Enhanced Resistance to Leaf Fall Disease Caused by Phytophthora palmivora in Rubber Tree Seedling by Sargassum polycystum Extract

Abstract

The brown seaweed (Sargassum polycystum C. Agardh-Sargassaceae) extract was examined for its bioelicitor properties in the rubber tree seedling (Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg. - Euphorbiaceae) and its application to reduce the leaf fall disease caused by Phytophthora palmivora (Edwin John) Butler, 1917 (Peronosporaceae). The major purpose of this study was to apply this seaweed extract (SWE) to improve the disease resistance in rubber tree seedling compared to a chemical fungicide (1% metalaxyl). After foliar spraying of SWE solution, two antioxidant enzymes, catalase (CAT) and peroxidase (POD) and systemic acquired resistance (SAR)-triggered enzyme, β-1,3-glucanase (GLU), were analyzed. Both secondary metabolites, a phytoalexin scopoletin (Scp) and a signaling molecule salicylic acid (SA) were measured by high performance liquid chromatography (HPLC). Both SWE- and metalaxyl-treated plants had a close disease index (DI)-score which were 16.90 ± 1.93 and 15.54 ± 1.25, respectively, while the positive control sprayed with P. palmivora showed DI-score of 29.27 ± 1.89 which was much higher than those treated with SWE or fungicide. CAT, POD, and GLU were increased in rubber tree leaves treated with SWE solution. Furthermore, Scp and SA were significantly increased in SWE-treated leaves. Enhanced systemic acquired resistance induction, 2.09 folds of SA accumulation, was observed in the distal area comparing to the local area of SWE application. In conclusion, the positive effects of SWE elicitation from these studies revealed that SWE could be used as an alternative biocontrol agent for foliar spraying to enhance the defense responses in rubber tree seedling against P. palmivora.

Comprehensive Overview of REDD+ in India: Status, Opportunities and Challenges

“…Among the clones studied, the clone RRII 105 and GT1 were reported as resistant clones to phytophthora leaf fall on prophylactic spraying (Edathil et al, 2000). In a recent report (Khompatara et al, 2019), Sargassum polycystum, a seaweed extract, was found effective to increase resistance to the Phytophthora mediated leaf fall disease in rubber seedlings. Bharat et al (2018) reported that an alga, Sargassum polycystum, has the elemental concentration of sodium (85.3 mg L -1 ), chlorine ( 75.02 mg L -1 ) and calcium (69 mg L -1 ) in higher quantity and among this Ca was in appreciable quantity.…”

“…The enhanced resistance may be due to high Ca content in these clones. Disease control using chemical fertilizers usually have an adverse effect on the environment, soil and a reason for toxicity of living beings associated (Khompatara et al, 2019). In consideration of these, the identification of inherently resistant clones is more beneficial and easier as a control measure.…”

Seaweed-Based Compounds and Products for Sustainable Protection against Plant Pathogens

“…The foliar application of an extract prepared by the alkali treatment of Sargassum polycystum was reported to reduce leaf fall disease caused by Phytophthora palmivora by inducing systemic acquired resistance. The application of the extract induced enzymatic activities of catalase, endo-1,3- d -glucanase, and peroxidase in response to P. palmivora [ 166 ].…”

Effects of Seaweed Extracts on the Growth, Physiological Activity, Cane Yield and Sucrose Content of Sugarcane in China

“…The colony counts in the soil and metabolic activities of soil microbes were found to increase following SEs applications, which contributed to increase plant root and shoot growth ( Alam et al, 2013 ). SEs increased the absorption of soil nutrients by plants, stimulated the growth of crops, increased yield ( Renaut et al, 2019 ; Boukhari et al, 2020 ), and enhanced plant resistance to biotic ( Machado et al, 2014 ; Ben Salah et al, 2018 ) and abiotic stress ( Bradáčová et al, 2016 ; Cabo et al, 2019 ; Khompatara et al, 2019 ). For example, SEs sprayed on onion grown under water stress significantly increased N, P, and K uptake by 116, 113, and 93% compared to the unsprayed plants ( Almaroai and Eissa, 2020 ).…”