From laboratory to field, a Zhejiang University student is determined to conquer wheat "infectious diseases"

Soft bread, chewy noodles

Fragrant steamed buns and crispy biscuits

......

These are the foods we love

All come from a single grain crop: wheat.

However, this staple food crop

However, it is seriously affected by fusarium wilt

Threats to my country's food security and food safety

How to solve wheat "epidemic"

Let people eat noodles that are safe?

College of Agriculture and Biotechnology, Zhejiang University

Resource Utilization and Plant Protection

Sun Jiaxin, Master's student of 2021

Propose a biological control plan of "using bacteria to treat bacteria"

Successfully isolated from wheat field soil

Biocontrol strains for efficient prevention and control of wheat scab

In basic research and industrial application

Both show great potential

To prevent and control wheat "infectious diseases"

Proposed a "new prescription"

Carefully select and dig out "good seedlings" for disease prevention

"The situation does look much better than before the spraying of fungicides. The symptoms of rot and red mildew are much lighter." After collecting the last bundle of wheat, Sun Jiaxin stood up with a satisfied smile on his face.

Back in 2021, Sun Jiaxin had just entered Zhejiang University and started his graduate career. Dedicated to studying agriculture, he always wanted to use his professional knowledge to do something for the country's agricultural production. He set his sights on wheat, an important food crop in my country.

Wheat fusarium head blight is a major fungal disease that currently restricts the development of my country's wheat industry. The average annual incidence area in the country accounts for about 20% of the total planting area, which seriously threatens the safety of wheat production. At the same time, the pathogen will produce fungal toxins such as vomitoxin during the infection of wheat, which endangers food safety. The disease has been listed as a Class I crop disease by the Ministry of Agriculture and Rural Affairs.

Biological control is a hot concept in the field of plant protection, which refers to the use of beneficial organisms to inhibit harmful organisms, thereby preventing the adverse effects of diseases on crops.

Wheat plants and kernels infected with fusarium head blight

Sun Jiaxin saw the potential and prospects of "biological control" in the field of plant disease control. With the support of Professor Ma Zhonghua, head of the wheat disease research team of the College of Agriculture and Biotechnology, and the guidance of his mentor Professor Chen Yun, he began to conduct relevant research on "exploration and utilization of biological control resources for wheat fusarium head blight."

All things are difficult at the beginning. In order to collect more strains of bacteria that have potential antagonism to Fusarium fusiformis, from March to May 2022, Sun Jiaxin went to 19 counties and cities in Jiangsu and Anhui provinces to collect rice, wheat and corn straw samples from local agricultural experimental fields.

From these samples, Sun Jiaxin isolated a total of 6,622 strains of culturable microorganisms. After evaluating the antibacterial activity of these more than 6,000 strains, he was pleasantly surprised to find that more than 600 strains had antibacterial effects, 12 of which were less studied in academia. These 12 strains became Sun Jiaxin's main research objects.

Cultivation of some bacterial species

"Isolating and screening strains is a highly repetitive job, and sometimes it can be very boring, but I thought that if I had to do it, I had to do it well, so I persisted." Sun Jiaxin said with emotion when recalling the experimental process.

His supervisor, Professor Chen Yun, always paid attention to his experimental progress, discussed the results with him, and made suggestions for the next experiment. He also provided him with spiritual encouragement and support. "I made a lot of culture media, and sometimes I didn't change the culture media in time. Professor Chen would remind me to avoid wasting my previous work. He also cared about my life. When he found that I was not in a good state, he would stop working and chat with me to comfort me."

Rooted in wheat fields, screening for "effective drugs" for Fusarium head blight

Practice is the best way to test experimental results. In addition to cultivating and isolating strains in the laboratory, Professor Chen Yun also encouraged Sun Jiaxin to go deep into the wheat fields to test the disease prevention effect of the strains. "This is the key to solving industrial problems and developing practical application technologies."

To ensure the best prevention and control effects, from April to June 2023, Sun Jiaxin raced against time and seized the window period of wheat flowering. He visited the wheat agricultural experimental fields in Anhui, Jiangsu and Shandong provinces again in the shortest time, sprayed the prepared fungal agents on the wheat in the experimental fields, observed the actual disease prevention effects, and verified the effectiveness of the strains.

"We visited multiple test sites in three provinces within a month. One month later, when the wheat matured, we collected the straw sprayed with fungi and screened out the fungi with practical effects based on the wheat's field performance." Sun Jiaxin recalled, "Although there was a month interval between spraying and verifying the statistical disease situation, because we needed to conduct pilot projects in wheat fields in three different provinces, we often had to run back to Jiangsu to conduct statistical surveys on the biological control effects in wheat fields right after spraying the fungi in Shandong." During this period, Sun Jiaxin basically carried various agricultural tools and walked through the wheat every day. He often kept his feet on the ground and stayed in the fields for a whole day.

Sun Jiaxin collecting straw

What is exciting is that, after experimental verification, the disease prevention and toxin reduction effects of 6 strains of Streptomyces among the bacteria exceeded 70%; the field control efficacy of the biocontrol Penicillium strain Pa810 also exceeded 50%. This is the first time that this type of fungus has been discovered to be used for the prevention and control of ergot disease, providing a new resource for the biological control of ergot disease.

At the same time, under the guidance of his tutor, Sun Jiaxin developed a technology for the coordinated prevention and control of Fusarium head blight by combining biological control with chemical fungicides, with a field control efficiency of over 85% and a reduction of more than 20% in the use of chemical pesticides. This achievement was awarded the Outstanding Practice Achievement of Professional Degree Graduate Students in Zhejiang Province. Professor Chen Yun combined this achievement with the long-term accumulated experience in biological control and summarized and refined it into a report, which attracted the attention of relevant national departments. "To serve the national strategy with what you have learned and researched and to meet practical needs is the greatest value of intellectuals." When talking about this achievement, Sun Jiaxin was very proud.

Research results data chart (partial)

While being busy, the work outside also brought Sun Jiaxin a different experience. There is a big difference between field work in the wheat field and basic research in the laboratory. He needs to independently complete all matters such as equipment preparation, transportation, and contact docking. "This has trained my ability to plan time to a certain extent." When talking about the gains from this experience, Sun Jiaxin said so.

Based on rigid needs, new farmers demonstrate their strong responsibility

Agricultural production faces serious threats from diseases and insect pests. Although the long-term use of traditional chemical pesticides has effectively controlled diseases, it has also brought many negative effects, including excessive pesticide residues in agricultural products, ecological environment damage, and pathogen resistance.

In addition, the public's demand for agricultural product safety and ecological protection is increasing, and green agriculture has gradually become the mainstream direction of global agricultural development. Using beneficial microbial resources to carry out biological control of crop diseases is an important measure for green control of plant pests and an important support for the development of green agriculture.

Sun Jiaxin comes from the countryside. He grew up in the fields and is familiar with farm work. He also has a strong desire for agricultural science. From the beginning of learning the basic knowledge of agronomy, he wanted to apply what he learned to actual production. He knows that any scientific research is a long process. In addition to considering the endless practical problems, there is also the gap between theory and practice, which tests the patience and reflection and summary ability of the researcher.

Just last year, Sun Jiaxin applied to transfer from his master's degree to a doctoral degree, not only to "renew" his research career, but also to realize his dream of contributing to agricultural production.

"Biological defense research requires a certain level of effort to produce results. I chose to transfer to a doctoral program because I wanted to further deepen my research on the topic I wanted to do on a high-level research platform like Zhejiang University, and truly produce some results that can respond to the needs of the country and the people. I don't want to end it hastily and stop at just a superficial level." Sun Jiaxin said firmly.

Sun Jiaxin is observing the culture of the strain

In addition to his own development, Sun Jiaxin is also keen to pass on his love for agronomy to his juniors. He assisted undergraduates and graduate students under the guidance of Professor Chen Yun in carrying out an innovative project, "Preventing Red Blight with Red Heart - Creating a New Remedy for Wheat Fusarium Head Blight", which won the special prize in the 2024 "Unveiling the Challenge" special competition of the 19th "Challenge Cup" National College Students' Extracurricular Academic and Scientific Works Competition.

Currently, Sun Jiaxin is leading two undergraduates in a scientific research training project and graduation project, passing on his experience in doing experiments to them to pave the way for their future development. "When I teach them how to do experiments, I also learn a lot from them. It can be regarded as a process of mutual learning."

Growing with encouragement and exploring truth through experiments, Sun Jiaxin will continue on the research path of exploring and utilizing wheat biological control resources with the aspirations in his heart.

(Source: Zhejiang University)