Assessment of nuclear,mitochondrial and chloroplast RFLP markers in oil palm (Elaeis guineensis Jacq.)

A variety of DNA probes was used to screen a diverse set of oil palm accessions in order to identify markers with a utility in genotype discrimination. This survey included samples of the commercial oil palm native to Africa (Elaeis guineensis Jacq.), the closely-related South American species [E.oleifera (HBK) Cortes] and inter-specific hybrids of the two. Of 106 major chloroplast bands none showed differences between E. guineensis and E. Oleifera. Mitochondrial and ribosomal probes were more informative inter-specifically (the former allowing identification of the maternal inheritance of mitochondria) and may be useful in hybrid breeding programmes; however, they were unable to identify polymorphism within E. guineensis. In contrast, low-copy nuclear genomic clones were able to identify intra-specific variation, though in most cases they revealed a relatively small number of allelic variants. One DNA probe showed a much larger number of band variants, revealing ten patterns amongst 13 E. guineensis accessions, and should prove useful in genetic fingerprinting and evaluation of oil-palm germplasm collections.     

Possible sources of genetic resistance in oil palm (<Emphasis Type="Italic">Elaeis guineensis</Emphasis> Jacq.) to basal stem rot caused by <Emphasis Type="Italic">Ganoderma boninense</Emphasis> – prospects for future breeding

Oil palm estates in southeast Asia suffer from substantial losses due to basal stem rot caused by Ganoderma boninense. Field observations have been carried out in North Sumatra, Indonesia, on a series of planting materials of known origin. Differences in susceptibility to the disease have been detected within the two Elaeis species, guineensis and oleifera. Within Elaeis guineensis, material of Deli origin is highly susceptible compared to material of African origin. It is also possible to detect differences in reaction between parents and between crosses within a given origin. The variability of resistance to basal stem rot within the same cross is also illustrated by the diverse responses of clones derived from palms of the same origin. The prospects opened up by these results are discussed, and the importance of performing an early selection test is highlighted.     

二疣犀甲对油棕、椰子的风险性分析及防控策略

二疣犀甲是危害椰子、油棕等木本油料作物的重要害虫,本文从形态学、生物学、分布及危害等不同方面对该虫进行了阐述,并对其风险性进行了定性定量评价,结果表明:二疣犀甲的R值为2.0,属于高风险有害生物。同时从生物防治、物理防治、化学防治、农事操作及检验检疫技术的应用等方面制定了二疣犀甲的综合防控策略,为该虫的危害评价和防护技术的制定提供了参考。     

Breeding for Short-stemmed Oil Palm in Nigeria: Fatty Acids, their Significance and Characteristics

The fatty acids of the progenies arising from the first back-crossfrom Elaeis guineensis and Elaeis oleifera interspecific hybridsto E. guineensis have been characterized. Fatty-acid patternsshowed striking variability which indicated that factors governingfatty-acid inheritance are polygenic. Although segregation forindividual fatty acids had no relationship with the large numberof morphological characters observed, a definite upward trendin the percentage of unsaturated fatty acids was clearly showncompared to the parent palms. The commercial and domestic advantagesof unsaturated fatty acids are discussed. Elaeis guineensis, oil palm, breeding, fatty acid content     

Oil palm (Elaeis guineensis) protoplasts: isolation, culture and microcallus formation

Procedures are deseribed for the efficient isolation of protoplasts from a variety of oil palm (Elaeis guineensis Jacq.) tissues. Various factors including donor source, composition of enzyme mixture and culture medium affected the yield and viability of the protoplasts Polyembryogenic cultures of oil palm were the most suitable starting material in terms of yield, viability and metabolic competence. Pectolyase Y-23 in association with cellulase and hemicellulase was required for the efficient release of protoplasts from the oil palm tissues. Limited cell division to form microcallus was observed at very low frequency (<0.01%) when glutathione and catalase were incorporated in the culture medium.Abbreviations 2,4-d dichlorophenoxyacetic acid - DTT dithiothreitol - MES 2[N-morpholino] ethanesulphonic acid - NAA 1-naphthalene acetic acid - PVP polyvinylpyrrolidone     

Molecular Characterization and Detection of African Oil Palm Ringspot Virus

African oil palm ringspot virus (AOPRV) had been previously described as a fovea‐like virus associated with a lethal disease of African oil palm (Elaeis guineensis) in South America. The original report was based on partial sequence and a distant relationship between AOPRV and Apple stem pitting virus, Apricot latent virus and Grapevine rupestris stem pitting‐associated virus, definitive species of the genus Foveavirus, family Flexiviridae. We report the full sequence of the RNA genome of AOPRV, and demonstrate that this virus is more closely related to two unassigned virus species of the family Flexiviridae (Cherry green ring mottle virus and Cherry necrotic rusty mottle virus) than to any definitive species of the genus Foveavirus. Thus, AOPRV should be considered as a new species of the Flexiviridae until the International Committee on Taxonomy of Viruses (ICTV) resolves the taxonomic status of the increasing number of unassigned species in this family. The molecular characterization of AOPRV has provided a highly sensitive and reliable RT‐PCR assay for the early detection of AOPRV in different genotypes of African, American (E. oleifera) and hybrid oil palms.     

The significance of the oil palm (Elaeis guineensis Jacq.) in the late Holocene environments of west and west central Africa: A further consideration

Abundant archaeological evidence of the occurrence of the endocarp of the oil palm,Elaeis guineensis, in the rain forest and woodland savanna zones of west and central Africa from about 5000 B.P. has shown the tree to be an important element in the subsistence economy of the region; its pollen also has been recorded in most of the regional terrestrial sediments studied so far. The distinct and consistently sudden and more marked increases in this pollen during the late Holocene when compared with the late Tertiary and late Pleistocene frequencies strongly indicate that the late Holocene upsurges were due to both natural and human factors favourable for the expansion of this heliophytic tree. Reasons are given for suggesting that upsurges in oil palm pollen during the late Holocene period in this region can be used as indices of plant cultivation. While the oil palm is known from early Tertiary deposits in west Africa, its earliest palynological record from terrestrial sediments in the west central part dates back only to the early Holocene. More palynological studies of Tertiary and Quaternary terrestrial cores are required to establish with more certainty the antiquity ofE. guineensis in west central Africa.     

Lipid metabolism in oil palm (Elaeis guineensis and Elaeis oleifera) protoplasts

Protoplasts were enzymatically prepared from the mesocarp of two species of oil palm (Elaeis guineensis Jacq. and E. oleifera HBK and Cortes) 16–20 weeks after anthesis and from rapidly multiplying embryogenic cultures of E. guineensis. The protoplasts were purified by density gradient centrifugation in 20% (w/v) sucrose. Radioactive incorporation studies showed that the protoplasts metabolized [1-¹⁴C]acetate to lipids, water-soluble compounds and ¹⁴CO₂. The [¹⁴C]fatty acids obtained consisted mainly of C16: 0, C18: 0 and C18: 1. C16: 1, a very minor fatty acid in palm oil, was also labelled and accounted for 8–39% of total fatty acids synthesized by the mesocarp and embryogenic culture protoplasts. The ratio of labelled C18: 0 to C18: 1 was found to vary with the age of the fruit from which the protoplasts were prepared. Thin layer chromatography (TLC) of the labelled lipids showed the presence of all neutral acylglycerol classes. However the distribution of radiolabel in the various classes differed from those previously reported for oil palm mesocarp [K.C. Oo et al. Lipids, 20 (1985) 205] and embryoid tissue slices [E. Turnham and D.H. Northcote, Phytochem., 23 (1984) 35]. Ozonolysis showed that all the labelled C18: 1 acid was vaccenic acid.     

Effects of tissue culture conditions during embryoid multiplication on the incidence of ``mantled' flowering in clonally propagated oil palm

New and established embryoid lines of oil palm (Elaeis guineensis Jacq.) clones, classified with regard to the expected risk of mantled flowering, were included in experiments to determine to what extent culture conditions during 48 weeks of embryoid multiplication could influence the incidence and severity of mantled flowering. Variables tested included clone risk status, duration of transfer interval, and plant growth regulator composition of the culture medium. Clones classified as high risk at the outset gave a significantly higher incidence of mantled flowering in the field than clones classified as low/medium risk, confirming that data on terminal inflorescences produced in vitro allows effective screening of material with regard to the risk of mantled flowering. The incidence of mantled flowering ranged from 0 to 100% depending on risk status of the clones, and the treatments applied. In general, a relatively long transfer interval (8 weeks) and a high auxin/cytokinin ratio resulted in the lowest incidence of mantled flowering with all types of material. Reducing the transfer interval down to 2 or 4 weeks, and/or using media with relatively high concentrations of kinetin (0.25 mg l^–1), and low concentrations of naphthalene acetic acid (0 or 0.1 mg l^–1), resulted in a high incidence of mantled flowering (above 30%), even with low/medium risk clones. Exclusion of plant growth regulators from the embryoid multiplication medium did not prevent some mantled flowering (12%) of new embryoid lines of low/medium risk clones following embryoid multiplication on a 4 week transfer interval, and a much higher incidence of mantling (above 90%) of lines from high risk clones.     

Insights from the GC content analysis of 76genome survey sequences (GSS) from Elaeisoleifera

South American oil-palm (Elaeis oleifera) is not cultivated in tropical countries like Malaysia on large scale due to low yield of palm oil derived from its fruit mesocarp. However, its fruit mesocarp oil contains about 68.6 % oleic acid (C_18:1) which is more than double in comparison to commercially cultivated oilpalm, E. guineensis Jacq Tenera (hybrid of Dura (♀) x Pisifera (♂)). It is also known that E. oleifera is a good source of tocotrienols and carotenoids. Therefore, it is of interest to know the genome sequence of E. oleifera. The objective of this study is to generate genome survey sequences (GSS) to get GC content insight in the E. oleifera genome. The nuclear genomic DNA isolated from young leaf‐tissues was digested with EcoRI and NdeI/DraI restriction enzymes; and three genomic DNA libraries were constructed using Lambda ZAP‐II, pGEM®‐T Easy, and pDONR 222™ as cloning vectors. Generated 76 GSSs were analyzed by using Bioinformatics tools. The analysis result indicates that the adenine, cytosine, guanine and thymine content in generated GSSs are 30%, 20%, 20%, and 30% respectively. In conclusion, based on the precise GC content analysis of the randomly isolated 76 GSSs by using Bioinformatics tools we hypothesize that GC content in E. oleifera genome is 40%. The hypothesized 40% GC content in E. oleifera genome is expected to remain close to the GC content based on the whole genome analysis.^ψThe nucleotide sequence data reported in this paper have been submitted to dbGSS division of the international DNA database (GenBank/DDBJ/EMBL) under accession numbers: {"type":"entrez-nucleotide-range","attrs":{"text":"DX575945- DX575972","start_term":"DX575945","end_term":"DX575972","start_term_id":"94323534","end_term_id":"94323561"}}DX575945- DX575972 and {"type":"entrez-nucleotide-range","attrs":{"text":"EI798032-EI798079","start_term":"EI798032","end_term":"EI798079","start_term_id":"146199019","end_term_id":"146199066"}}EI798032-EI798079.

Abbreviations

gDNA - Nuclear genomic DNA, GSSs - Genome survey sequences K12, SAOP - South American oil‐palm Db1     

油棕等热带植物DXS基因的生物信息学分析

油棕等热带植物含有丰富的胡萝卜素和维生素E等类异戊二烯物质,类胡萝卜素和甾醇等类异戊二烯物质在植物生命活动中扮演重要角色,并且对保护人类健康具有重要意义,MEP途径是合成类异戊二烯的重要途径之一。DXS是MEP途径中的第一个限速酶,其功能在油棕等热带植物中极其保守。为了弄清油棕等热带植物DXS的结构和功能特点,该研究利用生物信息学工具和软件对以油棕等热带植物类异戊二烯合成关键基因DXS为对象,进行核酸和氨基酸序列的理化性质、蛋白质结构以及功能结构域等分析,探讨了不同物种间的亲缘关系。结果表明:DXS基因起始密码子均为ATG,终止密码子则分为TAG、TAA和TGA,DXS蛋白质属于不具有信号肽的亲水性蛋白,可能作为转运蛋白在叶绿体基质中发挥作用,未发现明显的跨膜结构域,磷酸化位点有36个,其中丝氨酸、苏氨酸和酪氨酸位点分别为17、11和8个,无规则卷曲和α-螺旋是蛋白质二级结构主要的结构元件,三级结构预测具有DXS酶特征,硫胺素焦磷酸盐结合位点和PLN02582保守结构域,不同植物DXS功能结构域非常保守,可以作为判断不同物种间亲缘关系的重要依据。该研究结果为油棕等热带植物DXS的结构、功能分析和利用提供了进一步的信息,为其品质性状分子机制研究及遗传改良奠定了基础。     

Stem rots of oil palm caused by <Emphasis Type="Italic">Ganoderma boninense</Emphasis>: Pathogen biology and epidemiology

Oil palm (Elaeis guineensis Jacq.) has been grown in Papua New Guinea since the early 1960s. The most important disease of oil palm in PNG is a stem rot of the palm base. This is the same disease that constitutes a major threat to sustainable oil palm production in SE Asia. Investigations into the causal pathogen have revealed that the stem rots in PNG are caused predominantly by the basidiomycete Ganoderma boninense, with a minor pathogen identified as G. tornatum G. tornatum was found to have a broad host range whereas G. boninense appears to be restricted to palms. The population structure of G. boninense was investigated using inter-fertility studies between isolates collected from basal stem rots on oil palm. Although the G. boninense field populations are predominantly comprised of distinct individuals, a number of isolates were found that share single mating alleles. This indicates that out-crossing had occurred over several generations in the resident or wild population of G. boninense prior to colonization of oil palm. No direct hereditary relationship between isolates on neighbouring diseased palms was found, although an indirect link between isolates causing upper stem rot and basal stem rot was detected.     

Characterization of oil palm MADS box genes in relation to the mantled flower abnormality

In vitro propagation of oil palm (Elaeis guineensis Jacq.) frequently induces a somaclonal variant called ‘mantled’ abnormality, in which the stamens of both male and female flowers are transformed into carpels. This leads to a reduced yield or complete loss of the harvest of palm oil. The high frequency of the abnormality in independent lines and the high reversal rate suggest that it is due to an epigenetic change. The type of morphological changes suggest that it involves homeotic MADS box genes that regulate the identity of the flower whorls. We have isolated a number of MADS box genes from oil palm inflorescences by a MADS box-directed mRNA display approach. The isolated partial cDNAs included genes that were likely to function at the initial stages of flowering as well as genes that may function in determination of the inflorescence and the identity of the flower whorls. For four genes that were homologous to genes known to affect the reproductive parts of the flower, full length cDNAs were isolated. These were a B-type MADS box gene which may function in the determination of stamen formation, a C-type gene expected to be involved in stamen and carpel formation, and two putative SEP genes which act in concert with the A-, B- and C-type MADS box gene in determining flower whorl formation. The B-type gene EgMADS16 was functionally characterized as a PISTILLATA orthologue; it was able to complement an Arabidopsis thaliana pi mutant. Whether EgMADS16, or any of the other EgMADS genes, are functionally involved in the mantled condition remains to be established.     

人工引入传粉者对油茶丰产的意义及潜在的生物安全

动物传粉在全球生态系统中提供重要服务,全球农业生产对动物传粉服务的需求稳定增长。油茶是我国特有的重要木本油料植物,栽培历史悠久,由于严格自交不亲和而高度依赖动物传粉。基于我国油茶产业发展的新形势,从资源分配和花粉限制等生态因素系统分析了油茶产量受限制的原因,提出油茶的传粉者限制效果等同于花粉限制效果,人工引入潜在的高效传粉者是解除油茶资源限制措施和传粉生态限制措施之间冲突、提高油茶产量的有效途径。论述了人工引入传粉者传粉服务的优势和挑战。对人工引入传粉者,特别是外来传粉者所面临的潜在风险和控制途径进行了梳理,提出从传粉生态服务解决油茶产量和质量问题的新思路。全文旨在为人工引入传粉者在油茶丰产中的作用提供理论与科学依据,以期促进油茶产业健康有序发展。     

The glucosinolate-degrading enzyme myrosinase in Brassicaceae is encoded by a gene family

A full-length cDNA clone (MB3) and three partial clones (MA1, MB1 and MB2) which encode myrosinase (thioglucoside glucohydrolase, EC 3.2.3.1) were isolated from a Sinapis alba (white mustard) cDNA library. Nucleotide sequence analysis of these clones revealed that they are encoded by a gene family. Southern blot analysis with gene-specific probes showed that the gene family consists of a least two subfamilies (MA and MB) each with several members both in S. alba and in Brassica napus (oilseed rape). In Arabidopsis thaliana (wall cress) only three myrosinase genes seem to be present. Northern blot analysis indicated that all the myrosinase mRNA species have the same size, approximately 1.95 kb.     

Differential protein profiles in interspecific hybrids between Elaeis oleifera and E. guineensis with contrasting responses to somatic embryogenesis competence acquisition

Understanding the molecular events that initiate somatic embryogenesis (SE) may help optimize clonal propagation protocols in oil palm. The objective of this work was to identify differentially abundant proteins during the induction of SE in two interspecific F1 hybrids of Elaeis oleifera?×?Elaeis guineensis with contrasting responses (responsive and non-responsive) to the SE process. Leaf explants were obtained and submitted to SE induction medium for up to 180 days. Explants were collected at 0, 14, 90 and 150 days of induction (doi). Proteins were extracted and analyzed by two-dimensional electrophoresis. Analyses were focused at 14 and 150 doi, representing the initial and late stages of embryogenic competence acquisition, respectively. The results indicate that at 14 doi a high amount of stress is present which results in cellular dedifferentiation. At 90 doi, cells (of the responsive genotype) seem adapted and have kept stress under control, allowing the use of energy for cellular proliferation that occurs at 150 doi. Therefore, the control of stress and oxidation seem to be crucial for callus development. We highlight proteins associated to oxidative stress, protein processing, energy metabolism and development as potentially involved in embryogenic competence acquisition.

     

3个油茶品种幼苗对干旱胁迫的生理响应

在温室内模拟不同干旱胁迫,通过盆栽试验研究了3个油茶品种‘长林4号’(C4)、‘长林23号’(C23)和‘长林53号’(C53)2年生幼苗主要生理指标的变化,并利用相关分析、主成分分析和隶属函数法对各油茶品种抗旱性进行综合评价。结果表明:(1)随着干旱程度加重和胁迫时间延长,油茶叶片相对电导率和硫代巴比妥酸反应物(TBARS)含量均有不同程度上升。(2)超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均呈现先上升后下降趋势,且在干旱15d时,抗氧化酶活性达到最大。(3)叶绿素含量、净光合速率(Pn)、气孔导数(Gs)和蒸腾速率(Tr)随着胁迫程度加重和胁迫时间延长均有不同程度下降。(4)抗旱性综合评价表明,供试的3个油茶品种抗旱能力依次为C53>C4>C23。     

Die Perikarpentwicklung geflügelter Klausen aus demParacaryum-Verwandtschaftskreis (Cynoglosseae,Boraginaceae)

The anatomy and development of mericarps in four representatives ofBoraginaceae-Cynoglosseae has been investigated. In each case, the nutlets grow from a six-layered carpel. While the mesocarp becomes multilayered and thick in correlation with epizoochory inCynoglossum, it remains six-layered inMattiastrum, Paracaryum, andRindera. The wings are formed by both exo- and mesocarp and later on the inflated rim becomes hollow. Development of wings and reduction of glochids are discussed as adaptations to anemochory.