Dynamic parent-of-origin effects on small interfering RNA expression in the developing maize endosperm

Area of Science:

• Plant reproductive biology
• Epigenetics
• Molecular genetics

Background:

• The endosperm is vital for embryo development and embryogenesis regulation in angiosperms.
• It is the primary site of genomic imprinting, involving complex genetic and epigenetic interactions.

Purpose of the Study:

• To investigate the role and patterns of small interfering RNAs (siRNAs) in maize endosperm development.
• To explore the relationship between imprinted siRNAs and imprinted genes.

Main Methods:

• Sequencing of small interfering RNA (siRNA) transcriptomes in developing maize kernels and endosperms.
• Analysis of reciprocal crosses between maize B73 and Mo17.
• Identification and characterization of imprinted siRNA loci and their association with imprinted genes.

Main Results:

• Paternal siRNA expression increased gradually in early kernel stages.
• A 2:1 maternal to paternal ratio of siRNAs was observed in 7-day-old endosperm.
• 460 imprinted siRNA loci were identified, with 99.1% maternally expressed at 10 days after pollination (DAP).
• 13 imprinted genes were found near imprinted siRNA loci.
• Gene Ontology analysis revealed enrichment of specific terms associated with 10-DAP and 15-DAP specific siRNAs.

Conclusions:

• A subset of siRNAs exhibits imprinted expression in maize endosperm, likely correlating with imprinted gene expression.
• siRNAs may play a role in nutrient uptake and allocation during maize endosperm development.