近日,，國(guó)際著名雜志Nature在線刊登了諾丁漢大學(xué)等研究機(jī)構(gòu)研究人員的最新研究成果“A novel sensor to map auxin response and distribution at high spatio-temporal resolution”，研究人員在文章中人們長(zhǎng)久以來(lái)的疑問(wèn)：為什么植物根莖向下生長(zhǎng),，而不是向上生長(zhǎng),？
對(duì)于植物來(lái)說(shuō)，向下生長(zhǎng)的根莖可以深入土壤并最大化對(duì)水分的吸收,。但是“為什么”這個(gè)問(wèn)題一直讓回答了讓達(dá)爾文以來(lái)的無(wú)數(shù)科學(xué)家著迷,。如今諾丁漢大學(xué)的科學(xué)家們找到了答案。
重力對(duì)植物生長(zhǎng)的作用是舉足輕重的,。但是來(lái)自英國(guó),，德國(guó)，法國(guó),，比利時(shí),，瑞典和美國(guó)的科學(xué)家組成的研究小組在多年研究后最終確定了植物生長(zhǎng)的整個(gè)過(guò)程。在生物技術(shù)和生物科學(xué)研究理事會(huì)(BBSRC)的資助下,，諾丁漢大學(xué)植物科學(xué)教授和植物結(jié)合生物學(xué)中心生物學(xué)主任 Malcolm Bennett采用新技術(shù)探索植物根莖向下生長(zhǎng)時(shí)發(fā)生的狀況,。他說(shuō)： “這項(xiàng)研究真正體現(xiàn)了利用跨學(xué)科的方法探討植物科學(xué)問(wèn)題的價(jià)值。通過(guò)數(shù)學(xué)模型和試驗(yàn)生物學(xué)家的結(jié)合,，我們可采用一系列的工具研究根系生長(zhǎng)的問(wèn)題,。”
科學(xué)家們很早就發(fā)現(xiàn)植物因重力原因彎曲是由于根尖植物激素的再分配。這項(xiàng)研究結(jié)合DII-VENUS新技術(shù)（諾丁漢大學(xué)的另一項(xiàng)合作研究項(xiàng)目）,，運(yùn)用數(shù)學(xué)模型呈現(xiàn)出根莖在出現(xiàn)90度彎曲時(shí)生長(zhǎng)素開(kāi)始重新分配,，并且比之前認(rèn)為的要迅速很多,。
這種跨學(xué)科的研究方法揭示了生長(zhǎng)素在彎曲90度后迅速重新分配到了正在生長(zhǎng)的根部的低端。這表明根尖到達(dá)與水平方向呈40度的“轉(zhuǎn)折點(diǎn)”時(shí),，生長(zhǎng)素梯度將迅速消失,。這是導(dǎo)致根莖彎曲的“開(kāi)關(guān)”。（生物谷Bioon.com）
doi:10.1038/nature10791
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A novel sensor to map auxin response and distribution at high spatio-temporal resolution
Géraldine Brunoud,1 Darren M. Wells,2, 5 Marina Oliva,1, 5 Antoine Larrieu,2, 3, 5 Vincent Mirabet,1 Amy H. Burrow,4 Tom Beeckman,3 Stefan Kepinski,4 Jan Traas,1 Malcolm J. Bennett2 & Teva Vernoux1
Auxin is a key plant morphogenetic signal1 but tools to analyse dynamically its distribution and signalling during development are still limited. Auxin perception directly triggers the degradation of Aux/IAA repressor proteins2, 3, 4, 5, 6. Here we describe a novel Aux/IAA-based auxin signalling sensor termed DII-VENUS that was engineered in the model plant Arabidopsis thaliana. The VENUS fast maturing form of yellow fluorescent protein7 was fused in-frame to the Aux/IAA auxin-interaction domain (termed domain II; DII)5 and expressed under a constitutive promoter. We initially show that DII-VENUS abundance is dependent on auxin, its TIR1/AFBs co-receptors4, 5, 6, 8 and proteasome activities. Next, we demonstrate that DII-VENUS provides a map of relative auxin distribution at cellular resolution in different tissues. DII-VENUS is also rapidly degraded in response to auxin and we used it to visualize dynamic changes in cellular auxin distribution successfully during two developmental responses, the root gravitropic response and lateral organ production at the shoot apex. Our results illustrate the value of developing response input sensors such as DII-VENUS to provide high-resolution spatio-temporal information about hormone distribution and response during plant growth and development.
