Rapid Cycling Brassica Rapa Research Articles

Climate change and plant rhizosphere microbiomes: an experiential course-embedded research project.

The current and ongoing challenges brought on by climate change will require future scientists who have hands-on experience using advanced molecular techniques, can work with large data sets, and can make correlations between metadata and microbial diversity. A course-embedded research project can prepare students to answer complex research questions that might help plants adapt to climate change. The project described herein uses plants as a host to study the impact of climate change-induced drought on host-microbe interactions through next-generation DNA sequencing and analysis using a command-line program. Specifically, the project studies the impact of simulated drought on the rhizosphere microbiome of Fast Plants rapid cycling Brassica rapa using inexpensive greenhouse supplies and 16S rRNA V3/V4 Illumina sequencing. Data analysis is performed with the freely accessible Python-based microbiome bioinformatics platform QIIME 2.

Rapid-cycling Brassica rapa evolves even earlier flowering under experimental drought.

Changes in climate can impose selection on populations and may lead to rapid evolution. One such climatic stress is drought, which plant populations may respond to with escape (rapid growth and early flowering) or avoidance (slow growth and efficient water-use). However, it is unclear if drought escape would be a viable strategy for populations that already flower early from prior selection. In an experimental evolution study, we subjected rapid-cycling Brassica rapa (RCBr), which was previously selected for early flowering, to four generations of experimental drought or watered conditions. We then grew ancestral and descendant populations concurrently under drought and watered conditions to assess evolution, plasticity, and adaptation. The RCBr populations that evolved under drought had earlier flowering and lower water-use efficiency than the populations that evolved under watered conditions, indicating evolutionary divergence. The drought descendants also had a trend of earlier flowering compared to ancestors, indicating evolution. Evolution of earlier flowering under drought followed the direction of selection and increased fitness and was consistent with studies in natural and experimental populations of this species, suggesting adaptive evolution. We found rapid adaptive evolution of drought escape in RCBr and little evidence for constraints on flowering time evolution, even though RCBr already flowers extremely early. Our results suggest that some populations may harbor sufficient genetic variation for evolution even after strong selection has occurred. Our study also illustrates the utility of combining artificial selection, experimental evolution, and the resurrection approach to study the evolution of functional traits.

Damage and recovery from drift of synthetic-auxin herbicide dicamba depends on concentration and varies among floral, vegetative, and lifetime traits in rapid cycling Brassica rapa

Herbicides can drift from intended plants onto non-target species. It remains unclear how drift impacts plant functional traits that are important for fitness. To address this gap, we conducted an experiment where fast cycling Brassica rapa plants were exposed to one of three drift concentrations (0.5%, 1%, 10%) of synthetic-auxin dicamba. We evaluated damage to and capacity of floral and vegetative traits to recover as well as lifetime fitness by comparing treated plants to controls. Response to dicamba exposure was concentration-dependent across all traits but varied with trait type. At 0.5% dicamba, three out of five floral traits were affected, while at 1% dicamba, four floral traits and one out of two vegetative traits were negatively impacted. At 10% dicamba all floral and vegetative traits were stunted. Overall, floral traits were more responsive to all dicamba drift concentrations than vegetative traits and displayed a wide range of variation ranging from no response (e.g., pistil length) to up to 84% reduction (ovule number). However, despite floral traits were more affected across the dicamba drift concentrations they were also more likely to recover than the vegetative traits. There was also variation among lifetime traits; the onset of flowering was delayed, and reproductive fitness was negatively affected in a concentration-dependent manner, but the final biomass and total flower production were not affected. Altogether, we show substantial variation across plant traits in their response to dicamba and conclude that accounting for this variation is essential to understand the full impact of herbicide drift on plants and the ecological interactions these traits mediate.

Targeting Cytokinin Homeostasis in Rapid Cycling Brassica rapa with Plant Growth Regulators INCYDE and TD-K.

Modifying the cytokinin content in plants is a means of improving plant productivity. Here, we report the development and biological activity of compound TD-K (1-(furan-2-ylmethyl)-3-(1,2,3-thiadiazol-5-yl)urea)which is related to thidiazuron. TD-K—which exhibited extremely high antisenescence activity in the wheat leaf bioassay—and INCYDE (2-chloro-6-(3-methoxyphenyl)aminopurine)—a plant growth regulator reported to inhibit cytokinin oxidase/dehydrogenase (CKX), an enzyme involved in the degradation of the plant hormone cytokinin—were selected for investigation of their effects on the model plant Rapid Cycling Brassica rapa (RCBr). We monitored the expression of BrCKX and isopentenyl transferase (BrIPT), which codes for the key cytokinin biosynthesis enzyme, in developing leaves following INCYDE and TD-K application. Growth room experiments revealed that INCYDE increased RCBr seed yield per plant, but only when applied multiple times and when grown in 5 mM KNO3. Expression in control leaves showed transient, high levels of expression of BrCKX and BrIPT at true leaf appearance. Following INCYDE application, there was a rapid and strong upregulation of BrCKX3, and a transient downregulation of BrIPT1 and BrIPT3. Interestingly, the upregulation of BrCKX3 persisted in a milder form throughout the course of the experiment (16 days). TD-K also upregulated BrCKX3. However, in contrast to INCYDE, this effect disappeared after two days. These results suggest that both compounds (CKX inhibitor and cytokinin TD-K) influenced cytokinin homeostasis in RCBr leaves, but with different mechanisms.

Agrobacterium-mediated vacuum infiltration and floral dip transformation of rapid-cycling Brassica rapa

BackgroundRapid-cycling Brassica rapa (RCBr), also known as Wisconsin Fast Plants, are small robust plants with a short lifecycle that are widely used in biology teaching. RCBr have been used for decades but there are no published reports of RCBr genetic transformation. Agrobacterium-mediated vacuum infiltration has been used to transform pakchoi (Brassica rapa ssp. chinensis) and may be suitable for RCBr transformation. The floral dip transformation method, an improved version of vacuum infiltration, could make the procedure easier.ResultsBased on previous findings from Arabidopsis and pakchoi, plants of three different ages were inoculated with Agrobacterium. Kanamycin selection was suboptimal with RCBr; a GFP screen was used to identify candidate transformants. RCBr floral bud dissection showed that only buds with a diameter less than 1 mm carried unsealed carpels, a key point of successful floral dip transformation. Plants across a wide range of inflorescence maturities but containing these immature buds were successfully transformed, at an overall rate of 0.1% (one per 1000 T1 seeds). Transformation was successful using either vacuum infiltration or the floral dip method, as confirmed by PCR and Southern blot.ConclusionA genetic transformation system for RCBr was established in this study. This will promote development of new biology teaching tools as well as basic biology research on Brassica rapa.

Development and Application Effect of Open Inquiry Program for Elementary School Students Using Rapid-cycling Brassica rapa

Development and Application Effect of Open Inquiry Program for Elementary School Students Using Rapid-cycling Brassica rapa

Genome-wide analysis of gene expression to distinguish photoperiod-dependent and -independent flowering in Brassicaceae

Photoperiod is the most important environmental cue for the regulation of flowering time, a highly important agronomic trait for crop productivity. To help elucidate the photoperiodic control of flowering in Brassicaceae, we performed microarray experiments using species-specific oligo-arrays with the long day (LD) plant Arabidopsis thaliana and the photoperiod-independent plant rapid cycling Brassica rapa (RCBr). Enrichment analysis of the gene ontologies of differentially expressed genes (DEGs) did not uncover clear differences in gene expression between photoperiod-dependent and -independent plants. Most genes that were up-regulated under LD conditions in Arabidopsis were also up-regulated in RCBr. In addition, most genes associated with light signaling and the circadian clock showed similar expression patterns between Arabidopsis and RCBr, implying that most components known to be key regulators in the photoperiodic flowering pathway are not responsible for the photoperiod independence of RCBr. Nonetheless, we identified one clock-associated gene, PSEUDO-RESPONSE REGULATOR9 (PRR9), as a candidate gene explaining the photoperiod independence of RCBr. The mechanism underlying the role of PRR9 in photoperiodic control and genomic polymorphisms should be further explored using different B. rapa species.

'식물의 한살이' 단원에서 속성배추를 활용한 뇌기반 진화적 접근법이 초등학생의 흥미에 미치는 영향

The purpose of this study is to analyze the effects of elementary science instruction applying a Brain-Based Evolutionary (ABC-DEF) approach using Rapid-cycling Brassica rapa (RcBr) on the interests of elementary school students. For this study, two elementary school classes in Seoul and one elementary school class in Gyeonggi-do were selected. Comparison group received instruction using textbook and teacher's guidebook. A class taught using only brain-based evolutionary approach is experimental group A, and a class taught through brain-based evolutionary approach using RcBr is experimental group B. In order to analyze the quantitative differences about the interests of students, three kinds of test were administered to the students: 'Applied Unit-Related Interests', 'Follow-up Interests' and 'Interests in the observation material'. To get more information, qualitative data such as portfolios and interviews were analyzed. The major findings are as follows. First, for the test of applied unit-related interests, a statistically significant difference was found between comparison group and experimental group A, and between comparison group and experimental group B. As the results of interviews, the students have shown that the intensified exploration activities on plant in Brain-Based Evolutionary approach applied to experimental groups A and B had a positive effect. Second, for test of follow-up interests, we classified the students' follow-up interests into three types: extended-developed-deepened (EDD) type, simply expanded-maintained (SEM) type, and stopped or decreased (SD) type. Both experimental group A and experimental group B showed the highest percentage of EDD. Also, observation journal applying the evolutionary process (DEF) showed a positive effect on the students' interest. Comparison group showed the highest percentage of SEM. Third, for test of applied interests in the observation material, a statistically significant difference was found between comparison group and experimental group A, and comparison group and experimental group B. Experimental group B using RcBr showed the highest average score, while experimental group A showed a higher score than comparison group. Based on these findings, educational implications of Brain-Based Evolutionary approach and using RcBr are discussed.

The Gene Encoding Dihydroflavonol 4-Reductase Is a Candidate for the anthocyaninless Locus of Rapid Cycling Brassica rapa (Fast Plants Type).

Rapid cycling Brassica rapa, also known as Wisconsin Fast Plants, are a widely used organism in both K-12 and college science education. They are an excellent system for genetics laboratory instruction because it is very easy to conduct genetic crosses with this organism, there are numerous seed stocks with variation in both Mendelian and quantitative traits, they have a short generation time, and there is a wealth of educational materials for instructors using them. Their main deficiency for genetics education is that none of the genetic variation in RCBr has yet been characterized at the molecular level. Here we present the first molecular characterization of a gene responsible for a trait in Fast Plants. The trait under study is purple/nonpurple variation due to the anthocyaninless locus, which is one of the Mendelian traits most frequently used for genetics education with this organism. We present evidence that the DFR gene, which encodes dihyroflavonol 4-reductase, is the candidate gene for the anthocyaninless (ANL) locus in RCBr. DFR shows complete linkage with ANL in genetic crosses with a total of 948 informative chromosomes, and strains with the recessive nonpurple phenotype have a transposon-related insertion in the DFR which is predicted to disrupt gene function.

Multigenerational exposure to cerium oxide nanoparticles: Physiological and biochemical analysis reveals transmissible changes in rapid cycling Brassica rapa

The unique redox chemistry on the surface of cerium oxide nanoparticles (CeO2NPs) and their broad applications in society have caused many concerns over the release and accumulation of these materials in the environment. Many investigations have been conducted with regard to the environmental health and safety effect of CeO2NPs, including their impact on plant health. However, most previous studies were conducted on the early seedling development stage, with a small number of recent investigations examined the impact of CeO2NPs throughout the life cycle of plants (e.g. from seed to seed). However, the long term, multigenerational impact of CeO2NPs on plants remains unclear. The main aim of this study was to assess the physiological and biochemical consequences of multi-generational (three) CeO2NPs exposure over a range of concentrations (0–1000mg/L) on B. rapa. The results showed that plants in the second and third generation displayed slower plant growth and smaller biomass. The Brassica plants also bore 39%, 59% and 61% less siliques after two generations of exposure to 10, 100 and 1000mg/L of CeO2NPs. The numbers of seeds produced per silique were also reduced in the third generation plant by over 50% following the exposure to 100 and 1000mg/L of CeO2NPs. In addition, plants in the later generations generally contained higher concentrations of hydrogen peroxide (H2O2) in their tissues. Altogether, our results suggest that the second and third generation plants might have experienced higher oxidative stress than the first generation plants. This study provided first evidence that the impact of CeO2NPs varied across generations and long term evaluation extending several generations of plant growth is necessary to obtain a realistic understanding on the long term impact of engineered nanoparticles.

Regulated Changes in the Acetylation of α-Tubulin on Lys40during Growth and Organ Development in Fast Plants,Brassica rapaL.

Recently, we confirmed the widespread occurrence of α-tubulin acetylation on Lys(40) in angiosperms. In the present study, we found that α-tubulin acetylation is regulated in a growth stage- and organ development-dependent manner in the rapid cycling Brassica rapa, also known as Fast Plants. Organ distribution analysis showed that the proportion of acetylated α-tubulin is high in the cotyledons of young plants and in the true leaves and flowers of mature plants. A correlation between the increase in the levels of α-tubulin acetylation and the maturation of true leaves was observed. In the mature leaves, the acetylated α-tubulin showed an uneven distribution pattern, and the cells in the region of the leaf margins contained a high proportion of acetylated α-tubulin. These results indicate that α-tubulin acetylation is dynamically regulated in plant organs during development, and that it might play an important role in microtubule functioning throughout the angiosperm's life cycle.

Plant Reproduction & the Pollen Tube Journey – How the Females Lure the Males

The growth of pollen tubes is one of the most characteristic events in angiosperm reproduction. This article describes an activity for visualizing the journey and guidance of pollen tubes in the reproductive structures of a flowering plant. The activity uses a semi-in vivo system with rapid-cycling Brassica rapa, also known as Fast Plants. Isolated ovules were used to attract pollen tubes that were triggered to grow through explants of female flower parts. The activity provides insight into the in vivo situation of plant reproduction, appealing visual results, and the development of science process skills.

Protoplast isolation and culture for somatic hybridisation of rapid cycling Brassica rapa with ‘Anand’ CMS and Brassica juncea

Protoplasts were isolated from the young leaves of rapid cycling Brassica rapa and cotyledons and hypocotyls of 10-day-old Brassica juncea seedlings. Protoplasts were fused by 40% polyethylene glycol and cultured in modified K8p medium supplemented with 2.5 mg·l−1 isopentenyladenine (2ip), 0.5 mg·l−1 naphthaleneacetic acid, 1 mg·l−1 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1 mg·l−1 zeatin, 1% dimethyl sulfoxide, and 0.4 M mannitol as osmoticum. After 3 days of initial culture, 3 different culture methods were employed and evaluated. The highest plating efficiency (1.97%) was obtained with a semi-solid agarose embedding culture method. Both shoots and somatic embryos formed from protoplast culture-derived calli. The somatic embryos were derived from asymmetrically divided calli that developed progressively into deep-purple heart shapes as well as the early-torpedo and bipolar stages to finally form complete plantlets. Thirteen putative somatic hybrids were produced via somatic embryogenesis or organogenesis. Random amplified polymorphism DNA analysis was performed to identify somatic hybrids. Six regenerated plants had a chromosome number of 2n = 56 the same as the sum of B. juncea (2n = 36) and B. rapa (2n = 20) chromosomes; 2 plants had a chromosome number of 2n = 54. These regenerated plants exhibited morphology intermediate to those of their parents. The flowers of somatic hybrids exhibited a range of variation; some were normal, while others were abnormal. No pollen was produced from regenerated plants. Two plants had crinkled petal-like stamens.

DNA-Based Genetic Markers for Rapid Cycling Brassica Rapa (Fast Plants Type) Designed for the Teaching Laboratory

We have developed DNA-based genetic markers for rapid cycling Brassica rapa (RCBr), also known as Fast Plants. Although markers for B. rapa already exist, ours were intentionally designed for use in a teaching laboratory environment. The qualities we selected for were robust amplification in PCR, polymorphism in RCBr strains, and alleles that can be easily resolved in simple agarose slab gels. We have developed two single nucleotide polymorphism (SNP) based markers and 14 variable number tandem repeat (VNTR)-type markers spread over four chromosomes. The DNA sequences of these markers represent variation in a wide range of genomic features. Among the VNTR-type markers, there are examples of variation in a non-genic region, variation within an intron, and variation in the coding sequence of a gene. Among the SNP-based markers there are examples of polymorphism in intronic DNA and synonymous substitution in a coding sequence. Thus these markers can serve laboratory exercises in both transmission genetics and molecular biology.

Development and Application of the Photosynthesis Experimental Module Based on Scientist's Inquiry Processes

This study was intended to develop an experimental module based on inquiry processes conducted by photosynthesis scientists. It was aimed to enhance scientific inquiry ability of the middle school students by applying the developed module. Developed module included some experiments conducted by earlier photosynthesis scientists such as Helmont, Woodward, Priestly, Hales and Ingen-Hausz. Inquiry process was involved in the developed module for instructing the inquiry methods. Rapid-cycling Brassica rapa known as a Fast Plant was used for the experimental material. Developed module was applied to the experimental group consisting 27 eighth grader, while experiments suggested in the science textbook was applied to the control group consisting 30 eighth grader. Developed module was more effective in improving students' scientific inquiry ability, especially measuring, forecasting and hypothesizing ability as its subordinate elements. When the result of post-test was compared to one of pre-test in the experimental group, their observing, forecasting, and generalization ability were improved. Experimental group showed that students' conception in photosynthesis and conceptual development related with the role of plants in the ecosystem and plant's food and movement of the water and nutrients were also improved. Before application, students in the experimental group did not have enough understanding of the abstract concept such as the existence or the role of the materials like CO2 or O2 or the energy accumulation. Developed module could help students to achieve the comprehensive concept regarding the role of plants as producers of organic matter and oxygen and to enhance their scientific inquiry ability and concepts regarding photosynthesis.

Development and Application of the Creative Open Inquiry Module using Rapid-cycling Brassica rapa Based on the Creative Problem Solving Model

Development and Application of the Creative Open Inquiry Module using Rapid-cycling Brassica rapa Based on the Creative Problem Solving Model

Costs of defense: correlated responses to divergent selection for foliar glucosinolate content in Brassica rapa

The evolutionary response of plant populations to herbivore imposed selection for defense may theoretically be constrained by the costs of defense, yet few studies convincingly demonstrate such costs. We investigated possible constraints on the evolution of defense in rapid cycling Brassica rapa by divergently selecting lines for investment in foliar glucosinolate content, a chemical defense in this species. Costs would then result in a significant correlated response to artificially imposed selection in the direction opposite to the direct response of foliar glucosinolate production. Correlated responses of date of first flowering, total flower number, number of seeds per fruit, and mean seed mass were examined. After three generations of selection, there was a significant direct response in glucosinolate content of the leaves of B. rapa. Furthermore, we found significant correlated responses in both total flower production and number of seeds produced per fruit, but not date of first flowering or mean seed mass. Lines selected for high glucosinolates produced fewer flowers and seeds per fruit compared to those selected for low glucosinolates while lines selected for low glucosinolates showed the opposite response. Thus, costs of defense were demonstrated and may constrain the evolution of foliar glucosinolate production in this plant species.

Isopentenyl Transferase and Cytokinin Oxidase/Dehydrogenase Gene Family Members are Differentially Expressed During Pod and Seed Development in Rapid-cycling Brassica

The plant hormone group, the cytokinins, regulates many stages of plant growth and development. Regulation includes that of cell division and enhancement of sink strength, both of which are important processes in seed development and embryonic growth. Two gene families play a key role in maintaining cytokinin homeostasis: isopentenyl transferase (IPT), which catalyzes the rate-limiting step in the formation of cytokinins, and cytokinin oxidase/dehydrogenase (CKX), which irreversibly inactivates cytokinins by cleaving the N6 side chain. Quantitative reverse transcriptase polymerase chain reaction (PCR) was used to measure the expression of individual gene family members to investigate the source of cytokinin and its subsequent inactivation during the early stages of seed and pod development. In this study, rapid-cycling Brassica rapa (RCBr) was used because of its genetic relatedness to commercial Brassica species, its rapid life cycle, its small adult size, and its larger reproductive organs compared to Arabidopsis. Our results indicate that BrIPT1, -3, and -5 and BrCKX1, -2, -3, and -5 express differentially both temporally and spatially within RCBr root, stem, leaf, seed, and pod tissues. Particularly strong expression was shown by IPT3 and IPT5 and CKX2 in developing seeds.

Effects of the Experimental Modules of Mendelian Genetics using Rapid-cycling Brassica rapa on the Change of Preservice Teachers’ Concepts in Genetics

Pay off reel is the device to release in the form of coil. Every time the device becomes a hassle to exchange, each diameter of two forms has been applied to the coil reel. There is the change of reel diameter of the sleeve portion to be the part of segment geometry. This unit is conducting on 3-dimensional modeling design. The basic strength and deformation of the device could be checked in advance by the basis of 3-d modeling data to perform simulations. The production of each part can be completed and assembled. Conducted for the final product which is tested and measured, all items are satisfied within the limits of targets. Due to the development of this device, the efficiency on operations can be increased and the production time becomes shortened.

Development and Application of an Experimental Module about the Structure and Function of Plants using Rapid-cycling Brassica rapa

Development and Application of an Experimental Module about the Structure and Function of Plants using Rapid-cycling Brassica rapa