Nature：决定植物茎组织形式的第二种激素

里昂大学作物繁殖和发展研究院的研究人员在新研究中，揭示决定植物茎组织形式的第二种激素。相关文章发表于2013年12月15日的《Nature》杂志上。



Nature：决定植物茎组织形式的第二种激素

器官在植物茎周围的规则排列被称为“叶序”(phyllotaxis)。植物激素“茁长素”的积累触发器官开始形成，而器官周围“茁长素”耗尽会产生“抑制场”，后者被认为足以维持这些模式。

在这项研究中，Teva Vernoux及同事发现，该过程还可能涉及第二种基于激素的“场”。他们发现，“苗端”内细胞分裂素抑制因子AHP6在细胞间的运动会在“茁长素”的下游产生一些“场”，这些“场”会在分裂组织中产生细胞分裂素信号作用活动的空间模式，从而使得“叶序”具有稳定性。

原文摘要：

Cytokinin signalling inhibitory fields provide robustness to phyllotaxis

Fabrice Besnard, Yassin Refahi, Valérie Morin, Benjamin Marteaux, Géraldine Brunoud,Pierre Chambrier, Frédérique Rozier, Vincent Mirabet, Jonathan Legrand, Stéphanie Lainé, Emmanuel Thévenon, Etienne Farcot, Coralie Cellier, Pradeep Das, Anthony Bishopp, Renaud Dumas, François Parcy, Ykä Helariutta, Arezki Boudaoud, Christophe Godin, Jan Traas, Yann Guédon & Teva Vernoux

How biological systems generate reproducible patterns with high precision is a central question in science. The shoot apical meristem (SAM), a specialized tissue producing plant aerial organs, is a developmental system of choice to address this question. Organs are periodically initiated at the SAM at specific spatial positions and this spatiotemporal pattern defines phyllotaxis. Accumulation of the plant hormone auxin triggers organ initiation, whereas auxin depletion around organs generates inhibitory fields that are thought to be sufficient to maintain these patterns and their dynamics. Here we show that another type of hormone-based inhibitory fields, generated directly downstream of auxin by intercellular movement of the cytokinin signalling inhibitorARABIDOPSIS HISTIDINE PHOSPHOTRANSFER PROTEIN 6 (AHP6)14, is involved in regulating phyllotactic patterns. We demonstrate that AHP6-based fields establish patterns of cytokinin signalling in the meristem that contribute to the robustness of phyllotaxis by imposing a temporal sequence on organ initiation. Our findings indicate that not one but two distinct hormone-based fields may be required for achieving temporal precision during formation of reiterative structures at the SAM, thus indicating an original mechanism for providing robustness to a dynamic developmental system.

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