Transient Expression of <i>Nicotiana tabacum</i> Silicon-Induced Histidine-Rich Defensins in <i>N. benthamiana</i> Limits Necrotic Lesion Development Caused by Phytopathogenic Fungi

Silicon (Si) supplementation permits plants to better deter infection. Supplementing hydroponically propagated <i>Nicotiana tabacum</i> with 1 mM potassium silicate (K₂SiO₃) reduced necrotic lesion development on detached leaves by both <i>Botrytis cinerea</i> and <i>Sclerotinia sclerotiorum</i>. Previously, a family of Si-induced genes was identified in <i>N. tabacum</i>. These genes were members of the solanaceous <i>histidine-rich defensin</i> (<i>HRD</i>) superfamily and were termed <i>NtHRD1s</i> (the first identified family of <i>N. tabacum HRDs</i>). Defensins were originally identified to participate in innate immunity. Thus, the NtHRD1s were tested for antimicrobial effects on plant pathogens. Transient expression of <i>NtHRD1</i> genes within <i>N. benthamiana</i> leaves restricted the development of necrotic lesions caused by <i>B. cinerea</i> and <i>S. sclerotiorum</i>. Thus, the NtHRD1s may be an additional Si-responsive factor conferring beneficial effects on plants. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.