Sucrose transporter2 contributes to maize growth, development, and crop yield
Sucrose transporter2 contributes to maize growth, development, and crop yield
复制标题
DOI：
10.1111/jipb.12527
复制
发表时间：
2017-06-01
影响因子：
11.4
通讯作者：
Braun, David M.
中科院分区：
文献类型：
--
作者：
Leach, Kristen A.;Tran, Thu M.;Braun, David M.
在白天，植物产生过量的光合产物，包括蔗糖，暂时储存在液泡中。到了晚上，植物重新调动蔗糖以维持新陈代谢和生长。基于与其他蔗糖转运蛋白（SUT）的同源性，我们假设玉米（Zea mays）蔗糖转运蛋白2（ZmSUT 2）蛋白作为液泡膜上的蔗糖/H+同向转运体，输出瞬时储存的蔗糖。为了了解ZmSut 2的生物学作用，我们检查了其空间和时间基因表达，确定了蛋白质亚细胞定位，并表征了功能丧失突变。ZmSut 2 mRNA普遍表达，并表现出昼夜循环的转录丰度。在玉米叶肉细胞原生质体中表达与红色荧光蛋白融合的ZmSUT 2的翻译融合体，表明该蛋白定位于液泡膜。在田间条件下，zmsut 2突变体植物生长较慢，具有较小的穗和穗，并产生较少的籽粒相比，野生型的兄弟姐妹。与野生型相比，ZMSUT 2突变体还在源叶中积累两倍多的蔗糖、葡萄糖和果糖以及淀粉。这些发现表明：（i）ZmSUT 2的功能是将蔗糖从液泡中再动员出来，随后用于生长组织;以及（ii）其功能对玉米发育和农艺产量提供了重要贡献。
During daylight, plants produce excess photosynthates, including sucrose, which is temporarily stored in the vacuole. At night, plants remobilize sucrose to sustain metabolism and growth. Based on homology to other sucrose transporter (SUT) proteins, we hypothesized the maize (Zea mays) SUCROSE TRANSPORTER2 (ZmSUT2) protein functions as a sucrose/H+ symporter on the vacuolar membrane to export transiently stored sucrose. To understand the biological role of ZmSut2, we examined its spatial and temporal gene expression, determined the protein subcellular localization, and characterized loss-of-function mutations. ZmSut2 mRNA was ubiquitously expressed and exhibited diurnal cycling in transcript abundance. Expressing a translational fusion of ZmSUT2 fused to a red fluorescent protein in maize mesophyll cell protoplasts revealed that the protein localized to the tonoplast. Under field conditions, zmsut2 mutant plants grew slower, possessed smaller tassels and ears, and produced fewer kernels when compared to wild-type siblings. zmsut2 mutants also accumulated two-fold more sucrose, glucose, and fructose as well as starch in source leaves compared to wild type. These findings suggest (i) ZmSUT2 functions to remobilize sucrose out of the vacuole for subsequent use in growing tissues; and (ii) its function provides an important contribution to maize development and agronomic yield.