Production of rhamnolipids by a Pseudomonas alcaligenes strain

Brazil is one of the main producers of palm oil (Ellaus guineeusis). It is a low-cost product that has some interesting industrial qualities, such as its use as the raw material for the production of glycerin and soap as well as its use in the preparation of food. Some renewable sources and agroindustrial wastes have been used extensively in research on the production of biosurfactants of the Pseudomonas strains. However, to our knowledge, no studies have been published on the use of palm oil as a substrate for the synthesis of biosurfactants by Pseudomonas alcaligenes. This paper describes the production and characterization of biosurfactants synthesized by a strain of P. alcaligenes PCL previously isolated from soil that was contaminated with crude-oil. Furthermore, the paper presents the optimization of the production of biological surface-active compounds by applying experimental design tools and their capacity to emulsify hydrocarbons.     

Molecular Clocks and Archeogenomics of a Late Period Egyptian Date Palm Leaf Reveal Introgression from Wild Relatives and Add Timestamps on the Domestication

The date palm, Phoenix dactylifera, has been a cornerstone of Middle Eastern and North African agriculture for millennia. It was first domesticated in the Persian Gulf, and its evolution appears to have been influenced by gene flow from two wild relatives, P. theophrasti, currently restricted to Crete and Turkey, and P. sylvestris, widespread from Bangladesh to the West Himalayas. Genomes of ancient date palm seeds show that gene flow from P. theophrasti to P. dactylifera may have occurred by ∼2,200 years ago, but traces of P. sylvestris could not be detected. We here integrate archeogenomics of a ∼2,100-year-old P. dactylifera leaf from Saqqara (Egypt), molecular-clock dating, and coalescence approaches with population genomic tests, to probe the hybridization between the date palm and its two closest relatives and provide minimum and maximum timestamps for its reticulated evolution. The Saqqara date palm shares a close genetic affinity with North African date palm populations, and we find clear genomic admixture from both P. theophrasti, and P. sylvestris, indicating that both had contributed to the date palm genome by 2,100 years ago. Molecular-clocks placed the divergence of P. theophrasti from P. dactylifera/P. sylvestris and that of P. dactylifera from P. sylvestris in the Upper Miocene, but strongly supported, conflicting topologies point to older gene flow between P. theophrasti and P. dactylifera, and P. sylvestris and P. dactylifera. Our work highlights the ancient hybrid origin of the date palms, and prompts the investigation of the functional significance of genetic material introgressed from both close relatives, which in turn could prove useful for modern date palm breeding.     

Nutritional value of palm wine fromHyphaene coriacea andPhoenix reclinata (Arecaceae)

Palm wine is an alcoholic beverage consumed by rural people in Maputaland, Natal, South Africa. Nutritional information on the nutrient content of palm wine fromHyphaene coriacea andPhoenix reclinata was obtained in order to provide more detailed nutritional data than were previously available. The results showed that while palm wine is an important source of nicotinic acid and vitamin C, previous studies appear to have overestimated its value as a source of protein, thiamin, and riboflavin.     

Characterization of the chloroplast genome sequence of oil palm (Elaeis guineensis Jacq.)

Oil palm (Elaeis guineensis Jacq.) is an economically important crop, which is grown for oil production. To better understand the molecular basis of oil palm chloroplasts, we characterized the complete chloroplast (cp) genome sequence obtained from 454 pyrosequencing. The oil palm cp genome is 156,973 bp in length consisting of a large single-copy region of?85,192 bp flanked on each side by inverted repeats of 27,071 bp with a small single-copy region of 17,639 bp joining the?repeats. The genome contains 112 unique genes: 79 protein-coding genes, 4 ribosomal RNA genes and 29 tRNA genes. By aligning the cp?genome sequence with oil palm cDNA sequences, we observed 18 non-silent and 10 silent RNA editing events among 19 cp protein-coding genes. Creation of an initiation codon by RNA editing in rpl2 has been reported in several monocots and was also found in the oil palm cp genome. Fifty common chloroplast protein-coding genes from 33 plant taxa were used to construct ML and MP?phylogenetic trees. Their topologies are similar and strongly support for the position of E. guineensis as the sister of closely related species Phoenix dactylifera in Arecaceae (palm families) of monocot subtrees.     

The cohune palm (Orbignya cohune,Arecaceae) in Belize: A survey of uses

Although common throughout Belize in lowland forests and agricultural systems, the cohune palm,Orbignya cohune is relatively little used compared with its historic importance, according to a 1992 survey discussed here. Among uses found to persist are leaves for thatch, fruits for oil, and palm heart as food. Exploitation required only simple technology and was most notable at socio-economic extremes. Areas from which cohunes were exploited rarely coincided with high-density stands of the species. Alternatives exist for all cohune products. It seems unlikely that this palm will be the basis of a large-scale industry in Belize, primarily because of the uncertainty of wild yields and the widespread availability of alternatives.     

Biological control of bayoud disease in date palm: Selection of microorganisms inhibiting the causal agent and inducing defense reactions

Twenty-one isolates of microorganisms, including Bacillus spp., Rhizobium spp., Ulocladium atrum, Candida guilliermondii, Pseudomonas sp., Rahnella aquatilis and other bacteria not yet identified, were tested to determine their effects on the mycelial growth and the sporulation of Fusarium oxysporum f.sp. albedinis (Foa), the causal agent of bayoud on date palm. The potential of these antagonists in the induction of defense reactions in date palm seedlings was also studied. Four bacteria, B. pumilus W1, R. aquatilis W2, B. cereus X16 and n.d. S1, have exhibited a high inhibition toward mycelial growth of Foa (70–77%), and its sporulation (80–95% of the control). Moreover, cytological alterations have been detected in the Foa mycelium grown in the inhibition zone. Application of these antagonists into date palm seedlings has led to trigger defense reactions with an accumulation of non-constitutive hydroxycinnamic acid derivatives, such as the sinapic derivative I2, known to play a crucial role in resistance of date palm to Foa. This reaction was more pronounced in resistant cultivar (BSTN) than in susceptible (JHL). The combined effects of direct and indirect actions of Foa antagonists are discussed in the hope of providing a biocontrol strategy against bayoud.     

Expression Analysis of Fatty Acid Biosynthetic Pathway Genes during Interactions of Oil Palm (Elaeis guineensis Jacq.) with the Pathogenic Ganoderma boninense and Symbiotic Trichoderma harzianum Fungal Organisms

The fatty acid (FA) signaling pathway is emerging as an important mechanism in plant responses during interactions with microbial organisms. For a comprehensive evaluation of key FA biosynthetic pathway genes during interactions of oil palm (Elaeis guineensis Jacq.) with the pathogenic Ganoderma boninense and symbiotic Trichoderma harzianum fungal organisms, a lane-based array analysis of gene expression in artificially inoculated oil palm seedlings was performed. The results obtained demonstrated that acetyl-CoA carboxylase (ACC), β-ketoacyl-ACP synthases (KAS) II and III, palmitoyl-ACP thioesterase (PTE), oleoyl-ACP thioesterase (OTE) and glycerol-3-phosphate acyltransferase (ACT) showed identical responses in root and leaf tissues for the same fungi. The expression of these genes was up-regulated in both root and leaf tissues at 21 days post-inoculation (dpi) during interaction of oil palm with G. boninense. Thereafter, production of physical symptoms occurred at 42 and 63 dpi concomitantly with suppression of expression of these genes. An increase in the expression level of these genes was observed in both tissues at 3–63 dpi, which correlated with the colonization of roots and promotion of plant growth by T. harzianum. These data suggest that FA biosynthetic pathway genes are involved in the defense response of oil palm to infection. Identical plant responses by FA biosynthetic pathway genes may lead to enhanced resistance against G. boninense and could be a useful marker to contribute towards early detection of infection. The distinct expression profile during symbiotic interaction demonstrated its role in plant resistance mechanisms and growth promotion by T. harzianum.     

The Domestication Syndrome in Phoenix dactylifera Seeds: Toward the Identification of Wild Date Palm Populations

Investigating crop origins is a priority to understand the evolution of plants under domestication, develop strategies for conservation and valorization of agrobiodiversity and acquire fundamental knowledge for cultivar improvement. The date palm (Phoenix dactylifera L.) belongs to the genus Phoenix, which comprises 14 species morphologically very close, sometimes hardly distinguishable. It has been cultivated for millennia in the Middle East and in North Africa and constitutes the keystone of oasis agriculture. Yet, its origins remain poorly understood as no wild populations are identified. Uncultivated populations have been described but they might represent feral, i.e. formerly cultivated, abandoned forms rather than truly wild populations. In this context, this study based on morphometrics applied to 1625 Phoenix seeds aims to (1) differentiate Phoenix species and (2) depict the domestication syndrome observed in cultivated date palm seeds using other Phoenix species as a “wild” reference. This will help discriminate truly wild from feral forms, thus providing new insights into the evolutionary history of this species. Seed size was evaluated using four parameters: length, width, thickness and dorsal view surface. Seed shape was quantified using outline analyses based on the Elliptic Fourier Transform method. The size and shape of seeds allowed an accurate differentiation of Phoenix species. The cultivated date palm shows distinctive size and shape features, compared to other Phoenix species: seeds are longer and elongated. This morphological shift may be interpreted as a domestication syndrome, resulting from the long-term history of cultivation, selection and human-mediated dispersion. Based on seed attributes, some uncultivated date palms from Oman may be identified as wild. This opens new prospects regarding the possible existence and characterization of relict wild populations and consequently for the understanding of the date palm origins. Finally, we here describe a pipeline for the identification of the domestication syndrome in seeds that could be used in other crops.     

Role of native and exotic mycorrhizal symbiosis to develop morphological,physiological and biochemical responses coping with water drought of date palm,Phoenix dactylifera

Key Message

Arbuscular mycorrhizal (AM) symbiosis can improve date palm growth and alleviate drought-related impacts than non-mycorrhizal plants due to the ability of AMF for modifying plant metabolism and physiology.

Abstract

Date palm (Phoenix dactylifera L.) is an important agricultural and commercial crop in the North of Africa and Middle Eastern countries. During the last decade, date palm plantations were subjected to degradation due to an extensive exploitation and to drastic environmental conditions such as drought. Currently, there is a growing interest in the valorization of water due to environmental problems and economic aspects. The use of arbuscular mycorrhizal fungi (AMF) can offer a possibility to overcome these problems. The objective of this study was to study the influence of different Glomus species—Glomus intraradices, G. mosseae and Complex Aoufous (native AMF)—on the development of date palm grown under two water regimes (optimal irrigation, 75 % of field capacity or water deficit, 25 % of field capacity). Our results revealed that the beneficial effect of mycorrhizal symbiosis on plant growth depended on the fungal species and the water regime applied to the palm date seedling. While the native Complex Aoufous was the most effective in increasing the shoot height and biomass under well-watered conditions, G. intraradices was the most beneficial fungus for improving growth of plants that undergo restricted water supply. This positive effect of G. intraradices under drought conditions was not related to an enhancement of the antioxidant enzymatic activities in leaves; the association of palm date with G. intradices caused an increase in the elasticity of cell walls in leaves and allowed maintaining high water content in leaves without lowering leaf water potential under stressful conditions. The adequate selection of the AMF species is crucial for improving growth of palm date seedlings, and it must be in accordance with the water regime that will be applied to plants.     

Conservation implications of the mating system of the Pampa Hermosa landrace of peach palm analyzed with microsatellite markers

Peach palm (Bactris gasipaes) is cultivated by many indigenous and traditional communities from Amazonia to Central America for its edible fruits, and is currently important for its heart-of-palm. The objective of this study was to investigate the mating system of peach palm, as this is important for conservation and breeding. Eight microsatellite loci were used to genotype 24 open-pollinated progenies from three populations of the Pampa Hermosa landrace maintained in a progeny trial for genetic improvement. Both the multi-locus outcrossing rates (0.95 to 0.99) and the progeny level multi-locus outcrossing rates (0.9 to 1.0) were high, indicating that peach palm is predominantly allogamous. The outcrossing rates among relatives were significantly different from zero (0.101 to 0.202), providing evidence for considerable biparental inbreeding within populations, probably due to farmers planting seeds of a small number of open-pollinated progenies in the same plot. The correlations of paternity estimates were low (0.051 to 0.112), suggesting a large number of pollen sources (9 to 20) participating in pollination of individual fruit bunches. Effective population size estimates suggest that current germplasm collections are insufficient for long-term ex situ conservation. As with most underutilized crops, on farm conservation is the most important component of an integrated conservation strategy.     

The Use ofSabal uresana (Arecaceae) and other Palms in Sonora,Mexico

Sabal uresana was the palm most often discussed in published historic accounts from Sonora, Mexico, and the only palm mentioned from the earliest written documents to the present. An inventory of topographic maps identified 337 palm place names, thus reinforcing the cultural significance of palms in this region. Participant observation and formal interviews were used to learn how wild-harvested palms are utilized in present-day Sonora.Sabal uresana is the most economically important palm. Its leaves are employed for weaving, the major use of palms in this region, and for thatching and broom-making. Palm logs are used for construction and the fruits are eaten in certain parts of the state. The use of palms in Sonora is changing. Weaving and thatching could probably be maintained as viable crafts and sources of income with appropriate resource management and marketing.     

Genetic Architecture of Palm Oil Fatty Acid Composition in Cultivated Oil Palm (Elaeis guineensis Jacq.) Compared to Its Wild Relative E. oleifera (H.B.K) Cortés

We searched for quantitative trait loci (QTL) associated with the palm oil fatty acid composition of mature fruits of the oil palm E. guineensis Jacq. in comparison with its wild relative E. oleifera (H.B.K) Cortés. The oil palm cross LM2T x DA10D between two heterozygous parents was considered in our experiment as an intraspecific representative of E. guineensis. Its QTLs were compared to QTLs published for the same traits in an interspecific Elaeis pseudo-backcross used as an indirect representative of E. oleifera. Few correlations were found in E. guineensis between pulp fatty acid proportions and yield traits, allowing for the rather independent selection of both types of traits. Sixteen QTLs affecting palm oil fatty acid proportions and iodine value were identified in oil palm. The phenotypic variation explained by the detected QTLs was low to medium in E. guineensis, ranging between 10% and 36%. The explained cumulative variation was 29% for palmitic acid C16:0 (one QTL), 68% for stearic acid C18:0 (two QTLs), 50% for oleic acid C18:1 (three QTLs), 25% for linoleic acid C18:2 (one QTL), and 40% (two QTLs) for the iodine value. Good marker co-linearity was observed between the intraspecific and interspecific Simple Sequence Repeat (SSR) linkage maps. Specific QTL regions for several traits were found in each mapping population. Our comparative QTL results in both E. guineensis and interspecific materials strongly suggest that, apart from two common QTL zones, there are two specific QTL regions with major effects, which might be one in E. guineensis, the other in E. oleifera, which are independent of each other and harbor QTLs for several traits, indicating either pleiotropic effects or linkage. Using QTL maps connected by highly transferable SSR markers, our study established a good basis to decipher in the future such hypothesis at the Elaeis genus level.     

Phylogenetic utility of the nuclear genes AGAMOUS 1 and PHYTOCHROME B in palms (Arecaceae): an example within Bactridinae

Background and Aims

Molecular phylogenetic studies of palms (Arecaceae) have not yet provided a fully resolved phylogeny of the family. There is a need to increase the current set of markers to resolve difficult groups such as the Neotropical subtribe Bactridinae (Arecoideae: Cocoseae). We propose the use of two single-copy nuclear genes as valuable tools for palm phylogenetics.

Methods

New primers were developed for the amplification of the AGAMOUS 1 (AG1) and PHYTOCHROME B (PHYB) genes. For the AGAMOUS gene, the paralogue 1 of Elaeis guineensis (EgAG1) was targeted. The region amplified contained coding sequences between the MIKC K and C MADS-box domains. For the PHYB gene, exon 1 (partial sequence) was first amplified in palm species using published degenerate primers for Poaceae, and then specific palm primers were designed. The two gene portions were sequenced in 22 species of palms representing all genera of Bactridinae, with emphasis on Astrocaryum and Hexopetion, the status of the latter genus still being debated.

Key Results

The new primers designed allow consistent amplification and high-quality sequencing within the palm family. The two loci studied produced more variability than chloroplast loci and equally or less variability than PRK, RPBII and ITS nuclear markers. The phylogenetic structure obtained with AG1 and PHYB genes provides new insights into intergeneric relationships within the Bactridinae and the intrageneric structure of Astrocaryum. The Hexopetion clade was recovered as monophyletic with both markers and was weakly supported as sister to Astrocaryum sensu stricto in the combined analysis. The rare Astrocaryum minus formed a species complex with Astrocaryum gynacanthum. Moreover, both AG1 and PHYB contain a microsatellite that could have further uses in species delimitation and population genetics.

Conclusions

AG1 and PHYB provide additional phylogenetic information within the palm family, and should prove useful in combination with other genes to improve the resolution of palm phylogenies.     

Fruit production of the Ungurahua Palm (Oenocarpus bataua subsp.Bataua, Arecaceae) in an Indigenous Managed Reserve

The ungurahua palm (Oenocarpus bataua subsp.bataua) is widely used throughout the Amazon Basin for its thatch, fibers, wood, and edible fruits. The fruits of this species are especially important to indigenous peoples and yield a high quality oil. This study examines the use of this species by the Siona people of the Ecuadorian Amazon in the Cuyabeno Faunistic Reserve. The reproductive phenology, fruit production, and relationship between vegetative characteristics and fruit production is explored here. Fruit production varies greatly from palm to palm with a range of approximately 500–7000 fruits biennially. This amounts to approximately 700 kg/ha every two years. Height, diameter breast height (dbh), and number of leaves on an individual are poor predictors of tree productivity. Reproductive histories of individual palms are examined. The economic potential of this species and the implications of overharvesting are discussed.     

Peach palm (Bactris gasipaes) in tropical Latin America: implications for biodiversity conservation, natural resource management and human nutrition

Peach palm (Bactris gasipaes) is a multi-purpose palm tree native to tropical Latin America, which is predominantly cultivated by smallholders in agroforestry systems. The fruits are rich in starch and contribute importantly to food security and the cash income of farmers who cultivate them. Complex value chains have emerged that link producers to consumers, but irregular product quality and market chain inequalities undermine the economic well-being of producers and retailers. Peach palm is genetically diverse, but screening for traits of commercial and nutritional interest is required to enhance the use of its genetic resources. Alliances between public organizations and private enterprises are needed to realize the potential for processing novel products from peach palm, especially in the pharmaceutical and cosmetic sectors. The diverse challenges that emerge at different stages of production, processing and marketing require participatory research that directly involves stakeholders from the beginning.