Analysis of the tip-to-base gradient of CaM in pollen tube pulsant growth using in vivo CaM-GFP system

作者：Shi, Ya-Ya; Tao, Wen-Jing; Liang, Shu-Ping; Lue, Yingtang; Zhang, Lei^*

来源：Plant Cell Reports, 2009, 28(8): 1253-1264.

DOI：10.1007/s00299-009-0725-z

• Calmodulin
• Oscillation
• Pollen tube
• Growth rate

Ca2+-CaM signaling is involved in pollen tube development. However, the distribution and function of CaM and the downstream components of Ca2+-CaM signal in pollen tube development still need more exploration. Here we obtained the CaM-GFP fusion protein transgenic line of Nicotiana tobacum SRI, which allowed us to monitor CaM distribution pattern in vivo and provided a useful tool to observe CaM response to various exogenous stimulations and afforded solid evidences of the essential functions of CaM in pollen tube growth. CaM-GFP fusion gene was constructed under the control of Lat52-7 pollen-specific promoter and transformed into Nicotiana tobacum SRI. High level of CaM-GFP fluorescence was detected at the germinal pores and the tip-to-base gradient of fluorescence was observed in developing pollen tubes. The distribution of CaM at apical dome had close relationship with the pulsant growth mode of pollen tubes: when CaM aggregated at the apical dome, pollen tubes stepped into growth state; When CaM showed non-polarized distribution, pollen tubes stopped growing. In addition, after affording exogenous Ca2+, calmidazolium (antagonism of CaM) or Brefeldin A (an inhibitor of membrane trafficking), CaM turned to a uniform distribution at the apical dome and pollen tube growth was held back. Taken together, our results showed that CaM played a vital role in pollen tube elongation and growth rate, and the oscillation of tip-to-base gradient of CaM was required for the normal pulsant growth of pollen tube.

• 出版日期2009-8
• 单位武汉大学