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Journal ArticleDOI

Advances in development of transgenic pulse crops.

01 Mar 2008-Biotechnology Advances (Elsevier)-Vol. 26, Iss: 2, pp 162-168
TL;DR: With optimization of various factors which influence genetic transformation of pulse crops, it will be possible to develop transgenic plants in this important group of crop species with more precision and reproducibility, according to the reason for lack of commercialization of transgenic pulse crops.
About: This article is published in Biotechnology Advances.The article was published on 2008-03-01. It has received 68 citations till now.
Citations
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Journal ArticleDOI
TL;DR: Genomic examination of complex traits such as adaptation to low soil fertility and tolerance to high levels of soluble Al in the soil using conventional breeding methods should help bean breeders devise more effective selection strategies.
Abstract: Common bean (Phaseolus vulgaris L.) improvement programs have been successful using conventional breeding methods to accomplish a wide array of important objectives. Specific achievements include the extension of range of adaptation of the crop, the development of cultivars with enhanced levels of disease and pest resistance and breeding lines that possess greater tolerance to drought. The most effective breeding method depends on the expression and inheritance of the trait to be selected and the target environment. Many bean improvement programs use molecular markers to facilitate cultivar development. In fact, several recent germplasm releases have used molecular markers to introgress and or pyramid major genes and QTL for disease resistance. Related species (P. coccineus and P. acultifolius) via interspecific hybridizations remain an important albeit long-term source for resistance to economically important diseases. Slow progress has been made in the improvement of traits such as adaptation to low soil fertility and tolerance to high levels of soluble Al in the soil using conventional breeding methods. The inability to directly measure root traits and the importance of genotype × environment interaction complicate the selection of these traits. In addition, symbiotic relationships with Rhizobium and mycorrhiza need to be taken into consideration when selecting for enhanced biological N fixation and greater or more efficient acquisition of soil P. Genomic examination of complex traits such as these should help bean breeders devise more effective selection strategies. As integration of genomics in plant breeding advances, the challenge will be to develop molecular tools that also benefit breeding programs in developing countries. Transgenic breeding methods for bean improvement are not well defined, nor efficient, as beans are recalcitrant to regeneration from cell cultures. Moreover, if issues related to consumer acceptance of GMOs cannot be resolved, traits such as herbicide tolerance in transgenic bean cultivars which would help farmers reduce production costs and decrease soil erosion will remain unrealized.

103 citations


Cites background from "Advances in development of transgen..."

  • ...Transgenic beans Although genetic transformation has been reported for all major pulse crops, transgenic cultivars have not yet been commercially released (Eapen 2008)....

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  • ...…cells for transformation, the long period of time required to develop transgenics, lack of long-term funding, the absence of a coordinated research by the scientific community and, in some cases, an unfavorable public perception toward the use of transgenic crops (Dita et al. 2006; Eapen 2008)....

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Journal ArticleDOI
TL;DR: Genomics-assisted breeding (GAB) is anticipated to speed up the progress of genetic improvement of pulses, leading to the rapid development of cultivars with higher yield, enhanced stress tolerance and wider adaptability.
Abstract: Key message Given recent advances in pulse molecu‑ lar biology, genomics‑driven breeding has emerged as a promising approach to address the issues of limited genetic gain and low productivity in various pulse crops. Abstract The global population is continuously increas- ing and is expected to reach nine billion by 2050. This huge population pressure will lead to severe shortage of food, natural resources and arable land. Such an alarming situa- tion is most likely to arise in developing countries due to increase in the proportion of people suffering from protein and micronutrient malnutrition. Pulses being a primary and affordable source of proteins and minerals play a key role in alleviating the protein calorie malnutrition, micronutri- ent deficiencies and other undernourishment-related issues. Additionally, pulses are a vital source of livelihood genera- tion for millions of resource-poor farmers practising agri- culture in the semi-arid and sub-tropical regions. Limited

86 citations

Journal ArticleDOI
TL;DR: The role of legumes in sustainable agriculture, and particularly, their use in the reclamation of marginal lands, certainly has a very promising future.
Abstract: Mineral nitrogen deficiency is a frequent characteristic of arid and semi-arid soils. Biological nitrogen fixation by legumes is a sustainable and environmental-friendly alternative to chemical fertilization. Therefore, legumes have a high potential for the reclamation of marginal soils. Such issue is becoming more urgent due to the ever-rising requirement for food and feed, and the increasing extension of salinized and degraded lands, both as a consequence of global change and irrigation practices. This manuscript reviews current research on physiological and molecular mechanisms involved in the response and tolerance to environmental stresses of the Rhizobium–legume symbiosis. We report in particular recent advances on the isolation, characterization, and selection of tolerant rhizobial strains and legume varieties, both by traditional methods and through biotechnological approaches. The major points are the following. (1) Understanding mechanisms involved in stress tolerance is advancing fast, thus providing a solid basis for the selection and engineering of rhizobia and legumes with enhanced tolerance to environmental constraints. (2) The considerable efforts to select locally adapted legume varieties and rhizobial inocula that can fix nitrogen under conditions of drought or salinity are generating competitive crop yields in affected soils. (3) Biotechnological approaches are used to obtain improved legumes and rhizobia with enhanced tolerance to abiotic stresses, paying particular attention to the sensitive nitrogen-fixing activity. Those biotechnologies are yielding transgenic crops and inocula with unquestionable potential. In conclusion, the role of legumes in sustainable agriculture, and particularly, their use in the reclamation of marginal lands, certainly has a very promising future.

85 citations


Cites background or methods from "Advances in development of transgen..."

  • ...The distinct protocols for genetic transformation of the main legumes are in constant development to ensure food and environmental safety (Popelka et al. 2004 and references therein; Eapen 2008 and references therein)....

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  • ...Another method used involves transformation by particle gun bombardment (Eapen 2008 and references therein)....

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Journal ArticleDOI
TL;DR: The results have shown the significance of pyramiding and co-expression of two Cry toxins for efficient protection against lepidopteran pests of chickpea.
Abstract: The modified cry1Ab and cry1Ac insecticidal genes of Bacillus thuringiensis (Bt) under the control of two different constitutive promoters have been introduced into chickpea (Cicer arietinum L.) by Agrobacterium-mediated transformation of pre-conditioned cotyledonary nodes. 118 stable transformed T0 plants as independent transformation events were obtained expressing individual cry1Ab, cry1Ac or both pyramided genes for their co-expression driven by either cauliflower mosaic virus 35S promoter with duplicated enhancer (CaMV35S) or synthetic constitutive promoter (Pcec) and their combinations. Integration and inheritance of transgenes in T0 and T1 population of transgenic chickpea plants were determined by PCR, RT-PCR and Southern hybridization. Results of Southern hybridization showed single copy integration of cry1Ab or cry1Ac genes in most of the transgenic plants developed with either single or pyramided genes and reflected Mendelian inheritance of transgenes in T1 progeny. Real time PCR of pyramided transgenic plants clearly showed differential expression of transcripts for both the genes driven by CaMV35S and Pcec promoters. Quantitative assessment of Bt Cry toxins by ELISA of T0 transgenic chickpea plants showed expression of toxin ranging from 5 to 40 ng mg−1 of total soluble protein (TSP) in leaves of transgenic plants. Insect bioassay performed with transgenic plants showed relatively higher toxicity for plants expressing Cry1Ac protein as compared to Cry1Ab to Helicoverpa armigera. Pyramided transgenic plants with moderate expression levels (15–20 ng mg−1 of TSP) showed high-level of resistance and protection against pod borer larvae of H. armigera as compared to high level expression of a single toxin. These results have shown the significance of pyramiding and co-expression of two Cry toxins for efficient protection against lepidopteran pests of chickpea.

81 citations


Cites background from "Advances in development of transgen..."

  • ...However, the efficiency of Agrobacterium-mediated transformation and recovery of transgenics of grain legumes are restricted due to several inherent limitations including their complex genome (Eapen 2008; Dita et al. 2006)....

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References
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Journal ArticleDOI
TL;DR: The modified method should facilitate high-throughput transformation of Arabidopsis for efforts such as T-DNA gene tagging, positional cloning, or attempts at targeted gene replacement.
Abstract: Summary The Agrobacterium vacuum infiltration method has made it possible to transform Arabidopsis thaliana without plant tissue culture or regeneration. In the present study, this method was evaluated and a substantially modified transformation method was developed. The labor-intensive vacuum infiltration process was eliminated in favor of simple dipping of developing floral tissues into a solution containing Agrobacterium tumefaciens, 5% sucrose and 500 microliters per litre of surfactant Silwet L-77. Sucrose and surfactant were critical to the success of the floral dip method. Plants inoculated when numerous immature floral buds and few siliques were present produced transformed progeny at the highest rate. Plant tissue culture media, the hormone benzylamino purine and pH adjustment were unnecessary, and Agrobacterium could be applied to plants at a range of cell densities. Repeated application of Agrobacterium improved transformation rates and overall yield of transformants approximately twofold. Covering plants for 1 day to retain humidity after inoculation also raised transformation rates twofold. Multiple ecotypes were transformable by this method. The modified method should facilitate high-throughput transformation of Arabidopsis for efforts such as T-DNA

18,757 citations

Journal ArticleDOI
TL;DR: Legumes, broadly defined by their unusual flower structure, podded fruit, and the ability of 88% of the species examined to date to form nodules with rhizobia, are second only to the Graminiae in their importance to humans.
Abstract: Legumes, broadly defined by their unusual flower structure, podded fruit, and the ability of 88% of the species examined to date to form nodules with rhizobia ([de Faria et al., 1989][1]), are second only to the Graminiae in their importance to humans. The 670 to 750 genera and 18,000 to 19,000

1,513 citations

Journal ArticleDOI
TL;DR: The expression pattern of BABY BOOM in developing seeds combined with the BBM overexpression phenotype suggests a role for this gene in promoting cell proliferation and morphogenesis during embryogenesis.
Abstract: The molecular mechanisms underlying the initiation and maintenance of the embryonic pathway in plants are largely unknown. To obtain more insight into these processes, we used subtractive hybridization to identify genes that are upregulated during the in vitro induction of embryo development from immature pollen grains of Brassica napus (microspore embryogenesis). One of the genes identified, BABY BOOM (BBM), shows similarity to the AP2/ERF family of transcription factors and is expressed preferentially in developing embryos and seeds. Ectopic expression of BBM in Arabidopsis and Brassica led to the spontaneous formation of somatic embryos and cotyledon-like structures on seedlings. Ectopic BBM expression induced additional pleiotropic phenotypes, including neoplastic growth, hormone-free regeneration of explants, and alterations in leaf and flower morphology. The expression pattern of BBM in developing seeds combined with the BBM overexpression phenotype suggests a role for this gene in promoting cell proliferation and morphogenesis during embryogenesis.

811 citations

Journal ArticleDOI
TL;DR: The results suggest that WUS/PGA6 also plays a key role during embryogenesis, presumably by promoting the vegetative-to-embryogenic transition and/or maintaining the identity of the embryonic stem cells.
Abstract: Formation of somatic embryos in plants is known to require high concentrations of auxin or 2,4-dichlorophenoxyacetic acid (2,4-D), which presumably acts to trigger a signalling cascade. However, very little is known about the molecular mechanism that mediates the vegetative-to-embryogenic transition. We have employed a genetic approach to dissect the signal transduction pathway during somatic embryogenesis. In a functional screen using a chemical-inducible activation-tagging system, we identified two alleles of Arabidopsis gene PGA6 whose induced overexpression caused high-frequency somatic embryo formation in all tissues and organs tested, without any external plant hormones. Upon inducer withdrawal, all these somatic embryos were able to germinate directly, without any further treatment, and to develop into fertile adult plants. PGA6 was found to be identical to WUSCHEL (WUS), a homeodomain protein previously shown to be involved in specifying stem cell fate in shoot and floral meristems. Transgenic plants carrying an estradiol-inducible XVE-WUS transgene can phenocopy pga6-1 and pga6-2. Our results suggest that WUS/PGA6 also plays a key role during embryogenesis, presumably by promoting the vegetative-to-embryogenic transition and/or maintaining the identity of the embryonic stem cells.

556 citations

Journal ArticleDOI
10 Feb 2005-Nature
TL;DR: It is shown that several species of bacteria outside the Agrobacterium genus can be modified to mediate gene transfer to a number of diverse plants, which may lead to new uses of natural bacteria–plant interactions to achieve plant transformation.
Abstract: Agrobacterium is widely considered to be the only bacterial genus capable of transferring genes to plants. When suitably modified, Agrobacterium has become the most effective vector for gene transfer in plant biotechnology. However, the complexity of the patent landscape has created both real and perceived obstacles to the effective use of this technology for agricultural improvements by many public and private organizations worldwide. Here we show that several species of bacteria outside the Agrobacterium genus can be modified to mediate gene transfer to a number of diverse plants. These plant-associated symbiotic bacteria were made competent for gene transfer by acquisition of both a disarmed Ti plasmid and a suitable binary vector. This alternative to Agrobacterium-mediated technology for crop improvement, in addition to affording a versatile 'open source' platform for plant biotechnology, may lead to new uses of natural bacteria-plant interactions to achieve plant transformation.

369 citations