responsible for the starch structure diversity tested including
starch from the cassava ancestor.
This research financed by the National
Biotechnology Program (EMBRAPA)
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