Biochar-Enhanced Resistance to Botrytis cinerea in Strawberry Fruits (But Not Leaves) Is Associated With Changes in the Rhizosphere Microbiome

Abstract

Biochar has been reported to play a positive role in disease suppression against airborne pathogens in plants. The mechanisms behind this positive trait are not well-understood. In this study, we hypothesized that the attraction of plant growth-promoting rhizobacteria (PGPR) or fungi (PGPF) underlies the mechanism of biochar in plant protection. The attraction of PGPR and PGPF may either activate the innate immune system of plants or help the plants with nutrient uptake. We studied the effect of biochar in peat substrate (PS) on the susceptibility of strawberry, both on leaves and fruits, against the airborne fungal pathogen Botrytis cinerea. Biochar had a positive impact on the resistance of strawberry fruits but not the plant leaves. On leaves, the infection was more severe compared with plants without biochar in the PS. The different effects on fruits and plant leaves may indicate a trade-off between plant parts. Future studies should focus on monitoring gene expression and metabolites of strawberry fruits to investigate this potential trade-off effect. A change in the microbial community in the rhizosphere was also observed, with increased fungal diversity and higher abundances of amplicon sequence variants classified into Granulicella, Mucilaginibacter, and Byssochlamys surrounding the plant root, where the latter two were reported as biocontrol agents. The change in the microbial community was not correlated with a change in nutrient uptake by the plant in either the leaves or the fruits. A decrease in the defense gene expression in the leaves was observed. In conclusion, the decreased infection of B. cinerea in strawberry fruits mediated by the addition of biochar in the PS is most likely regulated by the changes in the microbial community.

Bamboo charcoal mediated plant secondary metabolites biosynthesis in tomato against South American tomato pinworm (Tuta absoluta)

“…Biochar amendment in soil/substrate has shown positive effects on plant defense against different pathogens, however, limited data is available for insect pests (De Tender et al, 2021). The spread of T. absoluta in mainland China (Zhang et al, 2021) calls for the exploration of possible strategies to reduce tomato crop losses.…”

“…The use of transcriptome sequencing and metabolome profiling can help us identify the key metabolites and genes that are accumulated or expressed, respectively, in tomato plants grown in soil amended with bamboo charcoal. A similar strategy has helped researchers identify genes and associated pathways such as protein processing, plant-pathogen interaction, photosynthesis, and signaling in response to different biotic stresses e.g., in pepper against Fusarium wild (Zhu et al, 2021), in oat against oat-stem-rust (Li et al, 2022), and in strawberry fruits against Botrytis cinerea (De Tender et al, 2021). In this study, we used a combined metabolome profiling and transcriptome sequencing approach to understand the key changes in the accumulated metabolites and respective changes in gene expression in leaves of tomato plants grown in coconut bran amended with bamboo charcoal.…”

Genotype, mycorrhizae, and herbivory interact to shape strawberry plant functional traits

“…In this study, the Wasatch genotype demonstrated relatively higher mycorrhizal colonization compared to controls, which likely underlie some of the observed genotype x AMF interactive effects. Previous studies indicate that plant genotypes, including different strawberry cultivars, can show variable responsiveness to different species or strains of AMF ( Chávez and Ferrera-Cerrato, 1990 ; Vestberg, 1992 ; Estaún et al., 2010 ; Sinclair et al., 2014 ), and recent research highlights the importance of fungal diversity ( De Tender et al., 2021 ; Frew et al., 2022 ). Because we did not identify fungal species when measuring root colonization, there is uncertainty about AMF community composition and the extent to which our inoculation contributed to higher colonization.…”

Biochar for the Control of Plant Pathogens

“…Thus, biochar helps to improve the population of soil beneficial microbial communities which in turn help in the suppression of soil-borne plant pathogens. Tender et al (2021) reported the attraction of plant beneficial rhizobacteria and fungi as the mechanism behind the role of biochar in plant disease suppression, based on the studies using the strawberry -Botrytis cinerea plant pathogen system. Botrytis cinerea is a pathogen that affects both fruits and leaves of strawberry plants.…”