ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1141

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1143

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1145

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1147

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

The 5' region of the rice actin 1 gene (Act1) has been developed as an efficient regulator of foreign gene expression in transgenic rice plants. To determine the pattern and level of rice Act1 5' region activity, transgenic rice plants containing the Act1 5' region fused to a bacterial beta-glucuronidase (Gus) coding sequence were generated. Two independent clonal lines of transgenic rice plants were analyzed in detail. Quantitative analysis showed that tissue from these transgenic rice plants have a level of GUS protein that represents as much as 3% of total soluble protein. We were able to demonstrate that Act1-Gus gene expression is constitutive throughout the sporophytic and gametophytic tissues of these transgenic rice plants. Plants from one transgenic line were analyzed for the segregation of GUS activity in pollen by in situ histochemical staining, and the inheritance and stability of Act1-Gus expression were assayed in subsequently derived progeny plants.

ISSN:1040-4651    

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

We constructed a chimeric gene consisting of a soybean small auxin up RNA (SAUR) promoter and leader sequence fused to an Escherichia coli [beta]-glucuronidase (GUS) open reading frame and a 3[prime]untranslated nopaline synthase sequence from Agrobacterium tumefaciens. This chimeric gene was used to transform tobacco by Agrobacterium-mediated transformation. In R2 etiolated transgenic tobacco seedlings, GUS expression occurred primarily in elongation regions of hypocotyls and roots. In green plants, GUS was expressed primarily in the epidermis and cortex of stems and petioles, as well as in elongation regions of anther filaments in developing flowers. GUS expression was responsive to exogenous auxin in the range of 10-8 to 10-3 M. During gravitropism and phototropism, the GUS activity became greater on the more rapidly elongating side of tobacco stems. Auxin transport inhibitors and other manipulations that blocked gravitropism also blocked the asymmetric distribution of GUS activity in gravistimulated stems. Light treatment of dark-grown seedlings resulted in a rapid decrease in GUS activity. Light-induced decay in GUS activity was fully reversed by application of auxin. Taken together, our results add support for the formation of an asymmetric distribution of auxin at sites of action during tropism.

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1167

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

The hy1 and hy2 long hypocotyl mutants of Arabidopsis contain normal levels of immunochemically detectable phytochrome A, but the molecule is photochemically nonfunctional. We have investigated the biochemical basis for this lack of function. When the hy1 and hy2 mutants were grown in white light on a medium containing biliverdin IX[alpha], a direct precursor to phytochromobilin, the phytochrome chromophore, the seedlings developed with a morphological phenotype indistinguishable from the light-grown wild-type control. Restoration of a light-grown phenotype in the hy1 mutant was also accomplished by using phycocyanobilin, a tetrapyrrole analog of phytochromobilin. Spectrophotometric and immunochemical analyses of the rescued hy1 and hy2 mutants demonstrated that they possessed wild-type levels of photochemically functional phytochrome that displayed light-induced conformational changes in the holoprotein indistinguishable from the wild type. Moreover, phytochrome A levels declined in vivo in response to white light in rescued hy1 and hy2 seedlings, indicative of biliverdin-dependent formation of photochemically functional phytochrome A that was then subject to normal selective turnover in the far-red-light-absorbing form. Combined, these data suggest that the hy1 and hy2 mutants are inhibited in chromophore biosynthesis at steps prior to the formation of biliverdin IX[alpha], thus potentially causing a global functional deficiency in all members of the phytochrome photoreceptor family.

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1177

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

Synthesis of the phytohormone ethylene is believed to be essential for many plant developmental processes. The control of ripening in climacteric fruits and vegetables is among the best characterized of these processes. One approach to reduce ethylene synthesis in plants is metabolism of its immediate precursor, 1-aminocyclopropane-1-carboxylic acid (ACC). Soil bacteria containing an enzyme, ACC deaminase, were identified by their ability to grow on ACC as a sole nitrogen source. The gene encoding ACC deaminase was cloned and introduced into tomato plants. Reduction in ethylene synthesis in transgenic plants did not cause any apparent vegetative phenotypic abnormalities. However, fruits from these plants exhibited significant delays in ripening, and the mature fruits remained firm for at least 6 weeks longer than the nontransgenic control fruit. These results indicated that ACC deaminase is useful for examining the role of ethylene in many developmental and stress-related processes in plants as well as for extending the shelf life of fruits and vegetables whose ripening is mediated by ethylene.

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1187

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

We have previously shown that the 15-amino acid carboxyl-terminal propeptide of probarley lectin is necessary for the proper sorting of this protein to the plant vacuole. A mutant form of the protein lacking the carboxyl-terminal propeptide is secreted. To test whether the carboxyl-terminal propeptide is the vacuole sorting determinant of probarley lectin, we examined in transgenic tobacco the processing and sorting of a series of fusion proteins containing the secreted protein, cucumber chitinase, and regions of probarley lectin. Pulse-labeling experiments demonstrated that the fusion proteins were properly translocated through the tobacco secretory system and that cucumber chitinase and cucumber chitinase fusion proteins lacking the carboxyl-terminal propeptide were secreted. The cucumber chitinase fusion protein containing the carboxyl-terminal propeptide was properly processed and sorted to the vacuole in transgenic tobacco as confirmed by organelle fractionation and electron microscopy immunocytochemistry. Therefore, the barley lectin carboxyl-terminal propeptide is both necessary and sufficient for protein sorting to the plant vacuole.

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1195

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB

摘要:

Through the action of opaque-2 modifier genes, the soft, floury endosperm of opaque-2 mutants is converted to a vitreous phenotype. This change in endosperm texture is associated with a twofold to threefold increase in gamma-zein content. To investigate the effect of opaque-2 modifiers on the expression of gamma-zein genes, we analyzed the synthesis and distribution of gamma-zein protein and the level of gamma-zein mRNAs in developing endosperms of the inbreds W64A and W64Ao2, a modified opaque-2 mutant Pool 34 QPM, and their reciprocal F1 hybrids. We also characterized the number and organization of gamma-zein genes in these and related maize genotypes. Our studies show that opaque-2 modifiers are semidominant genes, resulting in a twofold to threefold increase in gamma-zein gene expression in both opaque-2 and normal genetic backgrounds. The increase in gene expression appears to be a consequence of enhanced mRNA transcription or stability rather than gene amplification because gamma-zein genes occur in one or two copies in modified as well as nonmodified genetic backgrounds. Ultrastructural studies showed that gamma-zein occurs in high concentrations in the first few subaleurone cells of nonmodified endosperms, but high concentrations of gamma-zein occur in the subaleurone and central endosperm cells of modified opaque-2 mutants. The increased concentration and distribution of gamma-zein in modified endosperms are highly correlated with the activity of opaque-2 modifier genes.

ISSN:1040-4651    

DOI:10.1105/tpc.3.11.1207

出版商:American Society of Plant Biologists    

年代:1991

数据来源: ASPB