Application of heat-treated oyster shell powder to induce priming of Theobroma cocoa seedlings plant defense system against Phytophthora megakarya attack

• Published in: Current plant biology Vol. 34; p. 100283
• Main Authors: Martial, Tene Tayo Paul, Armel, Mouafo Tchinda Romaric, Juste, Yamoneka, Aristide, Dzelamonyuy, Collins, Wouamba Njonte Steven, Thaddee, Boudjeko
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2023; Elsevier
• Subjects: Bio-oyster shell; Black pod disease; Cocoa; Priming; LC/MS; Priming; Bio-oyster shell; Black pod disease; Cocoa; qRT PCR
• ISSN: 2214-6628; 2214-6628
• DOI: 10.1016/j.cpb.2023.100283

Priming with natural compounds is an interesting alternative for sustainable agriculture to explore the molecular mechanisms associated with the management of diseases caused by soil borne pathogens. The aim of this work was to evaluate the effect of the soil amendment with bio-oyster shell on the stimulation of the cocoa plant defense systems against P. megakarya in the nursery. For this purpose, the potential of bio-oyster shell to stimulate cocoa plant defense mechanisms was evaluated by soil amendment at 1% W/W under greenhouse conditions. After soil amendment, agronomic growth parameters and soil parameters were analyzed. The degree of expression of phytoalexins and defense genes was carried out by UPLC-DAD- HRESI–MS (+) and qRT-PCR analyses, respectively. The results obtained show that soil treatment with these composites improves the sanitary quality of cocoa seedlings in controlled conditions through the stimulation of agronomic growth parameters such as plant height, number of leaves, leaf surface area, and fresh weight of shoot and root. The latter leads to an increase in soil pH by about 32 % as well as the improvement of the nutritional status of the soil by 90%. Moreover, bio-oyster shell soil amendment induces up-regulation of TcPer-1, TcGlu1, TcChiB, and TcMYBPA genes and accumulation of primed metabolites such as flavonols, brevifolin, and isoflavone compounds before and after infection. This stimulation based on biological substances make it possible to pre-immunize cocoa plants against pathogen attacks and would be a good candidate to improve the quality of cocoa seeds in Cameroon.