SbRFP1 regulates cold-induced sweetening of potato tubers by inactivation of StBAM1
SbRFP1 regulates cold-induced sweetening of potato tubers by inactivation of StBAM1
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SbRFP1 通过 StBAM1 失活调节冷诱导的马铃薯块茎甜味
DOI：
10.1016/j.plaphy.2019.01.019
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发表时间：
2019
影响因子：
6.5
通讯作者：
Xie Conghua
中科院分区：
文献类型：
--
作者：
Zhang Hulling;Yao Ying;Chen Shuangchen;Hou Juan;Yu Yihe;Liu Tengfei;Du Juan;Song Botao;Xie Conghua
马铃薯冷甜化（CIS）是限制马铃薯加工业的一个主要缺点。淀粉降解和蔗糖分解被认为是马铃薯 CIS 的关键途径。我们前期的研究表明，RING指基因SbRFP1可以通过抑制冷藏块茎中的淀粉酶和转化酶活性来减缓淀粉降解和还原糖（RS）的积累。然而，SbRFP1的调控机制尚不清楚。在本文中，我们首先证明了SbRFP1可以促进淀粉合成并改变淀粉颗粒的形状。通过进一步的酵母二杂交、GST-pull down和抑制酶活性测定，我们证实SbRFP1主要通过抑制β-淀粉酶StBAM1活性来减缓块茎中淀粉向RS的转化。通过泛素化实验还证明SbRFP1具有E3泛素连接酶活性。因此，SbRFP1 可能通过 StBAM1 的泛素化和降解来调节冷藏块茎中 RS 的积累。因此，我们的研究揭示了SbRFP1在CIS过程中的调控机制，为淀粉降解对马铃薯CIS的影响提供了更有力的证据。
Potato cold-induced sweetening (CIS) is a major drawback restricting potato process industry. Starch degradation and sucrose decomposition are considered to be the key pathways in potato CIS. Our previous study showed that the RING finger geneSbRFP1could slow down starch degradation and the accumulation of reducing sugars (RS) through inhibiting amylase and invertase activity in cold-stored tubers. However, the regulation mechanism ofSbRFP1is not clear. In this paper, we first proved that SbRFP1 could promote starch synthesis and modify the shape of starch granules. By further yeast two hybrid, GST-pull down and inhibition of enzyme activity assays, we confirmed that SbRFP1 could slow down the transformation of starch to RS in tubers mainly through the inhibition of β-amylase StBAM1 activity. SbRFP1 was also proved to possess E3 ubiquitin ligase activity by ubiquitination assay. Thus, SbRFP1 may regulate the accumulation of RS in cold-stored tubers by ubiquitination and degradation of StBAM1. Therefore, our study reveals the regulatory mechanism of SbRFP1 in the process of CIS and provides more powerful evidence for the effect of starch degradation on potato CIS.