The Multilateral Efficacy of Chitosan and Trichoderma on Sugar Beet

Abstract

The majority of all fungal formulations contain Trichoderma spp., making them effective biological control agents for agriculture. Chitosan, one of the most effective natural biopolymers, was also reported as a plant resistance enhancer and as a biocide against a variety of plant pathogens. An in vitro three-way interaction assay of T. atroviride, chitosan, and important plant pathogens (such as Cercospora beticola and Fusarium oxysporum) revealed a synergistic effect on fungistasis. Furthermore, chitosan coating on Beta vulgaris ssp. vulgaris seeds positively affected the onset and efficiency of germination. We show that priming with T. atroviride spores or chitosan leads to the induced expression of a pathogenesis-related gene (PR-3), but only supplementation of chitosan led to significant upregulation of phytoalexin synthesis (PAL) and oxidative stress-related genes (GST) as a defense response. Repeated foliar application of either agent promoted growth, triggered defense reactions, and reduced incidence of Cercospora leaf spot (CLS) disease in B. vulgaris. Our data suggest that both agents are excellent candidates to replace or assist common fungicides in use. Chitosan triggered the systemic resistance and had a biocidal effect, while T. atroviride mainly induced stress-related defense genes in B. vulgaris. We assume that both agents act synergistically across different signaling pathways, which could be of high relevance for their combinatorial and thus beneficial application on field.

Priming seeds for the future: Plant immune memory and application in crop protection

“…Priming of cucumber with chitosan induced deposition of lignin and callose, enhanced the accumulation of defense-responsive enzymes, and increased disease resistance against powdery mildew (Jogaiah et al, 2020). Chitosan-primed sugar beet plants exhibited upregulation of PR3, PAL, and GST genes, as well as enhanced resistance against CLS disease (Kappel et al, 2022). Rice primed with CAGCs induced expression of defense genes EDS1, ICS1, NPR1, MKK4, and PR1 genes, and enhanced resistance against rice bacterial leaf blight disease (Pal et al, 2021).…”

“…Seed priming could secure the enhanced and uniformed seed germination and seedling establishment under field conditions, and greatly contributes to the improvement of crop growth and production (Marthandan et al, 2020;Johnson and Puthur, 2021). Increasing evidence revealed that seed priming could induce plant immune memory that is either stably maintained throughout developmental stages or transmitted over generations (Jogaiah et al, 2020;Joshi et al, 2021;Martínez-Aguilar et al, 2021;Pal et al, 2021;Yadav et al, 2021;Kappel et al, 2022). As summarized in Table 1, different types of seed priming approaches such as biological priming, chemical priming, and nanomaterials priming have been successfully established to protect crop plants against pathogen infections.…”

“…Seed priming of chilli with PGPFs T. harzianum, T. asperellum, and PGFR Paenibacillus dendritiformis triggers physiological, transcriptional, and metabolic changes such as ROS burst and induction of defense-related enzymes and phenolic compounds, as well as increased disease resistance against anthracnose disease (Mitra et al, 2021;Yadav et al, 2021). Sugar beet primed with the PGPF T. atroviride exhibited upregulation of defense gene BvPR3 and induced systemic resistance against Cercospora leaf spot (CLS) disease (Kappel et al, 2022). In addition, seed priming of crop plants with elicitors derived from beneficial microbes also could trigger immune memory, as well as induced resistance, throughout their developmental stages.…”

“…Defense priming requires immune memory to store the changes or information acquired from the initial pathogen perception, and retrieves this information upon a later pathogen challenge (Ramirez-Prado et al, 2018). As an environmental-friendly, pre-sowing enhancement technique, seed priming could effectively induce plant immune memory and have a great potential in sustainable crop protection (Jogaiah et al, 2020;Joshi et al, 2021;Martínez-Aguilar et al, 2021;Pal et al, 2021;Yadav et al, 2021;Kappel et al, 2022). Herein, we summarized recent development on the establishment and maintenance mechanisms of plant defense priming and the immune memory associated.…”

Sustainable Management of Diseases in Horticulture: Conventional and New Options

“…Seed dressing is another potential application of chitosan to reduce disease [191]. Interestingly, chitosan showed a synergistic effect with some biocontrol agents such as Trichoderma spp., indicating both castor seed protection [192] and a increased reduction in the pathogenicity of Cercospora beticola and Fusarium oxysporum [193]. Chitosan should also be added to the soil to reduce the severity of tomato crown and root rot caused by Fusarium oxysporum f. sp.…”