香蕉品质相关功能基因组学的研究进展

香蕉是重要的热带水果之一,是热区人民脱贫致富的主要经济来源。香蕉品质一直是人们关注的焦点。文章综述了近年来香蕉果实品质如成熟、软化、糖代谢及香气相关功能基因分离和鉴定等方面的最新研究进展,将有助于从源头上对香蕉进行创新性的探索与研究,支撑香蕉品质改良和新品种培育。     

香蕉基因组测序及胁迫相关功能基因研究进展

香蕉是重要的热带水果之一,是世界第四大粮食作物。香蕉抗性相关的功能基因组学研究一直是香蕉研究的热点和核心。综述了近年来香蕉基因组测序、胁迫相关功能基因分离和鉴定等方面的最新研究进展,将有助于从源头上对香蕉进行创新性的研究,为香蕉遗传改良和新品种培育提供一定的理论依据。     

香蕉生物技术研究进展

近50年来香蕉的生产得到了稳步的发展,同时正遭受越来越严重的病虫、霜冻和台风的侵害。鲜食蕉雌雄性高度不育的特性,使得传统的育种方法难以进行香蕉的遗传改良。这些现状迫切要求香蕉生物技术的不断发展和深入。近10年来,在香蕉体细胞胚胎发生、原生质体培养、基因克隆和序列分析以及基因转化等方面都取得了可喜的成果,并预计于2006年完成香蕉基因组的测序 。     

Genome-wide BAC-end sequencing of Musa acuminata DH Pahang reveals further insights into the genome organization of banana

Banana and plantain (Musa spp.) are grown in more than 120 countries in tropical and subtropical regions and constitute an important staple food for millions of people. A Musa acuminata ssp. malaccencis DH Pahang bacterial artificial chromosome (BAC) library (MAMB) was submitted for BAC-end sequencing. MAMB consists of 23,040 clones, with a 140-kbp average insert size, accounting for a five times coverage of the banana genome. A total of 46,080 reads were generated, and 42,750 (92.8%) high-quality sequences were obtained after trimming for vector and quality. Analysis of these data shows a GC content of 41.39%, whereas interspersed repeats comprise 32.3%. The most common repeated sequences found show homology to ribosomal RNA genes, particularly 18S rRNA, while the Ty3/gypsy type monkey retrotransposon is the most common retro element. The sequence data were used to generate a banana-specific repeat library containing 54 new repetitive elements which accounted for 11.86% of the total nucleotides. Simple sequence repeats represent 0.7% of the sequence data and allowed the identification of 2,455 potentially useful marker sites. Functional annotation identified 2,705 sequences that could code for proteins of known function. Microsynteny analysis shows a higher number of co-linear matches to Oryza sativa, in contrast to Arabidopsis thaliana. This database of BAC-end sequences is useful for the assembly of the complete banana genome sequence and is important for identification in functional genomics experiments.     

A PCR-based method, with internal control, for the detection of Banana bunchy top virus in banana

Banana bunchy top disease is a major constraint to banana production in most regions where this crop is grown. The disease is caused by Banana bunchy top virus (BBTV), a multicomponent, single-stranded DNA virus of the family Nanoviridae. We have designed primers to a conserved region of the master replication-associated protein that are useful for the polymerase chain reaction (PCR)-mediated detection of BBTV. In addition, primers to banana genomic sequence are used as an internal control, overcoming the uncertainty (owing to false-negatives) inherent in PCR diagnostics. Together these primer sets are a valuable tool in the effort to control BBTV, particularly in screening micropropagated banana plantlets for the absence of virus before release to farmers.     

An <i>in Vitro</i> Approach to Investigate the Role of Abscisic Acid in Alleviating the Negative Effects of Chilling Stress on Banana Shoots

Banana is a tropical crop cultivated in warm places. Chilling stress in Egypt is making banana crops less productive. Abscisic acid (ABA), a key plant hormone, regulates metabolic and physiological processes and protects plants from a variety of stresses. In vitro growing banana shoots were pre-treated with ABA at four concentrations (0, 25, 50, and 100 mM) and chilled at 5°C for 24 h, followed by a six-day recovery period at 25°C. By comparing ABA treatments to both positive and negative controls, physiological and biochemical changes were investigated. Chilling stress (5°C) caused a considerable increase in lipid peroxidation and ion leakage and reduced photosynthetic pigments in cold-treated plantlets. Increasing the concentration of ABA to 100 µM enhanced the response to chilling stress. ABA had a major effect on mitigating chilling injury in banana shoots by keeping cell membranes stable and lowering the amount of ion leakage and lipid peroxidation. Also, ABA significantly maintained the photosynthetic pigment concentration of banana shoots; accumulated higher amounts of total soluble carbohydrates and proline; and increased DPPH radical scavenging activity. Furthermore, ABA treatment enhanced cold tolerance in chilling-stressed banana shoots through the regulation of antioxidant enzyme activity. Overall, the results show that ABA is a good choice for protecting banana shoots from the damage caused by chilling stress.     

香蕉凝集素基因启动子的分离、序列分析及鉴定

香蕉是世界上最重要的水果之一,由于香蕉果实是利用转基因方法生产重组药用蛋白或有价值的化合物的理想器官,构建能在香蕉果实中高水平表达异源蛋白质的表达载体是非常有意义的。而一个高效表达的载体,启动子则是其最重要元件之一,因此,果实特异性表达启动子的获得是香蕉作为生物反应器的前提。香蕉凝集素是一种在香蕉果实中大量存在的蛋白质,其基因被证明在果肉组织中大量表达。利用染色体步移法克隆到香蕉凝集素基因5′端上游的一段长702bp的序列,经序列测定及软件分析表明,该序列具有典型的启动子结构。此序列置换植物表达载体pBI121的CaMV35S启动子,构建植物表达载体,命名为pBIL2,该启动子下游为gus基因。利用基因枪法转化香蕉的根、叶和果实薄片,对gus基因的瞬时表达进行测定,结果表明所获得的凝集素基因启动子,只在香蕉果肉中瞬时表达,该启动子的表达具有果实特异性,并且表达量较高。     

A PCR-based method, with internal control, for the detection of Banana bunchy top virus in banana

Banana bunchy top disease is a major constraint to banana production in most regions where this crop is grown. The disease is caused by Banana bunchy top virus (BBTV), a multicomponent, single-stranded DNA virus of the family Nanoviridae. We have designed primers to a conserved region of the master replication-associated protein that are useful for the polymerase chain reaction (PCR)-mediated detection of BBTV. In addition, primers to banana genomic sequence are used as an internal control, overcoming the uncertainty (owing to false-negatives) inherent in PCR diagnostics. Together these primer sets are a valuable tool in the effort to control BBTV, particularly in screening micropropagated banana plantlets for the absence of virus before release to farmers.     

Molecular Characterization of Banana streak virus Isolate from Musa Acuminata in China

Banana streak virus (BSV), a member of genus Badnavirus, is a causal agent of banana streak disease throughout the world. The genetic diversity of BSVs from different regions of banana plantations has previously been investigated, but there are relatively few reports of the genetic characteristic of episomal (non-integrated) BSV genomes isolated from China. Here, the complete genome, a total of 7722bp (GenBank accession number DQ092436), of an isolate of Banana streak virus (BSV) on cultivar Cavendish (BSAc...     

香蕉基因工程研究进展

香蕉是世界上一种重要的作物.基因工程技术的发展为培育具有优良性状的香蕉品种提供了有效的手段.本文综述了近年来香蕉基因工程研究的最新进展,包括香蕉遗传转化受体系统的建立,香蕉作物中一些有益功能基因的克隆以及香蕉遗传转化的最新科研成果.并对各种香蕉遗传转化受体系统和目前主要的香蕉遗传转化进行了客观评价,提出了香蕉遗传转化研究中存在的问题,最后对通过基因工程手段改良香蕉品种进行了展望.     

Within-plant distribution and binomial sampling of Pentalonia nigronervosa (Hemiptera: Aphididae) on banana

The banana aphid, Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae), infests banana (Musa spp.) worldwide. Pentalonia nigronervosa is the vector of Banana bunchy top virus (family Nanoviridae, genus Babuvirus) the etiological agent of Banana bunchy top disease (BBTD). BBTD is currently the most serious problem affecting banana in Hawaii. Despite the importance of this vector species, little is known about its biology or ecology. There are also no sampling plans available for P. nigronervosa. We conducted field surveys to develop a sampling plan for this pest. Ten plots were surveyed on seven commercial banana farms on the island of Oahu, HI, for the presence of P. nigronervosa on banana plantlets. We found aphids more frequently near the base of plants, followed by the newest unfurled leaf at the top of the plant. Aphids were least likely to be located on leaves in between the top and bottom of the plant. Aphid infestation on surveyed plots ranged from 8 to 95%. We developed a sequential binomial sampling plan based on our surveys. We also discovered that the within-plant distribution of P. nigronervosa is an important factor to consider when sampling for this pest. Our sampling plan will assist in the development of sustainable management practices for banana production.     

香蕉抗病基因工程

长期以来,香蕉生产遭受病害的严重威胁,制约了其发展,目前,随着转基因抗病香蕉基因工程技术的日趋成熟,为培育抗病香蕉品种开辟了新途径。     

A four-partner plant–virus interaction: enemies can also come from within

Plant viruses are disseminated by either vertical (vegetative multiplication or sexual reproduction) or horizontal (vector-mediated) propagation. Plant pararetroviruses—members of the Caulimoviridae family—have developed an alternative strategy for vertical propagation via integration within the host plant genome, although integration is not required for viral replication. Integrated endogenous pararetrovirus (EPRV) sequences have undergone extensive viral genome rearrangements and contain more than one copy of the viral genome. Furthermore, EPRV can become infectious upon spontaneous escape of active virus following stresses such as wounding, tissue culture, or interspecific crosses. Such infectious EPRV are of great importance, not only in terms of their ability to precipitate epidemic outbreaks but also because of their effect on breeding of numerous plant genomes in temperate and tropical crops. This is especially true for banana, a crop susceptible to banana streak viruses, the causative agents of banana streak disease. Thus, the classical three-component banana–Banana streak virus (BSV)–mealybug pathosystem can be expanded to include endogenous BSV as an alternative source of active virions. The BSV-banana pathosystem is one of only three pathosystems known to date to harbor this remarkable feature, and the present review focuses exclusively on it to illustrate this four-partner interaction.     

Isolation and characterization of diazotrophic bacteria from banana and pineapple plants

Banana and pineapple fruit crops are widely cultivated in tropical areas where high amounts of fertilizers are applied, principally nitrogen. Over 200 kg N.ha^-1.yr^-1 is often applied to these crops. Nevertheless, developing countries face the problem of high costs of chemical fertilizers. As already demonstrated for other tropical crops, like sugar cane, the utilization of nitrogen-fixing bacteria may support the growth of these fruit plants. In this work, we demonstrate the association of nitrogen-fixing bacteria with banana and pineapple. Samples from roots, stems, leaves and fruits of different genotypes showed the occurrence of diazotrophic bacteria, when evaluated in semi-specific semi-solid media. These isolates could be separated into seven different groups according to their morphological and physiological characteristics. Additional, phylogenetic assignments were performed with group- and species-specific oligonucleotide probes. Bacteria related to the groups of Azospirillum amazonense, Azospirillum lipoferum, Burkholderia sp. and a group similar to the genus Herbaspirillum could be detected in samples of both crops. However, Azospirillum brasilense and another two groups of Herbaspirillum-like bacteria were detected only in banana plants. Two isolates of the latter group were identified as Herbaspirillum seropedicae, whereas the other isolates may represent a new Herbaspirillum species.     

Assessing the Feasibility of Biofuel Production from Lignocellulosic Banana Waste in Rural Agricultural Communities in Peru and Colombia

Banana cultivation is widespread in tropical and subtropical regions where many rural agricultural communities exist. The banana plant bears fruit once in its life cycle, leaving behind a significant amount of usable agricultural residue. Current practice leaves this residue to decompose in the field spreading diseases and polluting water supplies. We evaluated the technological feasibility of converting lignocellulosic banana residue to ethanol as a localized biofuel production strategy to improve the livelihoods of rural agricultural communities in Peru and Colombia. Liquid hot water (LHW) and steam explosion pretreatment followed by saccharification and fermentation using commercial cellulolytic enzymes and yeast strain were evaluated for three different lignocellulosic residues independently (pseudostems, leaves, and rachis). Stems and rachis, with higher glucan conversion, appeared more promising for biofuel production than leaves (up to 93 and 77 % glucose yields for rachis and pseudostems, respectively). Steam explosion pretreatment allowed higher glucan conversion for stems and leaves, while LHW was better suited for rachis. Pseudostem is the most abundant residue generated with 306,000 tons/year in Uraba Province (Colombia) and 15,000 tons/year in the Chira Valley (Peru) on a dry weight basis. Potential ethanol production in the Chira Valley was estimated in 4.8 and 76.8 ML year^?1 in Colombia, processing stems and rachis combined. This study indicated that there is potential for biofuel production using the lignocellulosic banana residue, which could be expanded to other banana growing communities around the world. Process improvements such as increasing solids loading, water recycling, and optimizing fermentation are still required.     

香蕉转基因技术研究进展

香蕉具有高度不育性 ,难以通过传统育种的方法进行新品种的培育和遗传改良 ,因此转基因技术的建立尤为重要。综述近年来香蕉转基因技术 ,如受体材料、转基因方法、载体的构建等方面的研究进展     

香蕉束顶病毒研究进展

香蕉束顶病毒(Bananabunchytopvirus,BBTV)是引起香蕉束顶病害(Bananabunchytopdisease,BBTD)的病毒,它严重地危害了香蕉的生产。综述了近年来香蕉束顶病毒的分离提纯方法,株系划分以及分类地位,较为全面的介绍了BBTV病毒基因组分结构和各组分编码蛋白的功能等,并提出了目前需要进一步澄清的问题。