Production of transgenic rice with agronomically useful genes: an assessment

Giri, Charu Chandra; Laxmi, G. Vijaya

doi:10.1016/s0734-9750(00)00053-7

Cited by 47 publications

(30 citation statements)

References 111 publications

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“…The development of transgenic rice has been tried, especially Bt rice which is rice transformed with an insecticidal gene from Bacillus thuringiensis (7,11). In contrast to the success of Bt maize and Bt cotton, Bt rice is not cultivated commercially, because of its safety concerns (11).…”

Section: Resultsmentioning

confidence: 99%

Rice Seeds as Sources of Endophytic Bacteria

Mano²,

et al. 2009

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Endophytic bacteria are considered to originate from the external environment. To examine the hypothesis that rice (Oryza sativa, cultivar Kinuhikari) seeds are a source of endophytic bacteria, we isolated endophytic bacteria from the shoots, remains of the seeds, and roots of rice seedlings that were aseptically cultivated in vitro from surfacedisinfected seeds. Of the various bacterial strains isolated, the closest relatives, identified by 16S rRNA gene sequencing, were: Bacillus firmus, B. fusiformis, B. pumilus, Caulobacter crescentus, Kocuria palustris, Micrococcus luteus, Methylobacterium fujisawaense, Me. radiotolerans, and Pantoea ananatis. The latter three species have been detected frequently inside both rice seedlings and mature rice plants. These results indicate that rice seeds are an important source of endophytic bacteria. The bacteria that colonize the seed interior appear to infect the subsequent generation via rice seeds and become the dominant endophytic species in the mature plant.Key words: culturable endophytic bacteria, rice seed, infection from seed to shoot, 16S rRNA gene sequence Various types of microorganisms, including fungi, actinomycetes, and other bacteria, are found inside plants and designated endophytes. In general, microorganisms having visibly harmful effects on plants are not considered endophytes. Some endophytic bacteria have beneficial effects on the host, e.g., promoting plant growth, strengthening resistance to pathogens, and increasing the supply of fixed nitrogen to the plant (9). Studies are underway to exploit these beneficial features for agriculture. However, our knowledge of endophytic bacterial ecology, including the origins of these bacteria, remains incomplete.Endophytic bacteria are considered to originate from the external environment and to enter the plant through the stomata, lenticles, wounds (including broken trichomes), areas of emergence of lateral roots, and germinating radicles (12). The notion of seeds as a source of endophytic bacteria remains controversial (9). Sato (39) did not detect endophytic bacteria in rice seeds. Mundt and Hinkle (27) obtained endophytes only from the damaged seeds of 28 plant types other than rice. Endophytic bacteria were detected in cotton seeds at viable population densities that ranged from 1×10 3 to 1×105 CFU g −1 fresh weight, as well as in the seeds of sweet corn at viable population densities of <1×10 CFU g −1 fresh weight (26). Endophytic bacterial populations increased from nondetectable levels in cotton seeds to detectable levels in radicles 4 days after placing surface-disinfected cotton seeds on water agar (1).Rice (Oryza sativa) is the most important cereal crop in the world, feeding more than 50% of the global population (8). In our search for endophytic bacteria in rice plants, we detected culturable endophytic bacteria in rice seeds at viable population densities that ranged from 10 2 to 10 6 CFU g −1 fresh weight (22,31). Endophytes in seeds may be carried over to the subsequent generation. Thus, in the p...

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Section: Resultsmentioning

confidence: 99%

Rice Seeds as Sources of Endophytic Bacteria

Mano²,

et al. 2009

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“…The benefits range from manipulating generation time, plant protection, wood quality, production of compounds of pharmaceutical value and improvements to polluted soils. These successes have shown avenues to include more agronomically useful genes for transfer to tree species as has been demonstrated in crop plants (Giri and Vijaya Laxmi 2000). From the global trend forestry biotechnology joint venture information there are now at least 24 tree species that have been subject to transgenic modification and released into the environment through field trials.…”

Section: Resultsmentioning

confidence: 99%

Progress in tissue culture, genetic transformation and applications of biotechnology to trees: an overview

Giri

Shyamkumar

Anjaneyulu

2003

Trees

168

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Trees are an integral part of human life, and a vital component of biodiversity. Forest trees in particular are renewable sources of food, fodder, fuel wood, timber and other valuable non-timber products. Due to the rapid growth of population and the human desire to progress, there has been a tremendous reduction in forest cover from the earth's surface. To maintain and sustain forest vegetation, conventional approaches have been exploited in the past for propagation and improvement. However, such efforts are confronted with several inherent bottlenecks. Biotechnological interventions for in vitro regeneration, mass micropropagation and gene transfer methods in forest tree species have been practised with success, especially in the last decade. Against the background of the limitations of long juvenile phases and life span, development of plant regeneration protocols and genetic engineering of tree species are gaining importance. Genetic engineering assumes additional significance, because of the possibility of introducing a desired gene in a single step for precision breeding of forest trees. There are no comprehensive and detailed reviews available combining research developments with major emphases on tissue culture and basic genetic transformation in tree species. The present communication attempts to overview the progress in tissue culture, genetic transformation and biotechnological applications in the last decade and future implications.

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“…NIRS is time-saving and low-cost, and previous studies have used NIRS to determine quality characteristics such as moisture, protein, starch, amylose and lipids in buckwheat, wheat, barley, maize, soybean and rice [11][12][13][14][15][16][17]; the practice was widely accepted in the trade of these products. To date, many genes related to important agronomic traits and seed qualities have been identified through breeding and genetic transformation protocols [1,5,18], and quantitative trait locus (QTL) analysis and mapbased cloning have been applied to identify loci associated with seed quality control [19,20]. Chinese geneticists and breeders have made great progress in the hybrid rice technology [21], and marker-assisted selection has been widely used to pyramid functional genes into popular hybrid rice cultivars to improve the seed quality [22,23].…”

Section: Fang-fang Fu Et Al 381mentioning

confidence: 99%

“…To date, many genes related to important agronomic traits and seed qualities have been identified through breeding and genetic transformation protocols [1,5,18], and quantitative trait locus (QTL) analysis and mapbased cloning have been applied to identify loci associated with seed quality control [19,20]. Chinese geneticists and breeders have made great progress in the hybrid rice technology [21], and marker-assisted selection has been widely used to pyramid functional genes into popular hybrid rice cultivars to improve the seed quality [22,23].…”

Section: Introductionmentioning

confidence: 99%

Studies on rice seed quality through analysis of a large-scale T-DNA insertion population

et al. 2009

Cell Res

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A rice (Oryza sativa) T-DNA insertion population, which included more than 63 000 independent transgenic lines and 8 840 identified flanking sequence tags (FSTs) that were mapped onto the rice genome, was developed to systemically study the rice seed quality control. Genome-wide analysis of the FST distribution showed that T-DNA insertions were positively correlated with expressed genes, but negatively with transposable elements and small RNAs. In addition, the recovered T-DNAs were preferentially located at the untranslated region of the expressed genes. More than 11 000 putative homozygous lines were obtained through multi-generations of planting and resistance screening, and measurement of seed quality of around half of them, including the contents of starch, amylose, protein and fat, with a nondestructive near-infrared spectroscopy method, identified 551 mutants with unique or multiple altered parameters of seed quality. Analysis of the corresponding FSTs showed that genes participating in diverse functions, including metabolic processes and transcriptional regulation, were involved, indicating that seed quality is regulated by a complex network. IntroductionRice (Oryza sativa), as a wholesome and nutritious cereal grain, provides the staple food for more than half of the world's population [1]. Along with the growth of economies and population throughout the world, there is an increasing demand for high-yield and high-quality rice. The grain quality of rice, including that of milling, appearance, cooking and eating, and nutrition, is determined by multiple physicochemical properties [2], and studies on the involved key genes and relevant regulatory mechanisms will help to illustrate the regulatory networks of rice quality control and benefit for the breeding efforts.Starch, which is composed of amylose and amylopectin, comprises ∼90% of dry endosperm of rice seed.The apparent amylose content (AAC) is recognized as an important determinant of the appearance and texture of grain [3]. Thai jasmine rice (KDML 105), one of the best-quality rice with good cooking and eating qualities, has low amylose content (AC) and medium gel consistency (GC) [4].The nutritional quality includes the proportions of protein, fat, mineral and other substances [5]. The rice protein is rich in methionine and cysteine, and compares favorably with proteins of other cereals, but is poor in lysine and threonine, making it an incomplete protein source for human infants [6]. Storage triacylglycerols are stored in oil bodies containing phospholipids and oleosins at the surface [7], and oil bodies are abundant in embryo and aleurone layer of rice seed. However, the aleurone layer is usually removed by milling because it turns rancid upon storage [8]. In addition, oil also influences other aspects of seed quality, and a recent report showed that the quality and viability of Arabidopsis seeds can be enhanced by suppressing phospholipase D [9].The near-infrared spectroscopy (NIRS) technology, which is based on the fact that several natural pr...

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Production of transgenic rice with agronomically useful genes: an assessment

Cited by 47 publications

References 111 publications

Rice Seeds as Sources of Endophytic Bacteria

Rice Seeds as Sources of Endophytic Bacteria

Progress in tissue culture, genetic transformation and applications of biotechnology to trees: an overview

Studies on rice seed quality through analysis of a large-scale T-DNA insertion population

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