Fruitlet Core Rot Research Articles

Potential use of thymol to control fruitlet core rot (FCR) in pineapple cultivar ‘Queen Victoria’ in Reunion Island

Potential use of thymol to control fruitlet core rot (FCR) in pineapple cultivar ‘Queen Victoria’ in Reunion Island

Modulation of Growth and Mycotoxigenic Potential of Pineapple Fruitlet Core Rot Pathogens during In Vitro Interactions.

Pineapple Fruitlet Core Rot (FCR) is a fungal disease characterized by a multi-pathogen pathosystem. Recently, Fusarium proliferatum, Fusarium oxysporum, and Talaromyces stollii joined the set of FCR pathogens until then exclusively attributed to Fusarium ananatum. The particularity of FCR relies on the presence of healthy and diseased fruitlets within the same infructescence. The mycobiomes associated with these two types of tissues suggested that disease occurrence might be triggered by or linked to an ecological chemical communication-promoting pathogen(s) development within the fungal community. Interactions between the four recently identified pathogens were deciphered by in vitro pairwise co-culture bioassays. Both fungal growth and mycotoxin production patterns were monitored for 10 days. Results evidenced that Talaromyces stollii was the main fungal antagonist of Fusarium species, reducing by 22% the growth of Fusarium proliferatum. A collapse of beauvericin content was observed when FCR pathogens were cross-challenged while fumonisin concentrations were increased by up to 7-fold. Antagonism between Fusarium species and Talaromyces stollii was supported by the diffusion of a red pigmentation and droplets of red exudate at the mycelium surface. This study revealed that secondary metabolites could shape the fungal pathogenic community of a pineapple fruitlet and contribute to virulence promoting FCR establishment.

Economically Imperative Ananas comosus Diseases, Status, and Its Control Measures Documented in Producing Countries

Ananas comosus, commonly known as pineapple, is a fruit with a large potential market as a commodity and commercial fruit. Numerous pests and diseases affect pineapple, directly or indirectly, by lowering the quality and quantity. The fungal causative agents, namely Fusarium ananatum and Thalaromyces stolii (previously named Penicillium funiculosum), cause fruitlet core rot (FCR) and fusariosis by Fusarium guttiforme. Bacteria heart rot (BHR) is an infection by Erwinia chrysanthemi, newly known as Dickeya zeae. Nevertheless, the mealybug wilt of pineapple (MWP) is another pineapple treat to susceptible pineapple varieties caused by pineapple mealybug wilt-associated viruses (PMWaVs). Other diseases include destruction caused by pathogenic nematodes. This review discusses the status of these diseases and the control measures that greatly affect the economy of pineapple-producing countries due to the economic significance of these crops. Growers need up-to-date information on the identity of the diseases that affect pineapple crops in the various countries that produce them to effectively manage the diseases in the field.

Rapid identification and characterization of pineapple fruitlet core rot pathogens on the ‘TN20’ cultivar in Taiwan

Rapid identification and characterization of pineapple fruitlet core rot pathogens on the ‘TN20’ cultivar in Taiwan

A review of common diseases of pineapple: the causal pathogens, disease symptoms, and available control measures

Pineapple is a perennial fruit-bearing tropical plant that belongs to the Bromeliaceae family, which has more than 2500 species. Pineapple is known excellent source of minerals and vitamins. It produces substantial calcium, potassium, glucose, the proteindigesting enzyme bromelain, fibre, vitamin A, B and C. In Malaysia, twelve registered varieties of pineapple have been introduced and commercially planted such as Moris (AC1), Sarawak (AC2), Gandul (AC3), Maspine (AC4), Josapine (AC5) Yankee (AC6) Moris Gajah (AC7), N36 (AC8), MD2 (AC9), View of Sunset (AC10), Madu Kaca (AC11), and Keningau Diamond (AC12). The disease is one of the important factors that can contribute to the huge losses of pineapple yield worldwide. This review paper aimed to discuss the main diseases of pineapple and their control management, particularly in Malaysia. The common diseases of pineapple that cause significant yield losses in the farms such as mealybug wilt-associated virus, bacterial heart rot, fruit collapse, butt rot, fruitlet core rot, black rot, yeasty and fusariosis are highlighted and discussed in detail on the causal pathogens, disease symptoms and signs, disease infection and development. The available control measures for managing pineapple diseases were also included in this paper.

Exploration of microbial communities associated with fruitlet core rot (FCR) disease in ‘Queen’ pineapple from Reunion Island

Exploration of microbial communities associated with fruitlet core rot (FCR) disease in ‘Queen’ pineapple from Reunion Island

Diagnostic survey on the occurrence of pineapple fruitlet core rot and relationship with phenolic compounds in Réunion Island

ISHS IV International Symposium on Postharvest Pathology: Next Generation Innovation and Commercial Solutions for Postharvest Pathology to Reduce Losses, Enhance Quality, and Ensure Product Safety Diagnostic survey on the occurrence of pineapple fruitlet core rot and relationship with phenolic compounds in Réunion Island

Pineapple Mycobiome Related to Fruitlet Core Rot Occurrence and the Influence of Fungal Species Dispersion Patterns.

Fruitlet Core Rot (FCR) is a fungal disease that negatively impacts the quality of pineapple, in particular the ‘Queen Victoria’ cultivar. The main FCR causal agent has been identified as Fusarium ananatum. This study focused on the correlation between FCR disease occurrence, fungal diversity, and environmental factors. FCR incidence and fungal species repartition patterns were spatially contextualized with specific surrounding parameters of the experimental plots. The mycobiome composition of healthy and diseased fruitlets was compared in order to search for potential fungal markers. A total of 240 pineapple fruits were sampled, and 344 fungal isolates were identified as belonging to 49 species among 17 genera. FCR symptom distribution revealed a significant gradient that correlated to that of the most abundant fungal species. The association of wind direction and the position of proximal cultivated crops sharing pathogens constituted an elevated risk of FCR incidence. Five highly represented species were assayed by Koch’s postulates, and their pathogenicity was confirmed. These novel pathogens belonging to Fusarium fujikuroi and Talaromyces purpureogenus species complexes were identified, unravelling the complexity of the FCR pathosystem and the difficulty of apprehending the pathogenesis over the last several decades. This study revealed that FCR is an airborne disease characterized by a multi-partite pathosystem.

Diversity and Toxigenicity of Fungi that Cause Pineapple Fruitlet Core Rot.

The identity of the fungi responsible for fruitlet core rot (FCR) disease in pineapple has been the subject of investigation for some time. This study describes the diversity and toxigenic potential of fungal species causing FCR in La Reunion, an island in the Indian Ocean. One-hundred-and-fifty fungal isolates were obtained from infected and healthy fruitlets on Reunion Island and exclusively correspond to two genera of fungi: Fusarium and Talaromyces. The genus Fusarium made up 79% of the isolates, including 108 F. ananatum, 10 F. oxysporum, and one F. proliferatum. The genus Talaromyces accounted for 21% of the isolated fungi, which were all Talaromyces stollii. As the isolated fungal strains are potentially mycotoxigenic, identification and quantification of mycotoxins were carried out on naturally or artificially infected diseased fruits and under in vitro cultures of potential toxigenic isolates. Fumonisins B1 and B2 (FB1-FB2) and beauvericin (BEA) were found in infected fruitlets of pineapple and in the culture media of Fusarium species. Regarding the induction of mycotoxin in vitro, F. proliferatum produced 182 mg kg⁻1 of FB1 and F. oxysporum produced 192 mg kg⁻1 of BEA. These results provide a better understanding of the causal agents of FCR and their potential risk to pineapple consumers.

Culture medium for improved production of conidia for identification and systematic studies of Fusarium pathogens

Fusarium guttiforme and Fusarium ananatum are the etiological agents of fusariosis and fruitlet core rot in pineapple, respectively, producing mycotoxins that are harmful to the health of consumers. These two fungi are morphologically similar and difficulty in obtaining macroconidia of the species limits their identification. Different types of media are available for the culture of these pathogens, but not all of them favor F. ananatum and F. guttiforme macroconidia production. Therefore, the objective of this study was to develop a simple culture medium to improve rapid macro- and microconidia formation in both F. guttiforme and F. ananatum to facilitate taxonomic, pathogenicity and mycotoxin studies. In vitro analysis showed that basal medium with carboxymethyl cellulose (CMC) was better than other media tested with the highest macroconidia production at 7 days of incubation. The highest production of microconidia was with synthetic nutrient medium (SN) at 7 days. F. ananatum produced a relatively high number of microconidia with one septum in comparison to F. guttiforme when cultured in CMC, which suggests an additional character useful for Fusarium taxonomy. CMC medium may serve as an improved alternative to culture media currently used in Fusarium research and contribute to further knowledge of the taxonomy and mycotoxins of Fusarium species.

Potential Use of Essentials Oils to Control Fruitlet Core Rot (FCR) in Pineapple (Queen Victoria Variety) in Reunion Island

Fruitlet Core Rot (FCR) is one of the major postharvest diseases of pineapple (Ananas comosus var. comosus), especially on the prone variety Queen Victoria cultivated in Reunion Island. This aggressive disease is generally due to two pathogens: Fusarium ananatum and Thalaromyces stolii, and needs to be controlled during postharvest. In Reunion Island, F. ananatum is the principal causal agent impacting fruit exportation. Fruit produced for the export market is generally treated with chemicals. This type of postharvest treatment is not in line with consumer expectations, as consumers prefer fruits treated with nonharmful and natural products. The objective of this work was to study alternative postharvest treatments using the fungitoxic properties of essential oils and their ability to elicit the resistance mechanisms of the fruit. Six EAs were tested in vitro on mycelial growth of F. ananatum. Whether by volatilization or included in the culture medium, some essential oils such as thymol, eugenol, geraniol and the carvone/menthol mixture have a strong fungistatic effect. But only thymol has a fungitoxic effect. The thymol, a natural molecule synthesized by thyme (Thymus vulgaris L. thymoliferum) is the more effective in vitro and is the strongest potential to be used in postharvest treatment. Thymol, prepared at 0.025% in a terpene solvent that acts as a penetrating agent, was tested in vivo with inoculated fruits. The treatment was effective only on necrosis development from the upper part of the fruits. Pineapple polyphenol biosynthesis appears to have been suppressed by thymol treatment. Results and opportunities for this treatment are discussed. Additional experiments must be carried out in order to decide on the advisability of this type of treatment.

An Imaging Approach to Identify Mechanisms of Resistance to Pineapple Fruitlet Core Rot.

Fruitlet core rot is one of the major postharvest disease of pineapple (Ananas comosus var. comosus). In the past, control strategies were designed to eliminate symptoms without addressing their causes or mechanisms, thus achieving only moderate success. In this study, (i) we focused on the anatomy of the fruitlets in the resistant “MD-2” and susceptible “Queen” pineapple cultivars; (ii) we identified the key role of the carpel margin in the infection process; (iii) we identified the key role of the sinuous layer of thick-walled cells in the inhibition of Fusarium ananatum colonization; and (iv) we linked the anatomy of the fruitlets with the phenolic content of cell walls. The fruitlet anatomy of the two cultivars was studied using X-ray, fluorescence, and multiphoton microscopy. Sepals and bracts were not perfectly fused with each other, allowing the pathogen to penetrate the fruit even after flowering. In fact, the fungi were found in the blossom cups of both cultivars but only became pathogenic in the flesh of the “Queen” pineapple fruit under natural conditions. The outer layer of the “MD-2” cavity was continuous with thick cell walls composed of ferulic and coumaric acids. The cell walls of the “Queen” blossom cup were less lignified at the extremities, and the outer layer was interspersed with cracks. The carpel margins were fused broadly in the “MD-2” pineapple, in contrast to the “Queen” pineapple. This blemish allows the fungus to penetrate deeper into the susceptible cultivar. In pineapple fruitlets, the hyphae of F. ananatum mainly progressed directly between cell walls into the parenchyma but never reached the vascular region. A layer of thick-walled cells, in the case of the resistant cultivar, stopped the colonization, which were probably the infralocular septal nectaries. Anatomical and histochemical observations coupled with spectral analysis of the hypodermis suggested the role of lignin deposition in the resistance to F. ananatum. The major phenolics bound to the cell walls were coumaric and ferulic acids and were found in higher amounts in the resistant cultivar postinoculation. The combination of fruitlet anatomy and lignification plays a role in the mechanism of host resistance to fruitlet core rot.

Coumaroyl-isocitric and caffeoyl-isocitric acids as markers of pineapple fruitlet core rot disease

Introduction – Fruitlet core rot is the major postharvest disease affecting 'Queen' pineapple in La Reunion island. The symptoms are black spots located in the pineapple fruitlets. Materials and methods – Fusarium ananatum, the main causal agent of fruitlet core rot was inoculated in 'MD-2' and 'Queen' (Victoria), a tolerant and a susceptible cultivar, respectively. A metabolomics approach to healthy and inoculated fruitlets allowed to determine which putative metabolites are involved in fruitlet core rot disease. The evolution of fruitlet core rot was then followed-up with a focus on the phenolic compounds. Results and discussion – Based on the metabolomics results, the phenolic compounds seemed to be determining markers of black spots. Coumaroylisocitrate and caffeoylisocitrate dramatically increased in the infected fruitlets in both cultivars post-inoculation. The 'MD-2'-infected fruitlets reached higher hydroxycinnamic acid levels in a shorter time than those of the 'Queen'-infected fruitlets. In healthy fruits of 'MD-2', coumaroyl-isocitric acid and hydroxybenzoic acids were naturally produced as the fruit mature. Conclusion – These phenolic compounds play a major role in the pineapple disease resistance.

Evaluating the response to Fusarium ananatum inoculation and antifungal activity of phenolic acids in pineapple

Fusarium ananatum causes fruitlet core rot (FCR) in pineapple (Ananas comosus var. comosus) when the fruit reaches maturity. Hidden symptoms make it difficult to assess the disease, regardless of its stage, and basic questions concerning the involvement of the phenolic compounds in response to infection remain unknown. A direct inoculation method of F. ananatum in pineapple fruitlets was developed to monitor the growth of black spots and the changes in phenolic acids and ascorbic acid concentration under controlled conditions. After inoculation, infection began with a flesh discolouration at the inoculation point and then spread in a darker shade to form a black spot. Coumaroyl-isocitric and caffeoyl-isocitric acids levels respectively showed a 150- and 200-fold increase in infected fruitlet when compared to healthy fruitlet. These hydroxycinnamic acids increased minimally in the adjacent fruitlet and remained stable in the other parts of the fruit. By contrast, sinapic acid and hydroxybenzoic acid isomers (HBA) decreased after F. ananatum inoculation in the infected fruitlet, whereas they remained stable in the adjacent and healthy fruitlets. Ascorbic acid decreased to zero in the infected fruitlet. The antifungal activity of phenolic compounds and ascorbic acid was evaluated against the mycelial growth of F. ananatum. p-Coumaric acid exhibited a total inhibition of the mycelial growth at 1000 μg g−1. Ferulic acid inhibited 64 % of mycelial growth at a concentration of 1000 μg g−1. Caffeoylquinic acid, sinapic acid, and ascorbic acid also showed significant antifungal activity, but to a lesser extent. Finally, coinoculation of the hydroxycinnamic acids with the pathogen restrains its development in the fruit. This is the first study to highlight the involvement of phenolic compounds in the pineapple FCR disease.

First Report of Fusarium ananatum Causing Pineapple Fruitlet Core Rot in China

First Report of <i>Fusarium ananatum</i> Causing Pineapple Fruitlet Core Rot in China

A predictive model based on a pluviothermic index for leathery pocket and fruitlet core rot of pineapple cv. ‘Queen’

Leathery pocket (LP) and fruitlet core rot (FCR) of pineapple (Ananas comosus L.) caused by Penicillium funiculosum Thom. and/or Fusarium moniliforme Sheld cause significant damage in all production areas, resulting in a major economic impact that affects both the fresh fruit market and the processing sector. The detection of Penicillium and Fusarium in the two main areas of pineapple production in Reunion Island, and representing a large range of climatic conditions, indicated that these fungi responsible for FCR and LP diseases were present throughout the pineapple cycle, whatever the climatic conditions. The proportion of fruits naturally infected by these pathogens was not related to climatic conditions during the infection period, suggesting that the inoculum level was not limiting. As these diseases cannot be reliably controlled, due in particular to the role of climatic conditions, an important research goal is to predict periods of higher disease risk using a model based on weather data. Taking advantage of the great diversity of environments on the tropical island of Reunion (Indian Ocean), we were able to establish a link between a pluviothermic index (PTi: ratio between total rainfall and the average temperature over the fruit development stages), and LP or FCR incidence. Disease incidence was modelled as a function of the pluviothermic index via a Weibull model. The most accurate model was obtained during the open heart to harvest stage. Lastly, the model output can be used by pineapple production stakeholders in farm management strategies and to adapt fruit grading before marketing.

ON FARM APPROACH OF PINEAPPLE FRUITLET CORE ROT DISEASE IN MARTINIQUE

Fruitlet Core Rot is one on the main disease that affects pineapple fruit development in the world. However, factors promoting the disease are not well known. A large survey, including soil, climatic, physiological and pathological variables at a field scale, and including spatial heterogeneity and temporal variability, was designed and conducted in the pineapple production area in Martinique. This on farm-approach allowed the identification and specification of the main factors responsible for the disease. Fruit sampling analysis revealed the Penicillium funiculosum was involved in 95 % of the observer cases. However, although P. funiculosum was widespread in the soils of the survey, no quantitative relation was established between the quantity of inoculum in the soil or on the plant and the development of P. funiculosum in fruits. Fruit observations at harvest time showed a high level of variation between fruits within a field. However, significant correlations between the percentage of infected fruits within a field, the average number of spots per fruit and their size were established. A global analysis of the data showed that average ascorbic acid content in fruits at harvest is negatively linked with the percentage of infected fruits. The nutritional status of the plants, especially low levels of calcium and magnesium, and/or high levels of nitrogen, is also a significant promoting factor for the development of the disease. It is concluded that Fruitlet Core Rot in Martinique is promoted by a combination of factors which determine the sensitivity of fruits. Climatic conditions before harvest, acid content, and nutritional status are the main factors. (Resume d'auteur)

THE EU-FUNDED PROJECT ‘EVALUATION AND UTILIZATION OF PINEAPPLE GENETIC RESOURCES FROM THE AMAZON TO BREED RESISTANT VARIETIES’

This project aims at obtaining knowledge and tools for the development of varieties resistant to the main diseases in South America, by (i) characterising and evaluating available genetic resources (botanical and agromorphological description, nuclear and cytoplasmic DNA characterisation), (ii) studying the genetic structure of the genus Ananas, (iii) developing and applying resistance screening techniques for important diseases in the region (fusariosis, fruitlet core rot, thecla, and nematodes), (iv) studying the heredity of agronom.ic traits, and (v) testing the potential of partial inbreds in breeding. In addition, the establishment of a standard database will promote information and germplasm exchange between the partners, and, later, between all the existing pineapple germplasm collections. The project, which started in 1997, has produced a first germplasm inventory, allowing exchanges and repatriation of lost germplasm. The list of descriptors has been revised. Multivariate analysis of the first morphological description produced consistent results. Molecular markers are being developed for characterisation and genetic mapping. New sources of resistance to fusariosis have been identified. Characterisation studies will provide key information to assess the genetic diversity of pineapple and understand its structure. The project will favour new uses of neglected or traditional varieties, so widening the genetic base of pineapple cultivation. The development of new breeding schemes associated with genetic mapping should greatly improve breeding efficiency, allowing transferring resistances and thence promoting integrated and more environmentally friendly control of pests and diseases. (Resume d'auteur)

Field Induction of Pineapple Interfruitlet Corking, Leathery Pocket, and Fruitlet Core Rot with Penicillium funiculosum

Field Induction of Pineapple Interfruitlet Corking, Leathery Pocket, and Fruitlet Core Rot with Penicillium funiculosum