Biocontrol of root-knot nematode infected banana plants by some marine algae

255

157

The use of seaweed-based bioproducts has been gaining momentum in crop production systems owing to their unique bioactive components and effects. They have phytostimulatory properties that result in increased plant growth and yield parameters in several important crop plants. They have phytoelicitor activity as their components evoke defense responses in plants that contribute to resistance to several pests, diseases, and abiotic stresses including drought, salinity, and cold. This is often linked to the upregulation of important defense-related genes and pathways in the plant system, priming the plant defenses against future attacks. They also evoke phytohormonal responses due to their specific components and interaction with plant growth regulation. Treatment by seaweed extracts and products also causes significant changes in the microbiome components of soil and plant in support of sustainable plant growth. Seaweed extracts contain a plethora of substances which are mostly organic, but trace levels of inorganic nutrient elements are also present. Fractionation of seaweed extracts into their components and their respective bioassays, however, has not yielded favorable growth effects. Only the whole seaweed extracts have been consistently proven to be very effective, which highlights the role of multiple components and their complex interactive effects on plant growth processes. Since seaweed extracts are highly organic, they are ideally suited for organic farming and environmentally sensitive crop production. They are also very compatible with other crop inputs, paving the way for an integrated management approach geared towards sustainability. The current review discusses the growth and functional effects evoked by seaweed extracts and their modes and mechanisms of action in crop plants which are responsible for elicitor and phytostimulatory activities. The review further analyses the potential value of seaweed extracts in integrated crop management systems towards sustainable crop production.

Section: Mechanisms and Mode Of Biostimulatory Activitiesmentioning

confidence: 99%

Biostimulant Properties of Seaweed Extracts in Plants: Implications towards Sustainable Crop Production

Alí

Ramsubhag

Jayaraman

2021

255

157

“…Such effect was attributed to anti-juvenile hormonal content of SE, obstructing pest development at germ bund or blastokineis stages [99]. Furthermore, Ulva lactuca powder applied as soil treatment at the rate of 5 g/kg significantly diminished root knot nematode infections in banana plants, through reduction of number of galls (76%) and final population of nematodes, which was directly correlated with SE phenolic contents [100]. SE were also evaluated for their antifungal properties and solvent extract of some macroalgae specifies isolated from Brazilian Manguinhos beach (i.e., H. musciformis, O. secundiramea, P. capillacea, L. dendroidea, and P. gymnospora) successfully inhibited Colletotrichum gloeosporioides, a fungal species inducing anthracnose in papaya and banana plants, which severely hamper fruits postharvest.…”

Section: Mechanism Of Action Under Biotic Stressmentioning

confidence: 99%

Trends in Seaweed Extract Based Biostimulants: Manufacturing Process and Beneficial Effect on Soil-Plant Systems

Boukhari

Barakate

Bouhia

et al. 2020

191

129

The time when plant biostimulants were considered as “snake oil” is erstwhile and the skepticism regarding their agricultural benefits has significantly faded, as solid scientific evidences of their positive effects are continuously provided. Currently plant biostimulants are considered as a full-fledged class of agri-inputs and highly attractive business opportunity for major actors of the agroindustry. As the dominant category of the biostimulant segment, seaweed extracts were key in this growing renown. They are widely known as substances with the function of mitigating abiotic stress and enhancing plant productivity. Seaweed extracts are derived from the extraction of several macroalgae species, which depending on the extraction methodology lead to the production of complex mixtures of biologically active compounds. Consequently, plant responses are often inconsistent, and precisely deciphering the involved mechanism of action remains highly intricate. Recently, scientists all over the world have been interested to exploring hidden mechanism of action of these resources through the employment of multidisciplinary and high-throughput approaches, combining plant physiology, molecular biology, agronomy, and multi-omics techniques. The aim of this review is to provide fresh insights into the concept of seaweed extract (SE), through addressing the subject in newfangled standpoints based on current scientific knowledge, and taking into consideration both academic and industrial claims in concomitance with market’s requirements. The crucial extraction process as well as the effect of such products on nutrient uptake and their role in abiotic and biotic stress tolerance are scrutinized with emphasizing the involved mechanisms at the metabolic and genetic level. Additionally, some often overlooked and indirect effects of seaweed extracts, such as their influence on plant microbiome are discussed. Finally, the plausible impact of the recently approved plant biostimulant regulation on seaweed extract industry is addressed.

“…Soil treatments with dry powder of the brown alga J. laminarioides and the red algae Cystoclonium purpereum and Hypnea valentiae resulted in a strong reduction of root-gall formation on okra and tomato roots infested by M. javanica and in improved plant growth [ 34 ]. In a study of El-Ansary and Hamouda [ 52 ], the soil application of powdered dry biomass from U. lactuca (green alga), Jania rubens and Laurencia obtuse (red seaweeds) and the brown alga Sargassum vulgare significantly decreased galls and root-knot nematode egg masses on banana ( Musa spp.) roots and the nematode population in soil.…”

Section: Seaweedsmentioning

confidence: 99%

Marine Organisms for the Sustainable Management of Plant Parasitic Nematodes

Veronico

Melillo

2021

Plant parasitic nematodes are annually responsible for the loss of 10%–25% of worldwide crop production, most of which is attributable to root-knot nematodes (RKNs) that infest a wide range of agricultural crops throughout the world. Current nematode control tools are not enough to ensure the effective management of these parasites, mainly due to the severe restrictions imposed on the use of chemical pesticides. Therefore, it is important to discover new potential nematicidal sources that are suitable for the development of additional safe and effective control strategies. In the last few decades, there has been an explosion of information about the use of seaweeds as plant growth stimulants and potential nematicides. Novel bioactive compounds have been isolated from marine cyanobacteria and sponges in an effort to find their application outside marine ecosystems and in the discovery of new drugs. Their potential as antihelmintics could also be exploited to find applicability against plant parasitic nematodes. The present review focuses on the activity of marine organisms on RKNs and their potential application as safe nematicidal agents.