Nature本期封面所示為一個花粉管在一種新發(fā)現(xiàn)的化學(xué)引誘劑LURE1引誘下按“N-形”形狀生長,。
精確的花粉管引導(dǎo)是開花植物成功受精的關(guān)鍵,?；ǚ酃芤T劑的概念是十九世紀(jì)末提出的,，當(dāng)時人們發(fā)現(xiàn)花粉管朝介質(zhì)上被切除的雌蕊組織的方向生長,。2001年,，助細(xì)胞（英文名synergid cell，其位置在卵細(xì)胞旁）被發(fā)現(xiàn)分泌一種可溶因子,，該因子引導(dǎo)花粉管向胚囊生長?，F(xiàn)在，這些花粉管引誘劑終于被識別出來了,。助細(xì)胞是從名為“藍(lán)豬兒”（Torenia fournieri）的植物中分離出來的,，這種植物的獨特之處是有一個突出的胚囊。所分泌的引導(dǎo)因子被發(fā)現(xiàn)是富含半胱氨酸的多肽,，屬于類似防衛(wèi)素的蛋白,，被命名為LUREs。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 458, 357-361 (19 March 2009) | doi:10.1038/nature07882
Defensin-like polypeptide LUREs are pollen tube attractants secreted from synergid cells
Satohiro Okuda1,7, Hiroki Tsutsui1,7, Keiko Shiina1, Stefanie Sprunck2, Hidenori Takeuchi1, Ryoko Yui1, Ryushiro D. Kasahara1, Yuki Hamamura1, Akane Mizukami1, Daichi Susaki1, Nao Kawano1, Takashi Sakakibara1, Shoko Namiki1, Kie Itoh3, Kurataka Otsuka4, Motomichi Matsuzaki4, Hisayoshi Nozaki4, Tsuneyoshi Kuroiwa5, Akihiko Nakano4,6, Masahiro M. Kanaoka1, Thomas Dresselhaus2, Narie Sasaki1,7 & Tetsuya Higashiyama1,7
1 Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
2 Cell Biology/Plant Physiology, University of Regensburg, Universit?tsstrae 31, 93053 Regensburg, Germany
3 Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
4 Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
5 Research Information Center of Extremophile, Graduate School of Science, Rikkyo (Saint Paul's) University, Nishi-Ikebukuro, Tokyo 171-8501, Japan
6 Molecular Membrane Biology Laboratory, RIKEN Advanced Science Institute, Hirosawa, Wako, Saitama 351-0198, Japan
7 These authors contributed equally to this work.
8 Correspondence to: Tetsuya Higashiyama1,7 Correspondence and requests for materials should be addressed to T.H.
For more than 140 years, pollen tube guidance in flowering plants has been thought to be mediated by chemoattractants derived from target ovules1. However, there has been no convincing evidence of any particular molecule being the true attractant that actually controls the navigation of pollen tubes towards ovules. Emerging data indicate that two synergid cells on the side of the egg cell emit a diffusible, species-specific signal to attract the pollen tube at the last step of pollen tube guidance1, 2, 3. Here we report that secreted, cysteine-rich polypeptides (CRPs) in a subgroup of defensin-like proteins are attractants derived from the synergid cells. We isolated synergid cells of Torenia fournieri, a unique plant with a protruding embryo sac, to identify transcripts encoding secreted proteins as candidate molecules for the chemoattractant(s). We found two CRPs, abundantly and predominantly expressed in the synergid cell, which are secreted to the surface of the egg apparatus. Moreover, they showed activity in vitro to attract competent pollen tubes of their own species and were named as LUREs. Injection of morpholino antisense oligomers against the LUREs impaired pollen tube attraction, supporting the finding that LUREs are the attractants derived from the synergid cells of T. fournieri.
