Nematodes of Rhynchophorus palmarum, L. (Coleoptera: Curculionidae), vector of the Red Ring Disease in coconut plantations from the north of the Rio de Janeiro State

Generating the Baseline in the Early Detection of Bud Rot and Red Ring Disease in Oil Palms by Geospatial Technologies

Oil palm cultivation in Ecuador is important for the agricultural sector. As a result of it, the country generates sources of employment in some of the most vulnerable zones; it contributes 0.89% of the gross domestic product and 4.35% of the agricultural gross domestic product. In 2017, a value of USD $252 million was generated by exports, and palm contributed 4.53% of the agricultural gross domestic product (GDP). It is estimated that 125,000 hectares of palm were lost in the Republic of Ecuador due to Red Ring Disease (RRD) and specifically Bud Rot (BR). The current study aimed to generate an early detection of BR and RRD in oil palm. Image acquisition has been performed using Remotely Piloted Aircraft System (RPAS) with Red, Green, and Blue (RGB) cannons, and multispectral cameras, in study areas with and without the presence of the given disease. Hereby, we proposed two phases. In phase A, a drone flight has been conducted for processing and georeferencing. This allowed to obtain an orthomosaic that serves as input for obtaining several vegetation indices of the healthy crop. The data and products obtained from this phase served as a baseline to perform comparisons with plantations affected by BR and RRD and to differentiate the palm varieties that are used by palm growers. In phase B, the same process has been applied three times with an interval of 15 days in an affected plot, in order to identify the symptoms and the progress of them. A validation for the diseases detection has been performed in the field, by taking Global Positioning System (GPS) points of the palms that presented symptoms of BR and RRD, through direct observation by field experts. The inputs obtained in each monitoring allowed to analyze the spatial behavior of the diseases. The values of the vegetation indices obtained from Phase A and B aimed to establish the differences between healthy and diseased palms, with the purpose of generating the baseline of early responses of BR and RRD conditions. However, the best vegetation index to detect the BR was the Visible Atmospherically Resistant Index (VARI).

Improving transcriptome de novo assembly by using a reference genome of a related species: Translational genomics from oil palm to coconut

The palms are a family of tropical origin and one of the main constituents of the ecosystems of these regions around the world. The two main species of palm represent different challenges: coconut (Cocos nucifera L.) is a source of multiple goods and services in tropical communities, while oil palm (Elaeis guineensis Jacq) is the main protagonist of the oil market. In this study, we present a workflow that exploits the comparative genomics between a target species (coconut) and a reference species (oil palm) to improve the transcriptomic data, providing a proteome useful to answer functional or evolutionary questions. This workflow reduces redundancy and fragmentation, two inherent problems of transcriptomic data, while preserving the functional representation of the target species. Our approach was validated in Arabidopsis thaliana using Arabidopsis lyrata and Capsella rubella as references species. This analysis showed the high sensitivity and specificity of our strategy, relatively independent of the reference proteome. The workflow increased the length of proteins products in A. thaliana by 13%, allowing, often, to recover 100% of the protein sequence length. In addition redundancy was reduced by a factor greater than 3. In coconut, the approach generated 29,366 proteins, 1,246 of these proteins deriving from new contigs obtained with the BRANCH software. The coconut proteome presented a functional profile similar to that observed in rice and an important number of metabolic pathways related to secondary metabolism. The new sequences found with BRANCH software were enriched in functions related to biotic stress. Our strategy can be used as a complementary step to de novo transcriptome assembly to get a representative proteome of a target species. The results of the current analysis are available on the website PalmComparomics (http://palm-comparomics.southgreen.fr/).

Mononchoides macrospiculum n. sp. (Nematoda: Neodiplogastridae) and Teratorhabditis synpapillata Sudhaus, 1985 (Nematoda: Rhabditidae): nematode associates of Rhynchophorus ferrugineus (Oliver) (Coleoptera: Curculionidae) in Italy

Several juvenile and adult nematodes were isolated after dissection of pupae and adults of the red palm weevil,Rhynchophorus ferrugineus, recovered from an infestedPhoenix canariensisChabaud exemplar in Bari, Italy. Two species of nematodes were recovered,Teratorhabditis synpapillataandMononchoides macrospiculumn. sp. which is described herein. The mitochondrial cytochrome oxidase I (COI), the ITS-containing region, the 18S rRNA gene (SSU) and the D2-D3 expansion domains of the 28S rRNA gene (LSU) were amplified and sequenced. The new species,M. macrospiculumn. sp., is described at morphological and molecular level. Phylogenetic analyses using SSU and LSU sequences placedM. macrospiculumn. sp. together withM. composticolaandM. striatus. The sequences of the Italian population ofT. synpapillataare identical to those ofT. synpapillatafrom Japan. This is the first report on the association ofM. macrospiculumn. sp. andT. synpapillatawith the red palm weevil in Europe.

Rhyncophorus palmarum L. (Linnaeus, 1758): a morphological and histological study of the female reproductive system

Rhyncophorus palmarum (Coleoptera) is a pest of great economic importance because of the damage caused in the plants of the Palmae family. This study showed that the female reproductive system of this beetle is composed of two ovaries of the telotrophic meroistic type invariably containing two ovarioles per ovary. Each ovariole is home to about 50 oocytes at different stages of maturation. The proximal region of the ovary is rather peculiar because it houses inside it a large quantity of bacilliform structures immersed in a glycolipoprotein substance, which has never before been described in the literature. The function of these structures is still unknown. However, it is suggested that they can function as a method of neutralizing the resistance of the plant because these insects are responsible for the transmission of the red ring disease to the palm plants.