Song Won-Yong, Lee Hyun-Sook, Jin Sang-Rak, Ko Donghwi, Martinoia Enrico, Lee Youngsook, An Gynheung, Ahn Sang-Nag
POSTECH-UZH Cooperative Laboratory, Department of Integrative Bioscience and Biotechnology, Pohang University of Science and Technology, Pohang, 790-784, Korea.
College of Agriculture and Life Sciences, Chungnam National University, Daejeon, 305-764, Korea.
Plant Cell Environ. 2015 Nov;38(11):2327-39. doi: 10.1111/pce.12553. Epub 2015 Apr 29.
Proteins containing a placenta-specific 8 domain (PLAC8) function as major organ size regulators in Solanum lycopersicum and Zea may, and putative metal ion transporters in Arabidopsis thaliana, Oryza sativa and Brassica juncea. However, it is unknown how PLAC8 domain-containing proteins fulfill such diverse roles. Here, we found that plant cadmium resistance 1 (PCR1) influences both zinc (Zn) accumulation and grain weight in rice. OsPCR1 knockout and knockdown lines produced lighter grains than the wild type, while OsPCR1 overexpression lines produced heavier grains. Furthermore, the grains of OsPCR1 knockdown lines exhibited substantially higher Zn and lower cadmium (Cd) concentrations than the control, as did yeast heterologously expressing OsPCR1. Through sequence analysis, we showed that the amino acid sequence of japonica-type PCR1 was distinct from that of indica-type and wild rice accessions. This difference was correlated with distinct Zn-related phenotypes. Japonica-type PCR1 had a shorter N-terminus than did PCR1 in the other rice types, and yeast heterologously expressing japonica-type PCR1 was more sensitive to Zn than was yeast expressing indica-type PCR1. Furthermore, japonica-type grains accumulated less Zn than did indica-type grains. Our study suggests that rice PCR1 maintains metal ion homeostasis and grain weight and might have been selected for during domestication.
含有胎盘特异性8结构域（PLAC8）的蛋白质在番茄和玉米中作为主要的器官大小调节因子发挥作用，在拟南芥、水稻和芥菜中则被认为是金属离子转运蛋白。然而，尚不清楚含有PLAC8结构域的蛋白质是如何发挥如此多样的作用的。在这里，我们发现植物镉抗性1（PCR1）影响水稻中的锌（Zn）积累和粒重。OsPCR1基因敲除和敲低株系产生的籽粒比野生型轻，而OsPCR1过表达株系产生的籽粒更重。此外，OsPCR1敲低株系的籽粒中锌含量显著高于对照，镉（Cd）含量低于对照，异源表达OsPCR1的酵母也是如此。通过序列分析，我们发现粳稻型PCRA的氨基酸序列与籼稻型和野生稻种质不同。这种差异与不同的锌相关表型相关。粳稻型PCR1的N端比其他水稻类型的PCR1短，异源表达粳稻型PCR1的酵母对锌的敏感性高于表达籼稻型PCR1的酵母。此外，粳稻型籽粒积累的锌比籼稻型籽粒少。我们的研究表明，水稻PCR1维持金属离子稳态和粒重，并且可能在驯化过程中被选择。
