Team:CAU China/Human Practices


Integrated Human Practices

Integrated Human Practices



Values in SSR



Version 1.0

Symbiotic system


To better design


Learn advice

Version 2.0

Present version


To implement


Get inspirations


Learn advice


Learn advice

With companies

Learn the market

Version 3.0

Our future

Background Research

Overview of the problem

Soil, one of the most common and valuable resources on this planet, is the great parent of all. It gives birth to all plants and carries the hope of a bumper harvest. In Chinese culture particularly, soil stands for the origin of human beings and a paean to labor.

As students from China Agricultural University, we always pay special attention to soil, the mother of agriculture and Chinese cultivation culture. However, we must accept the fact that our soil has been going through serious degradation for decades, and soil salinization is one of the major threats.

How serious can the saline-alkaline soil problem be? We have been continuously doing surveys since we noticed this topic, and below are some results:

  • Globally, the saline-alkaline land covers 9.54 billion hectares and accounts for one fifth of the cultivated area (data collected from UNESCO).
  • Global soil salinization hotspots include Pakistan, China, India, Argentina, Sudan and many countries in Central and Western Asia (Da liakopoulos et al., 2016) , in other words, many developing countries.
  • In China particularly, 19 provinces are facing various threats of saline-alkaline land, such as drought, flood and infertility (data collected from China Daily).
  • Besides agriculture setbacks, salinization can also lead to disruption in biological (Smith et al., 2015) and erosional (Berendse et al., 2015) Earth Cylces.

To get a full view of this problem and what we can do further, we also did research in what have been done before by participating in related seminars.

The most valuable one was an online plant nutrition seminar organized by the Key Laboratory of Plant-Soil Interactions, MOE, National Academy of Agriculture Green Development. Prof. Liu Xiaojing from Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, gave a presentation on improvement and utilization of saline-Alkaline soil. Prof. Tibor Toth, from Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, gave a presentation on management of salt-affected soils.

Thanks to the report, we have a deeper understanding of soil problems. We learned that irrigative, agricultural, chemical and biological measures are four main approaches to this problem nowadays. According to professors, agricultural and chemical measures are often not effective enough in the long run, and irrigative measure leads to high costs, apparently not suitable for developing countries. Besides, these three measures have bad performance on dealing with secondary salinization and seawater intrusion.

Both Prof. Liu Xiaojing and Prof. Tibor Toth recommended biological measures as the final solution, for it is eco-friendly, safe and efficient. Particularly, Prof. Tibor Toth attached great importance to microbial engineering in soil restoration, naming some previous research in bacteria methods that inspired us to try synthetic biology later.

Fig. 1 Prof. Tibor Toth sharing his idea of microbial engineering in the seminar.

Engaging with those involved

To better understand the soil issue and grasp the core values of our project, we get in touch with people involved in soil salinization to absorb their opinions and expectations.

  • A worker in saline-alkaline soil restoration station
    We contacted one of the workers in saline-alkaline soil restoration station in Qu Zhou County, who is currently helping this region to get rid of saline-alkaline soil permanently. He told us that the solution they are using now is still the traditional irrigative method, and they are also doing research in wheats with high tolerance and better cooperation pattern between enterprises and farmers.
    He showed approval of our efforts in new approaches to soil salinization by synthetic biology. However, as a front-line worker, the critical thing he cared about our biological measure is whether this will harm the soil in other ways and how can farmers get easy access to our products.
    Engagement with him let us know that we should have an overall consideration of the safety in project design. Meanwhile, we should try our best to simplify our product and ensure that it is more cost-effective, compared with other measures.

  • Farmers, who once suffered from saline-alkaline land
    We contacted some of our relatives who are farmers themselves and once suffered from soil salinization.
    They all think soil salinization is a fatal problem in agriculture, which often comes along with poverty, hunger and departure from land. According to their memory, they experienced such a problem approximately between 1970s and 1980s. The problem was caused by floods and lasted for 3 to 5 years. It was finally solved through irrigation project and chemical methods.
    As farmers themselves, they hope that soil salinization can be solved as quick as possible in the future, because building irrigation project always seems a bit slow. As our main end users, they informed us of what they expect in the first place: effectiveness and efficiency.

  • A part-time guide in History Museum of CAU, responsible for the history of saline-alkaline soil restoration
    We contacted an undergraduate part-time guide in the History Museum of China Agricultural University. She is responsible for the narration of the history of saline-alkaline soil restoration.
    She told us how deeply touched she was by the story of Qu Zhou County. Qu Zhou is a county in He Bei province that had been facing serious saline-alkaline soil problem for ages. Soil experts form CAU has come there and prospered Qu Zhou’s agriculture by multiple restoration projects since 1973.
    She thought it was a great idea to focus on the soil problem in our project, since it’s like a form of “tradition and inheritance”. She hoped our project could carry on the spirit of Qu Zhou and arouse public concern in soil degradation.
    Engagement with her reminded us that we should probably bring the moral values into our project as well. Later, we visited the History Museum of CAU and listened to her detailed introduction on saline-alkaline soil restoration history. We also visited the statues related to this topic.

    Fig. 2 Visit the History Museum of CAU

    The first statue is about Mr.Xin Dehui, a respectable professor from CAU who devoted himself into soil restoration project. The second picture is a memorial which wrote “restoring the soil, benefits Qu Zhou County”. It is built by farmers from Qu Zhou.

    Fig. 3 Statues Related to the Spirit of Qu Zhou(Mr.Xin Dehui, a respectable professor from CAU who devoted himself into soil restoration project)

Related social attitudes

Synthetic biology project is not just a party for the minority with scientific background. Instead, as an environment project directly interacting with the society, we need to know how the public, especially the citizens, recognize the threat of saline-alkaline soil and how they feel about synthetic biology as a solution to environmental problems.

We sent out questionnaire and collected 60 valid results, 24 results from men, 33 results from women and 2 results from other genders.

Fig. 4 Questionnaire survey results

From the results we can know that 67% of the respondents agree to the urgency of improving the saline-alkaline land. However, only a few respondents say they know the problem of saline-alkaline soil well and thoroughly. Approximately 75% of the respondents say they’ve heard of soil salinization more or less before but never get to know the details. These results suggest us that the ultimate goal of our project is accepted and approved of by the public. Meanwhile, we should also take actions in public education on details about soil salinization.

We also asked the respondents on attitudes towards synthetic biology implementation. 81% say they know clearly or at least have heard of synthetic biology. However, only 57% show approval of its implementation in Agriculture & Food industry. If synthetic biology is used to improve the environment, people showed more tolerance, with 78% respondents approve of such an application. Nevertheless, they still express concerns on its influence in ecosystems and food chain.

As a project actually between the agriculture track and the environment track, CAU_China values these objections and approvals seriously. As a matter of fact, these worries warn us about the necessity of an effective kill switch and an overall risk management method, which has been fully described in Design and Safety.

Based on background research, we concluded and prioritized values for our project to achieve:

  • Restore the saline-alkaline land through synthetic biological measures;
    Based on the seriousness and urgency of the problem and what other measures fail to do;
  • Restore soil with high efficiency;
    Based on the engagement with farmers in salinization areas;
  • Ensure biosafety at the same time;
    Based on the engagement with soil restoration workers and public concerns learned in survey;
  • Present a user-friendly and cost-effective end-product;
    Based on the engagement with soil restoration workers and the fact of developing countries as global soil salinization hotspots;
  • Arouse public awareness in synthetic biology as a solution;
    Based on the engagement with a guide in history museum who knows the soil restoration history well and public opinions learned in survey;

You can go to Project, Implementation, and Education wiki pages to see our efforts to achieve those values.

Interviews: For a better project design

What we have done:

As undergraduates, we knew clearly that the first version of our project design definitely had flaws and unrealistic imagination. To polish our project design 1.0 into a simple and realistic one, we have consulted many experts in different fields to exchange thoughts and actively seek their help in design and experiments.

Special thanks to all the experts who had offered suggestions:

Yang Jinshui
Professor in Department of Microbiology and Immunology, College of Biology, China Agricultural University
Yang Jinshui
China Agricultural University
Tian Changfu
Professor in Department of Microbiology and Immunology, College of Biology, China Agricultural University
Tian Changfu
China Agricultural University
Guo Yan
Dean of College of Biology,China Agricultural University
Guo Yan
China Agricultural University
Feng Gu
Professor in College of Resources and Environment,China Agricultural University
Feng Gu
China Agricultural University
Zhou Wenkun
Professor in Department of Plant Science, College of Biology, China Agricultural University
Zhou Wenkun
China Agricultural University
Xu Li
Professor in College of Resources and Environmental Science,Nanjing Agricultural University
Xu Li
Nanjing Agricultural University
Li Huixin
Professor in College of Resources and Environmental Science,Nanjing Agricultural University
Li Huixin
Nanjing Agricultural University

What we have learned:

Professor Yang Jinshui informed us that transforming too many genes into the bacteria may put burden on their growth, which is not a good thing particularly when salt and alkali stress already exist. There would be plasmid incompatibility as well. Also, he pointed out that the symbiotic system in the first version of our design didn’t seem practical, because Bacillus subtilis and Corynebacterium glutamicum are not known mutually beneficial symbiotic relationship in soil, and if they are isolated in space, the treatment efficiency will be greatly reduced.

Professor Tian Changfu, an expert in rhizobia , suggested conducting relevant research in interaction between bacteria and plants’ roots in the soil, in order to help our bacteria proliferate. Secondly, we learned from him that using our bacteria through drip irrigation or spraying may lead to better restoration efficiency. More importantly, Professor Tian pointed out that if the bacteria will be put into the soil, its plasmid will soon be lost since there is no resistance stress for screening.

Professor Guo Yan told us that the restoration process of saline-alkaline land is very complicated and it is hard to finish the restoration with just one method. Therefore, he suggested using a series of comprehensive treatments. Besides, Professor Guo emphasized the importance of biosafety and suggested that we should test the efficiency of our toxin gene and kill switch periodically.

Professor Feng Gu introduced that the lack of water resources is the bottleneck of restoring saline-alkaline land and explained the toxic mechanism of saline-alkaline soil to plants. In addition, he suggested that in order to improve the survival rate of bacterial products in soil, we can consider their interaction with plants and colonize them in plant roots.

How we respond to HP works:

In the first version of our design, we planned to build a symbiotic system, in which B. subtilis can produce γ-PGA with the glutamic acid provided by C. glutamicum. After discussing with Professor Yang, we greatly changed our design into the version you see now, in which C. glutamicum has the ability to synthesize γ-PGA itself, in order to avoid inefficiency of the symbiotic system. What’s more, with advice from Professor Tian, we decided to insert every final genetic circuit into the genome of the bacteria so that they won’t be lost due to a lack of screening in natural environment. In addition, with advice from Professor Guo, we added a composite kill switch to our bacteria that can respond to salinity and pH changes. Finally, since professors all mentioned a combination with other soil restoring methods, we decided to focus on the interaction between bacteria and plants’ root system in the second stage of our project in the future.

Interviews: For a well-considered implementation

What we have done:

Having decided on the final design, we went on to have in-depth discussions with experts about our end products and future plans after iGEM. To ensure that our bacteria is applicable in the real environment, we need to find a carrier for bacteria and a possible way to turn into products. Our preliminary choice was the bacterial agent, so we focused on the advantages and feasibility of transforming our engineered bacteria into bacterial agents in this stage of interviews.

Fig. 5 Discussion with Professor Feng Gu

Fig. 6 Interview with Professor Zhou Wenkun

What we have learned:

Hearing that we planned to further include interaction with plants in our project, Professor Zhou Wenkun recommended Thellungiella salsuginea , which is a well-used model plant in salt stress research. It grows fast and can handle some basic environmental stress well, which is suitable for the comprehensive treatment of saline-alkaline soil.

Professor Xu Li let us pay attention to some details during the actual implementation of bacterial agents. It mainly lies in the secondary salinization of soil and the setbacks that viscosity of polyglutamic acid brings in the treatment of saline alkali soil.

On inspirations from Professor Xu, we further contacted Professor Li Huixin for more information on bacterial agents. He explained that using the bacterial agents instead of γ-polyglutamic acid is definitely a better choice, since the living bacteria can migrate in the soil and synthesize γ-PGA continuously, while using γ-PGA directly is more like a temporary solution and will cost a lot. Moreover, he informed us that measuring the salinity and alkalinity in soil in situ is indeed hard, and we have to do some preprocessing and allow small errors, which cleared up our confusion in the test paper we planned to design.

How we respond to HP works:

After so many interviews, we finally decided that our end product will be a kind of bacterial agent which contains our engineering bacteria and essential nutrients for growth. Also, reminded by professors about the production of bacterial agents, we decided to interact with related companies to know about the actual commercialization process. With advice from Professor Zhou, we planned to use Thellungiella salsuginea as our materials in experiments of the interaction between bacteria and plants in the future. Also, having included plant research in the future of our project, we will consult more experts in saline-alkaline tolerant plants and further develop our project into a comprehensive one.

Interact with companies

What we have done:

Though we had consulted many experts from colleges, we found our implementation still seemed impractical without detailed advice from the market and enterprises. Therefore, in order to further understand the selection of bacterial agents and actual production process, we interacted with companies in this area to get across the possible future and limitations of our project at this stage.

Fig. 7 Visit the company Sino Green Agri-Biotech

We got in touch with Sino Green Agri-Biotech, a company focuses on research and production of several bacterial agents in the agriculture market. Led by the manager Zhang Lixia, we visited the company's factories and laboratories to learn more about the operation of the bacterial agent company and the production process of related agents. To know more about bacterial agent as product, we consulted her about the feasibility of our engineered bacteria to be turned into real products, possible problems and restrictions in laws. She provided ideas for our bacterial agent design.

Fig. 8 Visiting the factories

After understanding the production process, we wanted to know more about the domestic market of microbial agents, in order to analyze the potential market value of our product and fix it an appropriate price. So we found AGB( an agricultural microbial agent company) in Shenzhen and invited their manager Kong Zongyao to communicate with us online in WeChat. During the communication, we asked about the situation of agricultural microbial agents and possible competitors to our product.

Fig. 9 Interacting with AGB

What we have learned:

Through the conversation with Manager Zhang Lixia, we learned that for different environments, there are mainly 4 forms of bacterial agents for us to choose from.

Liquid form is suitable for sprinkler irrigation and drip irrigation. The powder form is insoluble in water for the peat and vermiculite in it. It is feasible to apply the bacterial in powder form in a place where wind and sand is not large, such as a greenhouse, and apply it in a hole or ditch. In places with heavy sandstorm, dusting powder can easily be blown away by the wind, so a granular dosage form is developed, which makes it easier to enter the soil and mix it with chemical fertilizers. There is also a new form of bacterial agent called freeze-dried powder that is easy to store and use, at the cost of high price of course.

During the interview with Manager Kong, we learned that daily field management is another aspect that affects the effect of bacterial agent product. Saline-alkaline soil treatment should be integrated with the local situation, through a combination of fertilizer application, planting crops and other means of treatment. For the recipe of bacterial agents, their company's products are currently pure agents without synergists.

When it come to the market, manager Kong said that growers and farmers have got to know the advantage of bacterial agents and are willing to buy their products to solve the problem of low quality or low yield. However, the present market is in disorder and mistrust, since many manufacturers add synergists into their products and the customers can’t do the quality judgement themselves.

How we responded to HP works:

We responded to our interactions with companies by making changes and supplements to our future implementation plans. Originally we had been considering to develop our product in the liquid form, the most common form of bacterial agents. After the discussion with manager Zhang, we now think that the granular form may be another choice for us, since the most serious regions affected by soil salinization in the northwest of China are generally windy and sandy, where granular form performs the best. We plan to arrange some wet lab experiments to test the performance of granular bacterial agents in the future.

Besides, learning the situation of the bacterial agent market, we plan to focus more on engaging with possible end users and public education towards them specifically, in order to earn their trusts, show respects, and lay a foundation for our implementation.

Special thanks to Sino Green Agri-Biotech and AGB for their help and guidance!

Fig. 10 Companies’ Logo

Close the loop!

To close the loop between what was designed and what was desired, above all we did surveys and questionnaire towards the public to fully understand what the society expected from our project. More importantly, we get engaged with those involved and prioritized the values accordingly.

Next, we consulted many experts and collaborated with other iGEM teams in troubleshooting to ensure a better project design to satisfy people’s needs, and make adjustment in our design and experiments accordingly.

Following that, we continued to consider the execution and implementation of our project. We did public education and communication work, in which we presented our project, to collect public attitudes towards it. Knowing that the society approves of our project, we went on interviewing related experts for a practical product design. Besides, hearing that the society held worries towards the safety issues of bio-products, we emphasized our safety and security work.

Then, we interacted with related companies to further understand the selection of bacterial agents, actual production process, and the market conditions. With new information learned, we decided that our bacterial agent product would be in various forms to satisfy users’ needs, and we simulated different implementation schemes with the help of Cellular Automaton Model, to present to the public that our future product is able to live up to their expectations.

In short, we responded to what the society desired in our project by upgrading project design with experts’ advice, carrying out public communication frequently to collect public opinions, and polishing our implementation plans with help from companies and mathematic models.

Fig. 11 How we close the loop


[1] Da Liakopoulos I N , Tsanis I K , Koutroulis A , et al. The threat of soil salinity: A European scale review[J]. Science of the Total Environment, 2016, 573:727-739.
[2] Berendse F , Ruijven J V , Jongejans E , et al. Loss of Plant Species Diversity Reduces Soil Erosion Resistance[J]. Ecosystems, 2015, 18(5):881-888.
[3] Smith, P., Cotrufo, M. F., Rumpel, C., et al. Biogeochemical cycles and biodiversity as key drivers of ecosystem services provided by soils[J]. SOIL, 2015, 1 (2).