Bioassays and field observations revealed complex and different genetic bases in Pestalotiopsis and circular leaf fall disease in Hevea brasiliensis

Darojat Muhamad Rizqi, Kusdiana Alchemi Putri Juliantika, Montoro Pascal, Lopez David, Oktavia Fetrina, Ismawanto Sigit, Sudarsono Sudarsono. 2024. Bioassays and field observations revealed complex and different genetic bases in Pestalotiopsis and circular leaf fall disease in Hevea brasiliensis. Industrial Crops and Products, 222 (3):119829 Industrial Crops and Products, 12 p.

Résumé : Circular leaf fall disease (LFD) has been spreading in South-East Asia since 2018. This disease has been considered to be the most important factor that influences natural rubber yield. After identifying Pestalotiopsis as the causal agent of circular LFD, several studies reported the potential involvement of another primary agent. The aim of the present study was to understand the genetic basis of the infection caused by Pestalotiopsis in bioassays under controlled conditions and field observations of circular disease. Individuals from a biparental population resulting from a cross between clones PB 260 and SP 217 were phenotyped. The symptoms on leaves inoculated with two isolates of Pestalotiopsis in bioassays and natural infection in the field were found to be identical. Of the two Pestalotiopsis isolates, PE-001 produced a lesion with a larger average diameter in the population compared to PE-002. The severity of the disease observed in the field increased regularly for three years. Bioassays with Pestalotiopsis isolates and field observations revealed no correlation. The classification of genotypes has made it possible to identify classes with both small lesion diameters and low disease severity. Heritability of the lesion diameter was found to be much higher in bioassays than heritability of disease severity observed in the field. The QTLs detected differed between bioassay isolates and field observations. The latter QTLs did not remain stable over time and were no longer detected when disease severity increased in March 2023. The QTLs are associated with long chromosomal regions harbouring many genes associated with the gene ontology terms “molecular function” and “biological process”, the latter being associated with the response to biotic factors. The results of the bioassays confirmed Pestalotiopsis as the agent causing the symptoms of circular disease. This disease has a complex genetic basis which evolves over time.

Mots-clés Agrovoc : Hevea brasiliensis, Pestalotiopsis, résistance aux maladies, variation génétique, maladie des plantes, héritabilité, Corynespora cassiicola, résistance génétique, contrôle de maladies, génotype, feuille, latex

Mots-clés géographiques Agrovoc : Indonésie, Asie

Mots-clés libres : Breeding, Disease resistance, Heritability, Fungal disease, Marker-assisted selection, Quantitative traits loci, Rubber

Classification Agris : H20 - Maladies des plantes
F30 - Génétique et amélioration des plantes

Champ stratégique Cirad : CTS 4 (2019-) - Santé des plantes, des animaux et des écosystèmes

Agences de financement hors UE : Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Agropolis Fondation

Projets sur financement : (FRA) RUbber agroforestry Breeding Initiative for Smallholders, (FRA) Labex AGRO 2011-LBX-002

Auteurs et affiliations

• Darojat Muhamad Rizqi, IRRI [Indonesian Rubber Research Institute] (IDN)
• Kusdiana Alchemi Putri Juliantika, IRRI [Indonesian Rubber Research Institute] (IDN)
• Montoro Pascal, CIRAD-BIOS-UMR AGAP (FRA) - auteur correspondant
• Lopez David, CIRAD-BIOS-UMR AGAP (FRA)
• Oktavia Fetrina, IRRI [Indonesian Rubber Research Institute] (IDN)
• Ismawanto Sigit, CIRAD-BIOS-UMR AGAP (FRA)
• Sudarsono Sudarsono, IPB University (IDN)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/610741/)

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