浮游植物程序性细胞死亡研究进展

浮游植物是水生生态系统的基础,在生物地化循环中起着非常重要的作用,浮游植物的死亡势必引起水生生态系统的改变。近年来的研究表明,浮游植物的死亡是浮游植物水华衰退的一个重要原因。浮游植物中是否存在与后生动物类似的程序性细胞死亡（Programmed cell death,PCD）途径,也因此成了一个热点问题。文章对近年来浮游植物死亡表型、PCD生化证据、诱发条件、分子基础方面研究进行了总结。大量证据表明,浮游植物中存在类似细胞凋亡、类凋亡、自噬等途径的PCD,但Caspase基因除具有死亡执行者功能外,还可能具有看家功能。活性氧（ROS）和一氧化氮（NO）在浮游植物PCD过程中可能起到死亡信号分子的作用。部分浮游植物的PCD可以改善种群生存,但其生态学意义总体而言仍存在许多争论。

Programmed cell death in phytoplankton

Phytoplankton plays a critical role in regulating the biogeochemical cycles of numerous elements.A collapse,and or decline of phytoplankton can disrupt the ecological balance of aquatic ecosystems.Recent research has suggested that autolysis,cell death through self-digestion,is a key contributor to algal bloom die-off.As a result,current studies have focused on whether a programmed cell death（PCD）,like those found in metazoans,exists in phytoplankton.Scientific evidence has revealed the existence of PCD（apoptosis-like,paraptosis-like,and autophage-like） in the unicellular organisms.Many studies have suggested that some caspase-like genes are not only involved in PCD function,but might have a role in house-keeping as well.Additionally,reactive oxygen species and nitric oxide may function as a signal to initiate PCD in phytoplankton.This paper reviews the morphological characteristics of algae during senescence,the physiology of phytoplankton when exposed to various environmental stressors,the similarity of PCD genes between metazoans and phytoplankton,and summarized the significance of PCD to phytoplankton.Future studies should focus on the role of PCD in algal blooms,the signal pathway that initiates PCD,and how to regulate the function of PCD.This information can contribute to our understanding of PCD-related genes in ecology and evolutionary biology,and to the management of algal blooms.