The potato amylase inhibitor gene SbAI regulates cold-induced sweetening in potato tubers by modulating amylase activity.
The potato amylase inhibitor gene SbAI regulates cold-induced sweetening in potato tubers by modulating amylase activity.
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DOI：
10.1111/pbi.12221
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发表时间：
2014-09
影响因子：
13.8
通讯作者：
Huiling Zhang;Jun Liu;Juan Hou;Ying Yao;Yuan Lin;Yongbin Ou;Botao Song;C. Xie
中科院分区：
文献类型：
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作者：
Huiling Zhang;Jun Liu;Juan Hou;Ying Yao;Yuan Lin;Yongbin Ou;Botao Song;C. Xie
马铃薯冷致甜是影响马铃薯采后品质的关键因素。淀粉降解被认为是CIS过程中的关键途径之一。然而，编码CIS中淀粉降解相关酶的基因的功能以及这些酶的活性调控却很少受到关注。从野生马铃薯物种Solanum berthaultii中克隆了马铃薯淀粉酶抑制剂基因SbAI。这种遗传转化证实，与CIS抗性马铃薯中的SbAI抑制相反，CIS敏感马铃薯中过表达SbAI会导致淀粉酶活性降低、淀粉降解速率降低，并伴有冷藏块茎中还原糖（RS）含量降低。这一发现表明，SbAI基因可能通过调节淀粉酶活性在马铃薯CIS中发挥重要作用。进一步的研究表明，SbAI与α-淀粉酶StAmy 23、β-淀粉酶StBAM 1和StBAM 9之间存在成对的蛋白质-蛋白质相互作用。SbAI主要通过抑制StAmy 23和StBAM 1来抑制马铃薯块茎中α-淀粉酶和β-淀粉酶的活性。这些发现提供了第一个证据，SbAI是一个关键的调节淀粉酶，赋予淀粉降解和RS积累在冷藏马铃薯块茎。
Potato cold-induced sweetening (CIS) is critical for the postharvest quality of potato tubers. Starch degradation is considered to be one of the key pathways in the CIS process. However, the functions of the genes that encode enzymes related to starch degradation in CIS and the activity regulation of these enzymes have received less attention. A potato amylase inhibitor gene known as SbAI was cloned from the wild potato species Solanum berthaultii. This genetic transformation confirmed that in contrast to the SbAI suppression in CIS-resistant potatoes, overexpressing SbAI in CIS-sensitive potatoes resulted in less amylase activity and a lower rate of starch degradation accompanied by a lower reducing sugar (RS) content in cold-stored tubers. This finding suggested that the SbAI gene may play crucial roles in potato CIS by modulating the amylase activity. Further investigations indicated that pairwise protein-protein interactions occurred between SbAI and α-amylase StAmy23, β-amylases StBAM1 and StBAM9. SbAI could inhibit the activities of both α-amylase and β-amylase in potato tubers primarily by repressing StAmy23 and StBAM1, respectively. These findings provide the first evidence that SbAI is a key regulator of the amylases that confer starch degradation and RS accumulation in cold-stored potato tubers.