Cloning, localization and expression analysis of vacuolar sugar transporters in the CAM plant Ananas comosus (pineapple)
Cloning, localization and expression analysis of vacuolar sugar transporters in the CAM plant Ananas comosus (pineapple)
复制标题
DOI：
10.1093/jxb/ern077
复制
发表时间：
2008-05-01
影响因子：
6.9
通讯作者：
Borland, Anne M.
中科院分区：
文献类型：
--
作者：
Antony, Edna;Taybi, Tahar;Borland, Anne M.
在凸轮植物菠萝（Ananas comosus）的光合组织中，白天将可溶性糖储存在中央液泡中，并且需要在夜间进行重新涂抹，以提供偶然的二氧化碳固定碳骨架。然而，在光中产生的可溶性糖还必须导出以支持异养组织中的生长过程。为了开始解决液泡糖的储存和同化分区，在烟草曲霉中如何调节，简并PCR和cDNA库筛选用于从该物种的叶子中克隆三个候选糖转运蛋白。通过通过con-cocal显微镜在烟草表皮细胞中表达YFP融合蛋白在烟草表皮细胞中的表达及其与亚细胞标记的共定位，研究了三个转运蛋白的亚细胞定位。使用此策略，确定了推定的己糖转运蛋白（ACMST1）和推定的肌醇转运蛋白（ACINT1），即两个定位于托管时，而假定的蔗糖转运蛋白（ACSUT1）被发现以本地化为PrevAcuactol cartartments。还从A. comosus fruit EST数据库中鉴定出与最近表征的托盘六糖转运蛋白相似的cDNA（ACMST2）。对转录本丰度的分析表明，与Comosus的叶子相比，ACMST1在水果中更高表达，而ACINT1，ACSUT1和ACMST2的转录本在叶片中更丰富。推定的肌醇转运蛋白ACINT1的转录物丰度显示与Mesembryanthemum Crystallinum中其他与CAM相关的转录本的变化相当。根据液泡糖转运蛋白在调节CAM植物的DIEL周期中调节碳流动中的作用，讨论了结果。
In photosynthetic tissues of the CAM plant pineapple (Ananas comosus), storage of soluble sugars in the central vacuole during the daytime and their remobilization at night is required to provide carbon skeletons for nocturnal CO2 fixation. However, soluble sugars produced photosynthetically must also be exported to support growth processes in heterotrophic tissues. To begin to address how vacuolar sugar storage and assimilate partitioning are regulated in A. comosus, degenerate PCR and cDNA library screening were used to clone three candidate sugar transporters from the leaves of this species. Subcellular localization of the three transporters was investigated via expression of YFP-fusion proteins in tobacco epidermal cells and their co-localization with subcellular markers by con-focal microscopy. Using this strategy, a putative hexose transporter (AcMST1) and a putative inositol transporter (AcINT1) were identified that both localized to the tonoplast, whereas a putative sucrose transporter (AcSUT1) was found to localize to prevacuolar compartments. A cDNA (AcMST2) with high similarity to a recently characterized tonoplast hexose transporter in Arabidopsis was also identified from an A. comosus fruit EST database. Analyses of transcript abundance indicated that AcMST1 was more highly expressed in fruits compared to leaves of A. comosus, whilst transcripts of AcINT1, AcSUT1, and AcMST2 were more abundant in leaves. Transcript abundance of AcINT1, the putative inositol transporter, showed day-night changes comparable to those of other CAM-related transcripts described in Mesembryanthemum crystallinum. The results are discussed in terms of the role of vacuolar sugar transporters in regulating carbon flow during the diel cycle in CAM plants.