非生物胁迫下植物体内丙酮醛代谢的研究进展

Advance on the Methylglyoxal Metabolism in Plants Under Abiotic Stress

由于植物固着生长,其无法通过移动来逃避逆境,故非生物胁迫(如极端温度、盐胁迫、干旱或光胁迫等)会伴随着植物的整个生长发育过程,严重胁迫植物的分布、生长、品质和产量,甚至生存。植物只能通过改变自身形态结构以及生理生化反应来适应环境,或者通过释放化学物质来影响周边其他植物的生长发育,以改变微环境,使环境向着更适合自己生长的方向发展。丙酮醛(methylglyoxal,MG)又称之为甲基乙二醛,作为植物体内正常的生理代谢产物可由多条途径产生,其最主要的来源是糖酵解途径,如糖酵解中间体二羟丙酮磷酸和甘油醛3-磷酸去除磷酸基。而植物体内MG的分解主要靠乙二醛酶系统,包括乙二醛酶Ⅰ、乙二醛酶Ⅱ以及还原型谷胱甘肽,MG经乙二醛酶降解后形成D-乳酸。在正常生长条件下,植物体内的MG含量维持在较低水平,而当植物遭受非生物胁迫时,其含量会迅速升高;植物体内的MG含量过高会破坏植物细胞的增殖和生存,控制细胞的氧化还原状态以及其他许多方面的新陈代谢过程,最终导致生物大分子蛋白质、DNA、RNA、脂质和生物膜的破坏。因此,MG现在被认为是植物非生物胁迫耐受性的潜在生化标志物,并受到科学界的广泛关注。该文结合最新的研究进展,对非生物胁迫下植物体内丙酮醛合成及降解机制予以综述。

Because plants grow steadily, they cannot escape adversity by moving. Most of plants live in environments where they are constantly exposed to one or combinations of various abiotic stressors, such as extreme temperatures, salinity, drought, and excessive light, which can severely limit plant distribution, growth and development, quality, yield and even survival. Plants can only adapt to the environment by changing their morphological structure and physiological and biochemical reactions, or by releasing chemical substances to affect the growth and development of other surrounding plants, so as to change the microenvironment and make the environment more suitable for their growth. Methylglyoxal(MG) as a normal physiological metabolites, is formed from various metabolic pathways in plants, among them the glycolysis pathway provides the most important source, including elimination of phosphate groups from glycolysis intermediates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate. MG is mostly detoxified by the combined actions of the enzymes glyoxalase Ⅰ and glyoxalase Ⅱ that together with glutathione make up the glyoxalase system, and it converts to D-lactate finally. Under normal growth conditions, basal levels of MG remain low in plants;However, when plants are exposed to abiotic stress, MG can be accumulated to much higher levels. Stress-induced MG, as a toxic molecule, inhibited different developmental processes, including seed germination, photosynthesis and root growth, destroyed cell proliferation and survival, controlled of the redox status of cells, and many other aspects of general metabolism. The increase of MG content eventually leads to the destruction of biological macromolecule proteins, DNA, RNA, lipids and biological membranes. Thus, MG is now considered as a potential biochemical marker for plant abiotic stress tolerance, and is receiving considerable attention by the scientific community. The aim of this review was to summarize the mechanisms of MG in plants under abiotic stress. In this review, the recent findings regarding MG synthesis and degradation metabolism in plants under abiotic stress was summarized.