背景回顾：Cold stress negatively affects maize (Zea mays L.) growth, development and yield. Metabolic adjustments contribute to the adaptation of maize under cold stress. 

提出问题：We show here that the transcription factor INDUCER OF CBF EXPRESSION 1 (ZmICE1) plays a prominent role in reprogramming amino acid metabolome and COLD-RESPONSIVE (COR) genes during cold stress in maize. 

结果1-低温耐受性负调控：Derivatives of amino acids glutamate/asparagine (Glu/Asn) induce a burst of mitochondrial reactive oxygen species, which suppress the cold-mediated induction of DEHYDRATION RESPONSE ELEMENT-BINDING PROTEIN 1 (ZmDREB1) genes and impair cold tolerance. 

结果2-ICE1阻断上述负调控：ZmICE1 blocks this negative regulation of cold tolerance by directly repressing the expression of the key Glu/Asn biosynthesis genes, ASPARAGINE SYNTHETASEs. Moreover, ZmICE1 directly regulates the expression of DREB1s.

结果3-ICE1启动子自然变异：Natural variation at the ZmICE1 promoter determines the binding affinity of the transcriptional activator ZmMYB39, a positive regulator of cold tolerance in maize, resulting in different degrees of ZmICE1 transcription and cold tolerance across inbred lines. 

结论：This study thus unravels a mechanism of cold tolerance in maize and provides potential targets for engineering cold-tolerant varieties.

Proposed model of ZmICE1-mediated amino acid metabolism and cold tolerance in maize.

低温胁迫负调控玉米的生长、发育和产量。代谢调节有助于玉米适应低温胁迫。本文中，作者发现转录因子ICE1在玉米低温胁迫中，作用于氨基酸代谢组和COR基因的重编程。氨基酸谷氨酸/天冬酰胺衍生物诱导了线粒体活性氧物质的爆发，从而抑制低温介导的ZmDREB1基因诱导，损害玉米低温耐受性。ZmICE1可以通过直接抑制关键谷氨酸/天冬酰胺生物合成基因ASNSs的表达，从而阻断上述的玉米低温耐受性负调控。此外，ZmICE1直接调控DREB1s基因的表达。ZmICE1启动子区域的自然变异决定了转录激活子ZmMYB39的结合亲和性，从而导致了自交系中不同程度的ZmICE1基因转录水平和低温耐受性。本文的研究揭示了玉米中的一个低温耐受性机制，为未来的基因工程低温抗性育种提供了候选靶标。

** 杨淑华 **