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The OCL3 promoter from Sorghum bicolor directs gene expression to abscission and nutrient-transfer zones at the bases of floral organs.
- Source :
-
Annals of botany [Ann Bot] 2014 Sep; Vol. 114 (3), pp. 489-98. Date of Electronic Publication: 2014 Jul 31. - Publication Year :
- 2014
-
Abstract
- Background and Aims: During seed fill in cereals, nutrients are symplasmically unloaded to vascular parenchyma in ovules, but thereafter nutrient transport is less certain. In Zea mays, two mechanisms of nutrient passage through the chalaza and nucellus have been hypothesized, apoplasmic and symplasmic. In a recent study, nutrients first passed non-selectively to the chalazal apoplasm and were then selectively absorbed by the nucellus before being released to the endosperm apoplasm. This study reports that the promoter of OUTER CELL LAYER3 (PSbOCL3) from Sorghum bicolor (sorghum) directs gene expression to chalazal cells where the apoplasmic barrier is thought to form. The aims were to elucidate PSbOCL3 expression patterns in sorghum and relate them to processes of nutrient pathway development in kernels and to recognized functions of the homeodomain-leucine zipper (HD-Zip) IV transcription factor family to which the promoter belongs.<br />Methods: PSbOCL3 was cloned and transformed into sorghum as a promoter-GUS (β-glucuronidase) construct. Plant tissues from control and transformed plants were then stained for GUS, and kernels were cleared and characterized using differential interference contrast microscopy.<br />Key Results: A symplasmic disconnect between the chalaza and nucellus during seed fill is inferred by the combination of two phenomena: differentiation of a distinct nucellar epidermis adjacent to the chalaza, and lysis of GUS-stained chalazal cells immediately proximal to the nucellar epidermis. Compression of the GUS-stained chalazal cells during kernel maturation produced the kernel abscission zone (closing layer).<br />Conclusions: The results suggest that the HD-Zip IV transcription factor SbOCL3 regulates kernel nutrition and abscission. The latter is consistent with evidence that members of this transcription factor group regulate silique abscission and dehiscence in Arabidopsis thaliana. Collectively, the findings suggest that processes of floral organ abscission are conserved among angiosperms and may in some respects differ from processes of leaf abscission.<br /> (© The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)
- Subjects :
- Base Sequence
Cloning, Molecular
Flowers growth & development
Flowers metabolism
Plant Proteins metabolism
Plants, Genetically Modified genetics
Plants, Genetically Modified growth & development
Plants, Genetically Modified metabolism
Polymerase Chain Reaction
Promoter Regions, Genetic
Sequence Homology
Sorghum metabolism
Gene Expression Regulation, Plant
Plant Proteins genetics
Sorghum genetics
Sorghum growth & development
Subjects
Details
- Language :
- English
- ISSN :
- 1095-8290
- Volume :
- 114
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Annals of botany
- Publication Type :
- Academic Journal
- Accession number :
- 25081518
- Full Text :
- https://doi.org/10.1093/aob/mcu148