薰衣草叶片对低温胁迫的生理与分子响应机制

Physiological and Molecular Response Mechanisms Under Low-temperature Stress in Lavandula angustifolia Leaves

薰衣草(Lavandula angustifolia)作为名贵的芳香植物,其生长、繁育、品质和产量均受低温影响。前期研究已获得1个耐低温薰衣草品种。该研究将对其处理的温度从20℃降至0℃,揭示薰衣草响应冷胁迫的生理及分子调控机制,同时结合薰衣草的细胞质膜透性、可溶性糖和蛋白质含量及抗氧化酶活性等生理变化。采用转录组学和生物信息学方法挖掘分析相关耐寒基因,并探讨外施水杨酸缓解-10℃冻胁迫的可行性。研究发现7个编码脂肪酸去饱和酶和转移酶的基因(LaFADs)、3个参与合成可溶性糖的基因(LaBAM1和LaSS2)、19个编码胚胎晚期丰富蛋白的基因(LaLEAs)及7个编码过氧化物酶的基因(LaPODs),这些基因在低温胁迫下均上调表达,指导薰衣草合成并积累保护物质,维持膜稳定性以应对胁迫。此外,150 mg·L^(-1)水杨酸预处理能有效缓解植株冻害,可作为低温保护剂。该研究丰富了薰衣草重要抗逆基因家族的遗传背景,为后续分子遗传学功能分析和定向品种改良奠定基础。

The growth and reproduction as well as quality and yield of Lavandula angustifolia,a valuable aromatic plant,are severely affected by low temperatures.In our previous study,a low-temperature tolerant lavender variety was obtained.This study revealed the physiological and molecular regulatory mechanisms of L.angustifolia in response to cold stress.The relevant cold tolerance genes were mined and analyzed using transcriptomic and bioinformatics approaches.The feasibility of external application of salicylic acid to alleviate-10℃freezing stress was also explored.The results showed that seven genes encoding fatty acid desaturases and transferases(LaFADs),three genes involved in the synthesis of soluble sugars(LaBAM1,LaSS2),19 genes encoding late embryonic abundant proteins(LaLEAs),and seven genes encoding peroxidases(LaPODs)were found to be up-regulated at low temperatures,directing L.angustifolia to synthesize and accumulate protective substances which maintained membrane stability in response to stress.In addition,salicylic acid pretreatment at 150 mg·L^(-1) was effective in alleviating freezing damage to plants and could be used as a low-temperature protectant.This study provides a basis for further understanding molecular mechanism of L.angustifolia responding to low-temperature stress.