Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Pollen Germinates Precociously in the Anthers of Raring-to-Go, An Arabidopsis Gametophytic Mutant

Authors
item Johnson, Sheila - USDA/UCB PGEC
item McCormick, Sheila

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2001
Publication Date: June 1, 2002

Interpretive Summary: Pollen hydration is tightly regulated and usually occurs only when pollen grains acquire water from the female, thus enabling pollen tube growth. We identified a mutant, raring-to-go, in which pollen grains precociously germinate inside the anther. We show that raring-to-go is a gametophytic mutation. We devised a new technique for screening pollen in bulk and identified several additional mutants with a raring-to-go-like phenotype, demonstrating the usefulness of this technique. We isolated other mutants (gift-wrapped pollen, polka dot pollen, and emotionally fragile pollen) with unexpected patterns of callose staining. We suggest that raring-to-go and these other mutants may help dissect components of the pathway that regulates pollen hydration and pollen tube growth.

Technical Abstract: Pollen hydration is usually tightly regulated and occurs in vivo only when desiccated pollen grains acquire water from the female, thus enabling pollen tube growth. Pollen tubes are easily visualized by staining with decolorized aniline blue, a stain specific for callose. We identified a mutant, raring-to-go, in which pollen grains stained for callose before anther dehiscence. When raring-to-go plants are transferred to high humidity, pollen tubes dramatically elongate within the anther. As early as the bicellular stage, affected pollen grains in raring-to-go plants acquire or retain water within the anther, and precociously germinate. Thus, the requirement for contact with the female is circumvented. We used pollen tetrad analysis to show that raring-to-go is a gametophytic mutation, to our knowledge the first gametophytic mutation in Arabidopsis that affects early events in the pollination pathway. To aid in identifying raring-to-go alleles, we devised a new technique for screening pollen in bulk with decolorized aniline blue. We screened a new M1 mutagenized population and identified several additional mutants with a raring-to-go-like phenotype, demonstrating the usefulness of this technique. Further, we isolated other mutants (gift-wrapped pollen, polka dot pollen, and emotionally fragile pollen) with unexpected patterns of callose staining. We suggest that raring-to-go and these other mutants may help dissect components of the pathway that regulates pollen hydration and pollen tube growth.

Last Modified: 12/20/2014
Footer Content Back to Top of Page