NtProRP1, a novel proline-rich protein, is an osmotic stress-responsive factor and specifically functions in pollen tube growth and early embryogenesis in Nicotiana tabacum.
Proline-rich proteins (PRPs) are known to play important roles in sexual plant reproduction. Most of the known proteins in the family were found in styles or pollen and modulate pollen tube growth. Here, we identified a novel member of the gene family, NtProRP1, which is preferentially expressed in tobacco pollen grains, pollen tubes and zygotes. NtProRP1 could be secreted into the extracellular space including the cell wall, and the predicted N-terminal signal peptide is crucial for its secretion. In NtProRP1-RNAi plants, pollen germination and pollen tube growth were significantly slower and showed zigzag or swell morphology in vitro. Early embryogenesis also exhibited aberrant development, indicative of its critical role in both pollen tube growth and early embryogenesis. Further investigation revealed that NtProRP1 plays a crucial role in osmotic stress response during pollen tube growth and is likely regulated by Tsi, a stress-responsive gene, suggesting that the regulatory mechanism is also involved in the stress response during sexual plant reproduction. These data provide evidence that NtProRP1 functions as a downstream factor of Tsi1 in the stress response and converges the stress signal into the modulation of pollen tube growth and early embryogenesis.
Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, 430072, China.
Junyi
J
Chen
Jing
J
Zhao
Jue
J
Ning
Yuan
Y
Liu
Jing
J
Xu
Shujuan
S
Tian
Liyao
L
Zhang
Meng-Xiang
MX
Sun
D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D053205:Pollen Tube / Q000254:growth & development*; D012098:Reproduction; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D014026:Nicotiana / Q000196:embryology* / Q000254:growth & development / Q000502:physiology
D010940:Plant Proteins
PRP; embryo; pollen germination; stress response; tobacco.