Waqar Khan M, Yang Wenqi, Yu Ke, Zhang Xuebin
State Key Laboratory of Crop Stress Adaptation and Improvement, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, Kaifeng, China.
Front Microbiol. 2023 Aug 24;14:1257270. doi: 10.3389/fmicb.2023.1257270. eCollection 2023.
Agrobacterium-mediated soybean transformation is the simplest method of gene transfer. However, the low transformation due to the intractable nature of soybean genotypes hinders this process. The use of biochemicals (acetosyringone, cinnamic acid, flavonoids, etc.) plays an important role in increasing soybean transformation. These biochemicals induce chemotaxis and virulence gene activation during the infection process. Here we identified a biochemical, aztreonam (a monobactam), for high agrobacterium-mediated transformation in soybean. The soybean explants from three genotypes were inoculated with (GV3101) harboring the pMDC32 vector containing during two separate events. High transient GUS expression was obtained during cotyledon explant culture on MS media supplemented with 2.5 mg/L aztreonam. The aztreonam-treated explants showed high efficiency in transient and stable transformation as compared to the untreated control. The transformation of aztreonam-treated explants during seed imbibition resulted in an average of 21.1% as compared to 13.2% in control by using the pMDC32 vector and 28.5 and 20.7% while using the GUS gene cassette, respectively. Based on these findings, the metabolic analysis of the explant after aztreonam treatment was assessed. The high accumulation of flavonoids was identified during an untargeted metabolic analysis. The quantification results showed a significantly high accumulation of the four compounds, i.e., genistein, apigenin, naringenin, and genistin, in cotyledon explants after 18 hours of aztreonam treatment. Alongside this, aztreonam also had some surprising effects on root elongation and lateral root formation when compared to indole-3-butyric acid (IBA). Our findings were limited to soybeans. However, the discovery of aztreonam and its effect on triggering flavonoids could lead to the potential role of aztreonam in the agrobacterium-mediated transformation of different crops.
农杆菌介导的大豆转化是最简单的基因转移方法。然而，由于大豆基因型难以处理，导致转化率较低，这阻碍了该过程。使用生化物质（乙酰丁香酮、肉桂酸、类黄酮等）在提高大豆转化效率方面发挥着重要作用。这些生化物质在感染过程中诱导趋化性并激活毒力基因。在这里，我们鉴定出一种生化物质氨曲南（一种单环β-内酰胺类抗生素），可用于农杆菌介导的大豆高效转化。在两个独立的实验中，将来自三种基因型的大豆外植体用携带含有 的pMDC32载体的 （GV3101）进行接种。在添加了2.5 mg/L氨曲南的MS培养基上进行子叶外植体培养期间，获得了较高的瞬时GUS表达。与未处理的对照相比，经氨曲南处理的外植体在瞬时和稳定转化方面表现出高效率。使用pMDC32载体时，种子吸胀期间经氨曲南处理的外植体的转化率平均为21.1%，而对照为13.2%；使用GUS基因盒时，分别为28.5%和20.7%。基于这些发现，对氨曲南处理后的外植体进行了代谢分析。在非靶向代谢分析中鉴定出类黄酮的高积累。定量结果显示，氨曲南处理18小时后，子叶外植体中染料木黄酮、芹菜素、柚皮素和染料木苷这四种化合物的积累量显著较高。除此之外，与吲哚-3-丁酸（IBA）相比，氨曲南对根伸长和侧根形成也有一些惊人的影响。我们的研究结果仅限于大豆。然而，氨曲南的发现及其对类黄酮触发作用的影响可能导致氨曲南在农杆菌介导的不同作物转化中发挥潜在作用。
