缺磷胁迫下小麦叶片中磷脂酰甘油含量降低的机理(英文)

Mechanisms on the Decrease of Phosphatidylglycerol Content in Wheat Leaves under Phosphate Deprivation Stress

为了揭示缺磷胁迫下小麦叶片磷脂酰甘油(GP)含量降低的机理,比较分析了小麦不同发育阶段叶片中的PG含量与PG水解酶活性的变化,结果表明,当小麦第一叶刚刚展开时,缺磷处理与对照间PG含量、PG水解酶活性相似;随着叶片逐渐衰老,缺磷叶片中PG含量迅速下降,PG水解酶活性大幅度上升。这一结果表明,缺磷条件下衰老叶片中的PG水解酶活性增强是导致PG含量下降的一个重要原因。另外,通过比较不同叶位叶片刚刚展开时的PG含量与PG水解酶活性,探讨了缺磷条件下PG生物合成受阻对植物体内PG含量的影响。

Phosphatidylglycerol （PG） is crucial for the organization and function of the thylakoid membrane. Decrease of PG in plants under phosphate deprivation condition was previously considered to the inhibition of PG biosynthesis. We here reported the novel findings that the increased PG degradation was also responsible for PG loss in wheat leaves under phosphate deprivation condition. By comparing the change in PG content and the PG hydrolase activity in wheat leaves at different developmen- tal stages, we found that when the first leaves just fully developed, the relative amount of PG in phosphate-deficient leaves was similar to that of control, and that the difference in PG hydrolase activity was also not significant between treatments. However, along with the aging process of the leaf, a great loss of PG was observed and associated with rapid increase in PG hydrolase activity in the phosphate-deficit leaves. These results suggested that PG hydrolysis was dramatically activated under phosphate deprivation, consequently PG content was decreased after the full expansion of the leaves. Besides, compared with that in the first leaf of 7d-old plants, PG biosynthesis was inhibited in the second leaf of the 12 d-old plants and the third leaf of the 19 d-old plants, which could contribute to the decrease in PG content under phosphate deprivation stress.