Evolution of Development and Physiology
Anterola, Aldwin , Shanle, Erin , Mansouri, Katayoun , Schuette, Scott , Vidal-Russell, Romina , Coates, Robert , Von Schwartzenberg, Klaus , Renzaglia, Karen .
Gibberellin Biosynthesis and Function in Bryophytes.
Bryophytes are considered the earliest diverging lineages of land plants, which may have retained most of the features of ancient embryophytes. Hence, by comparing their genomes and developmental processes with those of higher plants, bryophytes can provide insights into the evolution of plant physiology and development. In this context, we are studying the biosynthesis and functions of gibberellins in bryophytes using the moss Physcomitrella patens as our model system. A survey of the P. patens genome suggests that this moss may have a shorter version of the gibberellin pathway relative to that of higher plants. For example, while higher plants use two enzymes, copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS), in the cyclization of geranylgeranyl diphosphate to ent-kaurene, P. patens employs a bifunctional ent-kaurene synthase to catalyze these two steps in the gibberellin pathway. The gene encoding this bifunctional enzyme was heterologously expressed in E. coli, and then tested for its sensitivity to AMO-1618, which is a known CPS and KS inhibitor in higher plants. After confirming that AMO-1618 inhibited the moss bifunctional ent-kaurene synthase, it was used to determine the potential roles of gibberellins in P. patens. In particular, the effects of AMO-1618 on antheridia formation and spore germination were tested because ferns use gibberellins as antheridiogens and/or spore germination inducers. Our results show that while AMO-1618 did not affect antheridia formation in P. patens, it did suppress the germination of its spores, suggesting that gibberellins may be involved in stimulating spore germination in mosses, which is similar to their function in ferns. The implications of our findings are discussed in the context of phytohormone evolution.
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1 - Southern Illinois University Carbondale, Department of Plant Biology, 1125 Lincoln Drive, Life Science II, Room 420, Carbondale, IL, 62901-6509, United States
2 - Southern Illinois University Carbondale, Department of Plant Biology
3 - University of Illinois Urbana Champaign, Department of Chemistry
4 - University of Hamburg, Biozentrum Klein Flottbek und Botanischer Garten
Presentation Type: ASPB Minisymposium
Location: Continental B/Hilton
Date: Monday, July 9th, 2007
Time: 11:55 AM