Department of Agronomy and Plant Breeding Sciences, College of Aburaihan, University of Tehran, Tehran, Iran.
Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA.
Biotechnol Appl Biochem. 2023 Aug;70(4):1480-1488. doi: 10.1002/bab.2458. Epub 2023 Mar 27.
Salinity and drought are significant abiotic stresses causing a considerable loss of seed and biomass yield in most commercial crops. Some of the most critical players in the abscisic acid pathway are drought responsive element binding (DREB) proteins that are a part of AP2/ethylene response factor transcription factors that bind to promoters of some family genes needed to be expressed under abiotic stresses. In this study, salt- and drought-tolerant maize plants were produced from immature maize embryos bombarded by the sorghum (Sorghum bicolor L.) DREB2 gene that is linked to hygromycin resistance (hpt) genes. The putative transgenic calli were transferred to an N6 medium containing 1 mg/L benzylaminopurine and 50 mg/L hygromycin. Regeneration was completed after 4 weeks on selective media under a 16/8 h light/dark condition at 25°C. Polymerase chain reaction (PCR) and reverse transcription-PCR approved the existence of upstream promoter (rd29a), hpt gene, and the expression of the DREB2 in transgenes up to the third generation (T2). It was found that the K+/Na+ ratio and the amount of proline as a screening indicator were higher in transgenic plants compared to their wild types. This result is a promising model to enhance maize tolerance to abiotic stressors.
盐度和干旱是两种重要的非生物胁迫因素，会导致大多数商业作物的种子和生物量产量大量损失。脱落酸（ABA）途径中的一些关键因子是干旱响应元件结合（DREB）蛋白，它们是 AP2/乙烯响应因子转录因子的一部分，可以与一些在非生物胁迫下需要表达的家族基因的启动子结合。在这项研究中，通过对玉米幼胚进行基因枪轰击，导入与潮霉素抗性（hpt）基因相连的高粱 DREB2 基因，培育出耐盐耐旱的玉米植株。将假定的转基因愈伤组织转移到含有 1 mg/L 苯丙氨酸和 50 mg/L 潮霉素的 N6 培养基中。在 25°C 下，16/8 h 光照/黑暗条件下，选择培养基上培养 4 周后完成再生。聚合酶链反应（PCR）和反转录-PCR 证实了上游启动子（rd29a）、hpt 基因和 DREB2 在转基因植物中的存在，直至第三代（T2）。结果发现，与野生型相比，转基因植株的 K+/Na+ 比值和脯氨酸含量作为筛选指标更高。这一结果为提高玉米对非生物胁迫的耐受性提供了一个有前景的模型。
