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The plant species Cedrela odorata has been largely exploited in the timber industry due to the high demand for its wood. Therefore, C. odorata has been considered a vulnerable species since 1994, under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). C. odorata is a key timber species included in the management and conservation plans for the Amazon and Central American rainforests. These plans include the development of genetic and genomic resources to study local populations of the species in Colombia. In this study, two novel chloroplast (cp) genomes were assembled and annotated using the MinION long-read sequencing technology. The new cp genomes were screened for sequence variants (SVs), and a total of 16 SNPs were identified, presumably unique to populations from the Amazon region in Colombia. Comparative genomics with other reported cp genomes from different populations of C. odorata support the hypothesis of intraspecific diversity associated with their place of origin. These cp genome sequences of C. odorata from Colombian individuals represent valuable genomic resources for the species, suitable for identifying novel DNA fingerprinting and barcoding applications. [ABSTRACT FROM AUTHOR]

Fusarium wilt of banana, caused by the pathogen Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), is a threat to food security as it affects the global banana industry. Control of this pathogen is complex due to the lack of resistant banana or plantain genotypes, lack of effective commercial fungicides, the production of chlamydospores, late appearance of symptoms in infected plants, high adaptability of the pathogen to diverse soil conditions and the polycyclic nature of the disease. Currently, the management strategy for Foc TR4 is exclusion and eradication, which is costly for the producer and the environment because the plants are treated with glyphosate and the affected area is quarantined for a long time. Thus, the development of early detection strategies for Foc TR4 from environmental samples and asymptomatic tissues with low inoculum concentration is essential; this would enable restriction of pathogen spread and minimize the environmental impact by eradication only in areas with accurate data of the pathogen's presence. In this study, three different PCR technologies (conventional PCR, quantitative PCR and droplet digital [dd] PCR) were evaluated for Foc TR4 detection in complex environmental samples. We report the development of a sensitive and specific ddPCR primer/probe set and protocols that can be used as a tool for Foc TR4 detection from symptomatic and asymptomatic plant tissue without prior DNA extraction. The limits of detection in drainage waters, footbaths and soil samples were evaluated using artificial inoculation assays. Finally, environmental samples from Foc TR4‐affected fields were analysed. [ABSTRACT FROM AUTHOR]

In this article, we describe the presence of genes encoding close homologues of an endogenous plant peptide, rapid alkalinization factor (RALF), within the genomes of 26 species of phytopathogenic fungi. Members of the RALF family are key growth factors in plants, and the sequence of the RALF active region is well conserved between plant and fungal proteins. RALF1-like sequences were observed in most cases; however, RALF27-like sequences were present in the Sphaerulina musiva and Septoria populicola genomes. These two species are pathogens of poplar and, interestingly, the closest relative to their respective RALF genes is a poplar RALF27-like sequence. RALF peptides control cellular expansion during plant development, but were originally defined on the basis of their ability to induce rapid alkalinization in tobacco cell cultures. To test whether the fungal RALF peptides were biologically active in plants, we synthesized RALF peptides corresponding to those encoded by two sequenced genomes of the tomato pathogen Fusarium oxysporum f. sp. lycopersici. One of these peptides inhibited the growth of tomato seedlings and elicited responses in tomato and Nicotiana benthamiana typical of endogenous plant RALF peptides (reactive oxygen species burst, induced alkalinization and mitogen-activated protein kinase activation). Gene expression analysis confirmed that a RALF-encoding gene in F. oxysporum f. sp. lycopersici was expressed during infection on tomato. However, a subsequent reverse genetics approach revealed that the RALF peptide was not required by F. oxysporum f. sp. lycopersici for infection on tomato roots. This study has demonstrated the presence of functionally active RALF peptides encoded within phytopathogens that harbour an as yet undetermined role in plant-pathogen interactions. [ABSTRACT FROM AUTHOR]