Caffeoyl Shikimate Esterase (CSE) Is an Enzyme in the Lignin Biosynthetic Pathway in Arabidopsis

Science ◽  
2013 ◽  
Vol 341 (6150) ◽  
pp. 1103-1106 ◽  
Author(s):  
Ruben Vanholme ◽  
Igor Cesarino ◽  
Katarzyna Rataj ◽  
Yuguo Xiao ◽  
Lisa Sundin ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Walls ◽  
Metabolite Profiling ◽  
Biosynthetic Pathway ◽  
Wild Type ◽  
Secondary Cell Walls ◽  
Phenolic Metabolite ◽  
In The Wild ◽  
Lignin Biosynthetic Pathway

Lignin is a major component of plant secondary cell walls. Here we describe caffeoyl shikimate esterase (CSE) as an enzyme central to the lignin biosynthetic pathway. Arabidopsis thaliana cse mutants deposit less lignin than do wild-type plants, and the remaining lignin is enriched in p-hydroxyphenyl units. Phenolic metabolite profiling identified accumulation of the lignin pathway intermediate caffeoyl shikimate in cse mutants as compared to caffeoyl shikimate levels in the wild type, suggesting caffeoyl shikimate as a substrate for CSE. Accordingly, recombinant CSE hydrolyzed caffeoyl shikimate into caffeate. Associated with the changes in lignin, the conversion of cellulose to glucose in cse mutants increased up to fourfold as compared to that in the wild type upon saccharification without pretreatment. Collectively, these data necessitate the revision of currently accepted models of the lignin biosynthetic pathway.

scholarly journals Cytokinesis in fra2 Arabidopsis thaliana p60-katanin Mutant: Defects in Cell Plate/Daughter Wall Formation

2021 ◽  
Author(s):  
Emmanuel Panteris ◽  
Anna Kouskouveli ◽  
Dimitris Pappas ◽  
Ioannis-Dimosthenis S. Adamakis
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Higher Plants ◽  
Cell Plate ◽  
Wild Type ◽  
Microtubule Organization ◽  
Root Cells ◽  
Wall Formation ◽  
In The Wild

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate, to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), while deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy, in root cells of the fra2 Arabidopsis thaliana mutant. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls appeared also faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild-type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild-type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.

scholarly journals Cytokinesis in fra2 Arabidopsis thaliana p60-Katanin Mutant: Defects in Cell Plate/Daughter Wall Formation

2021 ◽  
Vol 22 (3) ◽  
pp. 1405
Author(s):  
Emmanuel Panteris ◽  
Anna Kouskouveli ◽  
Dimitris Pappas ◽  
Ioannis-Dimosthenis S. Adamakis
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Walls ◽  
Higher Plants ◽  
Cell Plate ◽  
Wild Type ◽  
Microtubule Organization ◽  
Root Cells ◽  
Wall Formation ◽  
In The Wild

Cytokinesis is accomplished in higher plants by the phragmoplast, creating and conducting the cell plate to separate daughter nuclei by a new cell wall. The microtubule-severing enzyme p60-katanin plays an important role in the centrifugal expansion and timely disappearance of phragmoplast microtubules. Consequently, aberrant structure and delayed expansion rate of the phragmoplast have been reported to occur in p60-katanin mutants. Here, the consequences of p60-katanin malfunction in cell plate/daughter wall formation were investigated by transmission electron microscopy (TEM), in root cells of the fra2 Arabidopsis thaliana loss-of-function mutant. In addition, deviations in the chemical composition of cell plate/new cell wall were identified by immunolabeling and confocal microscopy. It was found that, apart from defective phragmoplast microtubule organization, cell plates/new cell walls also appeared faulty in structure, being unevenly thick and perforated by large gaps. In addition, demethylesterified homogalacturonans were prematurely present in fra2 cell plates, while callose content was significantly lower than in the wild type. Furthermore, KNOLLE syntaxin disappeared from newly formed cell walls in fra2 earlier than in the wild type. Taken together, these observations indicate that delayed cytokinesis, due to faulty phragmoplast organization and expansion, results in a loss of synchronization between cell plate growth and its chemical maturation.

scholarly journals The Simultaneous Repression of CCR and CAD, Two Enzymes of the Lignin Biosynthetic Pathway, Results in Sterility and Dwarfism in Arabidopsis thaliana

2011 ◽  
Vol 4 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Johanne Thévenin ◽  
Brigitte Pollet ◽  
Bruno Letarnec ◽  
Luc Saulnier ◽  
Lionel Gissot ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Biosynthetic Pathway ◽  
Lignin Biosynthetic Pathway

scholarly journals Characterization of .ALPHA.-L-arabinofuranosidase related to the secondary cell walls formation in Arabidopsis thaliana

2010 ◽  
Vol 27 (3) ◽  
pp. 259-266 ◽  
Author(s):  
Hitomi Ichinose ◽  
Nobuyuki Nishikubo ◽  
Taku Demura ◽  
Satoshi Kaneko
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Walls ◽  
Secondary Cell Walls

A new class of mutations in Arabidopsis thaliana, acaulis1, affecting the development of both inflorescences and leaves

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 751-764 ◽  
Author(s):  
H. Tsukaya ◽  
S. Naito ◽  
G. P. Redei ◽  
Y. Komeda
Keyword(s):  
Arabidopsis Thaliana ◽  
Apical Meristem ◽  
Developmental Stages ◽  
Temperature Shift ◽  
Wild Type ◽  
New Class ◽  
Group 4 ◽  
Consequent Reduction ◽  
In The Wild ◽  
Specific Temperature

We isolated and analyzed mutants of Arabidopsis thaliana, acaulis, with flower stalks that are almost absent or are much reduced in length. The mutations are divided between two loci, acaulis1 (acl1) and acaulis2 (acl2). The acl1-1 mutation has been assigned to linkage group 4 in the vicinity of locus ap2. The acl1-1 mutant showed premature arrest of the inflorescence meristem after the onset of reproductive development, followed by consequent reduction in the number of flower-bearing phytomers and therefore flowers. The apical meristem of the inflorescences was morphologically normal but its radius was about half that of the wild type. The acl1 mutants are also defective in the development of foliage leaves. Both defects could be rescued by growth at a specific temperature (28°C). The length of the cells in acl1-3 mutant was less than that in the wild type but the numbers of cells in leaves and internodes of acl1 mutants were calculated to be the same as those of the wild type. Thus, the defects in inflorescences and leaves were attributed to defects in the process of elongation (maturation) of these cells. Temperature-shift experiments showed that the Acl1+ product was necessary at all developmental stages. A critical stage was shown to exist for recovery from the cessation of development of inflorescence meristems that was caused by the acl1-1 mutation. Grafting experiments showed that the acl1-1 mutation does not affect diffusible substances. An analysis of double mutants carrying both acl1-1 and one of developmental mutations, ap1, clv1, lfy, or tfl1, showed that ACL1 is a new class of gene.

scholarly journals Arabidopsis thaliana cbp80, c2h2, and flk Knockout Mutants Accumulate Increased Amounts of Circular RNAs

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1937
Author(s):  
Anna Philips ◽  
Katarzyna Nowis ◽  
Michal Stelmaszczuk ◽  
Jan Podkowiński ◽  
Luiza Handschuh ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Circular Rnas ◽  
Wild Type ◽  
Proper Order ◽  
Knockout Mutants ◽  
In The Wild ◽  
And Function

Circular RNAs (circRNAs) are the products of the non-canonical splicing of pre-mRNAs. In contrast to humans and animals, our knowledge of the biogenesis and function of circRNAs in plants is very scarce. To identify proteins involved in plant circRNA generation, we characterized the transcriptomes of 18 Arabidopsis thaliana knockout mutants for genes related to splicing. The vast majority (>90%) of circRNAs were formed in more than one variant; only a small fraction of circRNAs was mutant-specific. Five times more circRNA types were identified in cbp80 and three times more in c2h2 mutants than in the wild-type. We also discovered that in cbp80, c2h2 and flk mutants, the accumulation of circRNAs was significantly increased. The increased accumulation of circular transcripts was not accompanied by corresponding changes in the accumulation of linear transcripts. Our results indicate that one of the roles of CBP80, C2H2 and FLK in splicing is to ensure the proper order of the exons. In the absence of one of the above-mentioned factors, the process might be altered, leading to the production of circular transcripts. This suggests that the transition toward circRNA production can be triggered by factors sequestering these proteins. Consequently, the expression of linear transcripts might be regulated through circRNA production.

Root Morphology Mutants in Arabidopsis thaliana

1992 ◽  
Vol 19 (4) ◽  
pp. 427 ◽  
Author(s):  
TI Baskin ◽  
AS Betzner ◽  
R Hoggart ◽  
A Cork ◽  
RE Williamson
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Mutational Analysis ◽  
Root Apex ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Wild Type ◽  
In The Wild ◽  
Root Morphogenesis ◽  
Type Rate

We have begun a mutational analysis of root morphogenesis in Arabidopsis thaliana. We report here the initial genetic and physiological characterisation of six mutations that affect root growth and development. Three of them (rsw1, rsw2, rsw3) cause extensive radial swelling of the root apex. These mutations are recessive at different loci and show temperature-sensitive expression, such that the roots appear wild type when grown at 18�C but express the mutant phenotype when transferred to 31�C. Following transfer to the restrictive temperature, these three mutations have different kinetic and morphological patterns of radial swelling, and grow at different rates with continued time at high temperature. We believe that these mutations represent three different loci active in the wild type in regulating the shape of the root. We have also characterised two mutations that affect only the root epidermis, causing many epidermal cells to bulge (reb1-1, reb1-2). The two mutations are recessive and are alleles. However, rebl-1 is constitutive whereas reb1-2 is temperature sensitive, only expressing at 33�C. Reb1-2 also causes a deviation from the normal straight growth of the root such that the affected roots grow with sharp bends or meanders. The final mutant reported here is a stunted plant (stp1), in which the root growth rate is approximately 25% of the wild type rate. Moreover, root growth steadily accelerates over 5 days following germination in the wild type but remains constant in stp1, which grows at a constant rate over the same interval.

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