OsPHR2对小麦酸性磷酸化酶活性和根系土壤有机酸含量的影响

为了明确水稻低磷胁迫转录因子OsPHR2对小麦酸性磷酸化酶活性、根系土壤有机酸含量和根系活力的影响，以转OsPHR2小麦纯合株系和受体对照为试验材料，在不施磷（低磷）、施易溶性磷（0.200 g·kg^-1，KH₂PO₄为磷源）和施难溶性磷（0.200 g·kg^-1，以AlPO₄为磷源）3个处理下开展转OsPHR2小麦酸性磷酸化酶活性、根际土壤有机酸含量和根系活力的研究。结果表明，拔节期、抽穗期和灌浆期，在低磷和施AlPO₄处理下2个转OsPHR2小麦株系旗叶和根部酸性磷酸化酶活性均显著高于受体对照；施KH₂PO₄处理下，2个转基因株系旗叶酸性磷酸化酶活性在抽穗期和灌浆期均显著高于对照，根部在抽穗期显著高于对照，其他时期差异均不显著。随着小麦生育进程，小麦根际土壤草酰乙酸、草酸、乙酸、丙二酸和柠檬酸等有机酸含量逐渐增加。拔节期和抽穗期，在低磷、施AlPO₄和施KH₂PO₄处理下转基因系OsT5-28根际土壤五种有机酸含量均显著高于对照。转基因小麦根际土壤有机酸含量较对照的提高幅度在拔节期或抽穗期较大。三种处理下转基因系OsT5-28根系TTC还原力在三个时期均显著高于对照。这说明低磷胁迫下OsPHR2可提高小麦酸性磷酸化酶活性和根系活力，促进根系有机酸的分泌，增加分泌量，从而提高小麦磷素吸收效率。

Effect of OsPHR2 on Acid Phosphatase Activity and Organic Acid Content in Rhizosphere Soil in Wheat

In order to investigate the effect of Oryza sativaphosphate response 2(OsPHR2)gene on acid phosphate activity, organic acid content in rhizosphere soil and root activity in wheat, transgenic OsPHR2 wheat homozygous line and receptor control were used as research materials, under three phosphorus treatments of no phosphorus application (low phosphorus), soluble phosphorus application (0.200 g·kg^-1, KH₂PO₄ as phosphorus source), and insoluble phosphorus application (0.200 g·kg^-1,AlPO₄ as phosphorus source), and the activity of acid phosphorylase, organic acid content in rhizosphere soil and root activity of transgenic OsPHR2 wheat were studied. The results showed that the activity of acid phosphorylase in flag leaf and root of two OsPHR2 transgenic lines were significantly higher than that of the recipient control at jointing, heading, and filling stage under low phosphate and AlPO₄ application treatments.Under the treatment of KH₂PO₄ application,the activity of acid phosphorylase in flag leaf of the two OsPHR2 transgenic lines was significantly higher than that of control at heading and filling stage, and the root was significantly higher than that of the control at heading stage, yet the difference was not significant at other stages. With the development of wheat growth period, the content of oxaloacetic acid, oxalic acid, acetic acid, malonic acid, and citric acid in wheat rhizosphere soil increased gradually. At jointing and heading stages, the contents of the five organic acids in transgenic line OsT5-28 rhizosphere soil were significantly higher than those of recipient control under low phosphorus, AlPO₄ application and KH₂PO₄ application treatments. Compared with the control, the content of organic acid in the rhizosphere soil of transgenic wheat increased significantly at the jointing stage or heading stage.The root TTC reductive activity of the transgenic line OsT5-28 was significantly higher than that of recipient control at three stages under three treatments. The results showed that OsPHR2 increased the activity of acid phosphorylase and root activity in wheat, promoted the secretion of organic acids in rhizosphere under low phosphorus treatment, and thus improved the phosphorus absorption efficiency of wheat.