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Plant growth-stimulating hormones brassinosteroids (BRs) function via interactions with other hormones. However, the mechanism
of these interactions remains to be elucidated. The unique phenotypes of brassinosteroid insensitive2/dwarf12-D (bin2/dwf12-D) mutants, such as twisted inflorescences and leaves, suggested that BIN2, a negative regulator of BR signaling, may be involved
in auxin signaling. Furthermore, previously, we showed that auxin stimulates DWF4 expression. To determine the possible role of BIN2/DWF12 in Auxin signaling, we measured DWARF4pro:GUS activity through both GUS histochemical staining and in vivo GUS assay. We found that the GUS activity in the bin2/dwarf12-1D background dramatically increased relative to control. In addition, the number of lateral roots (LR) in bin2/dwf12-1D was greater than wild type, and the optimal concentration for auxin-mediated lateral root induction was lower in bin2/dwf12-1D; these findings suggest that BIN2 plays a positive role in auxin signaling. In contrast, ABA repressed both DWF4pro:GUS expression and lateral root development. However, the degree of repression was lower in bin2/dwf12-1D background, suggesting that BIN2 plays a role in ABA-mediated DWF4pro:GUS expression and subsequently in lateral root development, too. Therefore, it is likely that BIN2 plays a role of signal integrator
for multiple hormones, such as BRs, auxin, and ABA. 相似文献
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Background
Protein prenylation is a common post-translational modification in metazoans, protozoans, fungi, and plants. This modification, which mediates protein-membrane and protein-protein interactions, is characterized by the covalent attachment of a fifteen-carbon farnesyl or twenty-carbon geranylgeranyl group to the cysteine residue of a carboxyl terminal CaaX motif. In Arabidopsis, era1 mutants lacking protein farnesyltransferase exhibit enlarged meristems, supernumerary floral organs, an enhanced response to abscisic acid (ABA), and drought tolerance. In contrast, ggb mutants lacking protein geranylgeranyltransferase type 1 exhibit subtle changes in ABA and auxin responsiveness, but develop normally. 相似文献4.
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Lisette Maria Catharina Nitsch Carla Oplaat Richard Feron Qian Ma Mieke Wolters-Arts Peter Hedden Celestina Mariani Wim Hendrik Vriezen 《Planta》2009,229(6):1335-1346
Although the hormones, gibberellin and auxin, are known to play a role in the initiation of fruits, no such function has yet
been demonstrated for abscisic acid (ABA). However, ABA signaling and ABA responses are high in tomato (Solanum lycopersicum L.) ovaries before pollination and decrease thereafter (Vriezen et al. in New Phytol 177:60–76, 2008). As a first step to understanding the role of ABA in ovary development and fruit set in tomato, we analyzed ABA content
and the expression of genes involved in its metabolism in relation to pollination. We show that ABA levels are relatively
high in mature ovaries and decrease directly after pollination, while an increase in the ABA metabolite dihydrophaseic acid
was measured. An important regulator of ABA biosynthesis in tomato is 9-cis-epoxy-carotenoid dioxygenase (LeNCED1), whose mRNA level in ovaries is reduced after pollination. The increased catabolism
is likely caused by strong induction of one of four newly identified putative (+)ABA 8′-hydroxylase genes. This gene was named
SlCYP707A1 and is expressed specifically in ovules and placenta. Transgenic plants, overexpressing SlCYP707A1, have reduced ABA levels and exhibit ABA-deficient phenotypes suggesting that this gene encodes a functional ABA 8′-hydroxylase.
Gibberellin and auxin application have different effects on the LeNCED1 and SlCYP707A1 gene expression. The crosstalk between auxins, gibberellins and ABA during fruit set is discussed. 相似文献
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Auxin regulates diverse molecular and physiological events at the cellular and organismal levels during plant growth and development
in response to environmental stimuli. It acts either through distinct signaling pathways or in concert with other growth hormones.
Its biological functions are adjusted by modulating biosynthesis, conjugate formation, and polar transport and distribution.
Several tryptophan-dependent and -independent auxin biosynthetic pathways have been proposed. Recent studies have shown that
a few flavin monooxygenase enzymes contribute to the tryptophan-dependent auxin biosynthesis. Here, we show that activation
of a flavin monooxygenase gene YUCCA7 (YUC7), which belongs to the tryptophan-dependent auxin biosynthetic pathway, enhances drought resistance. An Arabidopsis activation-tagged mutant yuc7-1D exhibited phenotypic changes similar to those observed in auxin-overproducing mutants, such as tall, slender stems and curled,
narrow leaves. Accordingly, endogenous levels of total auxin were elevated in the mutant. The YUC7 gene was induced by drought, primarily in the roots, in an abscisic acid (ABA)-dependent manner. The yuc7-1D mutant was resistant to drought, and drought-responsive genes, such as RESPONSIVE TO DESSICATION 29A (RD29A) and COLD-REGULATED 15A (COR15A), were up-regulated in the mutant. Interestingly, whereas stomatal aperture and production of osmoprotectants were not discernibly
altered, lateral root growth was significantly promoted in the yuc7-1D mutant when grown under drought conditions. These observations support that elevation of auxin levels in the roots enhances
drought resistance possibly by promoting root growth. 相似文献
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Melhorn V Matsumi K Koiwai H Ikegami K Okamoto M Nambara E Bittner F Koshiba T 《Journal of plant research》2008,121(1):125-131
Abscisic acid (ABA) regulates stomatal closure in response to water loss. Here, we examined the competence of guard cells
to synthesize ABA, using two Arabidopsis ABA biosynthetic enzymes. 35S pro::AtNCED3-GFP and AAO3-GFP were introduced into guard cells of broad bean leaves. AtNCED3-GFP expression was detected at the chloroplasts, whereas green
fluorescent protein (GFP) and AAO3-GFP were in the cytosol. The stomatal aperture was decreased in AtNCED3-GFP- and AAO3-GFP-transformed guard cells. This indicated that ABA biosynthesis is stimulated by heterologous expression of AtNCED3 and Arabidopsis
aldehyde oxidase 3 (AAO3) proteins, which both seem to be regulatory enzymes for ABA biosynthesis in these cells. Furthermore,
stomatal closure by the expression of AtNCED3 and AAO3 suggested that the substrates of the enzymes are present and native
ABA-biosynthesis enzymes are active in guard cells.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
V. Melhorn and K. Matsumi contributed equally to this work. 相似文献
10.
Yawo Mawunyo Nevame Adedze Baobing Feng Lei Shi Zhonghua Sheng Shaoqing Tang Xiangjin Wei Peisong Hu 《Plant Growth Regulation》2018,84(2):237-248
The rice EMS-derived mutant leaf adaxialized 1 (lad1) was isolated based on its upward rolling leaf phenotype. Besides the adaxially rolled leaf, many other agronomic traits were also compromised in lad1. The rolling trait was characterized by a noticeable alteration of bulliform cells in the adaxial side of the leaves. Map-based cloning showed a single nucleotide substitution in the promoter region of the KAN1 gene in lad1 mutant. Further, over-expressing and CRISPR/cas9-edited knockdown transgenic plants confirmed that KAN1 was responsible for the mutant phenotype of lad1. Yeast two-hybrid and bimolecular fluorescence complementation assay demonstrated that KAN1 can interact with the auxin response factors ARF3, ARF7 and ARF15. Physiologically, the contents of auxin (IAA), abscisic acid (ABA), jasmonic acid (JA) and gibberellin (GA) were all significantly increased in the lad1 mutant. Moreover, the GA3 content dramatically decrease in wild-type, but increased in lad1 under IAA induction. Additionally, the expression levels of several IAA and GA biosynthesis and responsive-related genes and genes involved in leaf polarity determination were altered in lad1. Therefore, we hypothesized that KAN1/ARFs protein complexes act as auxin-dependent regulatory units that play a conserved role in leaf development. 相似文献
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BREVIS RADIX is involved in cytokinin-mediated inhibition of lateral root initiation in <Emphasis Type="Italic">Arabidopsis</Emphasis> 总被引:1,自引:0,他引:1
Jing Li Xiaorong Mo Jirong Wang Nannan Chen Huan Fan Chunyan Dai Ping Wu 《Planta》2009,229(3):593-603
In contrast to auxin, relatively little is known about the molecular mechanism of cytokinin (CTK) inhibition of lateral root
initiation. Previous studies demonstrated that BREVIS RADIX (BRX), a protein of unknown biochemical function, maintains a
rate-limiting brassinosteroid biosynthesis enzyme expression to keep brassinosteroid biosynthesis above a critical threshold.
Here, we show that the brx-2 mutant is insensitive to exogenous CTK-induced inhibition of lateral root initiation and that this can be restored by embryonic
brassinosteroid treatment. However post-embryonic brassinosteroid treatment can not rescue brx-2 mutant phenotype in the presence of CTK. Meanwhile the brassinosteroid receptor defective mutant bri1-6 shows normal CTK-mediated inhibition on LR growth. These results suggest the CTK-mediated inhibition of LR initiation is
not directly dependent on brassinosteroid level. Furthermore, compared with wild type, brx-2 exhibits altered auxin response in presumptive founder cells, lateral root primodia and primary root tip in the presence
of exogenous CTK. We concluded that CTK inhibition on lateral root initiation depend on specific auxin response loss in presumptive
founder cell. The aberrant primary root growth caused by the embryonic brassinosteroid shortage can indirectly result in the
lateral root phenotype of brx-2 in presence of CTK.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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The ecology and physiology of ectomycorrhizal (EcM) symbiosis with conifer trees are well documented. In comparison, however,
very little is known about the molecular regulation of these associations. In an earlier study, we identified three EcM-regulated
Pinus expressed sequence tags (EST), two of which were identified as homologous to the Medicago truncatula nodulin MtN21. The third EST was a homologue to the receptor-like kinase Clavata1. We have characterized the expression patterns of these genes and of auxin- and mycorrhiza-regulated genes after induction
with indole-3-butyric acid in Pinus sylvestris and in a time course experiment during ectomycorrhizal initiation with the co-inoculation of 2,3,5-triiodobenzoic acid, an
auxin transport inhibitor. Our results suggest that different P. sylvestris nodulin homologues are associated with diverse processes in the root. The results also suggest a potential role of the Clv1-like gene in lateral root initiation by the ectomycorrhizal fungus. 相似文献
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Zhehao Chen Mengting Li Ye Yuan Jiangqin Hu Yanjun Yang Jiliang Pang Lilin Wang 《Plant Cell, Tissue and Organ Culture》2017,131(1):107-118
Auxin receptors TIR1/AFBs play an essential role in a series of signaling network cascades. These F-box proteins have also been identified to participate in different stress responses via the auxin signaling pathway in Arabidopsis. Cucumber (Cucumis sativus L.) is one of the most important crops worldwide, which is also a model plant for research. In the study herein, two cucumber homologous auxin receptor F-box genes CsTIR and CsAFB were cloned and studied for the first time. The deduced amino acid sequences showed a 78% identity between CsTIR and AtTIR1 and 76% between CsAFB and AtAFB2. All these proteins share similar characteristics of an F-box domain near the N-terminus, and several Leucine-rich repeat regions in the middle. Arabidopsis plants ectopically overexpressing CsTIR or CsAFB were obtained and verified. Shorter primary roots and more lateral roots were found in these transgenic lines with auxin signaling amplified. Results showed that expression of CsTIR/AFB genes in Arabidopsis could lead to higher seeds germination rates and plant survival rates than wild-type under salt stress. The enhanced salt tolerance in transgenic plants is probably caused by maintaining root growth and controlling water loss in seedlings, and by stabilizing life-sustaining substances as well as accumulating endogenous osmoregulation substances. We proposed that CsTIR/AFB-involved auxin signal regulation might trigger auxin mediated stress adaptation response and enhance the plant salt stress resistance by osmoregulation. 相似文献
17.
Y. Bao P. Dharmawardhana R. Arias M. B. Allen C. Ma Steven H. Strauss 《Plant cell reports》2009,28(6):947-962
We describe the development of a reporter system for monitoring meristem initiation in poplar using promoters of poplar homologs
to the meristem-active regulatory genes WUSCHEL (WUS) and SHOOTMERISTEMLESS (STM). When ~3 kb of the 5′ flanking regions of close homologs were used to drive expression of the GUSPlus gene, 50–60% of the transgenic events showed expression in apical and axillary meristems. However, expression was also common
in other organs, including in leaf veins (40 and 46% of WUS and STM transgenic events, respectively) and hydathodes (56% of WUS transgenic events). Histochemical GUS staining of explants during callogenesis and shoot regeneration using in vitro stems
as explants showed that expression was detectable prior to visible shoot development, starting 3–15 days after explants were
placed onto callus inducing medium. A minority of WUS and STM events also showed expression in the cambium, phloem, or xylem of regenerated, greenhouse grown plants undergoing secondary
growth. Based on microarray gene expression data, a paralog of poplar WUS was detectably up-regulated during shoot initiation, but the other paralog was not. Both paralogs of poplar STM were down-regulated threefold to sixfold during early callus initiation. We identified 15–35 copies of cytokinin response
regulator binding motifs (ARR1AT) and one copy of the auxin response element (AuxRE) in both promoters. Several of the events
recovered may be useful for studying the process of primary and secondary meristem development, including treatments intended
to stimulate meristem development to promote clonal propagation and genetic transformation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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The MADS box genes participate in different steps of vegetative and reproductive plant development, including the most important phases of the reproductive process. Here we describe the isolation and characterisation of two Asparagus officinalis MADS box genes, AOM3 and AOM4. The deduced AOM3 protein shows the highest degree of similarity with ZAG3 and ZAG5 of maize, OsMADS6 of rice and AGL6 of Arabidopsis thaliana. The deduced AOM4 protein shows the highest degree of similarity with AOM1 of asparagus, the SEP proteins of Arabidopsis and the rice proteins OsMADS8, OsMADS45 and OsMADS7. The high level of identity between AOM1 and AOM4 made impossible the preparation of probes specific for one single gene, so the hybridisation signal previously described for AOM1 is probably due to the expression of both genes. The expression profile of AOM3 and AOM1/AOM4 during flower development is identical, and similar to that of the SEP genes. Asparagus genes, however, are expressed not only in flower organs, but also in the different meristem present on the apical region of the shoot during the flowering season: the apical meristem and the three lateral meristems emerging from the leaf axillary region that will give rise to flowers and lateral inflorescences during flowering season, and to phylloclades and branches during the subsequent vegetative phase. The expression of AOM3 and AOM1/AOM4 in these meristems appears to be correlated with the reproductive function of the apex as the hybridisation signal disappears when the apex switches to vegetative function. 相似文献
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To investigate the spatial and temporal dependence of hormonal regulation during gravitropism, we compared the effects of root cap application of indole-3-acetic acid (IAA) and abscisic acid (ABA) with gene expression changes occurring naturally during gravitropic reaction of Brassica rapa roots. The expression of auxin, ABA, and metabolism-related genes in the tip, elongation zone, and maturation zone varied with time, location, and hormone concentration and characterized polar auxin transport. IAA was transported readily shootward and inhibited growth more than ABA. Expression of PIN3 and IAA5 in the elongation zone showed downregulation on the convex but upregulation on the concave side. Both PIN7 and IAA5 responded near maximally to 10?8 M IAA within 30 min, suggesting that auxin activates its own transport system. Ubiquitin 1 (UBQ1) responded after a lag time of more than 1 h to IAA. The metabolic control gene Phosphoenolpyruvate carboxylase 1 (PEPC1) was more sensitive to ABA but upregulated by high concentrations of either hormone. The time course and duration of gene activation suggests that ABA is not involved in gravitropic curvature, differential elongation is not simply explained by IAA-induced upregulation, and that reference genes are sensitive to auxin. 相似文献
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Bei Wu Yun-He Li Jian-Yong Wu Qi-Zhu Chen Xia Huang Yun-Feng Chen Xue-Lin Huang 《Molecular biology reports》2011,38(5):3189-3194