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Orchard and garden papaya crops grown in 47 Cuban municipalities were surveyed from 2008 to 2013, revealing the widespread distribution of papaya ringspot virus (PRSV) in Cuba. Phylodynamic analyses performed with the partial coat protein gene of all Cuban PRSV‐P isolates (34 sequences) and 107 sequences of isolates from the American continent and the Caribbean islands showed a most recent common ancestor in 1942 (95% highest posterior density, HPD 95% = 1911–1967). The substitution rate was estimated to be 7.7 × 10−4 substitutions per site per year (HPD 95% = 4.6 × 10−4 to 1.1 × 10−3), which is equivalent to those detected in other RNA viruses. Demographic reconstruction of PRSV showed that viral diversity increased in the 1985–1990 period, which coincides with the implementation of extensive production practices. Moreover in Cuba, viral dispersion occurred from Mexico and other unknown ancestral locations. The spatiotemporal diffusion analysis proposed Mexico as an ancestral area for the origin of diversification in the American continent and suggests new dispersion events between American and Caribbean isolates. The observed widespread distribution, clear geographic grouping of Cuban isolates, virus growth and genetic diversity provide strong evidence of the PRSV dispersion patterns, which has implications for the control strategies of PRSV. [ABSTRACT FROM AUTHOR]

Dasheen mosaic virus (DMV) is distributed in the tropical and subtropical regions where several genus and species of dasheen are cultivated. This virus produces symptoms on the Xanthosoma genus that vary from an intense mosaic to the deformation of the leaves, causing an evident reduction of photosynthetic pigments. The objective of this work was to determine the affectations caused by this virus on the chlorophyll content in dasheen plants Xanthosoma nigrum genotype INIVIT M 95-1. The chlorophyll «a», chlorophyll «b» and the total chlorophyll contents were determined spectrophotometrically at 645 and 663 nm. Based on fresh weight, the total chlorophyll concentration in healthy and diseased samples was 2,180 and 1,245 mg.g-1 respectively. Infected plants with intense damages showed a significant reduction in the content of pigments in leaves. The loss of pigments in the affected plants can reduce the efficiency in the production of carbon hydrates during the photosynthesis and the subsequent reduction of the yields. [ABSTRACT FROM AUTHOR]

Potyvirus diseases are one of the main challenges facing the production of yam ( Dioscorea spp.). The objective of this study was to identify the potyviruses present in the Dioscorea spp. germplasm collection at Instituto de Investigaciones de Viandas Tropicales (INIVIT) to establish methodologies for the characterization of the associated diseases. For this purpose, immunochemical and molecular methods were used to identify the potyviruses present. The symptomatology of Dioscorea spp. at INIVIT's germplasm collection was described. In addition, the severity and incidence in the germplasm collection and production areas were evaluated. As a result, the first report of yam mosaic virus ( Potyvirus yamtesselati ) and yam mild mosaic virus ( Potyvirus yamplacidum ) in Cuba is presented. The existence of resistant, tolerant, and susceptible cultivars to potyvirus-associated diseases in the germplasm collection was detected, and the incidence of these diseases was higher than 64% in the production areas evaluated. This study represents a step forward in the establishment of certification programs for propagating material of Dioscorea spp. in Cuba.

An emerging virus isolated from papaya ( Carica papaya ) crops in northwestern (NW) Argentina was sequenced and characterized using next-generation sequencing. The resulting genome is 6667-nt long and encodes five open reading frames in an arrangement typical of other potexviruses. This virus appears to be a novel member within the genus Potexvirus . Blast analysis of RNA-dependent RNA polymerase (RdRp) and coat protein (CP) genes showed the highest amino acid sequence identity (67% and 71%, respectively) with pitaya virus X. Based on nucleotide sequence similarity and phylogenetic analysis, the name papaya virus X is proposed for this newly characterized potexvirus that was mechanically transmitted to papaya plants causing chlorotic patches and severe mosaic symptoms. Papaya virus X (PapVX) was found only in the NW region of Argentina. This prevalence could be associated with a recent emergence or adaptation of this virus to papaya in NW Argentina.

Leucaena leucocephala represents a local protein source in tropical ruminant diets. However, its full exploitation is impaired by mimosine, unless it is degraded by the rumen microbial community. Recently, the ruminal bacterial communities of newborns were persistently modified through prenatal or postnatal dietary interventions. Such early-life interventions might enhance adaptation of ruminants to Leucaena leucocephala , which was investigated using a 2 × 2 factorial design trial that tested both supplementation of L. leucocephala in the late pregnancy diet of goat does, and supplementation of live yeast to their newborns. The composition of ruminal bacteria, immune status, as well as organic matter digestibility (OMD) and performance of kids were studied during and after the intervention. Ten pregnant goats were divided into two groups: the D+ and D- groups, which either received or did not receive 30 g of L. leucocephala forage meal during the last 7 ± 0.5 weeks of gestation. Twins from each goat were divided into the K+ and K- group (supplemented with or without 0.2 g/d of live yeast from day 3 until weaning at 8 weeks). Rumen samples were collected from 4-, 8-, 14-, and 20-weeks old kids to assess the bacterial community, while immune parameters (white blood cells, immunoglobulin M and G, and chitotriosidase activity) were measured in blood and saliva sampled at 4-, 8-, and 20-weeks. We found a stimulatory effect of the prenatal exposure on the post-weaning dry matter intake of the L. leucocephala supplemented diet, resulting in a higher daily gain and final body weight at 20 weeks in the D+ vs . D- group (406 vs . 370 g DM/d, 85.4 vs. 78.6 g/d, and 15.2 vs. 13.8 kg, respectively). Moreover, Ruminococcus represented a greater proportion of the rumen bacterial community of the D+ vs. D- kids (5.1 vs. 1.6%). Differences in the immune status were relatively small and not thought to be a driving factor of differences in animal performance. Furthermore, postnatal supplementation of live yeast favored maturation of the rumen bacterial community (i.e., greater abundance of Bacteroidetes, in particular Prevotella , and reduced abundance of Firmicutes) and protozoa colonization. Concomitantly, OMD was enhanced post-weaning, suggesting effects of the early-life intervention persisted and could have affected animal performance., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Artiles-Ortega, Portal, Jeyanathan, Reguera-Barreto, de la Fé-Rodríguez, Lima-Orozco and Fievez.)

The aim of this study was to evaluate the natural occurrence of Beauveria spp. in soil, from infections in the stink bug Piezodorus guildinii, an important pest of common bean (Phaseolus vulgaris) and as endophytes in bean plant tissue. Twelve conventional and 12 organic common bean fields in the Villa Clara province, Cuba were sampled from September 2014 to April 2015. One hundred and fifty Beauveria isolates were obtained from soil samples, bean plant parts and stink bugs. The overall frequency of occurrence of Beauveria isolates in conventional fields (8.4%) was significantly lower than that in organic fields (23.6%). Beauveria were also obtained significantly more frequently from bean roots in organic fields (15.0%) compared to bean roots in conventional fields (3.3%). DNA sequencing of the intergenic Bloc region was performed for Beauveria species identification. All isolates where characterized as Beauveria bassiana (Balsamo-Crivelli) Vuillemin, and clustered with isolates of neotropical origin previously described as AFNEO_1. The Cuban B. bassiana isolates formed five clusters in the phylogeny. Isolates of two clusters originated from all four locations, organic and conventional fields, as well as soil, plants and stink bugs. Organic fields contained isolates of all five clusters while conventional fields only harbored isolates of the two most frequent ones. Mating type PCR assays revealed that mating type distribution was skewed, with MAT1/MAT2 proportion of 146/4, indicating limited potential for recombination. The present study is the first to report of B. bassiana as a naturally occurring endophyte in common bean. Further, it shows that B. bassiana occurs naturally in diverse environments of common bean fields, and constitutes a potential reservoir of natural enemies against pest insects particularly in organic fields., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Brown rust caused by the fungus Puccinia melanocephala is a major disease of sugarcane (Saccharum spp.). A sugarcane mutant, obtained by chemical mutagenesis of the susceptible variety B4362, showed a post-haustorial hypersensitive response (HR)-mediated resistance to the pathogen and was used to identify genes differentially expressed in response to P. melanocephala via suppression subtractive hybridization (SSH). Tester cDNA was derived from the brown rust-resistant mutant after inoculation with P. melanocephala, while driver cDNAs were obtained from the non-inoculated resistant mutant and the inoculated susceptible donor variety B4362. Database comparisons of the sequences of the SSH recombinant clones revealed that, of a subset of 89 non-redundant sequences, 88% had similarity to known functional genes, while 12% were of unknown function. Thirteen genes were selected for transcript profiling in the resistant mutant and the susceptible donor variety. Genes involved in glycolysis and C4 carbon fixation were up-regulated in both interactions probably due to disturbance of sugarcane carbon metabolism by the pathogen. Genes related with the nascent polypeptide associated complex, post-translational proteome modulation and autophagy were transcribed at higher levels in the compatible interaction. Up-regulation of a putative L-isoaspartyl O-methyltransferase S-adenosylmethionine gene in the compatible interaction may point to fungal manipulation of the cytoplasmatic methionine cycle. Genes coding for a putative no apical meristem protein, S-adenosylmethionine decarboxylase, non-specific lipid transfer protein, and GDP-L-galactose phosphorylase involved in ascorbic acid biosynthesis were up-regulated in the incompatible interaction at the onset of haustorium formation, and may contribute to the HR-mediated defense response in the rust-resistant mutant.

Mycosphaerella fijiensis, a hemibiotrophic fungus, is the causal agent of black leaf streak disease, the most serious foliar disease of bananas and plantains. To analyze the compatible interaction of M. fijiensis with Musa spp., a suppression subtractive hybridization (SSH) cDNA library was constructed to identify transcripts induced at late stages of infection in the host and the pathogen. In addition, a full-length cDNA library was created from the same mRNA starting material as the SSH library. The SSH procedure was effective in identifying specific genes predicted to be involved in plant-fungal interactions and new information was obtained mainly about genes and pathways activated in the plant. Several plant genes predicted to be involved in the synthesis of phenylpropanoids and detoxification compounds were identified, as well as pathogenesis-related proteins that could be involved in the plant response against M. fijiensis infection. At late stages of infection, jasmonic acid and ethylene signaling transduction pathways appear to be active, which corresponds with the necrotrophic life style of M. fijiensis. Quantitative PCR experiments revealed that antifungal genes encoding PR proteins and GDSL-like lipase are only transiently induced 30 days post inoculation (dpi), indicating that the fungus is probably actively repressing plant defense. The only fungal gene found was induced 37 dpi and encodes UDP-glucose pyrophosphorylase, an enzyme involved in the biosynthesis of trehalose. Trehalose biosynthesis was probably induced in response to prior activation of plant antifungal genes and may act as an osmoprotectant against membrane damage.

Following standard care, nonhealing lower extremity (LE) ulcers were managed with a bacterial cellulose (BC) wound dressing, Dermafill™, (AMD/Ritmed, Tonawanda, NY), derived from Acetobacter xylinum. The time to 75% reduction in wound size was compared in 11 chronic wounds before and after the application of BC. The mean period of observation before the application of BC was 315 days; (95% CI: 239-392 days). With the application of BC to these chronic wounds, the mean time to 75% epithelization was reduced to 81 days (95% CI: 50-111 days) with a median of 79 days. The rate of wound closure with BC was significantly faster than with standard care (P < 0.001). When applied to nonhealing LE ulcers, a BC wound dressing shortens the time to wound closure over standard care.

Efficient RNA isolation is a prerequisite for gene expression studies and it has an increasingly important role in the study of plant-fungal pathogen interactions. However, RNA isolation is difficult in filamentous fungi. These organisms are notorious for their rigid cell walls and the presence of high levels of carbohydrates, excreted from the fungal cells during submerged growth, which interferes with the extraction procedures. Although many commercial kits are already available for RNA isolation, they do not provide, in most cases, enough amount of pure RNA to be used in upstream applications. In the present work, we propose an easy and efficient protocol for isolating total RNA from the filamentous fungus Mycosphaerella fijiensis, the most important foliar pathogen of Musa spp. varieties worldwide. In addition, we applied the proposed protocol to the isolation of total RNA from banana leaves infected with the pathogen. Our methodology was developed based on the SDS method with modifications including a carbohydrate precipitation step. The protocol resulted in high-quality total RNA, from fungal mycelium grown in PDB medium and infected banana leaves, suitable for further molecular studies. The proposed methodology is also applicable to the ascomycete fungus Passalora fulva (syn. Cladosporum fulvum).