A pollen allergen-encoding gene is expressed in wheat ovaries

Area of Science:

• Plant molecular biology
• Wheat genetics
• Reproductive biology

Background:

• Identifying genes crucial for early plant embryo development is essential for understanding plant reproduction.
• Wheat lines with different embryo development pathways (zygotic vs. autonomous) provide a model for studying gene expression.
• Pollen allergens are typically associated with pollen-specific functions.

Purpose of the Study:

• To isolate genes specifically expressed during the initiation of plant embryo development.
• To investigate the expression pattern of a novel pollen allergen-like gene in wheat.
• To explore the potential correlation between this gene's expression and male fertility in wheat.

Main Methods:

• Subtractive hybridization technique to identify differentially expressed genes.
• Northern and in situ hybridization to analyze gene expression patterns.
• Comparison of gene expression across three isogenic wheat lines with varying reproductive characteristics.

Main Results:

• A gene sequence, Tri a III, homologous to grass pollen allergens (type II/III) was identified.
• Tri a III transcripts were detected in the gynoecia (ovaries) of the male-fertile wheat line '(aestivum)-Salmon'.
• Tri a III transcripts were completely absent in the male-sterile, parthenogenetic wheat lines '(caudata)-Salmon' and '(kotschyi)-Salmon'.
• Expression in ovaries was localized to parenchymatous tissue and occurred specifically on the day of anthesis.
• Expression was also confirmed in pollen, consistent with its homology.

Conclusions:

• The pollen allergen-like sequence Tri a III is expressed in wheat ovaries, not just pollen.
• Its expression in ovaries correlates positively with male fertility in wheat.
• Tri a III may have a broader function in plant reproduction beyond its role as a pollen allergen.