Potential of Novel Magnesium Nanomaterials to Manage Bacterial Spot Disease of Tomato in Greenhouse and Field Conditions

Ying-Yu Liao; Jorge Pereira; Ziyang Huang; Qiurong Fan; Swadeshmukul Santra; Jason C White; Roberto De La Torre-Roche; Susannah Da Silva; Gary E Vallad; Joshua H Freeman; Jeffrey B Jones; Mathews L Paret

doi:10.3390/plants12091832

Potential of Novel Magnesium Nanomaterials to Manage Bacterial Spot Disease of Tomato in Greenhouse and Field Conditions

Plants (Basel). 2023 Apr 29;12(9):1832. doi: 10.3390/plants12091832.

Authors

Ying-Yu Liao^{1

2}, Jorge Pereira^{3

4}, Ziyang Huang^{3

4}, Qiurong Fan^{1

2}, Swadeshmukul Santra^{3

4

5}, Jason C White⁶, Roberto De La Torre-Roche⁶, Susannah Da Silva², Gary E Vallad⁷, Joshua H Freeman², Jeffrey B Jones¹, Mathews L Paret^{1

2}

Affiliations

¹ Department of Plant Pathology, University of Florida, Gainesville, FL 32611, USA.
² North Florida Research and Education Center, University of Florida, Quincy, FL 32351, USA.
³ Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA.
⁴ NanoScience Technology Center, University of Central Florida, Orlando, FL 32826, USA.
⁵ Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL 32816, USA.
⁶ Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, CT 06511, USA.
⁷ Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598, USA.

Abstract

Bacterial spot of tomato is among the most economically relevant diseases affecting tomato plants globally. In previous studies, non-formulated magnesium oxide nanoparticles (nano-MgOs) significantly reduced the disease severity in greenhouse and field conditions. However, the aggregation of nano-MgO in liquid suspension makes it challenging to use in field applications. Therefore, we formulated two novel MgO nanomaterials (SgMg #3 and SgMg #2.5) and one MgOH₂ nanomaterial (SgMc) and evaluated their physical characteristics, antibacterial properties, and disease reduction abilities. Among the three Mg nanomaterials, SgMc showed the highest efficacy against copper-tolerant strains of Xanthomonas perforans in vitro, and provided disease reduction in the greenhouse experiments compared with commercial Cu bactericide and an untreated control. However, SgMc was not consistently effective in field conditions. To determine the cause of its inconsistent efficacy in different environments, we monitored particle size, zeta potential, morphology, and crystallinity for all three formulated materials and nano-MgOs. The MgO particle size was determined by the scanning electron microscopy (SEM) and dynamic light scattering (DLS) techniques. An X-ray diffraction (XRD) study confirmed a change in the crystallinity of MgO from a periclase to an Mg(OH)₂ brucite crystal structure. As a result, the bactericidal activity correlated with the high crystallinity present in nano-MgOs and SgMc, while the inconsistent antimicrobial potency of SgMg #3 and SgMg #2.5 might have been related to loss of crystallinity. Future studies are needed to determine which specific variables impair the performance of these nanomaterials in the field compared to under greenhouse conditions. Although SgMc did not lead to significant disease severity reduction in the field, it still has the potential to act as an alternative to Cu against bacterial spot disease in tomato transplant production.

Keywords: Xanthomonas perforans; antimicrobial; crop protection; crystallinity; nanoparticles.

Grants and funding

Swadeshmukul Santra and Jorge Pereira recognize the support of the USDA NIFA SCRI project 2019-51181-30010. Mathews Paret recognize HATCH funds and University of Florida CALS funds through North Florida Research and Education Center for supporting this doctoral research project.