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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Chemistry Research » Research » Publications at this Location » Publication #332152

Title: The auxin-deficient defective kernel18 (dek18) mutation alters the expression of seed-specific biosynthethic genes in maize

item BERNARDI, JAMILA - Catholic University Of Leuven
item Li, Qin-Bao
item GAO, YANGBIN - University Of California
item ZHAO, YUNDE - University Of California
item BATTAGLIA, RAFFAELLA - Consiglio Per La Ricerca In Agricoltura E L'Analisi Dell'economia Agraria, Unita Di Ricerca Per I S
item MAROCCO, ADRIANO - Catholic University Of The Sacred Heart Italy
item CHOUREY, PREM - University Of Florida

Submitted to: Journal of Plant Growth Regulation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2015
Publication Date: 3/4/2016
Citation: Bernardi, J., Li, Q., Gao, Y., Zhao, Y., Battaglia, R., Marocco, A., Chourey, P.S. 2016. The auxin-deficient defective kernel18 (dek18) mutation alters the expression of seed-specific biosynthethic genes in maize. Journal of Plant Growth Regulation. 35(3):770-777.

Interpretive Summary: Very few auxin-defective mutants have been mapped and characterized in monocots. Interestingly, some defective endosperm mutants show differences in auxin accumulation Identification and characterization of mutants defective in phytohormones will increase understanding of the molecular control exerted by hormones during maize development. This often depends on the use of mutant lines from mutation screening where functional redundancy often complicates the process. This study reports on the mutant dek18 that accumulates only about 6 % of auxin in the endosperm compared to wild type. Interestingly, IAA levels and defects in seed size are very similar when comparing the dek18 mutant plants with the previously characterized de18 mutant that shows a reduction of 96 % in IAA content and 40 % in seed-weight Expression analysis of ZmYuc1, ZmTar1, and ZmTar3 in mutant dek18 revealed low transcript levels at 12 DAP, with respect to wild type.

Technical Abstract: The dek18 mutant of maize has decreased auxin content in kernels. Molecular and functional characterization of this mutant line offers the possibility to better understand auxin biology in maize seed development. Seeds of the dek18 mutants are smaller compared to wild type seeds and the vegetative development of dek18 is delayed. dek18 genes related to the auxin biosynthesis ( ZmAlliinase/Tar1 and ZmTar3 ) were highly down-regulated in the mutant compared to the wild type. Structural analysis of these genes revealed that no nucleotide difference is present in dek18 homozygous seeds compared to Dek18, but ZmTar1 or 3 are barely expressed in dek18 homozygous seeds, it is proposed that the mutation responsible for the dek1 8 phenotype alters the upstream regulation of the auxin biosynthetic pathway.