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ARS Home » Pacific West Area » Corvallis, Oregon » Forage Seed and Cereal Research Unit » Research » Publications at this Location » Publication #232451

Title: An Arabidopsis thaliana embryo arrest mutant exhibiting germination potential

item HONG, K - OSU
item LIU, PO-PU - OSU
item SUN, J - OSU
item Martin, Ruth

Submitted to: Seed Science Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/27/2008
Publication Date: 6/30/2008
Citation: Kristof, J.R., Coppersmith, J., Hong, K., Liu, P., Homrichhausen, T.M., Sun, J., Martin, R.C., Nonogaki, H. 2008. An Arabidopsis thaliana embryo arrest mutant exhibiting germination potential. Seed Science Research. 18: 55-65.

Interpretive Summary: An Arabidopsis embryo mutant, embryo ball (eb) was characterized. The mutant produced shrunken seeds with round or irregularly shaped embryos that were arrested during early stages of development. When the mutant embryos were cultured on nutrient media, they produced roots but not cotyledons. A leaf like structure with trichomes was produced at the apical region. These observations suggest that even though the embryos weren’t morphologically mature, they were capable of germination. The embryos also exhibited partial desiccation tolerance suggesting that cell maturation also progressed to some extent in the absence of morphological maturation. This mutant provides a useful tool for analyzing the mechanisms involved in the induction of germination potential and for examining cell and tissue identity in developing seeds.

Technical Abstract: The ability to initiate radicle elongation, or germination potential, occurs in developing embryos before the completion of seed maturation. Green embryos after walking-stick stage in developing Arabidopsis thaliana seeds germinate when excised from seeds and incubated in MS media containing 1 % sucrose. Germination potential is not observed during early embryogenesis at the globular, heart and torpedo stages. Here, we describe an Arabidopsis mutant with embryos arrested at early stages of development, but still exhibiting germination potential. The mutant, termed embryo ball (eb), produced shrunken seeds containing round or irregularly shaped embryos that did not germinate. The round embryos excised from developing eb seeds were capable of growing a main root with root hairs when incubated in media. In contrast, cotyledons were absent at the apical region of the eb embryos, although the apical region produced leaf-like structures with trichomes, indicating vegetative leaf identity. These observations suggested that morphological maturation was not essential for the induction of germination potential. The eb embryos exhibited partial desiccation tolerance that is characteristic of mature embryos at later stages of development, suggesting that cell maturation was also independent of morphological maturation. The eb mutant provides novel information on cell and tissue identity in developmental biology, as well as a useful tool to dissect the mechanisms underlying the induction of germination potential in developing seeds.