The additional stamens of flo10-1 mutants of Arabidopsis thaliana are compromised in production and viability of pollen

1998 ◽  
Vol 76 (10) ◽  
pp. 1733-1742
Author(s):  
Jeffrey D Pylatuik ◽  
Peta C Bonham-Smith ◽  
Arthur R Davis

flo10-1 (superman-2) is a floral mutant in Arabidopsis thaliana that normally produces female sterile flowers. This phenotypic aberration results from a combination of increased stamen number and reduced or abnormal carpels that are nonfunctional. The flowers of flo10-1 contain two lateral and four median stamens, as seen in wild-type plants; however, they also contain several additional stamens. All stamen types have been examined with respect to frequency and location within the flower. The amount of pollen produced from each of the three types of stamens of flo10-1 and the viability of this pollen were also examined and compared with wild-type (cv. Columbia) to determine the consequences of this mutation on male fertility. Both the lateral and median stamens of flo10-1 and wild-type plants produced similar amounts of pollen per stamen and demonstrated no significant difference in viability. Per stamen, the additionals of flo10-1 produced significantly less pollen than those of the laterals and medians. Furthermore, the pollen produced from these additional stamens was significantly less viable. Although less abundant and viable, pollen produced by additional stamens can effectively fertilize ovules, producing normal, healthy plants.Key words: pollen (viability, production), stamen, male fertility, flower development, Arabidopsis thaliana, flo10-1.

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2057-2067 ◽  
Author(s):  
S. E. Clark ◽  
M. P. Running ◽  
E. M. Meyerowitz

We have previously described the phenotype of Arabidopsis thaliana plants with mutations at the CLAVATA1 (CLV1) locus (Clark, S. E., Running, M. P. and Meyerowitz, E. M. (1993) Development 119, 397–418). Our investigations demonstrated that clv1 plants develop enlarged vegetative and inflorescence apical meristems, and enlarged and indeterminate floral meristems. Here, we present an analysis of mutations at a separate locus, CLAVATA3 (CLV3), that disrupt meristem development in a manner similar to clv1 mutations. clv3 plants develop enlarged apical meristems as early as the mature embryo stage. clv3 floral meristems are also enlarged compared with wild type, and maintain a proliferating meristem throughout flower development. clv3 root meristems are unaffected, indicating that CLV3 is a specific regulator of shoot and floral meristem development. We demonstrate that the strong clv3-2 mutant is largely epistatic to clv1 mutants, and that the semi- dominance of clv1 alleles is enhanced by double heterozygosity with clv3 alleles, suggesting that these genes work in the same pathway to control meristem development. We propose that CLV1 and CLV3 are required to promote the differentiation of cells at the shoot and floral meristem.


2020 ◽  
Vol 32 (10) ◽  
pp. 893
Author(s):  
Yuka Miki ◽  
Lalitha Devi ◽  
Yuji Imai ◽  
Naojiro Minami ◽  
Tsuyoshi Koide ◽  
...  

The PDZ-binding kinase (PBK) protein is localised exclusively in spermatogenic cells, such as spermatogonia, spermatocytes and round spermatids, of the adult testis. However, its role in male fertility remains unknown. Analysis of adult Pbk-knockout (KO) male mice showed no significant difference in the weight of the testes, epididymis and seminal vesicle compared with adult wild-type (WT) mice. There were no significant differences in testis morphology, tubule diameter and the number of offspring born to females mated with KO or WT male mice. Sperm number, motility and morphology did not differ significantly between KO and WT mice. The oocyte fertilisation rate and embryo development following IVF were comparable between groups fertilised using spermatozoa from KO versus WT mice (P>0.05). Further analysis revealed that the phosphorylation of the mitogen-activated protein kinases (MAPKs) p38 kinase, c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinases was dysregulated in the testis of KO mice. In conclusion, Pbk-KO male mice are fertile and their spermatozoa and testis do not show any morphological and functional abnormalities despite the dysregulated phosphorylation of MAPKs. It is likely that functional redundancy of PBK and overlapping substrate specificities of the MAPK superfamily compensated for the loss of PBK from the testis.


HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1039B-1039
Author(s):  
Barbara C. Hellier ◽  
Marie Pavelka

The USDA garlic (Allium sativum and Allium longicuspis) collection is maintained at the ARS, Western Regional Plant Introduction Station (WRPIS) in Pullman, Wash. This collection comprises 269 accessions, of which 153 are hardneck (flower producing) types. The fertility characteristics of these accessions was evaluated in the field at Pullman, Wash. After the spathes opened, bulbils were removed from all the evaluated accessions to facilitate flower development. The umbel and flower characteristics taken were anther color, flower color, flower shape, stigma position, flowers per umbel, umbel diameter, umbel shape, umbel defects, bulbil size, bulbil color, ease of bulbil removal, spathe opening, pollen production, and pollen viability. Of the 153 accessions, 10 produced only partial scapes with bulbils midstalk and no seed production capability. Viable pollen was shed in 85 accessions with viability ranging from 8% to 85%. Open-pollinated seed was generated by 19 of the Pullman, Wash., grown accessions. Seed production was low with yields from 6 to 91 seeds per accession.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
P Milani ◽  
L Obici ◽  
R Mussinelli ◽  
M Basset ◽  
G Manfrinato ◽  
...  

Abstract Background Cardiac wild type transthyretin (ATTRwt) amyloidosis, formerly known as senile systemic amyloidosis, is an increasingly recognized, progressive, and fatal cardiomyopathy. Two biomarkers staging systems were proposed based on NT-proBNP (in both cases) and troponin or estimated glomerular filtration rate, that are able to predict survival in this population. The availability of novel effective treatments requires large studies to describe the natural history of the disease in different populations. Objective To describe the natural history of the disease in a large, prospective, national series. Methods Starting in 2007, we protocolized data collection in all the patients diagnosed at our center (n=400 up to 7/2019). Results The referrals to our center increased over time: 5 cases (1%) between 2007–2009, 33 (9%) in 2010–2012, 90 (22%) in 2013–2015 and 272 (68%) in 2016–2019. Median age was 76 years [interquartile range (IQR): 71–80 years] and 372 patients (93%) were males. One hundred and seventy-three (43%) had atrial fibrillation, 63 (15%) had a history of ischemic cardiomyopathy and 64 (15%) underwent pacemaker or ICD implantation. NYHA class was I in 58 subjects (16%), II in 225 (63%) and III in 74 (21%). Median NT-proBNP was 3064 ng/L (IQR: 1817–5579 ng/L), troponin I 0.096 ng/mL (IQR: 0.063–0.158 ng/mL), eGFR 62 mL/min (IQR: 50–78 mL/min). Median IVS was 17 mm (IQR: 15–19 mm), PW 16 mm (IQR: 14–18 mm) and EF 53% (IQR: 45–57%). One-hundred and forty-eight subjects (37%) had a concomitant monoclonal component in serum and/or urine and/or an abnormal free light chain ratio. In these patients, the diagnosis was confirmed by immunoelectron microscopy or mass spectrometry. In 252 (63%) the diagnosis was based on bone scintigraphy. DNA analysis for amyloidogenic mutations in transthyretin and apolipoprotein A-I genes was negative in all subjects. The median survival of the whole cohort was 59 months. The Mayo Clinic staging based on NT-proBNP (cutoff: 3000 ng/L) and troponin I (cutoff: 0.1 ng/mL) discriminated 3 different groups [stage I: 131 (35%), stage II: 123 (32%) and stage III: 127 (33%)] with different survival between stage I and II (median 86 vs. 81 months, P=0.04) and between stage II and III (median 81 vs. 62 months, P<0.001). The UK staging system (NT-proBNP 3000 ng/L and eGFR 45 mL/min), discriminated three groups [stage I: 170 (45%), stage II: 165 (43%) and stage III: 45 (12%)] with a significant difference in survival: between stage I and stage II (86 vs. 52 months, P<0.001) and between stage II and stage III (median survival 52 vs. 33 months, P=0.045). Conclusions This is one of the largest series of patients with cardiac ATTRwt reported so far. Referrals and diagnoses increased exponentially in recent years, One-third of patients has a concomitant monoclonal gammopathy and needed tissue typing. Both the current staging systems offered good discrimination of staging and were validated in our independent cohort. Funding Acknowledgement Type of funding source: None


2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.


2021 ◽  
Vol 11 (15) ◽  
pp. 7118
Author(s):  
Ermina Hadzic ◽  
Garth Blackler ◽  
Holly Dupuis ◽  
Stephen James Renaud ◽  
Christopher Thomas Appleton ◽  
...  

Post-traumatic osteoarthritis (PTOA) is a degenerative joint disease, leading to articular cartilage breakdown, osteophyte formation, and synovitis, caused by an initial joint trauma. Pro-inflammatory cytokines increase catabolic activity and may perpetuate inflammation following joint trauma. Interleukin-15 (IL-15), a pro-inflammatory cytokine, is increased in OA patients, although its roles in PTOA pathophysiology are not well characterized. Here, we utilized Il15 deficient rats to examine the role of IL-15 in PTOA pathogenesis in an injury-induced model. OA was surgically induced in Il15 deficient Holtzman Sprague-Dawley rats and control wild-type rats to compare PTOA progression. Semi-quantitative scoring of the articular cartilage, subchondral bone, osteophyte size, and synovium was performed by two blinded observers. There was no significant difference between Il15 deficient rats and wild-type rats following PTOA-induction across articular cartilage damage, subchondral bone damage, and osteophyte scoring. Similarly, synovitis scoring across six parameters found no significant difference between genetic variants. Overall, IL-15 does not appear to play a key role in the development of structural changes in this surgically-induced rat model of PTOA.


2021 ◽  
Vol 14 (3) ◽  
pp. 235
Author(s):  
Jen-Sheng Pei ◽  
Chao-Chun Chen ◽  
Wen-Shin Chang ◽  
Yun-Chi Wang ◽  
Jaw-Chyun Chen ◽  
...  

The purpose of our study was to investigate whether genetic variations in lncRNA H19 were associated with susceptibility to childhood leukemia. Two hundred and sixty-six childhood leukemia patients and 266 healthy controls were enrolled in Taiwan, and two single nucleotide polymorphisms (SNPs), rs2839698 and rs217727, in H19 were genotyped and analyzed. There was a significant difference in the genotypic distribution of rs2839698 between patients and healthy controls (p = 0.0277). Compared to the wild-type CC genotype, the heterozygous variant CT and homozygous variant TT genotypes were associated with significantly increased risks of childhood leukemia with an adjusted odd ratio (OR) of 1.46 (95% confidence interval (CI), 1.08–2.14, p = 0.0429) and 1.94 (95%CI, 1.15–3.31, p = 0.0169), respectively (pfor tread = 0.0277). The difference in allelic frequencies between childhood leukemia patients and controls was also significant (T versus C, adjusted OR = 1.53, 95%CI, 1.13–1.79, p = 0.0077). There were no significant differences in the genotypic and allelic distributions of rs217727 between cases and controls. Interestingly, the average level of H19 rs2839698 was statistically significantly higher for patients with CT and TT genotypes than from those with the CC genotype (p < 0.0001). Our results indicate that H19 SNP rs2839698, but not rs217727, may serve as a novel susceptibility marker for childhood leukemia.


2017 ◽  
Vol 30 (11) ◽  
pp. 886-895 ◽  
Author(s):  
Maria Chiara Paccanaro ◽  
Luca Sella ◽  
Carla Castiglioni ◽  
Francesca Giacomello ◽  
Ana Lilia Martínez-Rocha ◽  
...  

Endo-polygalacturonases (PGs) and xylanases have been shown to play an important role during pathogenesis of some fungal pathogens of dicot plants, while their role in monocot pathogens is less defined. Pg1 and xyr1 genes of the wheat pathogen Fusarium graminearum encode the main PG and the major regulator of xylanase production, respectively. Single- and double-disrupted mutants for these genes were obtained to assess their contribution to fungal infection. Compared with wild-type strain, the ∆pg mutant showed a nearly abolished PG activity, slight reduced virulence on soybean seedlings, but no significant difference in disease symptoms on wheat spikes; the ∆xyr mutant was strongly reduced in xylanase activity and moderately reduced in cellulase activity but was as virulent as wild type on both soybean and wheat plants. Consequently, the ΔpgΔxyr double mutant was impaired in xylanase, PG, and cellulase activities but, differently from single mutants, was significantly reduced in virulence on both plants. These findings demonstrate that the concurrent presence of PG, xylanase, and cellulase activities is necessary for full virulence. The observation that the uronides released from wheat cell wall after a F. graminearum PG treatment were largely increased by the fungal xylanases suggests that these enzymes act synergistically in deconstructing the plant cell wall.


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