Editorial: Molecular Interactions and Control Strategies for Botrytis cinerea in Crop Production

Paulo Canessa^1*Simone Ferrari^2*

• ¹Andres Bello University, Plant Biotechnology Center, Santiago, Chile
• ²Dipartimento di Biologia e Biotecnologie "Charles Darwin", Sapienza University of Rome, Rome, RM, Italy

In the past two decades, B. cinerea has become a model organism for studying fungal necrotrophs. Indeed, it has been listed as the most scientifically and economically important fungus of its kind Activation of Pattern-Triggered Immunity (PTI) is the first tier of the plant innate immune system. Upon pathogen entry, PTI can activate multilayered defense responses with varied effectiveness against B. cinerea. However, the outcome of the interaction between the fungus and its host varies amply, depending on their genotypes and the environmental conditions. A striking example of this variability is the "noble rot" phenomenon, a latent form of infection occurring in grape berries under peculiar microclimatic conditions characterized by dry and sunny days and humid nights (Ribéreau-Gayon et al., 1980; Magyar, 2011;Vannini & Chilosi, 2013). Noble rot results in the rapid withering of the grape berry, which is required to produce famous sweet white Sauternes wines. In sharp contrast, under continuous mild wet weather (typically the same laboratory conditions used to study B. cinerea virulence), the infection results in grey rot, resulting in the loss of the berry (Williamson et al., 2007). A transcriptomic analysis revealed that the so-called noble rot phase exhibits significant differences from the other two stages (Váczy et al., 2024). This study shows that the initial stages of infection reflect a virulent fungus-plant interaction, regardless of whether the outcome is grey or noble. However, paradoxically, expression of host defenserelated genes is suppressed during the noble stage of rotting, suggesting that the plant is not actively defending itself against B. cinerea and that the host and the fungus have settled in equilibrium.Rounding out the picture portrayed in this Research Topic, emerging evidence indicates that epigenetic mechanisms also dictate how strongly plants resist pathogens. Epigenetic control of gene expression is crucial for all aspects of plant biology, including host-microbe interactions As the quest for plant targets that can be modified by gene editing to create resistant varieties to B. cinerea continues, this Research Topic also exemplifies a seldom observed dimension to our understanding of how plants fine-tune immunity: some genes that may be essential for developmental processes can incidentally or simultaneously downregulate defense. As indicated here, these targets must be carefully evaluated since it is possible to generate difficult-toanticipate effects, including diminished resistance or increased defense, depending on the pathogen.