干旱胁迫下大蒜果聚糖代谢关键酶基因的表达分析

Analysis of Gene Expressions of Fructan Metabolism Key Enzymes in Garlic under Drought Stress

果聚糖作为大蒜中干物质含量最高的贮存物质,其代谢过程对大蒜的产量形成及抗逆保护发挥着重要作用。为了探讨干旱胁迫对大蒜果聚糖代谢关键酶基因表达的影响,本研究以‘乐都紫皮大蒜’为试材,利用实时荧光定量PCR技术,对干旱胁迫下大蒜蔗糖:蔗糖1-果糖基转移酶基因(1-SST)和果聚糖外水解酶基因(1-FEH)的表达特性进行了分析。结果表明,随着胁迫时间的延长,1-SST和1-FEH的表达均呈现"先升高后降低"的变化趋势,但在干旱胁迫不同时期两者表达量存在显著差异;在干旱胁迫第14天时,1-SST的表达量最高,比胁迫0 d显著提高了913倍。而1-FEH的最高表达水平出现在干旱胁迫第28天,比胁迫0 d显著提高了140.4倍。这说明1-SST比1-FEH基因表达高峰出现的时间早,且表达水平高。推测果聚糖代谢基因1-SST表达量的显著增加可能是大蒜早期响应干旱胁迫的关键因素。

Fructan is the most abundant dry matter stored in garlic, whose metabolic process plays an important role in the yield formation and stress protection of garlic. To explore the effects of drought stress on metabolic key enzyme genes expression in garlic, the variety ＇Ledu purple skin garlic＇ was selected as the test material, and quantitative real time PCR was used to analyze the expression characterization of 1-SST and 1-FEH under drought stress. The results showed that 1-SST and 1-FEH expression exhibited the same ＂upward-downward＂ change tendency with the prolongation of stress time. However, expression levels of the two genes showed significant differences during different stress periods. On the 14th day of drought treatment, the gene expression of 1-SST was the highest, which was 913 times as high as that of the control. The highest level of 1-FEH expression occurred on the 28th day of drought stress, which enhanced approximately 140.4 times compared with that of the control. The result suggested that the highest gene expression of 1-SST occurred earlier than that of 1-FEH, and I-SST expression level was higher. It was supposed that the significant increase of I-SST expression might be the critical factor in the early response of garlic to drought stress.