Department of Plant and Animal Production, Plant Protection Program, Atabey Vocational High School, Isparta University of Applied Sciences, Isparta, Turkey.
Sci Rep. 2023 Jan 28;13(1):1580. doi: 10.1038/s41598-023-28849-w.
Coronatine (COR), a bacterial phytotoxin produced by Pseudomonas syringae, plays important roles in many plant growth processes. Onion bulbs were divided four groups to investigate the effects of COR against sodium chloride (NaCl) stress exposure in Allium cepa L. root tips. While control group bulbs were soaked in tap water medium, treatment group bulbs were grown in 0.15 M NaCl, 0.01 µM COR and 0.01 µM COR + 0.15 M NaCl medium, respectively. NaCl stress seriously inhibited the germination, root lenght, root number and fresh weight of the bulbs. It significantly decreased the mitotic index (MI), whereas dramatically increased the micronucleus (MN) frequency and chromosomal aberrations (CAs). Moreover, in order to determine the level of lipid peroxidation occurring in the cell membrane, malondialdehyde (MDA) content was measured and it was determined that it was at the highest level in the group germinated in NaCl medium alone. Similarly, it was revealed that the superoxide dismutase (SOD), catalase (CAT) and free proline contents in the group germinated in NaCl medium alone were higher than the other groups. On the other hand, NaCl stress caused significant injuries such as epidermis/cortex cell damage, MN formation in epidermis/cortex cells, flattened cells nuclei, unclear vascular tissue, cortex cell wall thickening, accumulation of certain chemical compounds in cortex cells and necrotic areas in the anatomical structure of bulb roots. However, exogenous COR application significantly alleviated the negative effects of NaCl stress on bulb germination and growth, antioxidant defense system, cytogenetic and anatomical structure. Thus, it has been proven that COR can be used as a protective agent against the harmful effects of NaCl on onion.
冠菌素（COR）是一种由丁香假单胞菌产生的细菌植物毒素，在许多植物生长过程中发挥着重要作用。本研究将洋葱鳞茎分为四组，研究 COR 对洋葱根尖暴露于氯化钠（NaCl）胁迫的影响。对照组鳞茎浸泡在自来水中，处理组鳞茎分别生长在 0.15 M NaCl、0.01 μM COR 和 0.01 μM COR+0.15 M NaCl 培养基中。NaCl 胁迫严重抑制了鳞茎的萌发、根长、根数和鲜重。它显著降低了有丝分裂指数（MI），而显著增加了微核（MN）频率和染色体畸变（CAs）。此外，为了确定细胞膜中发生的脂质过氧化水平，测量了丙二醛（MDA）含量，结果表明单独在 NaCl 培养基中萌发的组MDA 含量最高。同样，单独在 NaCl 培养基中萌发的组中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和游离脯氨酸含量也高于其他组。另一方面，NaCl 胁迫导致鳞茎根解剖结构的表皮/皮层细胞损伤、表皮/皮层细胞中 MN 形成、扁平细胞核、血管组织不清晰、皮层细胞壁增厚、皮层细胞中某些化合物的积累和坏死区等显著损伤。然而，外源 COR 的应用显著缓解了 NaCl 胁迫对鳞茎萌发和生长、抗氧化防御系统、细胞遗传学和解剖结构的负面影响。因此，已经证明 COR 可以用作洋葱抵御 NaCl 有害影响的保护剂。
