Suppression of the tonoplast sugar transporter, StTST3.1, affects transitory starch turnover and plant growth in potato
Suppression of the tonoplast sugar transporter, StTST3.1, affects transitory starch turnover and plant growth in potato
复制标题
抑制液泡膜糖转运蛋白 StTST3.1 影响马铃薯的短暂淀粉周转和植物生长
DOI：
10.1111/tpj.16050
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发表时间：
2022-12-08
期刊：
影响因子：
7.2
通讯作者：
Song, Botao
中科院分区：
文献类型：
--
作者：
Liu, Tengfei;Kawochar, Md Abu;Song, Botao
在植物叶细胞中，瞬时淀粉和液泡糖作为高度动态的可立即获得的代谢物库发挥作用。它们的代谢调节对植物的生存至关重要。液泡膜糖转运蛋白（TSTs）负责将糖吸收到液泡中，调节细胞内糖的分配和液泡中糖的积累。然而，TSTs是否参与叶片瞬时淀粉周转和植物生长尚不清楚。在此，我们发现抑制StTST 3.1导致马铃薯植物的生长迟缓和淡绿色叶。StTST3.1沉默的植物表现出异常的叶绿体和受损的光合性能。亚细胞定位分析和振荡表达模式显示，StTST3.1编码的tonoplast定位的蛋白质，并响应于光周期。此外，RNA-seq分析鉴定了淀粉合成酶（SS 2和SS 6）和葡聚糖水双激酶（GWD）在StTST3.1沉默的株系中下调。相应地，StTST3.1沉默株系的淀粉合成和降解能力降低。令人惊讶的是，StTST3.1沉默的叶子积累了异常高水平的麦芽糖，但低水平的蔗糖和己糖。此外，叶绿素含量在StTST3.1沉默的叶片中降低。叶绿素代谢途径的分析发现，非黄色着色1（NYC 1）样（NOL），编码叶绿体定位的关键酶，催化叶绿素B降解的初始步骤，在StTST 3.1沉默的叶片上调。StNOL的瞬时过表达加速了烟草叶片叶绿素B的降解。我们的研究结果表明，StTST3.1参与了短暂的淀粉周转和叶绿素代谢，从而在正常的马铃薯植物生长中发挥关键作用。
Transitory starch and vacuolar sugars function as highly dynamic pools of instantly accessible metabolites in plant leaf cells. Their metabolic regulation is critical for plant survival. The tonoplast sugar transporters (TSTs), responsible for sugar uptake into vacuoles, regulate cellular sugar partitioning and vacuolar sugar accumulation. However, whether TSTs are involved in leaf transient starch turnover and plant growth is unclear. Here, we found that suppressing StTST3.1 resulted in growth retardation and pale green leaves in potato plants. StTST3.1-silenced plants displayed abnormal chloroplasts and impaired photosynthetic performance. The subcellular localization assay and the oscillation expression patterns revealed that StTST3.1 encoded a tonoplast-localized protein and responded to photoperiod. Moreover, RNA-seq analyses identified that starch synthase (SS2 and SS6) and glucan water, dikinase (GWD), were downregulated in StTST3.1-silenced lines. Correspondingly, the capacity for starch synthesis and degradation was decreased in StTST3.1-silenced lines. Surprisingly, StTST3.1-silenced leaves accumulated exceptionally high levels of maltose but low levels of sucrose and hexose. Additionally, chlorophyll content was reduced in StTST3.1-silenced leaves. Analysis of chlorophyll metabolic pathways found that Non-Yellow Coloring 1 (NYC1)-like (NOL), encoding a chloroplast-localized key enzyme that catalyzes the initial step of chlorophyll b degradation, was upregulated in StTST3.1-silenced leaves. Transient overexpression of StNOL accelerated chlorophyll b degradation in tobacco leaves. Our results indicated that StTST3.1 is involved in transitory starch turnover and chlorophyll metabolism, thereby playing a critical role in normal potato plant growth.