Real-time [11C]methionine translocation in barley in relation to mugineic acid phytosiderophore biosynthesis
Real-time [11C]methionine translocation in barley in relation to mugineic acid phytosiderophore biosynthesis
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DOI：
10.1007/s004250100552
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发表时间：
2001-09-01
期刊：
影响因子：
4.3
通讯作者：
Mori, S
中科院分区：
文献类型：
--
作者：
Bughio, N;Nakanishi, H;Mori, S
[C-11]蛋氨酸通过大麦根部供应，使用实时成像系统(PEITS)跟踪C-11信号90分钟，随后显影整个植物的放射自显影图像。在所有的情况下，[C-11]蛋氨酸首先被转移到‘辨别中心’，也就是新梢的基本部分，这部分是最强标记的。被植物根部吸收的蛋氨酸随后被转移到植物的其他部分。在缺铁的大麦植株中，[C-11]蛋氨酸从根部到地上部的转运急剧减少，而在缺铁或经蛋氨酸处理的大麦植株的叶片中发现了更多的C-11。用烟氨酸氨基转移酶抑制剂氨基氧乙酸处理缺铁植物，增加了[C-11]蛋氨酸向地上部的转运。外源供应的[C-11]蛋氨酸在缺铁大麦根部的滞留表明蛋氨酸被用于大麦根部麦芽酸植物铁载体的生物合成。这一点以及没有蛋氨酸从茎到根的运动表明，芥酸前体蛋氨酸起源于植物的根。
[C-11]Methionine was supplied through barley roots and the C-11 signal was followed for 90 min using a real-time imaging system (PETIS), with subsequent development of autoradiographic images of the whole plant. In all cases, [C-11]methionine was first translocated to the 'discrimination center', the basal part of the shoot, and this part was most strongly labeled. Methionine absorbed by the roots of the plants was subsequently translocated to other parts of the plant. In Fe-deficient barley plants, a drastic reduction in [C-11]methionine translocation from the roots to the shoot was observed, while a greater amount of C-11 was found in the leaves of Fe-sufficient or methionine-pretreated Fe-deficient plants. Treatment of Fe-deficient plants with aminooxyacetic acid, an inhibitor of nicotianamine aminotransferase, increased the translocation of [C-11]methionine to the shoot. The retention of exogenously supplied [C-11]methionine in the roots of Fe-deficient barley indicates that the methionine is used in the biosynthesis of mugineic acid phytosiderophores in barley roots. This and the absence of methionine movement from shoots to the roots suggest that the mugineic acid precursor methionine originates in the roots of plants.