Poster: Seed biology

Abs # 729: An Arabidopsis mutant completing seed germination at 10^oC ahead of wild type ectopically expresses a PROTEIN PHOSPHATASE 1A (PP1A) gene.

Presenter:	Kar, Rup K, r_kkar@rediffmail.com
Authors	Salaita, Louai  (A)   Kar, Rup K (A)   Majee, Manoj  (A)   Downie, Bruce  (A)
Affiliations:	(A): University of Kentucky

Low, non-freezing soil temperature presents a barrier to the completion of seed germination thereby limiting plant production, species distribution, and direct seeding of many crops. Sub-optimal temperatures minimize degree-day accumulation prolonging the sojourn of seeds in a hostile soil environment where they are vulnerable to pathogen attack, predation, and seed-bed deterioration. We have isolated mutants capable of completing germination at 10^oC in advance of wild type from activation tagged lines of Arabidopsis thaliana. Following retrieval, plants from recessive (insertional) or dominant (activated) cold temperature germinating (ctg) mutant- and wild type-seeds were grown under controlled conditions, seeds were harvested from them on the same day and used for re-screening. Machine vision using automated data capture permitted wild type and mutant seeds to be assessed hourly for radicle protrusion during re-screening. These high resolution images also permitted classification of the mutants into those also affecting seed-/seedling-size and/or seed color. Among five non-allelic ctg mutants recovered so far, two recessive lines (ctg156 and ctg225), which were BASTA sensitive, are transparent testa mutants. Three other lines (ctg10-D, ctg41-D, and ctg144-D) were linked to BASTA resistance having a single full length insertion. Moreover, the size of seeds/seedlings was larger for ctg10-D than for wild type. The site of T-DNA insertion has been identified for ctg144-D and leads to ectopic expression of a flanking serine/threonine protein phosphatase 1A.