Maternal Gametophyte Effects on Seed Development in Maize

Area of Science:

• Plant reproductive biology
• Developmental genetics
• Seed science

Background:

• Flowering plants exhibit extensive maternal contributions to seed development, paralleling placental mammals.
• Unlike animals, plants possess a distinct, genetically active haploid gametophyte phase between meiosis and fertilization.
• Double fertilization in flowering plants uniquely produces two sister embryos: the endosperm and the zygotic embryo.

Purpose of the Study:

• To investigate the role of maternal gene expression in the female gametophyte during seed development.
• To identify and characterize mutations in Zea mays affecting maternal contributions to the seed.
• To elucidate the cellular mechanisms underlying maternal control of seed development through gametophyte regulation.

Main Methods:

• Analysis of Zea mays mutants with altered seed development.
• Examination of gene expression patterns, particularly in the basal endosperm transfer layer.
• Microscopic evaluation of female gametophyte morphology and cellular development prior to fertilization.

Main Results:

• Several maize mutations were identified that impair maternal gametophyte contributions to both endosperm and embryo development.
• Mutations frequently altered the expression of markers for the basal endosperm transfer layer, affecting nutrient transport.
• Abnormalities in female gametophyte development, including central cell size/architecture and antipodal/egg cell morphology, were observed prior to fertilization.

Conclusions:

• Maternal control of seed development is significantly influenced by the genetic and cellular state of the female gametophyte.
• Mutants affecting gametophyte development provide critical insights into the prerequisites for successful fertilization and seed formation.
• Further research into these mutants will illuminate the molecular mechanisms regulating maternal provisioning and developmental trajectories in seeds.