Hormetic UV‐C seed treatments for the control of tomato diseases

Abstract

Hormesis is a dose response phenomenon in which low, non-damaging doses of a stressor bring about a positive response in the organism undergoing treatment. Evidence is provided here that hormetic UV-C treatments of tomato seed can control disease caused by Botrytis cinerea, Fusarium oxysporum f. sp. lycopersici (FOL) and f. sp. radicis-lycopersici (FORL) on tomato (Solanum lycopersicum). Treating seeds with a 4 kJ m À2 dose of UV-C significantly reduced both the disease incidence and progression of B. cinerea, with approximately 10% reductions in both on cv. Shirley. Disease severity assays for FOL and FORL on cv. Moneymaker showed dose-dependent responses: UV-C treatments of 4 and 6 kJ m À2 significantly reduced the disease severity scores of FOL, whilst only the 6 kJ m À2 showed significant reductions for FORL. To determine the effects of treatment on germination and seedling growth, UV-C doses of 4, 8 and 12 kJ m À2 were performed on cv. Shirley. No negative impacts on germination or seedling growth were observed for any of the treatments. However, the 8 kJ m À2 treatment showed significant biostimulation, with increases in seedling, root and hypocotyl dry weight of 11.4%, 23.1% and 12.0%, respectively, when compared to the control. Furthermore, significant increases in the root-mass fraction (10.6%) and root:shoot ratio (13.1%) along with a decrease in shoot-mass fraction (2.0%) indicates that the 8 kJ m À2 treatment stimulated root growth to the greatest extent. There was no effect on hypocotyl and primary root length or the number of lateral roots, indicating no adverse effects to basic root architecture or seedling growth.

NB-LRRs Not Responding Consecutively to Fusarium oxysporum Proliferation Caused Replant Disease Formation of Rehmannia glutinosa

“…According to the original data associated with the relative values, we found that the upregulated expression of NB-LRRs was the strongest when the number of FO was at the lowest level (about 0.95 × 10 8 cell·g −1 soil), and gradually decreased with the increasing of FO number in six days after transplanting. These results exhibited that NB-LRR expressions have a typical regulars with “promotion in low concentration and suppression in high concentration” when countered FO invasion, which was consistent with Scott et al (2019) [54].…”

Evolving challenges and strategies for fungal control in the food supply chain

“…Relevant also to post-harvest fungal control (discussed later), UV-C treatment applied periodically in low doses induces a response of the plant that includes increased production of secondary metabolites and increased resistance to fungal pathogens such as B. cinerea ( Jin et al. , 2017 ; Scott et al. , 2019 ).…”

UV-C Rays to Simulate the Exposition of Photosynthetic Organisms to Solar Radiation in Space Environments

“…5,7,8,10 The majority of the recent articles on UV-C radiation has been focused on the control of the pathogens of edible plants. [13][14][15] Strictly related to pest control, many studies dealt with the pre-harvest application of UV-C radiation for improving the post-harvest quality, in terms of i) increased levels of health-promoting compounds, [16][17][18] ii) enhancement of the enzymatic and non-enzymatic antioxidant capacity of UV-C-irradiated crops, [19][20][21] and iii) higher product physical consistency. 16,22 Finally, a few papers were focused on the positive and promoting effects of UV-C radiation on germination, sprouting, growth and flowering.…”