Induced resistance to foliar diseases by soil solarization and Trichoderma harzianum

Abstract

The effect of soil solarization and Trichoderma harzianum on induced resistance to grey mould (Botrytis cinerea) and powdery mildew (Podosphaera xanthii) was studied. Plants were grown in soils pretreated by solarization, T. harzianum T39 amendment or both, and then their leaves were inoculated with the pathogens. There was a significant reduction in grey mould in cucumber, strawberry, bean and tomato, and of powdery mildew in cucumber, with a stronger reduction when treatments were combined. Bacillus, pseudomonad and actinobacterial communities in the strawberry rhizosphere were affected by the treatments, as revealed by denaturing gradient gel electrophoresis fingerprinting. In tomato, treatments affected the expression of salicylic acid (SA)‐, ethylene (ET)‐ and jasmonic acid (JA)‐responsive genes. With both soil treatments, genes related to SA and ET – PR1a, GluB, CHI9 and Erf1 – were downregulated whereas the JA marker PI2 was upregulated. Following soil treatments and B. cinerea infection, SA‐, ET‐, and JA‐related genes were globally upregulated, except for the LOX genes which were downregulated. Upregulation of the PR genes PR1a, GluB and CHI9 in plants grown in solarized soil revealed a priming effect of this treatment on these genes' expression. The present study demonstrates the capacity of solarization and T. harzianum to systemically induce resistance to foliar diseases in various plants. This may be due to either a direct effect on the plant or an indirect one, via stimulation of beneficial microorganisms in the rhizosphere.

Soil sterilization, pathogen and antagonist concentration affect biological control of Fusarium wilt of cape gooseberry by Bacillus velezensis Bs006

“…It could exert an effect on the pathogen and on natural microbial population that is changing because of the Bacillus introduction. A change in the native population towards more biocontrol activity including induced resistance by this population was demonstrated to take place when Trichoderma BCA was used in soil (Okon Levy et al 2015). Our result agrees with Abawi and Lorbeer (1972), who showed that biotic factors like the presence of the native microflora and inoculum density of the pathogen determined the potential for the disease development.…”

Induced systemic resistance in tomato (Solanum lycopersicum) against Botrytis cinerea by biochar amendment involves jasmonic acid signaling

“…The average of the relative expressions of the genes of interest in individual plants of the same genotype showed low variability and ranged between 83 to 104 % of the relative expressions in the pooled plants. Therefore, the leaf tissue collected from the three independent biological replicates was pooled within each experiment in order to reduce noise linked to variation between individual plants, following published protocols (Llorens et al 2013;Scalschi et al 2013;Meller Harel et al 2014;Okon Levy et al 2014). Reverse transcription was performed in two to three 800-ng replicates of DNAse I-treated total RNA (Applied Biosystems/Ambion, Austin, TX) using the M-MLV reverse transcriptase (Promega, Madison, WI), and cDNA products were pooled to reduce noise linked to the efficiency of the reverse transcription.…”

Methods for Management of Soilborne Diseases in Crop Production

“…For instance, biofortification of organic compost with beneficial microorganisms can also enhance the disease suppressiveness of the soil with higher efficacy and reliability [102]. Also, the addition of organic amendments followed by soil solarization can increase beneficial microbe interaction in the soil [34] with induced resistance in the host plant [103]. Thus, well balanced use of soil organic amendments together with the methods described such as soil solarization, biological antagonists can be an integrated approach for the management of soilborne pathogens.…”