利用代谢组学揭示脱落酸对高温胁迫龙须菜(Gracilariopsis lemaneiformis)的作用机制

METABOLOMICS REVEALED THE POTENTIAL MECHANISM OF ABSCISIC ACID IN GRACILARIOPSIS LEMANEIFORMIS UNDER HIGH TEMPERATURE STRESS

大型经济海藻龙须菜(Gracilariopsis lemaneiformis)在我国南北方海域广泛栽培,但其栽培周期与产量受到夏季高温天气的制约。植物激素脱落酸(ABA)在高等植物生长发育和抗逆胁迫中发挥了重要作用,但在藻类中研究较少。为揭示ABA对高温胁迫下龙须菜的保护作用及其潜在的作用机制,采用超高效液相色谱-质谱联用法(UPLC-MS/MS)研究了外源ABA对高温胁迫下龙须菜代谢产物的影响。结果表明,ABA处理72 h后龙须菜中104种代谢物发生变化,其中黄嘌呤、次黄嘌呤、芦丁、精氨酰琥珀酸等26种代谢物含量升高,而23种溶血磷脂酰乙醇胺(LPE)和35种溶血磷脂酰胆碱(LPC)含量下降;嘌呤代谢、黄酮和黄酮醇合成以及抗坏血酸和醛酸盐代谢这3条代谢通路受ABA影响显著。最后,利用生理生化方法检测了黄嘌呤对高温胁迫下龙须菜生长速率和活性氧(ROS)的影响,以及ABA添加后两种溶血磷脂代谢酶活性、精氨酰琥珀酸合成酶及其基因表达的变化,发现藻的生长、酶活性或基因表达变化等与代谢组结果相吻合。可见,ABA可以通过激活嘌呤代谢、黄酮和黄酮醇合成以及抑制溶血磷脂合成等来保护高温胁迫下的龙须菜。研究结果丰富了藻类中植物激素抗逆胁迫的资料,为龙须菜耐高温品系选育提供了新的思路。

The economic seaweed Gracilariopsis lemaneiformis is widely cultivated in the southern and northern coasts of China,yet its cultivation cycles and yields are restricted by high temperature in summer.Plant hormone abscisic acid(ABA)plays an important role in the growth,development,and stress resistance of higher plants,but the research onto algae is scarce.To reveal the protective role and potential mechanism of ABA on high-temperature stressed seaweed,the effect of exogenous ABA on metabolites of heat-resistant strain G.lemaneiformis 981 was analyzed using ultra-performance liquid chromatography-mass spectrometry(UPLC-MS/MS).The results show that 104 metabolites were influenced after ABA addition,among them,26 compounds including xanthine,hypoxanthine,rutin,argininosuccinic acid were accumulated;however,the contents of 23 lysophosphatidylethanolamines and 35 lysophosphatidylcholines were decreased.In addition,three pathways of flavone and flavonol biosynthesis,purine metabolism,ascorbate,and aldarate metabolism were significantly affected by ABA.Physiological and biochemical methods were used to verify the effects of xanthine on the growth and reactive oxygen species(ROS)of G.lemaneiformis under high temperature stress,and the effects of ABA addition on the activities of two lysophosphatidic metabolic enzymes and one enzyme of argininosuccinate synthetase and its gene expression.It was found that the changes in algal growth,enzyme activity or gene expression were consistent with the metabolome outcome.Therefore,ABA could protect high-temperature stressed G.lemaneiformis by up-regulating flavone and flavonol biosynthesis,purine metabolism and inhibiting lysophosphatide synthesis.This research provided a new insight for understanding the mechanism of plant hormones in algae against high temperature.