Sheldon nolan horticulture
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Recent work suggests that mutations in cis -regulatory mutations should play critical roles in the evolution of this as well as other important adaptive traits, but thus far there has been little evidence that directly links regulatory mutations to evolutionary change at the species level. Here we identify and characterize natural variation in the cis- regulatory sequence in the transcription factor CONSTANS that underlies flowering time diversity in Arabidopsis.
Mutation in this regulatory motif evolved recently and has spread to high frequency in Arabidopsis natural accessions, suggesting a role for these cis -regulatory changes in adaptive variation of flowering time. Flowering phenology is critically tied to the reproductive ecology of flowering plants, and is an important determinant of fitness in a variable environment 1 , 2. Flowering time in Arabidopsis thaliana , a weedy annual plant, has a wide range of variation, and molecular genetic studies have elucidated many of the key pathways that plants utilize to sense seasonal cues, providing unique opportunities for investigators to examine the molecular genetic basis of flowering time variation in an ecological and evolutionary context.
CO is a photoperiod-dependent flowering time locus 3 that encodes a zinc-finger transcription factor downstream of photoreceptor and circadian clock genes. Numbered dark grey boxes indicate the exons, while light grey boxes indicate UTRs. The horizontal line indicates extent of sequenced region for CO. The translation start site is indicated by ATG.
The light vertical lines are silent site SNPs and the thick vertical lines are nonsynonymous SNPs, which are shown with the amino-acid polymorphisms. The inverted triangle is the relative position of the 7-bp repeat motif at the CO promoter. The sequence of the motif in an individual in A. The thin tick marks are mutations, with the thick tick marks being nonsynonymous changes. The mutation that leads to an increase in the copy number of the 7-bp cis -regulatory repeat from 3X to 4X is indicated by an asterisk, while the decrease in copy number from 3X to 2X by two asterisks.
Here we show that natural variation in the copy number of this CO indel tandem repeat is associated with variation in the developmental transition of flowering time in Arabidopsis accessions. We further show that variation in flowering time can be explained by differences in expression between the alleles. Our results suggest that increased copy number of this tandem repeat evolved recently and quickly spread in Arabidopsis populations, and may play a role in life history variation in natural environments.
We observe allelic variation in a number of repeat units among the 25 A. Seven of the 25 accessions have four complete and one incomplete repeat of this 7-bp motif, resulting in four complete tandem copies of the DOF-binding site 4X. Seventeen accessions have three copies 3X of the binding site, and one accession Cvi-0 has two copies 2X Fig.
We also sequenced the CO orthologue in A. Using a haplotype network Fig. The only molecular difference between the haplotype group A and its ancestral haplotype in group B is the 7-bp insertion that results in an additional CDF1-binding site motif. We found that there are no other indels or single nucleotide polymorphisms that differentiate Hap A from Hap B among our 25 A. Among the accessions analysed, only Cvi-0 carries two repeats of the CDF1-binding site motif.
Moreover, previous work using the pairwise haplotype sharing test has shown that the region around CO has an extended haplotype 4 , although compared with genome-wide data the magnitude of pairwise haplotype sharing around CO is only marginally significant at the 95th percentile level Supplementary Fig.
These features are consistent with a scenario of the recent evolution of the additional 7-bp indel at the CO promoter that has rapidly risen to high frequency across the species. To examine whether the two most common cis -regulatory CO variants 4X and 3X promoter types lead to natural variation in flowering time in natural accessions, we undertook a structured candidate gene association analysis.
Previous work indicates that the FRIGIDA FRI gene has a key role in repressing the vegetative—reproductive developmental transition, with both wild-type delayed flowering and loss-of-function alleles early flowering prevalent in natural populations 7.
We asked whether a genetic background that represses flowering that is, FRI has an effect on the promoter type variation. This association test suggests that delaying flowering that is, in the presence of FRI functional alleles is more likely to show the phenotypic outcomes of natural variation of the CO promoter type. However, these results should be interpreted cautiously, as the definition of FRI functional alleles is not predictive of activity 8 , and associations can arise from other epistatic interactions in different A.
To validate that the two most common cis -regulatory CO variants 4X and 3X promoter types lead to functional differences in the ability to regulate flowering time, we created transgenic constructs of the Col-0 CO promoter fused to the Col-0 CO genomic region Fig. Approximately 50 individuals from each of the 18 lines were grown in a fully randomized block design and scored for bolting time and rosette leaf number.
The experiment was terminated after days when all genotypes flowered, except for several plants carrying FRI-Sf2 without vernalization Fig. The analysis indicates that an increase in the number of the cis -regulatory repeat motif in the CO promoter from 3X to 4X leads to later flowering Supplementary Table 2.
For example, least squares mean estimate for bolting time isWe also tested several CO 2X promoter constructs. The dark tick marks indicate the s.
NS, not significant. Error bars indicate s. Thus, the effect of CO promoter type seems to be dependent on how fast the developmental transition occurs as determined by the FRI background Fig. These patterns are consistent if we use rosette leaf number on bolting as a developmental surrogate for flowering time; the mean number of leaves for CO 4X plants areThe transgenic results are consistent with the structured association results, where 4X CO promoter types showed later flowering in the FRI -active background.
An obvious hypothesis is that variation in the number of the 7-bp indel motif may result in gene expression differences that lead to phenotypic variability in flowering time.
To study this expression difference in greater detail, we transformed A. LUC expression followed a circadian pattern under all three CO promoter types. Experimental periods of dark are shown by the light grey boxes. Although overall CO expression increases with greater numbers of the binding site, there are nevertheless clear differences in the pattern of daytime CO expression from the different promoter types.
We examined the ratio of the minimum CO expression level during the daytime to its maximum at dawn Fig. Therefore, based on our data, the simplest explanation is that the greater the number of the motif, the higher the daytime repression of the CO. The expression pattern of the CO 2X is unusual, overall expression is low and there is very little repression of CO during the daytime Figs 3 and 4. Ratio of daytime minimum over dawn maximum expression of LUC reporter gene driven by different CO promoter types.
We identified cis- regulatory variation in CO , a gene that plays a key role in the flowering time developmental transition. The sequence variation in the promoter region seems to have evolved relatively recently, and is responsible for differences in flowering time and gene expression under laboratory conditions. This CO promoter element may orchestrate a complex series of regulatory interactions.
While this motif at the CO promoter binds the Dof transcription factor CDF1, there are also multiple examples in which Dof factors interact with other types of transcription factors, such as basic leucine zipper proteins and MYB proteins, and modulate their binding with DNATogether, these suggest a complex interplay between activators and repressors on this cis -regulatory element, which might give subtle phenotypic outcomes in an early-flowering background, but larger phenotypic outcomes in genetic backgrounds with delayed reproductive transition that is, FRI and FLC -active backgrounds.
The molecular mechanisms that connect these regulatory interactions to flowering time phenotypes require further study, but it is clear that natural variation in this cis -regulatory motif has a significant effect on both CO expression and flowering time phenotype. Although it has been argued that cis -regulatory mutations underlie much of phenotypic evolution 14 , 22 , 23 , there are as yet relatively few functionally validated examples of identified cis- regulatory changes that are known to have high frequency in natural populations.
In the case of FRI , the natural allelic variation results functional variation in the protein-coding region or regulatory sequences 7. Our work now provides evidence for the role of a high-frequency CO promoter mutation in flowering time variation in A. It remains to be seen whether the role of the CO cis- regulatory variation we observe in controlled laboratory conditions extends to natural environments in the wild.
Comprehensive analyses of gene expression 24 and phenotype in the field 25 , as well as geographical allele distributions across the species range 26 , will be crucial in further understanding the evolutionary and ecological significance of this promoter polymorphism. Nevertheless, our study further supports the importance of modulation of gene expression levels in quantitative phenotypic variation and possibly in evolutionary diversification, and demonstrates that gene regulatory mutations can play important roles in life history diversification in this model wild plant species.
Savolainen Oulu, Finland. The co-1 -mutant line that is introgressed in Col-0 was provided by G. Coupland Koln, Germany. Amasino Madison, USA. For screening transgenic plants, plants were grown under continuous fluorescent light on 1. A mixed model was used for testing for genotype—phenotype association to control for population structure and kinship within the sample.
These analyses, including population stratification and kinship analyses, are carried out as described previouslyThese clones were used to transform the Agrobacterium strain GV by electroporation.
Three independent transformations were carried out for each construct. Transformed plants were screened in MS agar plates containing kanamycin in the T1 generation. Approximately 30 kanamycin-resistant T1 plants per construct were identified.
These transgenic plants were transferred onto soil and T2 seeds were harvested by selfing. Transgenic lines that segregated in ratio for kanamycin resistance were identified in the T2 generation as single-insertion lines. Every Arabidopsis accession was grown in 3—4 plates, and the pool of plants within each plate was considered a biological replicate. Pools of plant tissue were harvested at the start of the light period, when CO expression is the highest Fig.
Seeds were disinfected in ethanol-bleach-water and rinses of sterile water, and plated on MS media Sigma-Aldrich supplemented with sucrose 0. Twelve seedlings per line were sterilized and grown on MS agar plates 37 for 16 days after germination under short day 10LD , and transferred into individual wells of well microtiter plates containing substrates for LUC.
Nine to 15 independent transgenic lines for each construct were crossed with FRI Sf2 co-1 , and F1 seeds were selected for kanamycin resistance on MS agar plates. Plants carrying single-insertion transgene were selected by kanamycin resistance and FRI genotypes tested by simple sequence length polymorphism SSLP PCR for the absence of a characteristic bp deletion in Col-0 fri- in the F2 generation.
Homozygous lines for transgenes were identified in the F3 generation. Once a week we randomized the position of the trays within the chamber, and watered the plants with 1.
Bolting date and rosette leaf number were recorded at bolting. Number of primary leaves was also scored every week to avoid underestimating rosette leaf number due to senescence of old leaves. Statistical analyses were carried out in JMPGenomics 5. How to cite this article: Rosas, U. Bernier, G. The control of floral evocation and morphogenesis. Plant Physiol. Plant Mol.
Undergraduate Spring 2020 Graduates
President Eerkms reported that the trade-had had no material improvement within, the lastthree years. The total munber of factories of all kinds reported ds 14,,- of which number, 7, are strictly union arid 6, are mixed and non-nnion. The union f ac-dories-gfve-employment to Sjf , union workmen. The open shops employ 10, union and non-nnion workmen. ITelix Dulmente met George C. Dulmente then ran upon the bridge nearby and jumped over the railing into the water, 30 feet below, and was drowned.
—Tess Jieun Ha. Died on April 21, Ottawa, ON. Age. Share. all-audio.pro?obituary= Larry Nolan.
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Some high school students from 13 local and regional school systems participated in the 22 nd annual Agricultural Skills Day held at Alfred State College in October. Showmanship competition : new this year, the showmanship competition was open to the first 20 registrants. Contestants were judged on their ability to show and answer questions on dairy cattle, horses, and alpacas. Tractor Driving competition : an individual contest limited to the first 20 registrants age 14 and older with experience in the safe operation of modern agricultural tractors, this contest included a two-wheel trailer event, a written examination related to tractor safety, and identification of tractor parts. Each judge chose a "top five". Stockman's contest: More than contestants participated on 55 teams. Contest stations included two classes of dairy cow judging, dairy product identification, forage, weed, insect identification, dairy and livestock equipment and management questions, equine equipment and breed questions, and farm tool identification. Assisting the ASC Ag Program faculty members in delivering this portion of the contest was ASC Professor Emeritus John Bartell, who provided the expertise in setting up and judging the dairy products identification station. Livestock and Judging Identification Stations. Companion and Small Animal contest: More than 60 contestants identified parasites, surgical instruments and equipment, breeds, anatomical parts, and performed restraint techniques on animals.
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Burns and Ralph A. William Feeney. Kathleen was a librarian at St. Alexis School until her retirement in
Clare Sentinel, 9 October 1896 — Page 2
Photo by Steve C. Robinia pseudoacacia. Black locust hybridizes with Kelsey locust R. Several black locust cultivars are available [ ]. Black locust has been widely planted and frequently escapes cultivation [ 53 , , , , , , , ], review by [ ]. As of , it occurred throughout the conterminous United States and a number of Canadian provinces.
UK Ministers have reappointed Mike Sheldon chairman of the AHDB Pork board for a In accordance with the original Nolan recommendations.
Below is a list of those LSU varsity student-athletes who have received either undergraduate, graduate or advanced degrees from the University from to the present. Note: Some individuals who did not compete but received scholarships through the Athletics Department are included. If there is an edit or omission to this page, please send the information to athletics lsu.
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BBC's daytime garden makeover show is having a shake-up, with three new garden designers — Lee Burkhill, Flo Headlam and Chris Hull — joining the presenting team alongside Charlie Dimmock. Flo and Chris only began filming with Garden Rescue in early May, so they will make their first appearance in series seven of the programme, alongside Charlie and Lee, when it airs inIn , Gardeners' World presenter Arit joined the team. Garden Rescue , produced by Spun Gold TV, sees garden designers compete against each other to build dream gardens for homeowners across the country. Each programme sees the team descend on a garden that is badly in need of a makeover.
As of Monday, May 4, some s tudents, including those earning more than one degree, and who completed their studies this past summer and fall, are listed in the commencement program.
Please use the drop-down menus to select the year of graduation. You can send notifications of passing and your obituaries to alumni-enquiries nottingham. Emma became ill during her finals and was subsequently diagnosed with an adult-onset genetic condition called mitochondrial disease. Just before she died, Emma was instrumental in setting up a charity www. For a full obituary, please see The Guardian. In addition to her successful studies she volunteered throughout her undergraduate years for Phab and Intouniversity helping disadvantaged children. She continued to work with a number of charities after she graduated.
Abid Karray J. Water balance of the olive tree-annual crop association: a modeling approach. Agricultural Water ManagementAlbrecht R.