scholarly journals Localized Changes in Flavonoid Biosynthesis in Roots of Lotus pedunculatus after Infection by Rhizobium loti

1992 ◽  
Vol 100 (1) ◽  
pp. 444-450 ◽  
Author(s):  
James E. Cooper ◽  
J. Raghavendra Rao
Keyword(s):  
Flavonoid Biosynthesis ◽  
Rhizobium Loti ◽  
Lotus Pedunculatus

Comparative morphology and flavolan content of Rhizobium loti induced effective and ineffective root nodules on Lotus species, Leuceana leucocephala, Carmichaelia flagelliformis, Ornithopus sativus, and Clianthus puniceus

1987 ◽  
Vol 65 (12) ◽  
pp. 2676-2685 ◽  
Author(s):  
Clive E. Pankhurst ◽  
Douglas H. Hopcroft ◽  
William T. Jones
Keyword(s):  
Plasma Membrane ◽  
Root Nodules ◽  
Comparative Morphology ◽  
Lotus Corniculatus ◽  
Rhizobium Loti ◽  
Infection Threads ◽  
Membrane Bound ◽  
Lotus Pedunculatus ◽  
Ornithopus Sativus

The morphology of Rhizobium loti induced root nodules and the flavolan content of nodulated roots of several Lotus species, Leuceana leucocephala, Carmichaelia flagelliformis, Ornithopus sativus, and Clianthus puniceus were examined. Rhizobium loti strain NZP2037 formed effective (Nod+Fix+) nodules on all legumes, but strain NZP2213 formed Nod+Fix+ nodules only on Lotus corniculatus var. cree and ineffective (Nod+Fix−) nodules on all other legumes. The Nod+Fix− nodules developed by NZP2213 showed morphologies ranging from the complete absence of bacteria within “tumour-like” structures to the development of nodules containing bacteria that were either not released or only incompletely released from infection threads. Within nodules formed by NZP2213 on Lotus corniculatus var. hirsutus and Carmichaelia flagelliformis the rhizobia had multiplied extensively within unwalled, plasma membrane bound, infection droplets. Flavolans rich in prodelphinidin, which is toxic towards NZP2213, were present in the roots of Lotus angustissimus, Lotus pedunculatus, Lotus subbiflorus, and Leuceana leucocephala, but only trace amounts of flavolan were found in the roots of Carmichaelia flagelliformis, Ornithopus sativus, and Clianthus puniceus.

scholarly journals Peptidoglycan-bound Polysaccharide Associated with Resistance of Rhizobium loti Strain NZP2037 to Lotus pedunculatus Root Flavolan

Microbiology ◽  
1987 ◽  
Vol 133 (9) ◽  
pp. 2617-2629
Author(s):  
W. T. JONES ◽  
P. E. MACDONALD ◽  
S. D. JONES ◽  
C. E. PANKHURST
Keyword(s):  
Rhizobium Loti ◽  
Lotus Pedunculatus

scholarly journals Symbiotic effectiveness and ecological characterization of indigenous Rhizobium loti populations in Uruguay

1999 ◽  
Vol 34 (6) ◽  
pp. 1010-1017 ◽  
Author(s):  
Amalia Baraibar ◽  
Llillian Frioni ◽  
Maria Elena Guedes ◽  
Hans Ljunggren
Keyword(s):  
Culture Medium ◽  
Indigenous Populations ◽  
Symbiotic Effectiveness ◽  
Symbiotic Efficiency ◽  
Rhizobium Loti ◽  
Acid Tolerant ◽  
Resistant Strains ◽  
Lotus Pedunculatus ◽  
Tolerance Factors

The objectives of this work were to describe the distribution, density and seasonal variation of the indigenous populations of Rhizobium loti in different Uruguayan soils and to determine the symbiotic effectiveness and stress tolerance factors of different isolates, both with the aim of obtaining selected strains to re-introduce as inoculants in Lotus pastures. R. loti was present in ten soils studied and their densities varied from year to year and within each soil. All the isolates nodulated Lotus corniculatus effectively. The nodules in Lotus pedunculatus and Lotus subbiflorus were small, red on the surface and ineffective in nitrogen fixation. The study of 50 isolates from the ten soils showed high variability in their symbiotic efficiency and tolerance to pH. The indigenous population was acid tolerant in culture medium (pH 4.5), 83% of them could grow at pH 4.5 in 3 days. This work showed that there was a great diversity between the strains of R. loti isolated from Uruguayan soils and supports the importance of selecting among them the most efficient and resistant strains to be included in the inoculants.

A morphometric study of effective nodules induced by Rhizobium loti and Bradyrhizobium sp. (Lotus) on Lotus pedunculatus

1985 ◽  
Vol 63 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Susan M. Wood ◽  
David B. Layzell ◽  
William Newcomb ◽  
Clive E. Pankhurst
Keyword(s):  
Nitrogen Fixation ◽  
Root Nodules ◽  
Light And Electron Microscopy ◽  
Morphometric Study ◽  
Polar Bodies ◽  
Rhizobium Loti ◽  
Bradyrhizobium Sp ◽  
Infected Cells ◽  
Peribacteroid Space ◽  
Lotus Pedunculatus

Effective root nodules formed on Lotus pedunculatus by Rhizobium loti NZP2037 and Bradyrhizobium sp. (Lotus) CC814s were examined by light and electron microscopy. NZP2037 nodules were larger than CC814s nodules as a result of a much thicker nodule cortex. The smaller CC814s nodules had a much larger infected zone and, consequently, larger volumes of infected cells, peribacteroid space, and host cytosol per nodule. As well, CC814s nodules demonstrated a significantly higher number of bacteria which typically contained prominent polar bodies and beta-polyhydroxybutyrate (PHB) granules. The bacteria of NZP2037 nodules lacked the polar bodies, but PHB deposits were occasionally observed. A correlated physiological study in which acetylene reduction was used to estimate nitrogen fixation showed CC814s nodules to be more active than NZP2037 nodules (Pankhurst, C. E., and D. B. Layzell. 1984. Physiol. Plant. 62(3) : 404–409.). This measured difference in nitrogen-fixing activity was considered due to the degree of infection and bacterial proliferation as well as differences in the carbon and nitrogen metabolism of the two nodule types. The significance of the structural observations and morphometric analyses and their relationship to differences in nitrogen fixation are discussed.

Kinetin-Mediated Stimulation of Accumulation of Buckwheat Flavonoids in the Dark

1983 ◽  
Vol 38 (9-10) ◽  
pp. 711-718 ◽  
Author(s):  
U. Margna ◽  
T. Vainjärv
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Flavonoid Biosynthesis ◽  
Accumulation Rates ◽  
Sharp Rise ◽  
Short Treatment ◽  
Exogenous Substrate ◽  
Percent Increase ◽  
High Level ◽  
Fold Stimulation ◽  
Stimulation Of

A short treatment of excised buckwheat cotyledons with a solution of kinetin lead to an up to 9-fold stimulation of anthocyanin biosynthesis, to an about 50 percent increase in the accumula­tion of rutin, and to an about 30 percent increase, on the average, in the accumulation of C-glycosylflavones in the treated material during its posttreatment incubation in the dark. When the treated cotyledons were incubated in a solution of ʟ--phenylalanine anthocyanin accumulation in the dark practically attained the same high level as it was observed in the illuminated cotyledons fed with exogenous ʟ--phenylalanine. In experiments with l4C-labelled L-phenylalanine kinetin induced a sharp rise in the labelling (resp. in the utilization of exogenous substrate for biosynthesis) of anthocyanins and rutin in the dark and a slight increase in the radioactivity of C-glycosylflavones. Similar labelling changes occurred in the illuminated cotyledons. However, both kinetin and light still more effectively promoted biosynthetic use of the endogenous sub­strate. As a result the relative portion of flavonoids formed from exogenous L-phenylalanine under these conditions showed a decrease as compared with the ratio of precursor use in the un­treated cotyledons. The results show that low accumulation rates of anthocyanins and other flavo­noids in the dark are conditioned by the limited access of substrate (ʟ--phenylalanine) molecules to the flavonoid enzymes lending further support to the idea that flavonoid biosynthesis is normally controlled at the substrate rather than at the enzymic level.

scholarly journals NtbHLH1, a JAF13-like bHLH, interacts with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuxin Fan ◽  
Jiayu Peng ◽  
Jiacheng Wu ◽  
Ping Zhou ◽  
Ruijie He ◽  
...  
Keyword(s):  
Flavonoid Biosynthesis ◽  
Transcriptional Level ◽  
Flavonoid Pathway ◽  
Regulation Of Expression ◽  
Over Expression ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Regulatory Complex ◽  
Positive Regulators ◽  
R2r3 Myb

Abstract Background Flavonoid biosynthesis in plants is primarily regulated at the transcriptional level by transcription factors modulating the expression of genes encoding enzymes in the flavonoid pathway. One of the most studied transcription factor complexes involved in this regulation consists of a MYB, bHLH and WD40. However, in Chinese Narcissus (Narcissus tazetta L. var. chinensis), a popular monocot bulb flower, the regulatory mechanism of flavonoid biosynthesis remains unclear. Results In this work, genes related to the regulatory complex, NtbHLH1 and a R2R3-MYB NtMYB6, were cloned from Chinese Narcissus. Phylogenetic analysis indicated that NtbHLH1 belongs to the JAF13 clade of bHLH IIIf subgroup, while NtMYB6 was highly homologous to positive regulators of proanthocyanidin biosynthesis. Both NtbHLH1 and NtMYB6 have highest expression levels in basal plates of Narcissus, where there is an accumulation of proanthocyanidin. Ectopic over expression of NtbHLH1 in tobacco resulted in an increase in anthocyanin accumulation in flowers, and an up-regulation of expression of the endogenous tobacco bHLH AN1 and flavonoid biosynthesis genes. In contrast, the expression level of LAR gene was significantly increased in NtMYB6-transgenic tobacco. Dual luciferase assays showed that co-infiltration of NtbHLH1 and NtMYB6 significantly activated the promoter of Chinese Narcissus DFR gene. Furthermore, a yeast two-hybrid assay confirmed that NtbHLH1 interacts with NtMYB6. Conclusions Our results suggest that NtbHLH1 may function as a regulatory partner by interacting directly with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus.

scholarly journals Transcriptome and metabolome analyses revealing the potential mechanism of seed germination in Polygonatum cyrtonema

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rong Liu ◽  
Jing Lu ◽  
Jiayi Xing ◽  
Mei Du ◽  
Mingxiu Wang ◽  
...  
Keyword(s):  
Seed Germination ◽  
Organic Acids ◽  
Plant Hormones ◽  
Regulatory Networks ◽  
Amylase Activity ◽  
Flavonoid Biosynthesis ◽  
Market Demand ◽  
Potential Mechanism ◽  
Flavonoid Synthesis ◽  
Germinated Seeds

AbstractPolygonatum cyrtonema Hua (Huangjing, HJ) has medicinal and edible value in China. However, the seeds of this plant are naturally difficult to germinate. Therefore, to elucidate the mechanism underlying the germination of this plant in order to meet the market demand, the metabolomic and transcriptomic analyses were performed in this study. We observed that plant hormones and α-amylase activity were differentially regulated when comparing germinated and un-germinated seeds. In addition, the metabolites related to phenylpropanoid and flavonoid biosynthesis were significantly up-accumulated in germinated seeds. Hydroxycinnamoyl derivatives and organic acids were observed to be significantly decreased during germination. The results of this study suggested that compared to un-germinated seeds, germinated seeds promote flavonoid synthesis and inhibit lignin synthesis which could be beneficial to the germination of HJ seeds. Furthermore, these results suggested that starch if hydrolyzed into glucose, which could provide the necessary energy for germination. Our results may help to establish a foundation for further research investigating the regulatory networks of seed germination and may facilitate the propagation of HJ seeds.

scholarly journals Comparative Transcriptome Analysis Reveals Key Genes and Pathways Involved in Prickle Development in Eggplant

Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 341
Author(s):  
Lei Zhang ◽  
Haoyun Sun ◽  
Tao Xu ◽  
Tianye Shi ◽  
Zongyun Li ◽  
...  
Keyword(s):  
Transcriptome Analysis ◽  
Morphological Analysis ◽  
Molecular Mechanisms ◽  
Flavonoid Biosynthesis ◽  
Phenotypic Characterization ◽  
Comparative Transcriptome ◽  
Hub Genes ◽  
Breeding Programs ◽  
Comparative Transcriptome Analysis ◽  
Key Pathways

Eggplant is one of the most important vegetables worldwide. Prickles on the leaves, stems and fruit calyxes of eggplant may cause difficulties during cultivation, harvesting and transportation, and therefore is an undesirable agronomic trait. However, limited knowledge about molecular mechanisms of prickle morphogenesis has hindered the genetic improvement of eggplant. In this study, we performed the phenotypic characterization and transcriptome analysis on prickly and prickleless eggplant genotypes to understand prickle development at the morphological and molecular levels. Morphological analysis revealed that eggplant prickles were multicellular, lignified and layered organs. Comparative transcriptome analysis identified key pathways and hub genes involved in the cell cycle as well as flavonoid biosynthetic, photosynthetic, and hormone metabolic processes during prickle development. Interestingly, genes associated with flavonoid biosynthesis were up-regulated in developing prickles, and genes associated with photosynthesis were down-regulated in developing and matured prickles. It was also noteworthy that several development-related transcription factors such as bHLH, C2H2, MYB, TCP and WRKY were specifically down- or up-regulated in developing prickles. Furthermore, four genes were found to be differentially expressed within the Pl locus interval. This study provides new insights into the regulatory molecular mechanisms underlying prickle morphogenesis in eggplant, and the genes identified might be exploited in breeding programs to develop prickleless eggplant cultivars.

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