Morfologia e agressividade de isolados de Phytophthora palmivora de cacaueiro no estado da Bahia

Lessa, Irina Zélia Vieira; Luz, Edna Dora Martins Newman; Magalhães, Dilze Maria Argôlo; Bezerra, José Luiz; Pires, José Luís

doi:10.1590/0100-5405/222473

Cited by 7 publications

(4 citation statements)

References 14 publications

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“…The isolates of P. palmivora used were 1744, 1778, 1845, and 1913, obtained from the Arnaldo Medeiros collection at Cepec, originated from cacao pods samples collected in the following counties and years: Uruçuca (2011), Camacan (2011), Mutuípe (2011) and Belmonte (2010), respectively. These isolates were selected based on their high aggressiveness to cacao among 100 P. palmivora isolates tested in previous studies (Lessa, 2017). Healthy leaves of surviving plants from crossings were collected and taken to the laboratory of Phytophthora, where they were sanitized and 15-mm diameter discs were cut from the leaf blade.…”

Section: Assessment Tests For Black Podmentioning

confidence: 99%

Association of genes from different sources of resistance to major cacao diseases

2020

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This study aimed to select genotypes resistant to witches' broom (WB) and black pod (BP), major cacao diseases in Brazil, as well as incorporate resistance genes to moniliasis supplemented by clones EET75 and UF273, forming populations of second-cycle recurrent selection. Moniliophthora perniciosa (2 × 10 5 basidiospores/mL) was inoculated on 30-day-old seedlings from 72 different progenies, being assessed 60 days later, and a mixture of four isolates of Phytophthora palmivora (3 × 10 5 zoospores/mL) was inoculated on leaf discs from 58 progenies, observing lesions after seven days. Significant effects of progeny were observed in the tests of resistance to both diseases (p < 0.05). Scavina-6 expressed resistance to both pathogens, 26 crosses did not differ from free-pollinated progenies of Scavina-6 for WB, and ten crosses were higher and 27 similar for BP. Eight crosses were largely resistant to both diseases.

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Section: Assessment Tests For Black Podmentioning

confidence: 99%

Association of genes from different sources of resistance to major cacao diseases

2020

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“…Here, several isolates were identified as P. palmivora (clade 4), which are widespread throughout the sampling locations in the Bahia state. The production of cocoa beans in Brazil has been affected by P. palmivora since the 1920s (Oliveira and Luz, 2005;Lessa et al, 2020). Southeastern Asia is considered the center of diversity of P. palmivora, but it has been found associated with cacao trees worldwide and also being able to infect several wild and cultivated hosts in South America (Wang et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Seven Phytophthora species have been reported causing black pod disease on cacao, so far, with Phytophthora megakarya, Phytophthora palmivora, Phytophthora capsici, and Phytophthora citrophthora being considered the most important species (Ali et al, 2016;Marelli et al, 2019). In Brazil, P. capsici, P. citrophthora, Phytophthora heveae, and P. palmivora have been associated with high incidence levels of black pod disease, but these Phytophthora species were identified using only morphological comparisons (Luz et al, 2018;Lessa et al, 2020). It has been shown that molecular approaches, associated with morphological data, are required to resolve plant pathogen species complex, and they have revealed previously uncharacterized species affecting different crops (Cooke et al, 2000;Blair et al, 2008;Bezuidenhout et al, 2010;Martin et al, 2014;Jung et al, 2017;Yang et al, 2017;Ruano-Rosa et al, 2018;Yang and Hong, 2018;Alves et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Phytophthora theobromicola sp. nov.: A New Species Causing Black Pod Disease on Cacao in Brazil

et al. 2021

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Black pod disease, caused by Phytophthora species, is among the main limiting factors of cacao (Theobroma cacao L.) production. High incidence levels of black pod disease have been reported in Brazil, being induced by Phytophthora capsici, Phytophthora citrophthora, Phytophthora heveae, and Phytophthora palmivora. To assess the diversity of Phytophthora species affecting cacao in Brazil, 40 new isolates were obtained from cacao pods exhibiting symptoms of black pod disease collected in different smallholder farms in 2017. Further, ten cacao-infecting isolates morphologically identified as P. citrophthora and P. palmivora were molecularly characterized. The genomic regions beta-tubulin, elongation factor 1 alpha, heat shock protein 90, and internal transcribed spacer, and the mitochondrially encoded cytochrome c oxidase I and II genes were PCR-amplified and Sanger-sequenced from the cacao-infecting Phytophthora isolates. The morphological characterization and evaluation of the mycelial growth rates for the Phytophthora isolates were performed in vitro. Based on the molecular analysis and morphological comparisons, 19 isolates were identified as P. palmivora (clade 4). Interestingly, 31 isolates grouped together in the phylogenetic tree and were placed apart from previously known species in Phytophthora clade 2. Therefore, these isolates are considered as a new species herein referred to as Phytophthora theobromicola sp. nov., which produced papillate, semipapillate, and persistent sporangia on simple sporangiophores. The P. palmivora isolates were identified as A1 mating type by pairing each isolate with known A1 and A2 tester strains of P. capsici, but no oogonia/antheridia were observed when P. theobromicola was paired with the different tester strains. The P. theobromicola and P. citrophthora isolates showed higher mycelial growth rates, when compared to P. palmivora, on different media at 10, 15, and 20°C, but similar values were observed when grown on clarified CA media at 25 and 30°C. The pathogenicity tests carried out on pods of four cacao clones (CCN51, PS1319, Cepec2004, and CP49) showed significant variability among the isolates of both Phytophthora species, with P. theobromicola inducing higher rates of necrotic lesion expansion, when compared to P. palmivora. Here, two Phytophthora species were found associated with black pod disease in the state of Bahia, Brazil, and the previously undescribed P. theobromicola seems to be prevalent in field conditions. This is the first report of P. theobromicola on T. cacao. Also, these findings are crucial to improve the disease control strategies, and for the development of cacao materials genetically resistant to Phytophthora.

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“…Genetic material can influence the level of aggression of Phytophthora species, considering that the most aggressive isolates likely prevailed in the field owing to the variations incurred over the years (Lessa et al 2020). Rodrigues et al (2020) selected plants from progenies of five genetic crosses (CSUL3 × CCN10, CAB301 × CCN10, MO20 × CCN34, CAB148 × MO20, and CAB157 × MO20) as maternals for the second cycle of recurrent selection, which LSMEANS_SAS (1990).…”

Section: E Santos Et Almentioning

confidence: 99%

Cacao parents help their offsprings to fight witches’ broom and black pod rot infections

Santos

Pires

Monteiro

et al. 2022

Crop Breed. Appl. Biotechnol.

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Searching for new approaches to confer resistance to diseases in plants is one of the main objectives of the Cacao breeding program (CBP). Witches' broom (WB) and black pod rot (BPR) are important cacao diseases in Bahia,Brazil. This study aimed to evaluate the resistance in plants from 40 progenies of genetic crosses between elite clones to natural infection by high levels of Moniliophthora perniciosa and Phytophthora spp. WB and BPR infection assessments were conducted in the field, including evaluation of vegetative brooms (VB), cushion brooms (CB), and total brooms (TB), as well as the percentage of WB-diseased (FRUWB) and BPR-diseased (FRUBPR) fruits. Ten progenies showed resistance to infection in both the canopy and fruits. No significant differences between the progenies were detected for FRUBPR.

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Morfologia e agressividade de isolados de Phytophthora palmivora de cacaueiro no estado da Bahia

Cited by 7 publications

References 14 publications

Association of genes from different sources of resistance to major cacao diseases

Association of genes from different sources of resistance to major cacao diseases

Phytophthora theobromicola sp. nov.: A New Species Causing Black Pod Disease on Cacao in Brazil

Cacao parents help their offsprings to fight witches’ broom and black pod rot infections

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