Submitted to: Molecular Biology Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2010
Publication Date: 3/26/2010
Citation: Taliercio, E.W., Scheffler, J.A., Scheffler, B.E. 2010. Characterization of Two Cotton (Gossypium hirsutum) Invertase Genes. Molecular Biology Reports. 37:3915-3920.
Interpretive Summary: Plant invertases affect many aspects of development including responses to environmental stress, sink strength and cell expansion. Two cotton invertase genes have been isolated and sequenced. Analyses of the sequences indicated that these genes encoded proteins with typical invertase active sites and substrate binding motifs indicating both genes encoded vacuolar acid invertases. One of the genes was expressed in mature stems, mature roots and elongating fiber. This pattern of expression was inconsistent with a role for this gene in determining sink strength in starch-storing stems and roots because expression fluctuated during the starch utilization stage of plant development. The second gene was primarily expressed in elongating fiber consistent with a role for this gene in cell expansion. A variant of the second gene was identified that appeared to affect splicing of the transcript. This variant will help clarify the role of this gene in fiber development.
Technical Abstract: Two cotton vacuolar-invertase genes were identified and sequenced. Both genes had 7 exons, including an unusually small second exon typical of acid invertases. These genes encode peptides with many features shared by acid invertases from other species including, leader sequences that probably target the peptide to the vacuole, active site motifs and substrate binding motifs. Expression analyses indicated that one of the genes was expressed in roots during the starch filling stage of development. However, expression of the same gene fluxuated during the starch utilization stage of development. Therefore this gene was unlikely to play a role in determining sink strength of this tissue. Both genes were expressed in elongating fibers where they were likely to play a role in cell expansion. The invertase gene uniquely expressed in fiber had a simple sequence repeat (SSR) in the third intron that was polymorphic among various cotton species. An EST was identified with an expansion of the SSR that included the third intron indicating this SSR is associated with a splice variant. The polymorphic SSR may be useful in investigating the function of this gene in fiber development.