Variation in growth rate between Arabidopsis ecotypes is correlated with cell division and A-type cyclin-dependent kinase activity.
We used a kinematic analysis to investigate the growth processes responsible for variation in primary root growth between 18 ecotypes of Arabidopsis. Root elongation rate differed 4-fold between the slowest (Landsberg erecta, 71 microm h(-1)) and fastest growing line (Wassilewskija [Ws]; 338 microm h(-1)). This difference was contributed almost equally by variations in mature cortical cell length (84 microm [Landsberg erecta] to 237 microm [Ws]) and rate of cell production (0.63 cell h(-1) [NW108] to 1.83 cell h(-1) [Ws]). Cell production, in turn, was determined by variation in cell cycle duration (19 h [Tsu] to 48 h [NW108]) and, to a lesser extent, by differences in the number of dividing cells (32 [Weiningen] to 61 [Ws]). We found no correlation between mature cell size and endoreduplication, refuting the hypothesis that the two are linked. However, there was a strong correlation between cell production rates and the activity of the cyclin-dependent kinase (CDKA). The level of the protein could explain 32% of the variation in CDKA. Therefore, it is likely that regulators of CDKA, such as cyclins and inhibitors, are also involved. These data provide a functional link between cell cycle regulation and whole-plant growth rate as affected by genetic differences.
Beemster
Gerrit T S
GT
Department of Plant Genetics, University of Gent/Flanders Institute of Biotechnology, B-9000 Gent, Belgium.
De Vusser
Kristof
K
De Tavernier
Evelien
E
De Bock
Kirsten
K
Inzé
Dirk
D
D000465:Algorithms; D017360:Arabidopsis / Q000145:classification / Q000254:growth & development*; D001696:Biomechanical Phenomena; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D016213:Cyclins / Q000494:pharmacology; D018744:DNA, Plant / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020440:Gene Duplication; D018517:Plant Roots / Q000254:growth & development; D013997:Time Factors
D016213:Cyclins; D018744:DNA, Plant; D004791:Enzyme Inhibitors; D018844:Cyclin-Dependent Kinases