Breeding for Disease Resistance in Cacao

Gutiérrez, Osman A.; Campbell, Alina; Phillips‐Mora, Wilbert

doi:10.1007/978-3-319-24789-2_18

Cited by 20 publications

(16 citation statements)

References 101 publications

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“…Breeding programs in Ecuador have succeeded in furthering the generation of improved cacao varieties. The foundation of our current knowledge of frosty pod and witches' broom, two devastating cacao diseases, was built upon work done in Ecuador, where Moniliophthora roreri was first identified as the causal agent for frosty pod and where the first reports of witches' broom disease ( Moniliophthora perniciosa ) originated (Evans et al, 1977 ; Gutiérrez et al, 2016 ). The Tropical Experimental Station in Pichilingue was established, in part, to breed for resistance to these and other cacao diseases (Evans et al, 1977 ).…”

Section: Introductionmentioning

confidence: 99%

A Larger Chocolate Chip—Development of a 15K Theobroma cacao L. SNP Array to Create High-Density Linkage Maps

et al. 2017

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Cacao (Theobroma cacao L.) is an important cash crop in tropical regions around the world and has a rich agronomic history in South America. As a key component in the cosmetic and confectionary industries, millions of people worldwide use products made from cacao, ranging from shampoo to chocolate. An Illumina Infinity II array was created using 13,530 SNPs identified within a small diversity panel of cacao. Of these SNPs, 12,643 derive from variation within annotated cacao genes. The genotypes of 3,072 trees were obtained, including two mapping populations from Ecuador. High-density linkage maps for these two populations were generated and compared to the cacao genome assembly. Phenotypic data from these populations were combined with the linkage maps to identify the QTLs for yield and disease resistance.

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Section: Introductionmentioning

confidence: 99%

A Larger Chocolate Chip—Development of a 15K Theobroma cacao L. SNP Array to Create High-Density Linkage Maps

et al. 2017

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“…outbreaks can destroy all cacao fruit on a single farm. Because diseases are a persistent problem for cacao, improvement of disease resistance through breeding (Gutiérrez et al, 2016 ), biocontrol (Ten Hoopen and Krauss, 2016 ), and biotechnology (Guiltinan and Maximova, 2015 ; Mondego et al, 2016 ) approaches are all active areas of research.…”

Section: Introductionmentioning

confidence: 99%

Transient Expression of CRISPR/Cas9 Machinery Targeting TcNPR3 Enhances Defense Response in Theobroma cacao

et al. 2018

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Theobroma cacao, the source of cocoa, suffers significant losses to a variety of pathogens resulting in reduced incomes for millions of farmers in developing countries. Development of disease resistant cacao varieties is an essential strategy to combat this threat, but is limited by sources of genetic resistance and the slow generation time of this tropical tree crop. In this study, we present the first application of genome editing technology in cacao, using Agrobacterium-mediated transient transformation to introduce CRISPR/Cas9 components into cacao leaves and cotyledon cells. As a first proof of concept, we targeted the cacao Non-Expressor of Pathogenesis-Related 3 (TcNPR3) gene, a suppressor of the defense response. After demonstrating activity of designed single-guide RNAs (sgRNA) in vitro, we used Agrobacterium to introduce a CRISPR/Cas9 system into leaf tissue, and identified the presence of deletions in 27% of TcNPR3 copies in the treated tissues. The edited tissue exhibited an increased resistance to infection with the cacao pathogen Phytophthora tropicalis and elevated expression of downstream defense genes. Analysis of off-target mutagenesis in sequences similar to sgRNA target sites using high-throughput sequencing did not reveal mutations above background sequencing error rates. These results confirm the function of NPR3 as a repressor of the cacao immune system and demonstrate the application of CRISPR/Cas9 as a powerful functional genomics tool for cacao. Several stably transformed and genome edited somatic embryos were obtained via Agrobacterium-mediated transformation, and ongoing work will test the effectiveness of this approach at a whole plant level.

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“…The difficulty in this type of reaction is to know whether the absence or presence of symptoms on the plants is associated with host plant genotype, tree age, nutritional and/or environmental factors, or are specifically related to the virulence of a particular strain of the pathogen. In addition, before selecting resistant clones for breeding programs or commercial production, multi-site trials should be conducted to evaluate the stability of the resistance under a wide range of conditions [20].…”

Section: Discussionmentioning

confidence: 99%

Response of Forty (40) High-Producing Cacao Genotypes to Cacao Swollen Shoot Disease

Trebissou¹,

N’Guessan

Tahi

et al. 2020

JEAI

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Aims: Cocoa swollen shoot is a dreaded viral disease that is prevalent in the producing areas of West Africa. In Côte d'Ivoire, it undermines the sustainability of cocoa farming. Integrated pest management based on the use of disease-resistant or disease-tolerant plant material remains a sustainable solution. Place and Duration of Study: Integrated Pest Management Unit against Cocoa swollen shoot, Experimental greenhouse of Bouaflé, National Centre for Agronomic Research (CNRA). Methodology: Forty elite genotypes of cocoa trees selected from different populations in the Reciprocal Recurrent Selection program of Cocoa in Côte d'Ivoire were evaluated against strain D of Cacao Swollen Shoot Virus (CSSV). Five seedlings of each genotype were infected by patch grafting and observed for 5 months. Study Design: Plants are placed in a greenhouse in a completely random arrangement, with five repetitions. Results: Three cocoa genotypes (C77, C87 and C96) were free of disease symptoms and eight genotypes (C77, C87, C96, C3, C12, C26, C53 and C98) had the lowest infection scores. The disease significantly affected plant development and growth. Conclusion: Some genotypes selected within the Reciprocal Recurrent Selection program are promising for breeding against CSSV disease. These eight genotypes will be tested in a field environment to confirm their tolerance.

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Breeding for Disease Resistance in Cacao

Cited by 20 publications

References 101 publications

A Larger Chocolate Chip—Development of a 15K Theobroma cacao L. SNP Array to Create High-Density Linkage Maps

A Larger Chocolate Chip—Development of a 15K Theobroma cacao L. SNP Array to Create High-Density Linkage Maps

Transient Expression of CRISPR/Cas9 Machinery Targeting TcNPR3 Enhances Defense Response in Theobroma cacao

Response of Forty (40) High-Producing Cacao Genotypes to Cacao Swollen Shoot Disease

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