共查询到20条相似文献,搜索用时 56 毫秒
1.
Iron toxicity occurs under flooded conditions such as those prevailing in lowland rice fields and is due to an excess of ferrous ions. Ferritin is a multimeric protein responsible for Fe sequestration and storage, playing a key role in Fe homeostasis. Our aim was to study the modalities of overall ferritin synthesis in different organs of young seedlings from the African rice species (Oryza glaberrima) in relation to the putative involvement of abscisic acid (ABA) and oxidative stress in signalling processes. Seedlings from a moderately resistant to iron toxicity cultivar were grown in hydroponic culture for 2 weeks and treated with 500 mg l?1 Fe2+ in the presence or in the absence of 200?µM ABA, 50?µM methylviologen or 50?µM fluridone. Iron treatment increased iron and malondialdehyde concentration in all organs as well as ABA in roots and laminae. Although ferritin protein was detected in controls plants, iron treatment strongly reinforced its accumulation in sheaths and laminae after 24 h and 72 h. Ferritin mRNA was induced as early as 24 h after the beginning of the Fe-treatment in sheaths and, to a higher extent, in laminae. In the absence of iron treatment, exogenous ABA increased ferritin mRNA in laminae only but did not lead to further ferritin accumulation. Unexpectedly, it decreased ferritin mRNA levels in the sheaths of iron-treated plants and may thus have a dual influence depending on the considered organ. The inhibitor of ABA synthesis fluridone reduced endogenous ABA but did not compromise ferritin gene expression or ferritin synthesis, whatever the iron dose. Methyviologen application induced obvious oxidative damages but reduced ferritin synthesis. It is suggested that the signalling pathway leading to ferritin synthesis in the semi-aquatic African rice species may involve other components than those reported for typical terrestrial plants. 相似文献
2.
Adebayo A. OMOLOYE 《Entomological Science》2010,13(3):320-327
This study assessed the effects of genotype variations in two cultivated rice species: Oryza glaberrima and Oryza sativa on the biology and galling characteristics of the African rice gall midge (AfRGM), Orseolia oryzivora Harris and Gagné. The study was conducted in the screen house at ambient temperature (27 ± 3°C), 70 ± 5% relative humidity and 12:12 h photoperiod. Shoot galling, the most visible response of rice genotypes to attack by the insect, was greatly suppressed, being only 0.7 cm long in the O. glaberrima genotypes compared to 34 cm in the O. sativa species. Larval mortality (70–88%) in the O. glaberrima genotypes was significantly higher at the first instar compared to O. sativa. Gall setting was confirmed to be an irredeemable tiller loss. Even in the susceptible O. sativa genotypes, where many larvae may colonize a tiller, only one survived to the second instar. Resistant and susceptible rice genotypes had significantly different effects on the development and reproductive anatomy of the AfRGM. The female reproductive anatomy which consists of two ovaries, each with a potential complement of 192 eggs was affected by interspecific variation in rice genotypes causing reduced potential fecundity (32); morphological distortion, 60% reduction of egg size of F1 emergent in O. glaberrima compared to emergent from the susceptible O. sativa genotypes. 相似文献
3.
4.
Background and Aims Oryza glaberrima
is widely grown in flood-prone areas of African river basins and is subject to prolonged periods of annual submergence. The effects of submergence on shoot elongation, shoot biomass, leaf area and CO2 uptake were studied and compared with those of O. sativa.Methods
A wide selection of lines of O. sativa and O. glaberrima, including some classified as submergence tolerant, were compared in field and pot experiments. Plants were submerged completely for 31 d in a field experiment, and partially or completely for 37 d in a pot experiment in a growth chamber.Key Results
Leaf elongation and growth in shoot biomass during complete submergence in the field were significantly greater in O. glaberrima than in O. sativa. So-called submergence-tolerant cultivars of O. sativa were unable to survive prolonged complete submergence for 31–37 d. This indicates that the mechanism of suppressed leaf elongation that confers increased survival of short-term submergence is inadequate for surviving long periods underwater. The O. sativa deepwater cultivar ‘Nylon’ and the ‘Yélé1A’ cultivar of O. glaberrima succeeded in emerging above the floodwater. This resulted in greatly increased shoot length, shoot biomass and leaf area, in association with an increased net assimilation rate compared with the lowland-adapted O. sativa ‘Banjoulou’.Conclusions
The superior tolerance of deepwater O. sativa and O. glaberrima genotypes to prolonged complete submergence appears to be due to their greater photosynthetic capacity developed by leaves newly emerged above the floodwater. Vigorous upward leaf elongation during prolonged submergence is therefore critical for ensuring shoot emergence from water, leaf area extension above the water surface and a subsequent strong increase in shoot biomass.Key words: Flooding, leaf area, net assimilation rate, Oryza glaberrima, O. sativa, photosynthesis, rice, stress adaptation, submergence escape 相似文献5.
6.
Yi Zhang Guo Hong Zheng Peng Liu Jin Min Song Gen Di Xu Miao Zhen Cai 《Acta Physiologiae Plantarum》2011,33(3):683-689
Two genotypes of rice (Oryza sativa L.), Azucena (iron tolerant) and IR64 (iron sensitive), were used to investigate the numbers and survival rates of root border
cells (namely, in situ border cells) in plants that were exposed to excess iron (Fe2+). Additionally, we examined the changes in the root tip cell morphology and activities of protective enzymes in response
to Fe2+ toxicity. The results showed that Fe2+ toxicity hindered the development of root border cells (RBCs) and that higher Fe2+ concentrations caused root cap cell walls to thicken. In the iron-sensitive rice variety, these changes lowered RBC survival
rate and lead to programmed cell death. Low concentrations of Fe2+ were shown to facilitate the development of RBCs in the iron-tolerant rice variety and that the activities of the protective
enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were elevated in the iron-tolerant variety, thus
suggesting that rice root tips could defend against Fe2+ toxicity by producing RBCs, root cap cells, and protective enzymes. 相似文献
7.
M.T.N. Cabasan L. Fernandez D. De Waele 《Archives Of Phytopathology And Plant Protection》2013,46(9-12):740-750
The host response of 25 rice genotypes belonging to Oryza glaberrima and Oryza sativa to Meloidogyne graminicola infection was examined in a hydroponic system. The M. graminicola can build up high population densities in a hydroponic system. Resistance to this nematode species was found in O. glaberrima genotypes which supported significantly lower nematode numbers per plant and per unit root than O. sativa genotypes. The M. graminicola-infected O. sativa genotypes showed a higher root galling index than the O. glaberrima genotypes. The hydroponic system is efficient and reliable method to examine the host response of rice genotypes to M. graminicola infection, and can be useful for the fast screening of high numbers of rice genotypes for the selection of M. graminicola-resistant rice germplasm for breeding purposes. 相似文献
8.
Isaac Kofi Bimpong Rachid Serraj Joong Hyoun Chin Joie Ramos Evelyn M. T. Mendoza Jose E. Hernandez Merlyn S. Mendioro Darshan S. Brar 《Journal of Plant Biology》2011,54(4):237-250
Drought is a major abiotic stress that limits rice productivity in rain-fed and upland ecosystems. African rice, Oryza glaberrima, has low yields but is tolerant to drought and other stresses. We evaluated 513 BC2F3 progenies from alien introgression lines (AILs) that were derived from crosses of Oryza sativa (IR64) × O. glaberrima. They were assessed for yield and other traits when grown under drought at two locations. Such conditions reduced grain production
by 59% compared with the recurrent parent (IR64). However, 33 AILs had higher yields, thus demonstrating their potential as
genetic material for transferring drought-related traits from O. glaberrima to O. sativa. A set of 200 AILs was selectively genotyped with 173 simple sequence repeat and sequenced tagged site markers. Molecular
analysis showed that a mean of 4.5% of the O. glaberrima genome was introgressed in BC2F3 AILs. Our analysis revealed 33 quantitative trait loci (QTLs; including 10 novel) for different traits. O. glaberrima contributed 50% of the alleles to those newly identified QTLs, with one for grain yield per plant (ypp9.1) being new. A QTL at RM208 on chromosome 2 positively affected yield under stress, accounting for 22% of the genetic variation.
Our identification of drought-related QTLs for yield and yield components will be useful to future research efforts in marker-assisted
selection. 相似文献
9.
Iron toxicity is a major soil constraint to rice (Oryza sative L.) cropping in highland swamps of Burundi. These swamps have a wide range of carbon content. This study aims at determining the influence of carbon content and redox conditions on the release of iron from Fe-bearing minerals. The pe-pH pairs distribution and oxalate dissolution data strongly suggest a control of Fe2+ activity by a pool of poorly crystallized ferric oxides. Flooding results in high values of KCl-extractable Fe (up to 22 cmolc kg-1) being released from that pool. The iron release is positively correlated with organic matter. On the other hand, highly organic, peaty soils have large CEC and their adsorbed Fe fraction remains relatively low. As the exchangeable Fe fraction has previously been correlated with Fe toxicity to rice, we may conclude that very organic (> 25% C), peaty soils exhibit a lower Fe toxicity hazard than soils with intermediate carbon content (10–25%). 相似文献
10.
The comparative alterations of short term NaCl stress and recovery on growth, water relations, ionic composition, lipid peroxidation
and antioxidants in roots of two rice cultivars differing in salt tolerance were studied. Exposed for 24 h to increasing (50,
100 and 150 mmol l−1) concentrations of NaCl, roots of 12D Oryza sativa L. cv. Lunishree and cv. Begunbitchi decreased in fresh weight, dry weight and relative water content. Increased Na+ and decreased K+ ion were determined at increasing NaCl concentrations. Both peroxide content and lipid peroxidation measured in terms of
MDA level increased and the ratio was higher in Begunbitchi compared to Lunishree. Recovered roots showed lower peroxide and MDA content. Ascorbate and glutathione contents increased in the stressed and
recovered roots of Lunishree, but decreased in Begunbitchi with increasing NaCl concentrations. Although SOD, CAT and GR activities decreased in the stressed roots, CAT activity also
increased in recovered roots of both the cultivars. The POX activity increased in stressed and recovered roots of both Lunishree and Begunbitchi. Higher free radicals scavenging capacity and more efficient protection mechanism of Lunishree against salt stress, as revealed by the lower level of lipid peroxidation and improved plant water status as well as activities
of some of the antioxidants, suggest that significant cultivar differences in response to salt stress in rice are closely
related to differences in the activities of antioxidants and ion content. Another possible conclusion is that improved tolerance
to salt stress may be accomplished by increased capacity of antioxidative system. 相似文献
11.
We have cloned two full-length cDNAs from two ferritin genes (Aifer1 and Aifer2) of the bay scallop, Argopecten irradians (Lamarck 1819). The cDNAs are 1,019 and 827 bp in length and encode proteins of 171 and 173 amino acids, respectively. The
5′ UTR of each contains a conserved iron response element (IRE) motif. Sequence analyses reveal that both proteins belong
to the H-ferritin family with seven conserved amino acids in the ferroxidase center. Highest expression of Aifer1 is found in the mantle and adductor muscle, while that of Aifer2 is only in the latter tissue. These Aifer genes are differentially expressed following bacterial challenge of the scallop. The expression level of Aifer1 was acutely up-regulated (over 10 fold) at 6 h post-bacteria injection, whereas Aifer2 expression was not significantly changed by bacterial challenge. Both genes were effectively expressed in E. coli BL21 (DE3), producing proteins of similar molecular weight, approximately 23 kDa. Purified Aifer1 and Aifer2 proteins exhibited
iron-chelating activity of 33.1% and 30.4%, respectively, at a concentration of 5 mg/ml. Cations, Mg2+, Zn2+ and Ca2+, depressed iron-chelating activity of both proteins. Additionally, the E. coli cells expressing recombinant Aifer1 and Aifer2 showed tolerance to H2O2, providing a direct evidence of the antioxidation function of ferritin. The results presented in this study suggest important
roles of Aifer1 and Aifer2 in the regulation of iron homeostasis, immune response, and antioxidative stress in A. irradians. 相似文献
12.
Heuer S Miézan KM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,107(5):902-909
Interspecific crossing of the African indigenous rice Oryza glaberrima with Oryza sativa cultivars is hindered by crossing barriers causing 100% spikelet sterility in F1 hybrids. Since hybrids are partially female fertile, fertility can be restored by back crossing (BC) to a recurrent male parent. Distinct genetic models on spikelet sterility have been developed predicting, e.g., the existence of a gamete eliminator and/or a pollen killer. Linkage of sterility to the waxy starch synthase gene and the chromogen gene C, both located on chromosome 6, have been demonstrated. We selected a segregating BC2F3 population of semi-sterile O. glaberrima × O. sativa indica hybrid progenies for analyses with PCR markers located at the respective chromosome-6 region. These analyses revealed that semi-sterile plants were heterozygous for a marker (OSR25) located in the waxy promoter, whereas fertile progenies were homozygous for the O. glaberrima allele. Adjacent markers showed no linkage to spikelet sterility. Semi-sterility of hybrid progenies was maintained at least until the F4 progeny generation, suggesting the existence of a pollen killer in this plant material. Monitoring of reproductive plant development showed that spikelet sterility was at least partially due to an arrest of pollen development at the microspore stage. In order to address the question whether genes responsible for F1 sterility in intraspecific hybrids (O. sativa indica × japonica) also cause spikelet sterility in interspecific hybrids, crossings with wide compatibility varieties (WCV) were performed. WCV accessions possess "neutral" S-loci (Sn) improving fertility in intraspecific hybrids. This experiment showed that the tested Sn-loci had no fertility restoring effect in F1 interspecific hybrids. Pollen development was completely arrested at the microspore stage and grains were never obtained after selfing. This suggests that distinct or additional S-loci are responsible for sterility of O. glaberrima × O. sativa hybrids.Communicated by H.C. Becker 相似文献
13.
Distinct evolutionary patterns of Oryza glaberrima deciphered by genome sequencing and comparative analysis 总被引:1,自引:0,他引:1
Sakai H Ikawa H Tanaka T Numa H Minami H Fujisawa M Shibata M Kurita K Kikuta A Hamada M Kanamori H Namiki N Wu J Itoh T Matsumoto T Sasaki T 《The Plant journal : for cell and molecular biology》2011,66(5):796-805
Here we present the genomic sequence of the African cultivated rice, Oryza glaberrima, and compare these data with the genome sequence of Asian cultivated rice, Oryza sativa. We obtained gene‐enriched sequences of O. glaberrima that correspond to about 25% of the gene regions of the O. sativa (japonica) genome by methylation filtration and subtractive hybridization of repetitive sequences. While patterns of amino acid changes did not differ between the two species in terms of the biochemical properties, genes of O. glaberrima generally showed a larger synonymous–nonsynonymous substitution ratio, suggesting that O. glaberrima has undergone a genome‐wide relaxation of purifying selection. We further investigated nucleotide substitutions around splice sites and found that eight genes of O. sativa experienced changes at splice sites after the divergence from O. glaberrima. These changes produced novel introns that partially truncated functional domains, suggesting that these newly emerged introns affect gene function. We also identified 2451 simple sequence repeats (SSRs) from the genomes of O. glaberrima and O. sativa. Although tri‐nucleotide repeats were most common among the SSRs and were overrepresented in the protein‐coding sequences, we found that selection against indels of tri‐nucleotide repeats was relatively weak in both African and Asian rice. Our genome‐wide sequencing of O. glaberrima and in‐depth analyses provide rice researchers not only with useful genomic resources for future breeding but also with new insights into the genomic evolution of the African and Asian rice species. 相似文献
14.
Andrew J. Ghio Earl S. Ford Thomas P. Kennedy John R. Hoidal 《Free radical research》2013,47(3):337-342
Objective: Urate forms a coordination complex with Fe3+ which does not support electron transport. The only enzymatic source of urate is xanthine oxidoreductase. If a major purpose of xanthine oxidoreductase is the production of urate to function as an iron chelator and antioxidant, a system for coupling the activity of this enzyme to the availability of catalytically-active metal would be required. We tested the hypothesis that there is an association between iron availability and urate production in healthy humans by correlating serum concentrations of ferritin with uric acid levels.Materials and methods: The study population included 4932 females and 4794 males in the National Health and Nutrition Examination Survey III. They were 20 years of age or older and in good health.Results: Serum concentrations of ferritin correlated positively with uric acid levels in healthy individuals (R2=0.41, p<0.001). This association was independent of an effect of gender, age, race/ethnic group, body mass, and alcohol consumption.Conclusions: The relationship between serum ferritin and uric acid predicts hyperuricemia and gout in groups with iron accumulation. This elevation in the production of uric acid with increased concentrations of iron could possibly reflect a response of the host to diminish the oxidative stress presented by available metal as the uric acid assumes the empty or loosely bound coordination sites of the iron to diminish electron transport and subsequent oxidant generation. 相似文献
15.
A comparative study of genetic relationships among the AA-genome<Emphasis Type="Italic"> Oryza</Emphasis> species using RAPD and SSR markers 总被引:8,自引:0,他引:8
Ren F Lu BR Li S Huang J Zhu Y 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2003,108(1):113-120
In order to estimate genetic relationships of the AA-genome Oryza species, RAPD and SSR analyses were performed with 45 accessions, including 13 cultivated varieties (eight Oryza sativa and five Oryza glaberrima) and 32 wild accessions (nine Oryza rufipogon, seven Oryza nivara, three Oryza glumaepatula, four Oryza longistaminata, six Oryza barthii, and three Oryza meridionalis). A total of 181 clear and repeatable bands were amplified from 27 selected RAPD primers, and 101 alleles were detected from 29 SSR primer pairs. The dendrogram constructed using UPGMA from a genetic-similarity matrix based on the RAPD data supported the clustering of distinct five groups with a few exceptions: O. rufipogon/O. nivara/O. meridionalis, O. barthii/O. glaberrima, O. glumaepatula, O. sativa and O. longistaminata. The dendrogram based on the SSR analysis showed a more-complicated genetic variation pattern, but the O. longistaminata and O. barthii/O. glaberrima accessions were consistently separated from all other accessions, indicating significant differentiation of the African AA-genome Oryza species. For accessions in the O. rufipogon/O. nivara/O. sativa complex, it is apparent that geographical isolation has played an important role in differentiation of the Asian AA-genome Oryza taxa. It is also demonstrated from this study that both RAPD and SSR analyses are powerful methods for detecting polymorphisms among the different AA-genome Oryza accessions. However, the RAPD analysis provides a more-informative result in terms of the overall genetic relationships at the species level compared to the SSR analysis. The SSR analysis effectively reveals diminutive variation among accessions or individuals within the same species, given approximately the same number of primers or primer-pairs used in the studies.Communicated by Q. Zhang 相似文献
16.
《Free radical research》2013,47(11):1363-1370
AbstractObjective. Recently, iron and the adaptor protein “p66Shc” have been shown to play an important role in the development of amyotrophic lateral sclerosis (ALS) in rats. We hypothesized that changes in muscle p66Shc activity and iron metabolism would appear before visible symptoms of the disease occurred. Methods. In the present study, we used transgenic rats bearing the G93A hmSOD1 gene mutation and their non-transgenic littermates to test this hypothesis. We examined muscle p66Shc phosphorylation and iron metabolism in relation to oxidative stress in animals at three disease stages: asymptomatic (ALS I), disease onset (ALS II), and end-stage disease (ALS III). Results. Significant changes in iron metabolism and markers of lipid and protein oxidation were detected in ALS I animals, which manifested as decreased levels of ferritin H and ferroportin 1 (Fpn1) and increased levels of ferritin L levels. Muscles of ALS I rats possessed increased levels of p66Shc phosphorylated at Ser36 compared with muscles of control rats. During disease progression, level of ferritin H significantly increased and was accompanied by iron accumulation. Conclusions. This study showed that multiple mechanisms may underlie iron accumulation in muscles of ALS transgenic rats, which include changes in blood hepcidin and muscle Fpn1 and increased level of muscle ferritin H. These data suggest that impaired iron metabolism is not a result of changes in motor activity. 相似文献
17.
M. Lorieux M.-N. Ndjiondjop A. Ghesquière 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,100(3-4):593-601
Oryza glaberrima is an endemic African cultivated rice species. To provide a tool for evaluation and utilisation of the potential of O. glaberrima in rice breeding, we developed an interspecific O. glaberrima×Oryza sativa genetic linkage map. It was based on PCR markers, essentially microsatellites and STSs. Segregation of markers was examined
in a backcross (O. sativa/O. glaberrima//O. sativa) population. Several traits were measured on the BC1 plants, and major genes and QTLs were mapped for these traits. Several of these genes correspond well to previously identified
loci. The overall map length was comparable to those observed in indica×japonica crosses, indicating that recombination between the two species occurs without limitation. However, three chromosomes show
discrepancies with the indica×japonica maps. The colinearity with intraspecific maps was very good, confirming previous cytological observations. A strong segregation-distortion
hot spot was observed on chromosome 6 near the waxy gene, indicating the presence of s
10
, a sporo-gametophytic sterility gene previously identified by Sano (1990). The main interests of such a PCR-based map for
African rice breeding are discussed, including gene and QTL localisation, marker-assisted selection, and the development of
interspecific introgression lines.
Received: 1 June 1991 / Accepted: 22 June 1999 相似文献
18.
The interactive effects of increased carbon dioxide (CO2) concentration and ultraviolet-B (UV-B, 280–320 nm) radiation on Acacia karroo Hayne, a C3 tree, and Themeda triandra Forsk., a C4 grass, were investigated. We tested the hypothesis that A. karroo would show greater CO2-induced growth stimulation than T. triandra, which would partially explain current encroachment of A. karroo into C4 grasslands, but that increased UV-B could mitigate this advantage. Seedlings were grown in open-top chambers in a greenhouse in ambient (360 μmol mol-1) and elevated (650 μmol mol-1) CO2, combined with ambient (1.56 to 8.66 kJ m-2 day-1) or increased (2.22 to 11.93 kJ m-2 day-1) biologically effective (weighted) UV-B irradiances. After 30 weeks, elevated CO2 had no effect on biomass of A. karroo, despite increased net CO2 assimilation rates. Interaction between UV-B and CO2 on stomatal conductance was found, with conductances decreasing only where elevated CO2 and UV-B were supplied separately. Increases in water use efficiencies, foliar starch concentrations, root nodule numbers and total nodule mass were measured in elevated CO2. Elevated UV-B caused only an increase in foliar carbon concentrations. In T. triandra, net CO2 assimilation rates were unaffected in elevated CO2, but stomatal conductances and foliar nitrogen concentrations decreased, and water use efficiencies increased. Biomass of all vegetative fractions, particularly leaf sheaths, was increased in elevated CO2. and was accompanied by increased leaf blade lengths and individual leaf and leaf sheath masses. However, tiller numbers were reduced in elevated CO2. Significantly moderating effects of elevated UV-B were apparent only in individual masses of leaf blades and sheaths, and in total sheath and shoot biomass. The direct CO2-induced growth responses of the species therefore do not support the hypothesis of CO2-driven woody encroachment of C4 grasslands. Rather, differential changes in resource use efficiency between grass and woody species, or morphological responses of grass species, could alter the competitive balance. Increased UV-B radiation is unlikely to substantially alter the CO2 response of these species. 相似文献
19.
20.
Auxin-dependent microtubule responses and seedling development are affected in a rice mutant resistant to EPC 总被引:2,自引:0,他引:2
Peter Nick Osamu Yatou Masaki Furuya Anne-Marie Lambert 《The Plant journal : for cell and molecular biology》1994,6(5):651-663
Mutants in rice (Oryza sativa L. cv. japonica) were used to study the role of the cytoskeleton in signal-dependent morphogenesis. Mutants obtained by gamma ray irradiation were selected that failed to show inhibition of coleoptile elongation by the antimicrotubular drug ethyl-N-phenylcarbamate (EPC). The mutation EPC-Resistant 31 (ER31), isolated from such a screen, caused lethality in putatively homozygous embryos. Heterozygotes exhibited drug resistance, impaired development of crown roots, and characteristic changes in the pattern of cell elongation: cell elongation was enhanced in mesocotyls and leaf sheaths, but inhibited in coleoptiles. The orientation of cortical microtubules changed correspondingly: for etiolated seedlings, compared with the wild-type, they were more transverse with respect to the long cell axis in mesocotyls and leaf sheaths, but more longitudinal in coleoptiles. In mutant coleoptiles, in contrast to wild-type, microtubules did not reorient in response to auxin, and their response to microtubule-eliminating and microtubule-stabilizing drugs was conspicuously reduced. In contrast, they responded normally to other stimuli such as gibberellins or red light. Auxin sensitivity as assayed by the dose-response for callus induction did not show any significant differences between wild-type and mutant. The mutant phenotype is interpreted in terms of an interrupted link between auxin-triggered signal transduction and microtubule reorientation. 相似文献