Diarylheptanoid Derivatives (Musellins A-F) and Dimeric Phenylphenalenones from Seed Coats of Musella lasiocarpa, the Chinese Dwarf Banana.

Phenylphenalenones (PPs) are phytoalexins protecting banana plants (Musaceae) against various pathogens. However, how plants synthesize PPs is still poorly understood. In this work, we investigated the major secondary metabolites of developing seed coats of Musella lasiocarpa to determine if this species might be a good model system to study the biosynthesis of PPs. We found that PPs are major components of M. lasiocarpa seed coats at middle and late developmental stages. Two previously undescribed PP dimers (M-4 and M-6) and a group of unreported diarylheptanoid (DH) derivatives named musellins A-F (B-7, B-9, B-10, B-12, B-14, and B-15) were isolated along with 14 known compounds. Musellin D (B-12) and musellin F (B-15) contain the first reported furo[3,2-c]pyran ring and represent a previously undescribed carbon skeleton. The chemical structures of all new compounds were characterized by spectroscopic data, including NMR, HRESIMS, and ECD analysis. Plausible biosynthetic pathways for the formation of PPs and DHs are proposed.

Comparative plastome analysis of Musaceae and new insights into phylogenetic relationships.

BACKGROUND: Musaceae is an economically important family consisting of 70-80 species. Elucidation of the interspecific relationships of this family is essential for a more efficient conservation and utilization of genetic resources for banana improvement. However, the scarcity of herbarium specimens and quality molecular markers have limited our understanding of the phylogenetic relationships in wild species of Musaceae. Aiming at improving the phylogenetic resolution of Musaceae, we analyzed a comprehensive set of 49 plastomes for 48 species/subspecies representing all three genera of this family. RESULTS: Musaceae plastomes have a relatively well-conserved genomic size and gene content, with a full length ranging from 166,782 bp to 172,514 bp. Variations in the IR borders were found to show phylogenetic signals to a certain extent in Musa. Codon usage bias analysis showed different preferences for the same codon between species and three genera and a common preference for A/T-ending codons. Among the two genes detected under positive selection (dN/dS > 1), ycf2 was indicated under an intensive positive selection. The divergent hotspot analysis allowed the identification of four regions (ndhF-trnL, ndhF, matK-rps16, and accD) as specific DNA barcodes for Musaceae species. Bayesian and maximum likelihood phylogenetic analyses using full plastome resulted in nearly identical tree topologies with highly supported relationships between species. The monospecies genus Musella is sister to Ensete, and the genus Musa was divided into two large clades, which corresponded well to the basic number of n = x = 11 and n = x =10/9/7, respectively. Four subclades were divided within the genus Musa. A dating analysis covering the whole Zingiberales indicated that the divergence of Musaceae family originated in the Palaeocene (59.19 Ma), and the genus Musa diverged into two clades in the Eocene (50.70 Ma) and then started to diversify from the late Oligocene (29.92 Ma) to the late Miocene. Two lineages (Rhodochlamys and Australimusa) radiated recently in the Pliocene /Pleistocene periods. CONCLUSIONS: The plastome sequences performed well in resolving the phylogenetic relationships of Musaceae and generated new insights into its evolution. Plastome sequences provided valuable resources for population genetics and phylogenetics at lower taxon.

Microbial community shifts association with physicochemical parameters: Visualizing enset bacterial wilt from different states of enset health.

Bacterial wilt of enset caused by Xanthomonas campestris is a devastating disease in Ethiopia, where enset is domesticated and served as a staple food for about 20 million people in the country. While enset is infected by bacteria, it shows different wilting stages. However, the microbial community shifts at the different stages of enset infection and associated physicochemical parameter changes remain poorly understood. This study was aimed to visualize the proportion of enset wilt bacterium from other microbial community and its association with physicochemical parameter at different states of enset health. Soil and enset (zero, first, second and third stages) samples were collected from three districts in Gamo Highlands for physicochemical and biological (culture dependent and16S rRNA gene sequence) analysis. The results of culture dependent analysis which has been complemented by 16S rRNA gene sequence confirmed that increasing trends were observed for Xanthomonadaceae, Pseudomonadaceae, Lactobacillaceae and Flavobacteriaceae, while Bacillaceae and Enterobacteriaceae showed progressive decrease from zero to the third stage. Particularly, the 16S rRNA data showed that Xanthomonadaceae increased significantly from zero to different (2.5 × 102 times at the onset of disease and 1.0-2.0 × 104 times at the second and third) stages of enset infection. Most physicochemical results showed that a decreasing trends from zero to third stage, while few parameters are showing an increasing trend. Moisture content (R2 ≥ 0.951, P ≤ 0.049) of the soil and plant samples positively influenced Xanthomonas abundance, while this bacterium showed a strongly negative significant correlation with pH (R2 ≥ -0.962, P ≤ 0.038), temperature (R2 ≥ -0.958, P ≤ 0.042), OM (R2 ≥ -0.952, P ≤ 0.048), and TN (R2 ≥ -0.951, P ≤ 0.049). A strongly negative significant correlation (R2 ≥ -0.948, P ≤ 0.050) was also observed between Xanthomonas and nutrients (K, Mg, Ca, and Cu). Overall, this study implies that different environmental factors found a key driving force of Xanthomonas proportional increment from low abundance at zero stage to higher abundance at the last stage of enset infection suggesting that considering these factors help to design an effective enset disease management strategy, for which further studies will be needed.

Ensete ventricosum: A Multipurpose Crop against Hunger in Ethiopia.

Ensete ventricosum is a traditional multipurpose crop mainly used as a staple/co-staple food for over 20 million people in Ethiopia. Despite this, scientific information about the crop is scarce. Three types of food, viz., Kocho (fermented product from scraped pseudostem and grated corm), Bulla (dehydrated juice), and Amicho (boiled corm) can be prepared from enset. These products are particularly rich in carbohydrates, minerals, fibres, and phenolics, but poor in proteins. Such meals are usually served with meat and cheese to supplement proteins. As a food crop, it has useful attributes such as foods can be stored for long time, grows in wide range of environments, produces high yield per unit area, and tolerates drought. It has an irreplaceable role as a feed for animals. Enset starch is found to have higher or comparable quality to potato and maize starch and widely used as a tablet binder and disintegrant and also in pharmaceutical gelling, drug loading, and release processes. Moreover, enset shows high genetic diversity within a population which in turn renders resilience and food security against the ever-changing environmental factors and land use dynamics. Therefore, more research attention and funding should be given to magnify and make wider use of the crop.

Endophytic fungal diversity isolated from different agro-ecosystem of Enset (Ensete ventericosum) in Gedeo zone, SNNPRS, Ethiopia.

BACKGROUND: Endophytic Fungi (EF) are an underexplored group of microorganisms as only a few plants have been studied with regards to their community. Diversity of EF found in young and old leaves of Enset plant has not been well studied. We analyzed and compared the colonization frequency (CF), richness diversity and fungal communities of the EF inhabiting the young and old leaves of Enset plant from Southern region of Ethiopia. Standard methods were used for isolation and identification of endophytic species from Enset leaves. RESULTS: The study investigates the difference in quantity, in variety, in consistent pattern of community of EF along with different Enset varieties. A total number of 18 samples were analyzed and 108 morphospecies of EF were isolated and distributed among 17 genera. Aspergillus sp. and Penicillium sp. were the most common fungi reported in Enset plant. The largest numbers of EF isolates were observed in Maziya and Arkiya variety and the diversity index and species richness were found to be significant in Enset plant among these varieties. A high number of EF was isolated from old leaves in comparison to young leaves among all the varieties studied. Composition of EF at different altitudinal location also varied within each sites. CONCLUSION: Isolation, characterization and distribution of the EF from Enset plant is the first approach that has been conducted in the developing country like Ethiopia. The findings of the present study show that the Enset agro-forestry system produces potential variability in the colonization, richness diversity and composition of EF in Enset plants. The assemblage of EF in healthy tissues of Enset plants may indicate that some of the fungi are possible latent pathogens and some may become saprophytic.

Enset in Ethiopia: a poorly characterized but resilient starch staple.

BACKGROUND: Enset (Ensete ventricosum, Musaceae) is an African crop that currently provides the staple food for approx. 20 million Ethiopians. Whilst wild enset grows over much of East and Southern Africa and the genus extends across Asia to China, it has only ever been domesticated in the Ethiopian Highlands. Here, smallholder farmers cultivate hundreds of landraces across diverse climatic and agroecological systems. SCOPE: Enset has several important food security traits. It grows over a relatively wide range of conditions, is somewhat drought-tolerant, and can be harvested at any time of the year, over several years. It provides an important dietary starch source, as well as fibres, medicines, animal fodder, roofing and packaging. It stabilizes soils and microclimates and has significant cultural importance. In contrast to the other cultivated species in the family Musaceae (banana), enset has received relatively little research attention. Here, we review and critically evaluate existing research, outline available genomic and germplasm resources, aspects of pathology, and explore avenues for crop development. CONCLUSION: Enset is an underexploited starch crop with significant potential in Ethiopia and beyond. Research is lacking in several key areas: empirical studies on the efficacy of current agronomic practices, the genetic diversity of landraces, approaches to systematic breeding, characterization of existing and emerging diseases, adaptability to new ranges and land-use change, the projected impact of climate change, conservation of crop wild relatives, by-products or co-products or non-starch uses, and the enset microbiome. We also highlight the limited availability of enset germplasm in living collections and seedbanks, and the lack of knowledge of reproductive and germination biology needed to underpin future breeding. By reviewing the current state of the art in enset research and identifying gaps and opportunities, we hope to catalyse the development and sustainable exploitation of this neglected starch crop.

Effect of fermentation system on the physicochemical and microbial community dynamics during enset (Ensete ventricosum) fermentation.

AIMS: The present study was conducted to assess the effect of three different fermentation systems on fermentation of enset into kocho. METHODS AND RESULTS: Nine enset plants were processed, mixed and fermented in either a pit, a bamboo basket or a sauerkraut jar. Samples were taken on days 1, 7, 15, 31, 60 and 90. Moisture content and pH generally decreased and titratable acidity increased during fermentation. Total viable aerobic counts were generally high for all samples and Enterobacteriaceae counts were reduced to below the detectable level after day 1 for the pits and jars and after day 7 for the baskets. Illumina MiSeq sequencing of 16S ribosomal RNA genes revealed that Leuconostoc and Lactococcus spp. were the most abundant lactic acid bacteria in the initial phases of the fermentation. Later on, Lactobacillus, Weissella and Bifidobacterium dominated. CONCLUSIONS: The type of fermentation system used had an effect on the microbial dynamics and the effect increased towards the end of fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: Millions of people in Ethiopia daily consume kocho prepared in either a pit or a basket. These systems show practical problems, but this study shows that fermentation is also possible in a sauerkraut jar.

Yeasts and bacteria associated with kocho, an Ethiopian fermented food produced from enset (Ensete ventricosum).

Enset (Ensete ventricosum) is the basis of the staple food consumed by about 20% of the Ethiopian population. Kocho is one of the food products generated from enset by spontaneous fermentation of decorticated and pulverized pseudostem and corm sections. We isolated culturable microbes associated with kocho from different stages of fermentation. Twelve yeast species, six lactic acid bacteria (LABs) species and eleven species of aerobic bacteria were identified by sequencing ITS/D1D2 regions of 26S rDNA of yeasts and 16S rDNA of bacteria, respectively. More yeast species were identified in fresh (fermented for 2-5 days) kocho, compared to long-term (7-12 months) fermented kocho, while we observed an opposite trend for LABs. In fresh kocho, the most frequently isolated yeast species were Pichia exigua, Galactomyces geotrichum, and Pichia fermentans. From mid-term (3-4 months) kocho most frequently Candida cabralensis, G. geotrichum, and Candida ethanolica were isolated. In the long-term fermentations, the most frequently isolated yeast was Saturnispora silva. Lactobacillus plantarum was the most frequently isolated LAB in both fresh and mid-term kocho. In long-term fermented kocho, Acetobacter pasteurianus and L. plantarum were most frequently isolated. L. plantarum was consistently isolated from all the three stages of fermentation. Aerobic bacteria in fresh kocho were mostly gram-negative, with Raoultella planticola and Pantoea agglomerans being the most frequently isolated species. In long-term fermented kocho, mainly gram-positive, spore-forming bacteria of the genus Bacillus were found, among them also species of the Bacillus cereus group, Bacillus anthracis and Bacillus thurigiensis.

Fermentation of enset (Ensete ventricosum) in the Gamo highlands of Ethiopia: Physicochemical and microbial community dynamics.

Enset (Ensete ventricosum) provides staple food for 15 million people in Ethiopia after fermentation into kocho. The fermentation process has hardly been investigated and is prone to optimization. The aim of this study was to investigate the physicochemical and microbial dynamics of fermentation practices in the Gamo highlands. These practices show local variation, but two steps were omnipresent: scraping of the pseudostem and fermenting it in a pit or a bamboo basket. Enset plants were fragmented and fermented for two months in order to investigate the physicochemical (temperature, moisture content, pH and titratable acidity) and microbial dynamics (total viable aerobic counts, counts of Enterobacteriaceae, lactic acid bacteria, yeasts and moulds and Clostridium spores counts, and Illumina Miseq sequencing). Samples were taken on days 1, 7, 15, 17, 31 and 60. The pH decreased, whereas the titratable acidity increased during fermentation. Of all counts those of lactic acid bacteria and Clostridium spores increased during fermentation. Leuconostoc mesenteroides initiated the fermentation. Later on, Prevotella paludivivens, Lactobacillus sp. and Bifidobacterium minimum dominated. These three species are potential candidates for the development of a starter culture.

Evolutionary dynamics and biogeography of Musaceae reveal a correlation between the diversification of the banana family and the geological and climatic history of Southeast Asia.

Tropical Southeast Asia, which harbors most of the Musaceae biodiversity, is one of the most species-rich regions in the world. Its high degree of endemism is shaped by the region's tectonic and climatic history, with large differences between northern Indo-Burma and the Malayan Archipelago. Here, we aim to find a link between the diversification and biogeography of Musaceae and geological history of the Southeast Asian subcontinent. The Musaceae family (including five Ensete, 45 Musa and one Musella species) was dated using a large phylogenetic framework encompassing 163 species from all Zingiberales families. Evolutionary patterns within Musaceae were inferred using ancestral area reconstruction and diversification rate analyses. All three Musaceae genera - Ensete, Musa and Musella - originated in northern Indo-Burma during the early Eocene. Musa species dispersed from 'northwest to southeast' into Southeast Asia with only few back-dispersals towards northern Indo-Burma. Musaceae colonization events of the Malayan Archipelago subcontinent are clearly linked to the geological and climatic history of the region. Musa species were only able to colonize the region east of Wallace's line after the availability of emergent land from the late Miocene onwards.

Development of SSR markers and genetic diversity analysis in enset (Ensete ventricosum (Welw.) Cheesman), an orphan food security crop from Southern Ethiopia.

BACKGROUND: Enset (Ensete ventricosum (Welw.) Cheesman; Musaceae) is a multipurpose drought-tolerant food security crop with high conservation and improvement concern in Ethiopia, where it supplements the human calorie requirements of around 20 million people. The crop also has an enormous potential in other regions of Sub-Saharan Africa, where it is known only as a wild plant. Despite its potential, genetic and genomic studies supporting breeding programs and conservation efforts are very limited. Molecular methods would substantially improve current conventional approaches. Here we report the development of the first set of SSR markers from enset, their cross-transferability to Musa spp., and their application in genetic diversity, relationship and structure assessments in wild and cultivated enset germplasm. RESULTS: SSR markers specific to E. ventricosum were developed through pyrosequencing of an enriched genomic library. Primer pairs were designed for 217 microsatellites with a repeat size > 20 bp from 900 candidates. Primers were validated in parallel by in silico and in vitro PCR approaches. A total of 67 primer pairs successfully amplified specific loci and 59 showed polymorphism. A subset of 34 polymorphic SSR markers were used to study 70 both wild and cultivated enset accessions. A large number of alleles were detected along with a moderate to high level of genetic diversity. AMOVA revealed that intra-population allelic variations contributed more to genetic diversity than inter-population variations. UPGMA based phylogenetic analysis and Discriminant Analysis of Principal Components show that wild enset is clearly separated from cultivated enset and is more closely related to the out-group Musa spp. No cluster pattern associated with the geographical regions, where this crop is grown, was observed for enset landraces. Our results reaffirm the long tradition of extensive seed-sucker exchange between enset cultivating communities in Southern Ethiopia. CONCLUSION: The first set of genomic SSR markers were developed in enset. A large proportion of these markers were polymorphic and some were also transferable to related species of the genus Musa. This study demonstrated the usefulness of the markers in assessing genetic diversity and structure in enset germplasm, and provides potentially useful information for developing conservation and breeding strategies in enset.

Assessment of different levels of enset (Ensete ventricosum) corm as an energy supplement in sheep fed a basal diet of Rhodes grass hay.

The objective of this experiment was to evaluate the effect of feeding different levels of enset corm as a supplement to sheep fed Rhodes grass hay. Thirty local yearling rams with a mean (±SD) body weight of 16.97 (±1.13) kg were used. Six sheep were allocated to each of the five treatments in a completely randomized design. The treatments were hay ad libitum and 129 g dry matter (DM) corm (T1), 188 g DM corm (T2), 248 g DM corm (T3), 100 g DM noug (T4) cake, and hay alone (T5). One hundred grams of noug seedcake was supplemented for all treatments except T5. Total DM and organic matter (OM) intakes of sheep in T1, T2, and T3 were the highest (P < 0.05) compared with sheep in other treatments, while sheep in T5 consumed the lowest DM and OM. The total crude protein (CP) intakes of sheep in T3 and T2 were greater (P < 0.05) than the other treatments, while sheep in T5 consumed the lowest CP. The apparent DM and OM digestibility coefficients of T1, T2, and T3 diets were higher (P < 0.05) compared with T5. The lowest (P < 0.05) CP digestibility was in T5, whereas the digestibility among the supplemented groups was similar (P > 0.05). The daily body weight gain for T1, T2, and T3 diets was greater (P < 0.05) than that of T5. The feed conversion efficiency for T1 and T2 was higher (P < 0.05) than T5, while T4 had an intermediate value. The highest (P < 0.05) nitrogen retention was in sheep fed T3 diet, while the lowest was in those fed T5. It is concluded that farmers can supplement enset corm at 129 g DM/day as an alternative energy source to improve the productivity of sheep for small-scale farmers under enset-livestock production systems.

Phytochemical profiling, toxicity studies, wound healing, analgesic and anti-inflammatory activities of Musa paradisiaca L. Musaceae (Plantain) stem extract in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The stem of Musa paradisiaca (plantain) has found application in traditional medicine for the treatment of diabetes, inflammation, ulcers and wound injuries. AIM OF THE STUDY: This study investigated the phytochemical composition, toxicity profile, wound healing, anti-inflammatory and analgesic effects of aqueous Musa paradisiaca stem extract (AMPSE) in rats. METHODS: Phytochemical analysis of methanol-MPSE was performed by gas chromatography-mass spectrometry (GC-MS). Acute toxicity testing was carried out through oral administration of a single dose of AMPSE up to 5 g/kg. Four separate groups of rats were used for the subacute toxicity testing (n = 6). Group 1 served as a normal control and did not receive AMPSE, groups 2-4 received AMPSE daily by gavage for 28 days. In the experiments with excision and incision wounds, the rats were treated with 10 w/w AMPS extract. The anti-inflammatory and analgesic effects of AMPSE were assessed using egg albumin-induced paw oedema and acetic acid-induced writhing methods, respectively. For the subacute, anti-inflammatory and analgesic studies, AMPSE was administered to the experimental rats at doses of 300, 600 and 900 mg/kg body weight. RESULTS: Bioactive compounds identified include ß-sitisterol, n-hexadecanoic acid, octadecanoic acid, diethyl sulfate, p-hydroxynorephedrine, phenylephrine, nor-pseudoephedrine, metaraminol, pseudoephedrine and vanillic acid. No signs of toxicity and no deaths were observed in all the groups. For the groups treated with AMPSE for 28 days, a significant reduction in alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, urea, sodium, chloride, total cholesterol, triglycerides, and low-density lipoprotein cholesterol were observed while high density lipoprotein cholesterol, glutathione and superoxide dismutase increased compared to control (p < 0.05). In wound healing experiments, AMPSE showed greater percent wound contraction and wound resistance fracture compared to the povidone-iodine (PI) treated and control groups. Treatment with 900 mg/kg AMPSE resulted in significant (p < 0.05) anti-inflammatory and analgesic effects compared to the control. CONCLUSION: This study shows that AMPSE is not toxic but contains biologically active compounds with hepatoprotective, anti-inflammatory, lipid-lowering and wound-healing effects. Treatment of rats with AMPSE has shown that AMPSE has anti-inflammatory, analgesic, hepatoprotective, lipid-lowering and wound-healing effects, supporting its therapeutic use in ethnomedicine.

Antioxidant capacity, total phenolics and nutritional content in selected ethiopian staple food ingredients.

The total antioxidant capacity, total phenolics content (TPC) and nutritional content of five types of enset (Enset ventricosum) flour in comparison with four staples (teff [Eragrostis tef], wheat, corn and tapioca) were evaluated. Teff, corn and "amicho" (corm of enset) had the highest ferric reducing antioxidant power (FRAP). The FRAP and TPC of teff (1.8 mmol Trolox equivalence/100 g dry matter (DM) and 123.6 mg gallic acid equivalent/100 g DM, respectively) were over 4-fold larger than the lowest obtained from "bulla" (dehydrated juice of pseudostem of enset). Corn had the lowest IC(50) value of 1,1-diphenyl-2-picrylhydrazyl radical scavenging (10.27 mg DM mL(-1)). Teff had the highest crude fat content (3.71%) and some mineral profile (P, Mg, Mn and Cu). Enset products had higher fiber, Ca, K, Mg and Mn content as compared to wheat and corn. Ethiopian staple teff has a potential for developing value-added food products with nutritional and health benefits.

On-farm diversity, use pattern, and conservation of enset (Ensete ventricosum) genetic resources in southern Ethiopia.

BACKGROUND: Enset is an important source of food and is consumed by about 25 million people as a staple or co-staple food crop mainly in southern parts of Ethiopia. Large numbers of enset landraces exist in different administrative zones of Ethiopia with a wide range of altitudes and agroclimatic zones. However, limited information is available on the diversity, distribution, and utilization pattern corresponding to the diverse ethnolinguistic as well as sociocultural communities of the country. Hence, this study was devised to explore and document the richness of farmers' tradition and practice on the diversity and distribution of enset landraces on the farm level and selection pattern for different purposes regarding the production, utilization, and conservation of enset genetic resources. METHODS: The study was conducted in four major enset-growing administrative zones of Ethiopia, namely Hadiya, Kembata-Tembaro, Gurage, and Silte. A total of 240 farm households were surveyed using individual interviews, 18 key informant interviews, 36 focus group discussions with 5 participants, and direct on-farm field observations for data collection. Considering that enset has a rich cultural background and indigenous knowledge, ethnobotanical research approach was applied to data collection and analysis. The Shannon-Weaver, Simpson, Pielou, and Jaccard's similarity indices were used to evaluate the diversity and similarity of the landraces as well as using descriptive statistics in SPSS Ver. 24. Preference in direct matrix ranking was also used to compute and rank the enset landraces most preferred by the people in the context of specific use value in the study area. RESULTS: A total of 282 farmer-named enset landraces have been identified, with a range from 2 to 32 on individual homegardens. The largest number of landraces was found in the Hadiya Zone (86), while the lowest was scored in the Silte Zone (57). The Shannon diversity index (H') ranged from 3.73 (Silte) to 3.96 (Hadiya). Similarly, landraces revealed a very narrow range of variances in Simpson's 1-D diversity index, and it ranged from 0.963 (Silte) to 0.978 (Hadiya). Likewise, the similarity index ranged from 0.24 to 0.73 sharing 16-47 landraces in common. Of the 282 landraces, 210 (74.5%) were recorded in more than one zones, whereas 72 (25.5%) had narrow distribution being restricted to a single zone. CONCLUSIONS: Farmers have established long-term practices and experiences in cultivation, utilization, and conservation of a diverse group of enset landraces to fill their domestic and market purposes in each zone. The variation is likely to be related to agroclimatic differences, ethnicity factors, food cultures, and historical backgrounds. Therefore, to facilitate on-farm conservation as well as sustainable utilization of the enset genetic resources, farmers need to be supported by different stakeholders for all their worth and also in crop improvement programs.

Thirty-four Musa (Musaceae) expressed sequence tag-derived microsatellite markers transferred to Musella lasiocarpa.

We assembled 31,308 publicly available Musa EST sequences into 21,129 unigenes; 4944 of them contained 5416 SSR motifs. In all, 238 unigenes flanking SSRs were randomly selected for primer design and then tested for amplification in Musella lasiocarpa. Seventy-eight primer pairs were found to be transferable to this species, and 49 displayed polymorphism. A set of 34 polymorphic SSR markers was analyzed in 24 individuals from four wild M. lasiocarpa populations. The mean number of alleles per locus was 3.0, ranging from 2 to 7. The observed and expected heterozygosities per marker ranged from 0.087 to 0.875 (mean 0.503) and from 0.294 to 0.788 (mean 0.544), respectively. These markers will be of practical use for genetic diversity and quantitative trait loci analysis of M. lasiocarpa.

Raoiella indica (Acari: Tenuipalpidae): an exploding mite pest in the neotropics.

Major infestations of the flat mite species Raoiella indica Hirst affecting bananas, palms and other ornamental plants have been reported from the Caribbean islands, Mexico, FL (USA), Venezuela, Colombia and Brazil. Specimens from these localities were examined using traditional light microscopy and low-temperature scanning electron microscopy techniques. While little is known about the biology of this mite, its recent appearance in the Americas in both commercial coconut and banana plantations has raised concerns about its economic impact as an invasive pest.

The pangenome of banana highlights differences between genera and genomes.

Banana (Musaceae family) has a complex genetic history and includes a genus Musa with a variety of cultivated clones with edible fruits, Ensete species that are grown for their edible corm, and monospecific Musella whose generic status has been questioned. The most commonly exported banana cultivars belong to Cavendish, a subgroup of Musa triploid cultivars, which is under threat by fungal pathogens, though there are also related species M. balbisiana Colla (B genome), M. textilis Née (T genome), and M. schizocarpa N. W. Simmonds (S genome), along with hybrids of these genomes, which potentially host genes of agronomic interest. Here we present the first cross-genus pangenome of banana, which contains representatives of the Musa and Ensete genera. Clusters based on gene presence-absence variation (PAV) clearly separate Musa and Ensete, while Musa is split further based on species. These results present the first pangenome study across genus boundaries and identifies genes that differentiate between Musaceae species, information that may support breeding programs in these crops.

Reproductive biology of wild and domesticated Ensete ventricosum: Further evidence for maintenance of sexual reproductive capacity in a vegetatively propagated perennial crop.

Loss of sexual reproductive capacity has been proposed as a syndrome of domestication in vegetatively propagated crops, but there are relatively few examples from agricultural systems. In this study, we compare sexual reproductive capacity in wild (sexual) and domesticated (vegetative) populations of enset (Ensete ventricosum (Welw.) Cheesman), a tropical banana relative and Ethiopian food security crop. We examined floral and seed morphology and germination ecology across 35 wild and domesticated enset. We surveyed variation in floral and seed traits, including seed weight, viability and internal morphology, and germinated seeds across a range of constant and alternating temperature regimes to characterize optimum germination requirements. We report highly consistent floral allometry, seed viability, internal morphology and days to germination in wild and domesticated enset. However, seeds from domesticated plants responded to cooler temperatures with greater diurnal range. Shifts in germination behaviour appear concordant with a climatic envelope shift in the domesticated distribution. Our findings provide evidence that sexual reproductive capacity has been maintained despite long-term near-exclusive vegetative propagation in domesticated enset. Furthermore, certain traits such as germination behaviour and floral morphology may be under continued selection, presumably through rare sexually reproductive events. Compared to sexually propagated crops banked as seeds, vegetative crop diversity is typically conserved in living collections that are more costly and insecure. Improved understanding of sexual propagation in vegetative crops may have applications in germplasm conservation and plant breeding.

A chromosome-level reference genome of Ensete glaucum gives insight into diversity and chromosomal and repetitive sequence evolution in the Musaceae.

BACKGROUND: Ensete glaucum (2n = 2x = 18) is a giant herbaceous monocotyledonous plant in the small Musaceae family along with banana (Musa). A high-quality reference genome sequence assembly of E. glaucum is a resource for functional and evolutionary studies of Ensete, Musaceae, and the Zingiberales. FINDINGS: Using Oxford Nanopore Technologies, chromosome conformation capture (Hi-C), Illumina and RNA survey sequence, supported by molecular cytogenetics, we report a high-quality 481.5 Mb genome assembly with 9 pseudo-chromosomes and 36,836 genes. A total of 55% of the genome is composed of repetitive sequences with predominantly LTR-retroelements (37%) and DNA transposons (7%). The single 5S ribosomal DNA locus had an exceptionally long monomer length of 1,056 bp, more than twice that of the monomers at multiple loci in Musa. A tandemly repeated satellite (1.1% of the genome, with no similar sequence in Musa) was present around all centromeres, together with a few copies of a long interspersed nuclear element (LINE) retroelement. The assembly enabled us to characterize in detail the chromosomal rearrangements occurring between E. glaucum and the x = 11 species of Musa. One E. glaucum chromosome has the same gene content as Musa acuminata, while others show multiple, complex, but clearly defined evolutionary rearrangements in the change between x= 9 and 11. CONCLUSIONS: The advance towards a Musaceae pangenome including E. glaucum, tolerant of extreme environments, makes a complete set of gene alleles, copy number variation, and a reference for structural variation available for crop breeding and understanding environmental responses. The chromosome-scale genome assembly shows the nature of chromosomal fusion and translocation events during speciation, and features of rapid repetitive DNA change in terms of copy number, sequence, and genomic location, critical to understanding its role in diversity and evolution.