Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Silesian University of Technology, 44-100 Gliwice, Poland.
Institute of Plant Protection, National Research Institute, Sosnicowice Branch, 44-153 Sosnicowice, Poland.
Pestic Biochem Physiol. 2018 Jun;148:166-174. doi: 10.1016/j.pestbp.2018.04.008. Epub 2018 Apr 26.
Cultivation of oilseed rape requires application of specific fungicides. Besides their protective role, they can potentially influence the expression and activity of crucial enzymes in the plant. Among the large number of enzymes expressed in plants, aminopeptidases play a key role in all crucial physiological processes during the whole life cycle (e.g. storage protein mobilization and thus supplying plant with needed amino acids, as well as plant aging, protection and defense responses). In the present paper, we evaluate for the first time, the influence of the treatment of winter oilseed rape with commercially available fungicides (Pictor 400 SC, Propulse 250 SE and Symetra 325 SC), on the activity of aminopeptidases expressed in each plant organ (flowers, leaves, stems and pods separately). Fungicides were applied once, at one of the three stages of oilseed rape development (BBCH 59-61, BBCH 63-65 and BBCH 67-69). The aminopeptidase activity was determined using six different amino acid p-nitroanilides as substrates. The results have shown, that in control plants, at the beginning of intensive pods development and seeds production, hydrophobic amino acids with bulky side chains (Phe, Leu) were preferentially hydrolysed. In control plants, the activity was ~3.5 times higher in stems and pods, compared to leaves. The treatment with all pesticides caused significant increase in aminopeptidases hydrolytic activity toward small amino acids Gly, Ala as well as proline, mostly in flowers and leaves. These amino acids are proven to be crucial in the mechanisms of delaying of plant aging, development of better resistance to stress and plant defense. It can be suggested, that studied fungicides enhance such mechanisms, by activating the expression of genes coding for aminopeptidases, which are active in hydrolysis of N-terminal amino acids such as Gly, Ala, Pro from storage peptides and proteins. Depending on fungicide, the major increase of aminopeptidase activity was observed after application at BBCH 67-69 (Pictor 400 SC and Symetra 325 SC) and BBCH 63-65 (Propulse 250 SE) stages of development. Our study revealed, that agrochemical treatment and time of application, influenced the expression and activity of aminopeptidases, even though they were not molecular targets of applied fungicides. Since aminopeptidases are widely distributed throughout all organisms and are crucial in many key physiological processes, it can be expected, that factors influencing their expression and activity in plants, can also influence these enzymes in other organisms, especially humans and other mammals.
油菜种植需要应用特定的杀菌剂。除了其保护作用外，它们还可能影响植物中关键酶的表达和活性。在植物中表达的大量酶中，氨肽酶在整个生命周期的所有关键生理过程中都起着关键作用（例如，储存蛋白的动员，从而为植物提供所需的氨基酸，以及植物衰老、保护和防御反应）。在本文中，我们首次评估了用市售杀菌剂（Pictor 400 SC、Propulse 250 SE 和 Symetra 325 SC）处理冬油菜对每个植物器官（花、叶、茎和荚）中表达的氨肽酶活性的影响。杀菌剂在油菜发育的三个阶段之一（BBCH 59-61、BBCH 63-65 和 BBCH 67-69）进行了一次处理。用六种不同的氨基酸对硝基苯胺作为底物测定氨肽酶活性。结果表明，在对照植物中，在荚果和种子大量生产的开始阶段，优先水解疏水性大侧链氨基酸（苯丙氨酸、亮氨酸）。在对照植物中，茎和荚中的活性比叶高约 3.5 倍。所有杀虫剂的处理都导致对小氨基酸甘氨酸、丙氨酸以及脯氨酸的氨肽酶水解活性显著增加，主要在花和叶中。这些氨基酸被证明在延缓植物衰老、提高对胁迫的抗性和植物防御的机制中是至关重要的。可以推测，研究中的杀菌剂通过激活编码氨肽酶的基因的表达来增强这些机制，这些基因在从储存肽和蛋白质中水解 N 端氨基酸（如甘氨酸、丙氨酸、脯氨酸）方面是活跃的。根据杀菌剂的不同，在 BBCH 67-69（Pictor 400 SC 和 Symetra 325 SC）和 BBCH 63-65（Propulse 250 SE）发育阶段应用后，氨肽酶活性的主要增加。我们的研究表明，农业化学处理和应用时间影响了氨肽酶的表达和活性，尽管它们不是应用杀菌剂的分子靶标。由于氨肽酶广泛存在于所有生物体中，并且在许多关键生理过程中起着关键作用，因此可以预期，影响植物中这些酶表达和活性的因素也可能影响其他生物体（特别是人类和其他哺乳动物）中的这些酶。
