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Little is known of the mechanisms that induce the dedifferentiation of a single somatic cell into a totipotent embryogenic cell that can either be regenerated or develop into an embryo and subsequently an entire plant. In this Opinion article, we examine the cellular, physiological and molecular similarities and differences between different plant stem cell types. We propose to extend the plant stem cell concept to include single embryogenic cells as a totipotent stem cell based on their capacity to regenerate or develop into an embryo under certain conditions. Our survey suggests that differences in chromatin structure might ensure that meristem-localized stem cells have supervised freedom and are pluripotent, and that embryogenic stem cells are unsupervised, autonomous and, hence, freely totipotent. 相似文献
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Mantelin S Desbrosses G Larcher M Tranbarger TJ Cleyet-Marel JC Touraine B 《Planta》2006,223(3):591-603
Both root architecture and plant N nutrition are altered by inoculation with the plant growth-promoting rhizobacteria (PGPR)
Phyllobacterium strain STM196. It is known that NO3− and N metabolites can act as regulatory signals on root development and N transporters. In this study, we investigate the
possible interrelated effects on root development and N transport. We show that the inhibition of Arabidopsis lateral root growth by high external NO3− is overridden by Phyllobacterium inoculation. However, the leaf NO3− pool remained unchanged in inoculated plants. By contrast, the Gln root pool was reduced in inoculated plants. Unexpectedly,
NO3− influx and the expression levels of AtNRT1.1 and AtNRT2.1 genes coding for root NO3− transporters were also decreased after 8 days of Phyllobacterium inoculation. Although the mechanisms by which PGPR exert their positive effects remain unknown, our data show that they can
optimize plant development independently from N supply, thus alleviating the regulatory mechanisms that operate in axenic
conditions. In addition, we found that Phyllobacterium sp. elicited a very strong induction of AtNRT2.5 and AtNRT2.6, both genes preferentially expressed in the shoots whose functions are unknown. 相似文献
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Chatthai Malinee Kaukinen Karia H. Tranbarger Timothy J. Gupta Pramod K. Misra Santosh 《Plant molecular biology》1997,34(2):243-254
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Comparative Transcriptome Analysis of Three Oil Palm Fruit and Seed Tissues That Differ in Oil Content and Fatty Acid Composition 总被引:1,自引:0,他引:1
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Timothy John Tranbarger Wanwisa Kluabmongkol Duangjai Sangsrakru Fabienne Morcillo James W Tregear Somvong Tragoonrung Norbert Billotte 《BMC plant biology》2012,12(1):1
Background
The oil palm (Elaeis guineensis Jacq.) is a perennial monocotyledonous tropical crop species that is now the world's number one source of edible vegetable oil, and the richest dietary source of provitamin A. While new elite genotypes from traditional breeding programs provide steady yield increases, the long selection cycle (10-12 years) and the large areas required to cultivate oil palm make genetic improvement slow and labor intensive. Molecular breeding programs have the potential to make significant impacts on the rate of genetic improvement but the limited molecular resources, in particular the lack of molecular markers for agronomic traits of interest, restrict the application of molecular breeding schemes for oil palm. 相似文献7.
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Expression and Accumulation Patterns of Nitrogen-Responsive Lipoxygenase in Soybeans 总被引:3,自引:1,他引:2 下载免费PDF全文
Gene expression and protein accumulation patterns of nitrogen-responsive lipoxygenase (LOX-NR), as a representative vegetative storage protein, were investigated in nonnodulated soybeans (Glycine max [L.] Merr. cv Wye). The form of available nitrogen (supplied as NH4NO3, NH4+, NO3-, or urea) influenced the mRNA level and the amount of LOX protein, indicating that preferential accumulation of LOX may occur. Soybeans were grown with 0, 2, 5, and 16 mM total nitrogen to determine the extent to which LOX accumulation responded to soil nitrogen levels. Analysis of both mRNA and protein levels was conducted in shoot tips, stems, pod walls, and leaves over the entire life cycle of the plant. A general correlation between increasing available nitrogen level and LOX level was seen in the shoot tip and other organs throughout the soybean life cycle. However, appreciable amounts of LOX-NR mRNA and protein accumulated even when plants were grown under conditions of nitrogen deficiency. The results indicate that LOX may play an important role as a temporary storage site for amino acids in the developing shoot tip. The expression patterns of LOX-NR in plants grown under nitrogen deficiency suggest that these proteins, although responsive to nitrogen status, may not function solely as temporary storage pools for amino acids. 相似文献