Automating plant tissue culture

In this publication we shed light on the concept of plant tissue culture, the techniques employed, the main benefits, and the ways to enhance the process through automation.

Plant tissue culture involves a set of techniques with multiple applications, and it is currently a booming activity. This activity is carried out in specialized laboratories, whose professionals are dedicated to cultivate explants in vitro, that is, a separate part of a plant such as protoplasts, cells, tissues or organs, under strictly controlled environmental conditions with the purpose of producing large quantities of plants with the same genotype.

Plant tissue culture is defined as the cultivation of explants in vitro under strictly controlled environmental conditions with the objective of obtaining large numbers of identical plants.

From a biological point of view, plant tissue culture is possible thanks to the cellular totipotentiality of meristematic tissues of plants, which are present in several organs. This attribute allows these plant cells to reproduce asexually and reverse their cellular differentiation and then differentiate again to form a new plant.

Plant tissue culture applies the knowledge of plant biotechnology, which covers different areas of life science as diverse as biochemistry, molecular biology, immunology, virology, food industry, pharmaceutical industry, genetics and agriculture.

The main applications of plant tissue culture

Plant tissue culture allows the study and genetic modification of plants in order to improve their resistance to viruses and insects, their nutritional value, their physical appearance or their metabolism. It also allows a greater understanding of the genetic and physiological processes of plants, since the environmental conditions of in vitro culture can be controlled and analyzed in-depth. It is the main approach used to develop the totipotency potential of plants and induce genotypic and phenotypic manipulation in plant cells.

Nowadays, plant tissue culture is an important tool, both in basic research and commercial applications. For example, biotech companies are continually innovating to develop better seeds that can yield more fruits per plant. In the cosmetics sector, collagen protein extracts or growth factors are produced from plant stem cells, avoiding the use of animals or animal tissues. In medicine, many pharmaceutical products and vaccines are obtained from genetically modified plants. However, the horticulture sector is witnessing a profound impact, as a significant number of companies are implementing vertical production of vegetables and fruits in greenhouses through the means of plant tissue culture. This approach offers several advantages, including the ability to cultivate plants with an identical genotype, higher productivity per unit of land, and increased resistance to pests.

Types of plant tissue culture

As we mentioned at the beginning of this publication, the term plant tissue culture covers multiple techniques, which, depending on their purpose and type of tissue ussed, can be distinguished into different types:

Advantages and disadvantages of plant tissue culture over traditional techniques

Plant tissue culture has many advantages over traditional methods, and the following comparison table summarizes the main advantages of this set of techniques.

Advantages

Tasks such as weeding and spraying are unnecessary.
This process provides uniform biomass in terms of genotype and phenotype available at all times and completely independent of soil conditions and climatic changes.
Production is timeless and can be carried out throughout the year, avoiding seasonal limitations. In addition, the biomass yield is larger and can be optimized over time.
It allows for the study of the effects of various mutagens and the attempted immobilization of cells for biotransformation or biochemical reactions.
It can provide a continuous and reliable source of phytopharmaceuticals. Novel option for the synthesis of compounds whose chemical synthesis is difficult or even impossible. It could also be used for large-scale culture of plant cells.
It can be easily used to produce hybrid plants through interspecific and intergeneric hybridization processes.
It allows the culture of species that would be difficult to obtain with traditional techniques.

Disadvantages

Plant tissue culture requires specialized personnel, backed by good training and advanced facilities, both at laboratory and greenhouse level, which implies a significant initial economic investment.
The plants produced rely on specific sources of nutrition.
It requires an aseptic environment since contamination can compromise an entire crop.
Seedlings are more susceptible to contamination and water loss in outdoor environments, as they are grown at relatively high humidity.
The cultivated plants are not autotrophic and have to go through a transition phase before their independent growth.
It requires intensive monitoring and inspection of the different stages of development compared to traditional cultivation.

Standard procedure for plant tissue culture

We will not go into details about the different steps that constitute this technique because the laboratories dedicated to this task already know what it consists of. In addition, there are multiple varieties of plant tissue culture with different particularities. However, we believe it is appropriate to mention the main phases and then emphasize some of them. Generally, in vitro plant tissue culture consists of 5 stages:

Species selection

Preparation of culture media

Tissue or explant development

Rooting

Conditioning and acclimatization

Most of these steps are performed manually by qualified personnel and their duration fluctuates depending on the type of application used. Although a common denominator in all cases is the way of preparing culture media, which can be particularly tedious and manual. There are three ways of dealing with this procedure: procurement of finished product by purchasing it from an external supplier, manual preparation using an autoclave or automatic preparation using a media preparator.

Preparation of culture media used in plant tissue culture

Culture media used in plant tissue culture usually contain inorganic salts, growth regulators, vitamins, amino acids, carbohydrates and sometimes a gelling agent, although this is not a mandatory element. Other compounds such as antioxidants, growth retardants or natural organic complexes can also be added.

The pH of culture media must also be taken into account, because it affects both plant growth and the activity of growth regulators. Generally, pH should be adjusted to values around 5.5. In addition, culture media must be sterilized to avoid contamination with other microorganisms, and the most popular technique is moist heat sterilization using a laboratory autoclave.

As we already know, the correct preparation of culture media requires precision and control. It is necessary to add different components, ensure the accuracy of quantities and keep an exhaustive record of the provided amounts of each nutrient. The entire preparation is then sterilized at the desired temperature and duration, making the mixture homogeneous and ready to be dispensed into the corresponding glass or polypropylene containers under a laminar flow hood. The success of our work depends on all this. Accuracy and control can be difficult to achieve, considering that this task is carried out manually. Moreover, it is imperative to pay specific attention to the potential risk of contamination at every stage of the process.

We are confident in the professionalism of the personnel at your plant tissue culture laboratory. We are quite sure about their dedication and expertise. However, it must be acknowledged that there is always the possibility of human error. This potential risk should not be disregarded, as it could result in significant consequences, particularly with regards to the well-being and safety of our personnel. As well as regarding the quality of the prepared product and also a considerable loss of time, stamina and money.

The manual culture of plant tissue involves certain hazards, for the outcome of that process as well as for the personnel that handle those fluids. Below, we explain the reasons for this.

The risks of manually preparing culture media used in plant tissue culture

As we have already mentioned, in plant tissue culture there are three aspects that you should try to prevent:

All three aspects can represent a serious problem for your preparations, your laboratory and your employees. To overcome these issues, the solution lies in the automation of plant tissue culture. Automating the process to its fullest extent can save you from making mistakes during preparation and potential accidents, while saving both time and money.

We will review the different difficulties that may arise during a manual procedure, which can be solved by using an automatic equipment suitable for this purpose.

In culture media sterilization, one of the major obstacles is related to heat exposure, which can vary among samples, since the sterilization temperature, in most cases, is only monitored in a reference vessel or simply just for the chamber temperature. Also, during this process, the bottles with agar medium cannot be shaked, preventing the liquid from mixing uniformly.

Once the sterilization process is finished, the medium must be cooled down until it reaches its dispensing temperature, which requires a long waiting time to prevent the operator from getting burned when handling the containers. Additionally, if it is excessively cooled, the agar will gelify, and if it was prepared for subsequent dispensing, this will pose a significant challenge.

Inaccuracy is another characteristic related to the manual preparation of culture media, particularly in the preparation and dispensing steps. It can cause problems of homogeneity and composition, out-of-specification batches and variations in dispensed volumes. To solve this issue, any reputable laboratory should have a quality assurance system in place to ensure the quality of the production process. This system is often manual and laborious to report on a daily basis as it involves recording a lot of data derived from periodic controls.

Another major problem regarding plant tissue culture is related to potential accidents and, consequently, sick leave. Certainly, due to the nature of the work, you may have noticed that your staff performs repetitive tasks and is required to adopt uncomfortable postures that can lead to work-related illnesses, such as chronic lower back pain, joint pain, or other conditions over time. Likewise, the handling of objects at high temperatures can lead to burns and/or serious and dangerous irritations, despite the technical training provided to your operators, the established protocols and the required clothing and equipment.

Enhance the quality, increase your productivity, save labor, eliminate human error, and minimize occupational hazards with the RAYPA media preparator.

At RAYPA we have a thorough understanding of the needs of this sector. For this reason, we have created the AE-MP Series media preparator. Thanks to it, the aforementioned issues are resolved, leading to a faster, cheaper, and less risky work process, fully automated in a single device.

With our media preparator:

You will have ample flexibility to conveniently prepare large volumes of culture media.
The dispensing lines can be easily cleaned and disinfected before, during and after each cycle through the use of steam pulses at high temperature.
The sterilization temperature is adjustable and uniform throughout the medium. In addition, the stirring speed is adjustable by means of an easy-to-use potentiometer located on the control panel.
It is possible to dispense nutrients, pH adjusters, and antibiotics comfortably during or after sterilization in the case of thermolabile substances.
Regarding the cooling of media for subsequent dispensing, the media preparator has a pressure pump and a water cooling coil built around the inner vessel that ensures extremely fast cooling at the end of the cycle, without removing the media from the machine. In this manner, we avoid potential burns and also ensure that the preparation is not exposed to high temperatures for an extended period of time, which is not desirable. Also, the dispensing temperature is adjustable and can be maintained indefinitely and the equipment has multiple dispensing options with dispensing speeds ranging from 9mL/s to 90ml/s through the use of an optical sensor, foot pedal or time delay.

Finally, it is worth mentioning the ergonomic design of RAYPA’s AE-MP media sterilizer and its various safety devices, which prevent uncomfortable postures during long hours, irritations and injuries, thus avoiding accidents and work-related injuries. At RAYPA we prioritize, first and foremost, prevention and safety of the end user, therefore, our media preparators are equipped with the following safety features:

Automating processes involves managing and improving control over the entire cycle by tracking performance indicators to obtain a more reliable control and analysis. This guarantees homogeneous and higher quality samples with a lower risk of medium contamination and an increase in productivity with a significant reduction in costs.

In order to better manage this procedure, the media preparator records the entire process, step-by-step. Also, thanks to its large capacity, we can scale up and increase production if necessary, producing bigger volumes in less time. Therefore, the process is faster, and the laboratory is more efficient.

Please contact us if you would like to know more details about our AE-MP series culture media sterilizer, fully capable of preparing, sterilizing, cooling and dispensing your culture media in a single unit and with an excellent batch-to-batch reproducibility. We will be glad to attend you.

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