Integrative proteomic and cytological analysis of the effects of extracellular Ca(2+) influx on Pinus bungeana pollen tube development.
Ca (2+) is an essential ion in the control of pollen germination and tube growth. However, the control of pollen tube development by Ca (2+) signaling and its interactions with cytoskeletal components, energy-providing pathways, and cell-expansion machinery remain elusive. Here, we used nifedipine (Nif) to study Ca (2+) functions in differential protein expression and other cellular processes in Pinus bungeana pollen tube growth. Proteomics analysis indicated that 50 proteins showed differential expression with varying doses of Nif. Thirty-four of these were homologous to previously reported proteins and were classified into different functional categories closely related to tip-growth machinery. Blocking the L-type Ca (2+) channel with Nif in the pollen tube membrane induced several early alterations within a short time, including a reduction of extracellular Ca (2+) influx and a subsequently dramatic decrease in cytosolic free Ca (2+) concentration ([Ca (2+)] c), concomitant with ultrastructural abnormalities and changes in the abundance of proteins involved in energy production and signaling. Secondary alterations included actin filament depolymerization, disrupted patterns of endocytosis/exocytosis, and cell wall remodeling, along with changes in the proteins involved in these processes. These results suggested that extracellular Ca (2+) influx was necessary for the maintenance of the typical tip-focused [Ca (2+)] c gradient in the P. bungeana pollen tube, and that reduced adenosine triphosphate production (ATP), depolymerization of the cytoskeleton, and abnormal endocytosis/exocytosis, together with enhanced rigidity of cell walls, were responsible for the growth arrest observed in pollen tubes treated with Nif.
Wu
Xiaoqin
X
Key Laboratory of Photosynthesis and Molecular Environment Physiology, Institute of Botany, Chinese Academy of Sciences, 100093 Beijing, China.
Chen
Tong
T
Zheng
Maozhong
M
Chen
Yanmei
Y
Teng
Nianjun
N
Samaj
Jozef
J
Baluska
Frantisek
F
Lin
Jinxing
J
D000199:Actins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002473:Cell Wall / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D003599:Cytoskeleton / Q000378:metabolism; D004734:Energy Metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology; D009930:Organic Chemicals / Q000378:metabolism; D028223:Pinus / Q000033:anatomy & histology / Q000737:chemistry / Q000502:physiology; D010940:Plant Proteins / Q000032:analysis*; D011058:Pollen / Q000166:cytology / Q000378:metabolism; D053205:Pollen Tube / Q000737:chemistry* / Q000187:drug effects / Q000254:growth & development* / Q000648:ultrastructure; D020543:Proteome / Q000032:analysis*
D000199:Actins; D002121:Calcium Channel Blockers; D005456:Fluorescent Dyes; D009930:Organic Chemicals; D010940:Plant Proteins; D020543:Proteome; C071336:calcium green; D009543:Nifedipine; D002118:Calcium