ABSTRACT

Maize (Zea mays L.) is a food crop sensitive to low temperatures. As one of the abiotic stress hazards, low temperatures seriously affect the yield of maize. However, the genetic basis of low-temperature adaptation in maize is still poorly understood. In this study, maize S-adenosylmethionine decarboxylase (SAMDC) was localized to the nucleus. We used Agrobacterium-mediated transformation technology to introduce the SAMDC gene into an excellent maize inbred line variety GSH9901 and produced a cold-tolerant transgenic maize line. After three years of single-field experiments, the contents of polyamines (PAs), proline (Pro), malondialdehyde (MDA), antioxidant enzymes and ascorbate peroxidases (APXs) in the leaves of the transgenic maize plants overexpressing the SAMDC gene significantly increased, and the expression of elevated CBF and cold-responsive genes effectively increased. The agronomic traits of the maize overexpressing the SAMDC gene changed, and the yield traits significantly improved. However, no significant changes were found in plant height, ear length, and shaft thickness. Therefore, SAMDC enzymes can effectively improve the cold tolerance of maize.

摘要

玉米 ( Zea mays L.) 是一种对低温敏感的粮食作物。作为非生物胁迫危害之一，低温严重影响玉米产量。然而，玉米低温适应的遗传基础仍然知之甚少。在这项研究中，玉米 S-腺苷甲硫氨酸脱羧酶(SAMDC ) 定位于细胞核。我们使用农杆菌介导的转化技术来引入SAMDC将基因导入优良玉米自交系品种GSH9901，并产生了耐寒转基因玉米系。经过三年的单田试验，过表达SAMDC基因的转基因玉米植株叶片中多胺（PAs）、脯氨酸（Pro）、丙二醛（MDA）、抗氧化酶和抗坏血酸过氧化物酶（APXs）的含量显着增加，升高的CBF和冷反应基因的表达有效增加。过表达SAMDC基因的玉米农艺性状发生变化，产量性状显着提高。然而，在株高、穗长和轴厚方面没有发现显着变化。因此，SAMDC酶能有效提高玉米的耐寒性。