Journal Article

Humic Substances Isolated from Recycled Biomass Trigger Jasmonic Acid Biosynthesis and Signalling

Canellas, Natália A., Cangemi, Silvana, Spaccini, Riccardo, Silva, Rakiely M., Olivares, Fábio L., Sangi, Sara, Peres, Lázaro E. P., Canellas, Luciano P., Peres, Alice N. A.

2023

Overview

Intensive agriculture maintains high crop yields through chemical inputs, which are well known for their adverse effects on environmental quality and human health. Innovative technologies are required to reduce the risk generated by the extensive and harmful use of pesticides. The plant biostimulants made from humic substances isolated from recyclable biomass offer an alternative approach to address the need for replacing conventional agrochemicals without compromising the crop yield. The stimulatory effects of humic substances are commonly associated with plant hormones, particularly auxins. However, jasmonic acid (JA) is crucial metabolite in mediating the defence responses and governing plant growth and development. This work aimed to evaluate the changes in the biosynthesis and signalling pathway of JA in tomato seedlings treated with humic acids (HA) isolated from vermicompost. We use the tomato model system cultivar Micro-Tom (MT) harbouring a reporter gene fused to a synthetic promoter that responds to jasmonic acid (JERE::GUS). The transcript levels of genes involved in JA generation and activity were also determined using qRT-PCR. The application of HA promoted plant growth and altered the JA status, as revealed by both GUS and qRT-PCR assays. Both JA enzymatic synthesis (LOX, OPR3) and JA signalling genes (JAZ and JAR) were found in higher transcription levels in plants treated with HA. In addition, ethylene (ETR4) and auxin (ARF6) signalling components were positively modulated by HA, revealing a hormonal cross-talk. Our results prove that the plant defence system linked to JA can be emulated by HA application without growth inhibition.

• Publisher: MDPI AG,MDPI
• Subject: Agricultural chemicals / Agricultural production / Agricultural research / Agrochemicals / Amino acids / Auxins / Biological activity / Biomass / Biosynthesis / biotic stress / Carbohydrates / Chemical properties / Composting / Crop yield / Crop yields / Cultivars / eco-compatible chemicals / Environmental effects / Environmental quality / Enzymatic synthesis / Enzymes / ethylene / Genes / growth retardation / hormonal effect / Hormones / human health / Humic acid / Humic acids / Humic substances / Intensive farming / Jasmonates / Jasmonic acid / Lignin / Liquid oxygen / Metabolism / Metabolites / NMR / Nuclear magnetic resonance / Organic compounds / Pesticides / Physiological aspects / Physiology / Plant biomass / Plant growth / Plant resistance / Polymerase chain reaction / Reporter gene / reporter genes / Risk reduction / Seedlings / Signal transduction / Tomatoes / Vermicomposting / vermicomposts / Water shortages / Worms