高等植物对磷饥饿自我拯救的分子生物学机制

Molecular Mechanisms of Self-rescue of Higher Plants for Phosphorus Starvation

磷饥饿状态下，植物通过一系列生理、生化变化主动适应胁迫逆境，包括植物对土壤难溶性磷的活化、根系对低浓度有机磷的有效吸收，以及对吸收磷的再利用等。而这些生理生化反应都有其特定的分子生物学基础。本文着重综述与这三方面特性有关的分子生物学研究进展，包括与根系有机酸合成以活化难溶性磷有关的ＰＥＰ羧化酶（ＰＥＰＣ）；与有效吸收低浓度有机磷有关的高亲和力磷转运子；以及与利用生长介质中的有机磷有关的ＲＮａｓｅ、磷酸酶（ＡＰａｓｅ）；Ｃａ２＋－ＡＴＰａｓｅ；低磷营养胁迫导致的植物与菌根菌互作的分子生物学；以及磷饥饿诱导差异表达的基因等。

Under phosphorus starvation condition, a series of physiological and biochemical changes take place to actively adapt to the stress environment, including the activation of plants to unavailable inorganic phosphorus in soils into the available form, the enhanced ab-sorption of roots to low concentration phosphorus and the efficient mobiliztion and reutiliza-tion to absorbed P. Accordingly, all the physiological and biochemical changes are based on their molecular biological mechanisms. In this paper, the advances in molecular biology concering these three aspects were summarized, especially refered to phosphoenolpyruvate carboxylase(PEPC) contributing to the synthesis of organic acids excreted extracellularly into soils, high affinity phosphate transporter playing very important role on the absorption to low concentration Pi, ribonuclease (RNase), Ca 2+ -ATPase, differentially expressed under the interraction between plants and vesicular-arbuscular (VA) mycorrhizal under phosphorus starvation, and other genes with unknown functions but differentially expressed under the starvation.