Demand-driven control of root ATP sulfurylase activity and SO42- uptake in intact canola - The role of phloem-translocated glutathione
Demand-driven control of root ATP sulfurylase activity and SO42- uptake in intact canola - The role of phloem-translocated glutathione
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DOI：
10.1104/pp.111.1.147
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发表时间：
1996-05-01
期刊：
影响因子：
7.4
通讯作者：
Touraine, B
中科院分区：
文献类型：
--
作者：
Lappartient, AG;Touraine, B
甘蓝型油菜(Brassica napus L.cv Drakkar)根中提取的三磷酸腺苷硫酰基酶活性在停止使用S源后升高，在S饥饿的植株中重新补饲后活性下降。根吸收SO42的速率也受到类似的影响。S饥饿全根后，根系中SO42-和谷胱甘肽含量均下降，但裂根实验中只有+S根中的谷胱甘肽含量下降。将植物转移到不含S的溶液中，韧皮部分泌物中的谷胱甘肽浓度降低。通过韧皮部汁液向根内或外源供应GSH或半胱氨酸，抑制了ATP硫酰基酶活性和SO42-的吸收。谷胱甘肽合成的抑制剂丁硫氨酸亚磺胺可逆转半胱氨酸对三磷酸腺苷硫酰化酶的抑制作用。据推测，CSH负责调解对S可用性的反应。ATP硫酰酶活性和SO42-吸收速率受类似的需求驱动过程的调节，该过程涉及韧皮部运输的信息(可能是CSH)转移到根，提供有关叶片营养状况的信息。
The activity of ATP sulfurylase extracted from roots of intact canola (Brassica napus L. cv Drakkar) increased after withdrawal of the S source from the nutrient solution and declined after refeeding SO42- to S-starved plants. The rate of SO42- uptake by the roots was similarly influenced. identical responses were obtained in SO42--fed roots when one-half of the root system was starved for S. The internal levels of SO42- and glutathione (GSH) declined after S starvation of the whole root system, but only GSH concentration declined in +S roots of plants from split root experiments. The concentration of GSH in phloem exudates decreased upon transfer of plants to S-free solution. Supplying GSH or cysteine to roots, either exogenously or internally via phloem sap, inhibited both ATP sulfurylase activity and SO42- uptake. Buthionine sulfoximine, an inhibitor of GSH synthesis, reversed the inhibitory effect of cysteine on ATP sulfurylase. It is hypothesized that CSH is responsible for mediating the responses to S availability. ATP sulfurylase activity and the SO42- uptake rate are regulated by similar demand-driven processes that involve the translocation of a phloem-transported message (possibly CSH) to the roots that provides information concerning the nutritional status of the leaves.