|Pressoir, Gael -|
|Brown, Patrick -|
|Zhu, Wenyan -|
|Upadyayula, Narasimham -|
|Rocheford, Torbert -|
|Kresovich, Stephen -|
Submitted to: Plant Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2009
Publication Date: February 23, 2009
Citation: Pressoir, G., Brown, P.J., Zhu, W., Upadyayula, N., Rocheford, T., Buckler IV, E.S., Kresovich, S. 2009. Natural variation in maize architecture is mediated by allelic differences at the PINOID co-ortholog barren inflorescence2. Plant Journal. 58:618-628. Interpretive Summary: Plant hormones are how various parts of plants communicate with one another. Auxin is one of the key hormones in plants. One of the key maize genes involved in auxin is barren inflorescence2, which, when mutated, results in maize with tassels or ears without branches. This study evaluated the effects of natural variation at the barren inflorescence2 gene using two different genetic mapping approaches. Natural variation at gene appears not only to have effect on the ear and tassel, but also for the number of leaves on the plant. This provides insight into how variation at a key gene is controlling basic development of the maize plant.
Technical Abstract: We characterized allelic variation at barren inflorescence2 (bif2), a maize co-ortholog of the Arabidopsis PINOID protein kinase (PID), and tested for trait associations with bif2 in both an association mapping population of 277 diverse maize inbreds and in the inter-mated B73-Mo17 (IBM) linkage population. Results from the quantitative analyses were compared with previous reports of bif2 phenotypes in mutagenesis studies. All three approaches (association, linkage, and mutagenesis) detect a significant effect of bif2 on tassel architecture. Association mapping implicates bif2 in an unexpectedly wide range of traits including plant height, node number, leaf length, and flowering time. Linkage mapping finds a significant interaction effect for node number between bif2 and other loci, in keeping with previous reports that bif2;spi1 and Bif2;Bif1 double mutants produce fewer phytomers. The Mo17 allele is associated with a reduced tassel branch zone and shows lower expression than the B73 allele in hybrid B73–Mo17 F1 inflorescences, consistent with the complete absence of tassel branches in the bif2 knockout mutant. Overall, these data suggest that allelic variation at bif2 affects maize architecture by modulating auxin transport during vegetative and inflorescence development.