TY - JOUR
T1 - Exocytosis precedes and predicts the increase in growth in oscillating pollen tubes
AU - McKenna, Sylvester T.
AU - Kunkel, Joseph G.
AU - Bosch, Maurice
AU - Rounds, Caleb M.
AU - Vidali, Luis
AU - Winship, Lawrence J.
AU - Hepler, Peter K.
N1 - McKenna, S. T., Kunkel, J. G., Bosch, M., Rounds, C. M., Vidali, L., Winship, L. J., Hepler, P. K. (2009). Exocytosis precedes and predicts the increase in growth in oscillating pollen tubes. Plant Cell, 21, (10), 3026-3040.
IMPF: 09.29
Sponsorship: National Science Foundation 3026-3040
PY - 2009/10/27
Y1 - 2009/10/27
N2 - We examined exocytosis during oscillatory growth in lily (Lilium formosanum and Lilium longiflorum) and tobacco (Nicotiana tabacum) pollen tubes using three markers: (1) changes in cell wall thickness by Nomarski differential interference contrast (DIC), (2) changes in apical cell wall fluorescence in cells stained with propidium iodide (PI), and (3) changes in apical wall fluorescence in cells expressing tobacco pectin methyl esterase fused to green fluorescent protein (PME-GFP). Using PI fluorescence, we quantified oscillatory changes in the amount of wall material from both lily and tobacco pollen tubes. Measurement of wall thickness by DIC was only possible with lily due to limitations of microscope resolution. PME-GFP, a direct marker for exocytosis, only provides information in tobacco because its expression in lily causes growth inhibition and cell death. We show that exocytosis in pollen tubes oscillates and leads the increase in growth rate; the mean phase difference between exocytosis and growth is –98° ± 3° in lily and –124° ± 4° in tobacco. Statistical analyses reveal that the anticipatory increase in wall material predicts, to a high degree, the rate and extent of the subsequent growth surge. Exocytosis emerges as a prime candidate for the initiation and regulation of oscillatory pollen tube growth.
AB - We examined exocytosis during oscillatory growth in lily (Lilium formosanum and Lilium longiflorum) and tobacco (Nicotiana tabacum) pollen tubes using three markers: (1) changes in cell wall thickness by Nomarski differential interference contrast (DIC), (2) changes in apical cell wall fluorescence in cells stained with propidium iodide (PI), and (3) changes in apical wall fluorescence in cells expressing tobacco pectin methyl esterase fused to green fluorescent protein (PME-GFP). Using PI fluorescence, we quantified oscillatory changes in the amount of wall material from both lily and tobacco pollen tubes. Measurement of wall thickness by DIC was only possible with lily due to limitations of microscope resolution. PME-GFP, a direct marker for exocytosis, only provides information in tobacco because its expression in lily causes growth inhibition and cell death. We show that exocytosis in pollen tubes oscillates and leads the increase in growth rate; the mean phase difference between exocytosis and growth is –98° ± 3° in lily and –124° ± 4° in tobacco. Statistical analyses reveal that the anticipatory increase in wall material predicts, to a high degree, the rate and extent of the subsequent growth surge. Exocytosis emerges as a prime candidate for the initiation and regulation of oscillatory pollen tube growth.
U2 - 10.1105/tpc.109.069260
DO - 10.1105/tpc.109.069260
M3 - Article
C2 - 19861555
SN - 1040-4651
VL - 21
SP - 3026
EP - 3040
JO - Plant Cell
JF - Plant Cell
IS - 10
ER -