Use of Biosolids to Enhance Tomato Growth and Tolerance to Fusarium oxysporum f. sp. radicis-lycopersici

Abstract

Aims: A biosolid made from municipal sludge, acting as an organic fertilizer that enhanced plant growth and crop productivity, was evaluated for its effect on tomato growth and tolerance enhancement against the phytopathogenic fungus Fusarium oxysporum f. sp. radicis-lycopersici (Forl).Methods: Peat and/or two soil types were amended with mixtures of this biosolid (0, 80 and 160 tn/ha) in order to study the growth of tomato plants and their response to Forl, either under controlled conditions or outdoors in a net protected area.Results: The results showed that biosolid addition increased tolerance of tomato plants against the disease. There was also an increase of tomato fresh weight, root weight, stem height and leaf number compared to the Forl-inoculated control soils. Forl, at 5 weeks after tomato transplanting, caused higher disease index on plants grown outdoors in biosolid plus clay soil than in biosolid plus sandy soil, while the opposite occurred under laboratory conditions where higher disease index was recorded on plants grown in peat plus sandy soil than in peat plus clay soil. Conclusions:The ndings strongly support the evidence that this biosolid may act as an organic fertilizer and as a possible stimulant of tomato tolerance against Forl. Therefore, this type of biosolid, previously proven to be minimal ecotoxicological impact, should be considered for its possible use in agriculture according to the principles of circular economy and waste minimization.

Biosolid-Amended Soil Enhances Defense Responses in Tomato Based on Metagenomic Profile and Expression of Pathogenesis-Related Genes

“…However, there is limited research related to the molecular mechanisms associated with biosolid-elicited suppression of soilborne diseases, such as TFFR and the enhanced plant performance. In a previous work, biosolid application in the soil has been shown to enhance tomato growth and reduce the effects of Forl infection [12]. In the present work, a molecular approach was employed to provide further insight into the mechanistic effect of biosolid application in alleviating the negative impact of Forl on tomato plants.…”

“…As a follow-up to the report of Giannakis et al [12] on the beneficial effects of sludgebased biosolids on tomato growth and TFFR severity, in the present work, we have investigated the plant-pathogen interactions at a molecular level and how they are affected by the addition of biosolids in the soil. More specifically, it was examined whether biosolids: (i) could act in vitro as an inhibitor of growth and sporulation of Forl, (ii) could induce gene expression related to plant response against pathogens in tomato, and (iii) would provide a beneficial substrate for the growth of non-pathogenic antagonistic microorganisms against Forl in the tomato rhizosphere.…”

“…Biosolid application can enhance tomato tolerance against the Forl [12], which was mainly attributed to the indirect beneficial effects of biosolid application on biotic and abiotic factors [31]. Although growth and sporulation of Forl in the presence of biosolids were not studied in planta, it would have been expected that biosolids could suppress the growth and sporulation of Forl, thus reducing its aggressiveness against tomato.…”

“…Expression patterns of defense-related genes (GLUA, CHI3, PR1-a, LOX, and AOC) following application of biosolid and inoculation with Forl were analyzed using RT-qPCR (Figure 2). The induction patterns were evaluated in tomato plants at 12,24,48, and 72 h after inoculation. As internal control the reference gene β-actin was used.…”

“…Recently, Giannakis et al [12] reported that sludge-based biosolids enhance tomato growth and reduce TFFR severity. Biosolids may benefit the plant's health by improving the soil properties and enhancing the diversity of the rhizosphere bacterial community [13,14].…”