Assessing relationship between phenolic compounds and resistance to Phytophthora megakarya using two cocoa (Theobroma cacao) families

Abstract

Black pod disease is an important fungal infection in cocoa (Theobroma cacao L.) which causes high production losses. In Cameroon, these losses reached 80% of cocoa production depending on ecological zones. In order to contribute to the efficiency of selection methods used in resistance or tolerance to black pod disease with the aim of improving on cocoa farming, the content of phenolic compounds was analyzed on the genotypes of two hybrid families (F79:♀T 79/467 x♂SNK 13 and F13:♀SNK 13 x♂T 79/467) of cocoa which are different in productivity and vulnerability to black pod disease. After artificial inoculation of the pods by mycelium of Phytophthora megakarya, the content of the phenolic compounds significantly increased in all genotypes of the two families. The heterosis effect of each family revealed a higher variability within both families. These results alike showed that productive and tolerant genotypes (F1307, 1314, F7902 and F7928) have a high phenols content and positive heterosis meanwhile the less tolerant and productive genotypes (F1321, F1326, F7904 and F7911) have a weak content and negative heterosis.

Effect of Biofertilizers on the Phenolic Content in a Hybrid Family of Cacao After Leaf Infection with <i>Phytophthora megakarya</i> and Exogenous Application of Salicylic Acid

“…This increase was due to the activation of phenylalanine ammonia lyases (PAL), the enzymes most involved in phenolic metabolism, by the elicitors produced by P. megakarya. Our results are in agreement with those of Simo et al (2014) indicated that the increase in phenolic content under infectious conditions was greater in tolerant individuals [14]. These results are also in agreement with those obtained by Effa et al (2017) who found that parental or hybrid tolerant genotypes accumulated elevated total phenolic compounds relative to susceptible hybrid genotypes after infection of pods with P. megakarya mycelium [27].…”

“…The extraction of phenolic compounds for quantitative analysis was done according to the method described by Simo et al (2014) [14]. Twenty mg of fresh leaf cut past the necrotic part were crushed in 5ml of methanol (80%) by adding a pinch of sterile fine sand and the resulting maceration was centrifuged at 6000 g for 20 min.…”

“…This protection of arbuscular mycorrhizal fungi (AMF) against pathogens is certainly linked to a set of processes such as competition for root colonization and nutrient absorption, activation by the fungus of the mechanisms of defense of the plant or even the production of fungal substances disturbing the development of pathogens. The increase in the biosynthesis of phenolic compounds is among the defence mechanisms stimulated by these biofertilizers [13][14].…”

Virulence Test of Some Phytophthora Megakarya Isolates on Cocoa (Theobroma Cacao L.) Hybrid Pods

“…In a study assessing relationship between phenolic compounds and resistance to P. megakarya using two cocoa families, some authors [32]found that productive and tolerant genotypes displayed high phenols content meanwhile less tolerant and productive ones had a weak content. The role of phenolic compounds in plant defense is well documented [33]. These metabolites accumulate at different levels in infected tissues in response to pathogen attack.…”

Pengelompokan 33 Aksesi Kakao Berdasarkan Karakter Morfologi Komponen Buah

“…Beberapa karakter komponen buah kakao, yang meliputi ukuran buah (pod), biji, kulit buah, dan pulpa, berhubungan langsung dengan produktivitas tanaman serta ketahanan terhadap hama penggerek buah (PBK) (Susilo, Mangoendidjojo, Witjaksono, Sulistyowati, & Mawardi, 2009;Wijaya, Prawoto, & Ihromi, 2009;Asrul, Agus, Daryati, & Mollah, 2012;Limbongan, 2012;Pertiwi, Asrul, & Baja, 2013;Susilo, Mawardi, Witjaksono, & Mangoendidjojo, 2015) dan penyakit busuk buah Ondobo et al, 2014;Simo et al, 2014) .…”