When applying for internships I was worried I would not be a to find a position in the field of agriculture genetics and research, as those positions are usually filled by individuals with graduate degrees, pHds, masters and post-doctoral students. Fortunately, I contracted a position with the United States Department of Agriculture-Agriculture Research Service (USDA-ARS) working as a Biological Science Aid at the Soybean and Nitrogen Fixation Unit located in Raleigh, North Carolina. My contracted position is not to exceed June 2, 2019 and is limited to 180 days of service.
Working with the USDA has opened my eyes to several opportunities within the field of agriculture such as; Public Service (Government) Employment, research opportunities within public service, soybean production and career opportunities in soybean production, planting/harvesting, crop maintenance, traditional plant breeding and genetic research. The Soybean and Nitrogen Fixation Unit harvests approximately 110 acres of test plots, 17,000 yield plots and 8,000 nursery plots annually. It is evident that the Soybean and Nitrogen Fixation Research Unit strives to improve varieties of soybeans to benefit the future of agriculturalist. My position was contracted under the supervision of Dr. Rouf Mian and Dr. Thomas Carter.
The ongoing project that had the opportunity to assisted was ‘Developing Soybean Cultivars and Germplasms with Increased Protein Quantity and Quality for the Midwest and South[ern varieties].’ As a prospective agricultural geneticist, I understand the need to improve this paramount industry and I share great interest in the focus areas of developing germplasm, agronomic performance, drought/environmental stresses, and improvement of nutritional value. Working on this project came with great responsibility and a multitude of crop production and lab oriented tasks; ranging from watering flowers performing Cetyltrimethylammonium bromide (C-TAB) DNA extractions (USDA-ARS, 2018).
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What was done during the experience?
- Field Lay Out: When laying out fields I would take thousands of seed packets and lay them out by row and seed number. I would lay the field out according to the field map (example of field map on page 9) provided by one of the field technicians. I would then rubber band these seed packets and put them in sleeves, labeling the boxes in numerical order so they were ready to take to the field for planting.
- Planting: I had the opportunity to plant 5 plots; B6, G3, A4, H1A and AxB. Plot AxB is also considered the Crossing Block becauses that is where we perform cross-pollination. Sometimes planting was done by hand with push planters (usually in the crossing block) and sometimes used a walk-behind planter.
- Plant Tissue Collection: In the crossing block I collected around 600 plant tissue samples to perform DNA extractions. Plant tissue collection usually consisted of sitting in the middle of the crossing block under an umbrella all day.
- DNA Extractions: Performing DNA extractions did not last more than a week. With two lab technicians and myself, it did not take long to extract DNA on 600 plant tissue samples.
- Cross-pollinating: Crossing ‘season’ lasted about three weeks. Mostly everyone working at the Soybean and Nitrogen Fixation Unit would come out to the field to help cross.
- Weeding: Between the time of crossing and harvest, there was not too much going on at the research unit. For that reason, most of us temporary employees would go to the field everyday to weed fields and rouge.
- Rouging: Rouging is the action of walking through the fields and picking out the plants with undesirable characteristics. This helps keep the seed line pure. I had the opportunity to do this at the Sandhills research station.
- Harvesting: Harvesting is currently taking place at the research unit. Most days we are hand harvesting soybeans by maturity level. Each week a field technician will visit the field and spray plant the tips of the soybeans indicating those are the plants we will harvest that week. After cutting and drying the plants in tobacco driers, threshing takes place. This is the action of putting the individual soybeans plants through a machine that separates the seed from the trash. The seeds will be collected in individual envelopes for each plant and the trash will be burned.
What parts of the experience were valuable?
My internship working at the soybean and nitrogen fixation unit was a very valuable experience overall. I had the opportunity to experience research methods, working with research plots, general crop maintenance, planting, harvesting, crossing plants and extracting DNA. Personally I think I gained the most experience through tangible tasks such as extracting DNA and maintaining crops as well as intangible tasks such as communication and networking. Performing DNA extractions with them USDA has began to prepare me for a future career in the area of agricultural genetics and plant breeding. Learning how to properly maintain your crop is obviously a very crucial part to crop production, the plants need to be alive and well in order to perform research.
Although communication and networking are not tangible tasks, they are both very important when at work and my valuable to future career. Communication is important in any work environment, especially in the field of research where one simple miscommunication can ruin a trial, even years worth of research. Networking with coworkers during weekly round table discussions has opened my eyes to other career opportunity in the area of plant breeding as well as learn more about my co-workers educational journeys. Learning more about my coworkers educational journeys and pursuits has brought to my attention the multitude of plant breeding and genetics masters programs and opportunities around the country and internationally.
What parts of the experience were least valuable?
Communication errors were probably the least valuable part of my internship experience. Even in highly structured environments, such as the government workplaces, communication errors are made like any other area of workforce. One time we were planting at the Clayton Research Station and half of the seeds we needed to plant were left at the soybean unit in Raleigh. This mistake was made due to a lack of communication and could have been avoided if the field technicians communicated which technicial was suppose to transport the seeds to the field that was going to be planted.
Even parts that didn’t seem like they were very valuable experiences, such as laying irrigation pipe, picking through seeds and labeling bags. Simple, small tasks are always important and serve a purpose to help build towards the ideal end result. These tasks were very time consuming and almost seemed like busy work most times.
What specific skills, experience and knowledge were gained?
I gained the most knowledge and skills that I can use in my future career when I was preparing CTAB DNA buffer and performing DNA extractions; both of these tasks required an intense amount of attention to detail and accuracy. Isolating DNA from plant tissue can be a very difficult task as the biochemistry between plant species can be extremely diverse. Plants also can have inconsistent levels of structural biomolecules and metabolites. Plant biomolecules such as polysaccharides and polyphenols can interfere with the manipulation and isolation of DNA. C-TAB buffer works as a separation of polysaccharides and can aid in the removal of polyphenols, which is why C-TAB based extractions are widely used in the scientific community when assisting with the purification of DNA.
One significant disadvantage to C-TAB buffer is the use of chloroform. Chloroform is carcinogenic and is usually frowned upon by many institutions. I was not the biggest fan of mixing and using C-TAB buffer because the presence of chloroform. Chloroform is silent but deadly, you recognize the symptoms of being exposed (in close proximity) soon after exposure. I experienced extreme headaches and fatigue when working with C-TAB buffer (OPS Diagnostics, 2018). I consider having knowledge and experience with C-TAB DNA buffer very beneficial to me because I most likely be using the buffer again during future employment in the field of agriculture genetics and plant breeding.
Preparing for DNA extractions was another task where I gained a vast amount of knowledge and skill. The process of extracting begins with preparing X-number of 2 mL Microcentrifuge tubes, dropping one metal BB into the tube and labeling the top and side of tube with sample ID. After preparing the 2 mL tubes for tissue collection, it is time to collect plant tissue samples. Tissue samples are collected in a field setting at Central Crops Research Station located in Clayton, NC. The samples harvested should barely be an expanded trifoliate. Trifoliates are new, compound leaves with 3 parts or leaflets (Pioneer, 2018).
The key to a successful DNA extraction is proper storage of collected samples before DNA isolation; this is to prevent the degradation of DNA. Flash freezing samples is a common solution to prevent the degradation of DNA. Directly after collecting tissue samples, place sample tubes in a mesh bag inside of a foam cooler filled half-way with liquid nitrogen (-196°C). Upon returning to a lab setting, store samples in -80°C freezer prior to desiccation. At these temperatures, the nucleases remain inactive and the DNA remains stable (Sample Collection and Storage, 2017).
Now that the samples have been collected and stored in a cool setting for 24-48 hours, lyophilize the leaves for 1-2 days before grinding. Lyophilization (freeze-drying) the leaves allows the BB to grind the dry leaves into a fine powder once placed in the grinder. Grind the samples at 1,200 rpm for 30-45 seconds. Once the leaf samples are grinded into a powder, place samples in a rack to hold tubes. Add 700μL (Microliter) of 65°C pre-warmed Cetyl trimethylammonium bromide (CTAB) buffer and 2μL, 100mg/mL RNase to each sample. RNase is used to breakdown the RNA into oligonucleotides, a molecule with a small number of nucleotides. Vortex the samples allowing the powder, CTAB buffer and RNase to become a homogenous mixture.
After vortexing the samples, place sample tubes in floating boats and incubate in a 65°C water bath for 10-30 minutes. After incubation, let the samples cool down to room temperature and spin down tubes for 3 minutes at 10,000 rpm. After spin down, add 700μL 24:1 Chloroform(CHCl3) and Octanol (C8H18O). Inverse the samples by placing between two racks and slowly rock back-and-forth for 20 seconds. Centrifuge for 10 minutes at 10,000 rpm. After centrifuge, pipette the aqueous (upper layer in sample tube) phase (400 μL) into a new 1.5mL Microcentrifuge tube and add 400 μL of ice cold 95% Ethanol and mix again by inversion.
Allow the samples to sit at room temperature for 10 minutes before spinning down for 2 minutes at 10,000 rpm. Pour off the supernatant, liquid above solid residue, and gently dab excess liquid onto a KimWipe. Add 500μL of 70% Ethanol and spin for 3 minutes at 10,000 rpm. Once again,pour off supernatant and dab excess onto a KimWipe. The DNA extracted from the plant tissue samples will be located in the bottom of the sample tube in the form of a cloudy mass.
How was the new knowledge related to prior knowledge gained in the academic setting prior to the experience?
Prior to my experience, I was familiar with the career qualification for being a plant geneticist/plant breeder, but I did not know what these geneticist/breeders do on an everyday basis. I personally feel that I learned more about tasks as a geneticist/breeders first hand at work versus in the academic setting. Although I have gained lab experience and crop science knowledge through academic settings, it is a different, more impactful experience when I have the opportunity to do these tasks hands-on.
Overall, were you satisfied with your experience?
My summer spent at the Soybean and Nitrogen Fixation Unit was a very satisfying experience. I learned a lot not only in the lab and in my field of interest, I also learned a lot about the actual skill of farming. I did not grow up with a farming background and it was very eye opening to experience the effort and time it takes to produce the most favorable outcome for your crop. This part of the experience has made me reevaluate my appreciation for farmers.
How have I grown academically, personally and professionally as a result of the experience?
Academically I feel that I have learned a lot through my hands on experiences working and understand material I learn in the classroom with better understanding. I also learned a lot of information that I have not learned in the classroom, yet. I am looking forward to the day that I am sitting in a plant genetics class and I fully understand the materials being taught because the amount of knowledge I obtained through my internship. On a personal level, I feel like my strive for personal excellence has grown. Not many students in my position get amazing opportunities like I have experienced thus far.
With this being said, I believe that I need to shoot for 115% in my school and extracurricular activities. This has also helped me grow professionally. I have had hands on experience in an area of agriculture that requires a lot of knowledge, precision and focus. I believe having my experience with the USDA-ARS makes me a top candidate for beginning job positions in my area of interest. I have also had the opportunity to network with several professionals at the Soybean and Nitrogen Fixation Unit. Overall I have grown academically, personally and professionally and I am looking forward to spending more time working at the USDA-ARS Soybean and Nitrogen Fixation Unit.
