Gomes Erik Nunes, Patel Harna, Yuan Bo, Lyu Weiting, Juliani H Rodolfo, Wu Qingli, Simon James E
New Use Agriculture and Natural Plant Products, Department of Plant Biology, Rutgers University, New Brunswick, NJ, United States.
Federal Agency for Support and Evaluation of Graduate Education (CAPES), Ministry of Education of Brazil, Brasilia, DF, Brazil.
Front Plant Sci. 2023 Feb 13;14:1121582. doi: 10.3389/fpls.2023.1121582. eCollection 2023.
Catnip ( L.) produces volatile iridoid terpenes, mainly nepetalactones, with strong repellent activity against species of arthropods with commercial and medical importance. Recently, new catnip cultivars CR3 and CR9 have been developed, both characterized by producing copious amounts of nepetalactones. Due to its perennial nature, multiple harvests can be obtained from this specialty crop and the effects of such practice on the phytochemical profile of the plants are not extensively studied.
In this study we assessed the productivity of biomass, chemical composition of the essential oil and polyphenol accumulation of new catnip cultivars CR3 and CR9 and their hybrid, CR9×CR3, across four successive harvests. The essential oil was obtained by hydrodistillation and the chemical composition was obtained via gas chromatography-mass spectrometry (GC-MS). Individual polyphenols were quantified by Ultra-High-Performance Liquid Chromatography- diode-array detection (UHPLC-DAD).
Although the effects on biomass accumulation were independent of genotypes, the aromatic profile and the accumulation of polyphenols had a genotype-dependent response to successive harvests. While cultivar CR3 had its essential oil dominated by -nepetalactone in all four harvests, cultivar CR9 showed -nepetalactone as the main component of its aromatic profile during the 1, 3 and 4 harvests. At the second harvest, the essential oil of CR9 was mainly composed of caryophyllene oxide and ()-β-caryophyllene. The same sesquiterpenes represented the majority of the essential oil of the hybrid CR9×CR3 at the 1 and 2 successive harvests, while -nepetalactone was the main component at the 3 and 4 harvests. For CR9 and CR9×CR3, rosmarinic acid and luteolin diglucuronide were at the highest contents at the 1 and 2 harvest, while for CR3 the peak occurred at the 3 successive harvest.
The results emphasize that agronomic practices can significantly affect the accumulation of specialized metabolites in N. cataria and the genotype-specific interactions may indicate differential ecological adaptations of each cultivar. This is the first report on the effects of successive harvest on these novel catnip genotypes and highlights their potential for the supply of natural products for the pest control and other industries.
荆芥（Nepeta cataria L.）能产生挥发性环烯醚萜类化合物，主要是荆芥内酯，对具有商业和医学重要性的节肢动物种类具有很强的驱避活性。最近，已培育出荆芥新品种CR3和CR9，其特点均是能大量产生荆芥内酯。由于其多年生特性，这种特色作物可进行多次收获，而这种做法对植物化学特征的影响尚未得到广泛研究。
在本研究中，我们评估了荆芥新品种CR3和CR9及其杂交种CR9×CR3在连续四次收获过程中的生物量生产力、精油化学成分和多酚积累情况。通过水蒸馏法获得精油，并通过气相色谱 - 质谱联用（GC - MS）分析其化学成分。通过超高效液相色谱 - 二极管阵列检测（UHPLC - DAD）对单个多酚进行定量分析。
虽然对生物量积累的影响与基因型无关，但芳香成分和多酚积累对连续收获具有基因型依赖性反应。在所有四次收获中，CR3品种的精油均以α - 荆芥内酯为主，而CR9品种在第1、3和4次收获时，其芳香成分的主要成分是α - 荆芥内酯。在第2次收获时，CR9的精油主要由氧化石竹烯和（） - β - 石竹烯组成。在连续的第1和第2次收获中，相同的倍半萜类化合物占杂交种CR9×CR3精油的大部分，而在第3和第4次收获时，α - 荆芥内酯是主要成分。对于CR9和CR9×CR3，迷迭香酸和木犀草素二葡萄糖醛酸在第1和第2次收获时含量最高，而对于CR3，峰值出现在连续第3次收获时。
结果强调农艺措施可显著影响荆芥中特殊代谢产物的积累，基因型特异性相互作用可能表明每个品种的不同生态适应性。这是关于连续收获对这些新型荆芥基因型影响的首次报道，并突出了它们在为害虫防治和其他行业提供天然产物方面的潜力。
