Knoeller, Anne , Blakeslee, Joshua , Richards, Elizabeth , Peer, Wendy , Murphy, Angus .
"The Benefits of Being Short" - Impact of P-Glycoproteins for Auxin Transport in Monocotyledons.
The success of the green revolution during the second part of the 20th century was largely the result of the introduction of “high yield varieties” (HYVs) of cereals with enhanced nitrogen assimilation characteristics. However, the heavier infructescences of these lines often caused lodging, and introgression of GA-dependent dwarf and semi-dwarf traits was required to make HYV lines viable for production. Established dwarf mutations in sorghum (dw3) and maize (br2) have recently been shown to harbor lesions in genes encoding p-glycoproteins (PGPs) shown to transport the phytohormone auxin. Phylogenetic analysis of rice, maize, and Arabidopsis PGP sequences indicates that a number of Arabidopsis PGPs in clades that include auxin transporters (I and II) form clusters with PGPs from rice and maize rather than with other Arabidopsis PGPs.PGP In all cases, the protein sequence similarity between members of these clusters is very high (e.g. 62% identity, 95.2% consensus for AtPGP19 / OsPGP8 / ZmPGP3), suggesting a conserved function of these proteins. Using genomic markers to align Arabidopsis and rice PGP loci with syntenous chromosomal regions in maize, genomic sequences associated with two characterized maize mutants, gs4 and br3, have been identified as PGP alleles. These maize mutants share some potentially auxin-related phenotypes that are similar to those of Arabidopsis PGP mutants. All mutants display a dwarf phenotype, although the developmental stage at which the phenotype becomes visible is different for each mutant. Results suggest that these PGPs are function in polar auxin transport in a manner similar to what is observed in dicots despite the substantial anatomical differences between these classes.
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1 - Purdue University, Horticulture and Landscape Architecture, 625 Agriculture Mall Drive, West Lafayette, IN, 47907, USA
2 - Purdue University, Horticulture and Landscape Architecture
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM