The transcription factor StTINY3 enhances cold-induced sweetening resistance by coordinating starch resynthesis and sucrose hydrolysis in potato
The transcription factor StTINY3 enhances cold-induced sweetening resistance by coordinating starch resynthesis and sucrose hydrolysis in potato
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转录因子StTINY3通过协调马铃薯淀粉再合成和蔗糖水解增强冷诱导的甜味抗性
DOI：
10.1093/jxb/erac171
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发表时间：
2022
期刊：
影响因子：
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通讯作者：
Xun Liu
中科院分区：
文献类型：
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作者：
Weiling Shi;Qiuqin Ma;Wang Yin;Tiantian Liu;Yuhao Song;Yuanya Chen;Linjin Song;Hui Sun;Shuting Hu;Tengfei Liu;Rui Jiang;Dianqiu Lv;Botao Song;Jichun Wang;Xun Liu
摘要冷藏马铃薯块茎中还原糖的积累对马铃薯加工品质有负面影响。冷藏CIS块茎中淀粉到糖的相互转化途径已经被阐明，但调节它们的机制在很大程度上仍然不清楚。本研究确定了一个CBF/DREB转录因子(StTINY3)，它通过激活淀粉的生物合成和抑制蔗糖向还原糖的水解来增强冷藏块茎的顺式抗性。在顺式抗性基因中沉默StTINY3可以降低顺式反应抗性，而在顺式反应敏感类型中过表达StTINY3会增加顺式反应的抗性，并且改变StTINY3的表达与淀粉再合成相关基因的表达变化有关。我们首先证明了过表达StTINY3通过促进转化酶抑制基因StInvInh2的表达来抑制蔗糖的水解，其次StTINY3通过上调ADP-葡萄糖焦磷酸化酶基因StAGPaseL3和葡萄糖-6-磷酸转运蛋白基因StG6PT2的一个大亚基来促进淀粉的再合成。通过电泳迁移率改变分析，我们发现StTINY3是一个核定位的转录激活子，直接与StInvInh2和StAGPaseL3启动子中的脱水反应元件/CRT顺式元件结合。综上所述，这些结果表明，StTINY3通过协调调节淀粉到糖的转化途径来影响冷藏块茎的顺式抗性，是改良马铃薯加工品质的良好靶标。
Abstract The accumulation of reducing sugars in cold-stored tubers, known as cold-induced sweetening (CIS), negatively affects potato processing quality. The starch to sugar interconversion pathways that are altered in cold-stored CIS tubers have been elucidated, but the mechanism that regulates them remains largely unknown. This study identified a CBF/DREB transcription factor (StTINY3) that enhances CIS resistance by both activating starch biosynthesis and repressing the hydrolysis of sucrose to reducing sugars in detached cold-stored tubers. Silencing StTINY3 in a CIS-resistant genotype decreased CIS resistance, while overexpressing StTINY3 in a CIS-sensitive genotype increased CIS resistance, and altering StTINY3 expression was associated with expression changes in starch resynthesis-related genes. We showed first that overexpressing StTINY3 inhibited sucrose hydrolysis by enhancing expression of the invertase inhibitor gene StInvInh2, and second that StTINY3 promoted starch resynthesis by up-regulating a large subunit of the ADP-glucose pyrophosphorylase gene StAGPaseL3, and the glucose-6-phosphate transporter gene StG6PT2. Using electrophoretic mobility shift assays, we revealed that StTINY3 is a nuclear-localized transcriptional activator that directly binds to the dehydration-responsive element/CRT cis-element in the promoters of StInvInh2 and StAGPaseL3. Taken together, these findings established that StTINY3 influences CIS resistance in cold-stored tubers by coordinately modulating the starch to sugar interconversion pathways and is a good target for improving potato processing quality.