scholarly journals An Allelic Series of Blue Fluorescent trp1 Mutants of Arabidopsis thaliana

Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 197-205 ◽  
Author(s):  
Alan B Rose ◽  
Jiayang Li ◽  
Robert L Last

Nine blue fluorescent mutants of the flowering plant Arabidopsis thaliana were isolated by genetic selections and fluorescence screens. Each was shown to contain a recessive allele of trp1, a previously described locus that encodes the tryptophan biosynthetic enzyme phosphoribosylanthranilate transferase (PAT, called trpD in bacteria). The trp1 mutants consist of two groups, tryptophan auxotrophs and prototrophs, that differ significantly in growth rate, morphology, and fertility. The trp1 alleles cause plants to accumulate varying amounts of blue fluorescent anthranilate compounds, and only the two least severely affected of the prototrophs have any detectable PAT enzyme activity. All four of the trp1 mutations that were sequenced are G to A or C to T transitions that cause an amino acid change, but in only three of these is the affected residue phylogenetically conserved. There is an unusually high degree of sequence divergence in the single-copy gene encoding PAT from the wild-type Columbia and Landsberg erecta ecotypes of Arabidopsis.

1992 ◽  
Vol 84 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Poul E. Jensen ◽  
Michael Kristensen ◽  
Tine Hoff ◽  
Jan Lehmbeck ◽  
Bjarne M. Stummann ◽  
...  

1992 ◽  
Vol 84 (4) ◽  
pp. 561-567 ◽  
Author(s):  
Poul E. Jensen ◽  
Michael Kristensen ◽  
Tine Hoff ◽  
Jan Lehmbeck ◽  
Bjarne M. Stummann ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Tatiana P. Fedorchuk ◽  
Inga A. Kireeva ◽  
Vera K. Opanasenko ◽  
Vasily V. Terentyev ◽  
Natalia N. Rudenko ◽  
...  

We studied bicarbonate-induced stimulation of photophosphorylation in thylakoids isolated from leaves of Arabidopsis thaliana plants. This stimulation was not observed in thylakoids of wild-type in the presence of mafenide, a soluble carbonic anhydrase inhibitor, and was absent in thylakoids of two mutant lines lacking the gene encoding alpha carbonic anhydrase 5 (αCA5). Using mass spectrometry, we revealed the presence of αCA5 in stromal thylakoid membranes of wild-type plants. A possible mechanism of the photophosphorylation stimulation by bicarbonate that involves αCA5 is proposed.


2019 ◽  
Vol 116 (52) ◽  
pp. 27115-27123 ◽  
Author(s):  
Huiying Miao ◽  
Rongfang Guo ◽  
Junlin Chen ◽  
Qiaomei Wang ◽  
Yuh-Ru Julie Lee ◽  
...  

γ-Tubulin typically forms a ring-shaped complex with 5 related γ-tubulin complex proteins (GCP2 to GCP6), and this γ-tubulin ring complex (γTuRC) serves as a template for microtubule (MT) nucleation in plants and animals. While the γTuRC takes part in MT nucleation in most eukaryotes, in fungi such events take place robustly with just the γ-tubulin small complex (γTuSC) assembled by γ-tubulin plus GCP2 and GCP3. To explore whether the γTuRC is the sole functional γ-tubulin complex in plants, we generated 2 mutants of theGCP6gene encoding the largest subunit of the γTuRC inArabidopsis thaliana. Both mutants showed similar phenotypes of dwarfed vegetative growth and reduced fertility. Thegcp6mutant assembled the γTuSC, while the wild-type cells had GCP6 join other GCPs to produce the γTuRC. Although thegcp6cells had greatly diminished γ-tubulin localization on spindle MTs, the protein was still detected there. Thegcp6cells formed spindles that lacked MT convergence and discernable poles; however, they managed to cope with the challenge of MT disorganization and were able to complete mitosis and cytokinesis. Our results reveal that the γTuRC is not the only functional form of the γ-tubulin complex for MT nucleation in plant cells, and that γ-tubulin-dependent, but γTuRC-independent, mechanisms meet the basal need of MT nucleation. Moreover, we show that the γTuRC function is more critical for the assembly of spindle MT array than for the phragmoplast. Thus, our findings provide insight into acentrosomal MT nucleation and organization.


1999 ◽  
Vol 12 (5) ◽  
pp. 419-429 ◽  
Author(s):  
S. L. Woo ◽  
B. Donzelli ◽  
F. Scala ◽  
R. Mach ◽  
G. E. Harman ◽  
...  

The biocontrol strain P1 of Trichoderma harzianum was genetically modified by targeted disruption of the single-copy ech42 gene encoding for the secreted 42-kDa endochitinase (CHIT42). Stable mutants in which ech42 was interrupted, and unable to produce CHIT42, were obtained and characterized. These mutants lacked the ech42 transcript, the protein, and endochitinase activity in culture filtrates, and they were unable to clear a medium containing colloidal chitin. Other chitinolytic and glucanolytic enzymes expressed during mycoparasitism were not affected by the disruption of ech42. The disrupted mutant D11 grew and sporulated similarly to the wild type. In vitro antifungal activity of the ech42 disruptant culture filtrates against Botrytis cinerea and Rhizoctonia solani was reduced about 40%, compared with wild type; antifungal activity was fully restored by adding an equivalent amount of CHIT42 as secreted by P1. The mutant exhibited the same biocontrol effect against Pythium ultimum as strain P1, but the antagonism against B. cinerea on bean leaves by the mutant was significantly reduced (33% less biocontrol), compared with strain P1. Conversely, the endochitinase-deficient mutant performed better than the wild type (16% improvement of survival) in biocontrol experiments in soil infested with the soilborne fungus R. solani. These results indicate that the antagonistic interaction between the T. harzianum strain and various fungal hosts is based on different mechanisms.


2021 ◽  
Author(s):  
Janis Kaneps ◽  
◽  
Biruta Bankina ◽  
Inga Moročko-Bičevska ◽  

Pyrenophora tritici-repentis is a major wheat pathogen in all wheat (Triticum spp.) growing areas worldwide. Up to date, eight P. tritici-repentis races have been described based on chlorosis, necrosis, or both symptoms caused on race differential wheat genotypes: ‘Glenlea’, 6B662, 6B365, and ‘Salamouni’. Symptom development on differential genotypes depends on the interaction of the pathogen’s necrotrophic effectors named Ptr ToxA, Ptr ToxB, and Ptr ToxC with host susceptibility genes. Ptr ToxA is encoded by the single copy gene ToxA and induces necrosis on sensitive wheat cultivars. Ptr ToxB causes chlorosis and is encoded by the multicopy gene ToxB. The Ptr ToxC is the non-proteinaceous, polar, low molecular mass molecule that also induces chlorosis, but up to date, the gene encoding this toxin is unknown. Races producing Ptr ToxA are predominant in the global Ptr population. There are several reports about new putative races of P. tritici-repentis that do not conform with the current race system, so further research is required. This study aims to collect and systematise available information about the virulence and races of P. tritici-repentis.


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