Maize unstable factor for orange1 is essential for endosperm development and carbohydrate accumulation

Area of Science:

• Plant genetics
• Molecular biology
• Developmental biology

Background:

• The maize gene Ufo1 (unstable factor for orange1) is specific to Poaceae grasses and highly expressed during seed development.
• A spontaneous dominant mutation, Ufo1-1, and a loss-of-function allele, ufo1-Dsg, were previously identified.

Purpose of the Study:

• To characterize the Ufo1-1 and ufo1-Dsg mutant alleles.
• To elucidate the function of the Ufo1 gene in maize development.

Main Methods:

• Characterization of mutant alleles (Ufo1-1 and ufo1-Dsg).
• Analysis of sugar and hormone levels.
• Examination of basal endosperm transfer layer (BETL) cell morphology and cell wall ingrowth.
• Gene expression analysis in various tissues (BETL, pericarp, leaf).
• Overexpression studies of Ufo1-1.

Main Results:

• Both ufo1 mutant alleles affect sugars and hormones, causing defects in BETL cells, including reduced cell elongation, abnormal cell wall ingrowth, and altered cell shape.
• Ufo1 mutation impacts the expression of genes critical for BETL development.
• Overexpression of Ufo1-1 induces ectopic phenotypes in various tissues, such as abnormal cell organization and stomatal defects.
• Transcriptomic analysis reveals ectopic expression of endosperm development-specific genes in Ufo1-1 mutants in pericarp and leaf tissues.

Conclusions:

• The Ufo1 gene is essential for normal maize seed development, particularly for BETL formation and function.
• Ufo1 influences the expression of a broad spectrum of genes involved in diverse developmental processes.
• Mutations in Ufo1 lead to significant alterations in cellular structure and gene regulation across different maize tissues.