Root treatment with a vitamin K3 derivative: a promising alternative to synthetic fungicides against Botrytis cinerea in tomato plants.

BACKGROUND: Botrytis cinerea, the causal agent of gray mold has a great economic impact on several important crops. This necrotrophic fungus causes disease symptoms during vegetative growth and also into postharvest stages. The current method to combat this disease is fungicide application, with high economic costs and environmentally unsustainable impacts. Moreover, there is an increasing general public health concern about these strategies of crop protection. We studied the protection of tomato plants against B. cinerea by previous root treatment with menadione sodium bisulfite (MSB), a known plant defense activator. RESULTS: Root treatment 48 h before inoculation with MSB 0.6 mmol L-1 reduced leaf lesion diameter by 30% and notably cell deaths, compared to control plants 72 h after inoculation. We studied the expression level of several pathogenesis-related (PR) genes from different defense transduction pathways, and found that MSB primes higher PR1 expression against B. cinerea. However, this stronger induced resistance was impaired in transgenic salicylic acid-deficient NahG line. Additionally, in the absence of pathogen challenge, MSB increased tomato plant growth by 28% after 10 days. Our data provide evidence that MSB protects tomato plants against B. cinerea by priming defense responses through the salicylic acid (SA)-dependent signaling pathway and reducing oxidative stress. CONCLUSION: This work confirms the efficacy of MSB as plant defense activator against B. cinerea and presents a novel alternative to combat gray mold in important crops.

A Beginner's Guide to Osmoprotection by Biostimulants.

Water is indispensable for the life of any organism on Earth. Consequently, osmotic stress due to salinity and drought is the greatest threat to crop productivity. Ongoing climate change includes rising temperatures and less precipitation over large areas of the planet. This is leading to increased vulnerability to the drought conditions that habitually threaten food security in many countries. Such a scenario poses a daunting challenge for scientists: the search for innovative solutions to save water and cultivate under water deficit. A search for formulations including biostimulants capable of improving tolerance to this stress is a promising specific approach. This review updates the most recent state of the art in the field.

Pure Organic Active Compounds Against Abiotic Stress: A Biostimulant Overview.

Biostimulants (BSs) are probably one of the most promising alternatives nowadays to cope with yield losses caused by plant stress, which are intensified by climate change. Biostimulants comprise many different compounds with positive effects on plants, excluding pesticides and chemical fertilisers. Usually mixtures such as lixiviates from proteins or algal extracts have been used, but currently companies are interested in more specific compounds that are capable of increasing tolerance against abiotic stress. Individual application of a pure active compound offers researchers the opportunity to better standarise formulations, learn more about the plant defence process itself and assist the agrochemical industry in the development of new products. This review attempts to summarise the state of the art regarding various families of organic compounds and their mode/mechanism of action as BSs, and how they can help maximise agricultural yields under stress conditions aggravated by climate change.