Zinc uptake kinetics in the low and high-affinity systems of two contrasting rice genotypes
Zinc uptake kinetics in the low and high-affinity systems of two contrasting rice genotypes
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两种对比水稻基因型的低亲和力和高亲和力系统中的锌吸收动力学
DOI：
10.1002/jpln.201200621
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发表时间：
2014-06
影响因子：
2.5
通讯作者：
Feng, Ying
中科院分区：
文献类型：
--
作者：
Yang, Juncheng;Li, Tingqiang;Lu, Lingli;Feng, Ying
水稻 (Oryza sativa L.) 品种对锌 (Zn) 缺乏的敏感性差异很大。锌效率 (ZE) 的生理基础尚不清楚。在本研究中，在两种对比水稻基因型（锌高效 IR36 和锌低效 IR26）中，在低锌供应水平（0-160 nM）和高锌供应水平（0-80 μM）下，研究了锌充足和缺锌预处理对锌的时间和浓度依赖性吸收动力学的影响。结果表明，缺锌预处理厂的 65Zn2+ 流入速率是锌充足预处理厂的 10 倍以上。在低锌供应量下，发现高效锌基因型的 65Zn2+ 流入率显着高于低效基因型，在缺锌预处理中，当锌供应量 > 80 nM 时，差异更大（超过三倍）。然而，在高锌供应水平下，仅在缺锌预处理中才注意到两种基因型之间 65Zn2+ 流入速率的差异（2.5 倍）。同样，经缺锌预处理的高效锌IR36根部和地上部的65Zn2+积累量随时间急剧增加，并且高于低锌IR26，在2小时吸收时间时差异超过四倍。然而，在缺锌预处理中，锌高效基因型在锌供应量较高时表现出较高的地上部：根 65Zn 比。在缺锌预处理中，两种基因型的根和地上部 65Zn2+ 积累量存在显着差异，特别是在低锌水平 (0.05 μM) 下，在 120 分钟的吸收时间下，IR36 的值比 IR26 高 2-3 倍。在高效基因型中似乎有两个独立的锌转运系统介导低亲和力和高亲和力锌流入。低亲和力系统显示出明显的米氏速率常数 (Km) 值，范围为 10 至 20 nM，而高亲和力摄取系统显示出明显的 Km 值，范围为 6 至 20 μM。在低锌水平下，IR36 的 Vmax 值显着升高，并且 IR36 比 IR26 高 3-4 倍，表明低亲和力吸收系统中根质膜转运蛋白的数量对水稻的锌效率起着重要作用。
Rice (Oryza sativa L.) cultivars differ widely in their susceptibility to zinc (Zn) deficiency. The physiological basis of Zn efficiency (ZE) is not clearly understood. In this study, the effects of Zn-sufficient and Zn-deficient pretreatments on the time and concentration-dependent uptake kinetics of Zn were examined at low (0–160 nM) and high Zn supply levels (0–80 μM) in two contrasting rice genotypes (Zn-efficient IR36 and Zn-inefficient IR26). The results show that 65Zn2+ influx rate was over 10 times greater for the Zn-deficient pretreatment plants than for the Zn-sufficient pretreatment plants. At low Zn supply, significant higher 65Zn2+ influx rates were found for the Zn-efficient genotype than for the inefficient genotype, with a greater difference (over three-fold) at Zn supply > 80 nM in the Zn-deficient pretreatments. At high Zn supply levels, however, a difference (2.5-fold) in 65Zn2+ influx rate between the two genotypes was only noted in the Zn-deficient pretreatments. Similarly, the 65Zn2+ accumulation in the roots and shoots of Zn-efficient IR36 pretreated with Zn-deficiency were sharply increased with time and higher than that in the Zn-inefficient IR26 with an over four-fold difference at 2 h absorption time. However, with Zn-deficient pretreatments, the Zn-efficient genotype showed a higher shoot : root 65Zn ratio at higher Zn supply. Remarkable differences in root and shoot 65Zn2+ accumulation were noted between the two genotypes in the Zn-deficiency pretreatment, especially at low Zn level (0.05 μM), with 2–3 times higher values for IR36 than for IR26 at an uptake time of 120 min. There appear to be two separate Zn transport systems mediating the low and high-affinity Zn influx in the efficient genotype. The low-affinity system showed apparent Michaelis–Menten rate constant (Km) values ranging from 10 to 20 nM, while the high-affinity uptake system showed apparent Km values ranging from 6 to 20 μM. The Vmax value was significantly elevated in IR36 and was 3–4-fold greater for IR36 than for IR26 at low Zn levels, indicating that the number of root plasma membrane transporters in low-affinity uptake systems play an important role for the Zn efficiency of rice.
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影响因子：
9.4
作者：
Widodo;Broadley, Martin R.;Wissuwa, Matthias
通讯作者：
Wissuwa, Matthias
影响因子：
1
作者：
B. Singh;S. Natesan;Brijendra Singh;K. Usha
通讯作者：
B. Singh;S. Natesan;Brijendra Singh;K. Usha
影响因子：
4.9
作者：
R. Hajiboland;X. Yang;V. Römheld
通讯作者：
R. Hajiboland;X. Yang;V. Römheld
影响因子：
5.5
作者：
Ishimaru, Yasuhiro;Bashir, Khurram;Nishizawa, Naoko K.
通讯作者：
Nishizawa, Naoko K.
影响因子：
7.4
作者：
Ramesh, SA;Shin, R;Schachtman, DP
通讯作者：
Schachtman, DP