The Reason I’m Here — Science!
utilizing microorganisms, increasing plant production
The overall goal of a majority of the work being done in Mahyco’s molecular microbiology lab is to reduce the use of fertilizers, which can cause pollution of air, water, and soil when overused. Fertilizers can also alter pH levels in rhizospheric soil, which surrounds root systems and sustains high populations of microorganisms. As pH levels change, some beneficial rhizobacteria aren’t able to adapt and plant productivity may decrease, leading to an increase in fertilizer use. It’s easy for a cycle of decreased rhizobacteria and increased fertilizer use to start.
Microorganisms play a big role in plant health- they help facilitate the uptake of nutrients from the environment and can lessen the harmful effects of pathogenic organisms. Useful microorganisms like these are called plant growth-promoting rhizobacteria. By identifying and utilizing beneficial rhizobacteria, this lab is able to create commercialized microbial seed treatments that help provide essential nutrients to crops without the use of fertilizers.
Since the entire process of creating a commercialized seed treatment can take 2–3 years, my project is only a snapshot of the amount of dedication and patience this type of research takes. My work has been scaled down so that I can accomplish as much as possible with my limited time while still providing experience in many of the steps that come after sample collection. My final project consists of observing the quantity of microorganisms in rhizospheric soil samples and screening isolated microbial colonies for plant growth-promoting characteristics.
I collected soil samples from pomegranate, banana, lemon, cotton, soybean, and maize fields. Samples for each crop type were taken from two different locations. After I dilute the samples and incubate them on petri plates, I will be able to estimate the amount of microorganisms in one gram of soil and determine if there are differences in the quantity of microflora in fields around Jalna.
One sample from each crop type has been serially diluted, spread on petri plates, and incubated until microbial colonies were grown. I identified any isolated colonies and spread them on new plates in order to obtain pure cultures. Since hundreds of colonies can grow on a single plate, I had to narrow them down based on physical characteristics. I chose 48 differing cultures to test for plant growth-promoting characteristics. I tested these cultures for beneficial qualities such as nitrogen fixation, phosphorus solubilization, and zinc solubilization. This process involves spreading the cultures on different types of media plates. After incubation, positive cultures will have a differently colored zone around them.
Out of the 48 tested cultures, I chose the 15 most promising, showing larger zones on multiple tests. I inoculated these cultures into liquid media and incubated them until there was sufficient growth. After adding a binding agent to each of the cultures, I used the solutions to treat maize seed. Beginning next week, I will start to uproot these treated plants and look for root and shoot length differences when compared to the untreated control. The best performing cultures will undergo DNA extraction in order to identify the bacteria.
As the world’s population increases and the amount of available agricultural land decreases, obtaining high yields is incredibly important to meet high demands for food. Microbial seed treatments have a promising future in helping farmers meet those requirements.
So far my time working on this project has been met with mistakes, confusion, and an incredible amount of learning. Thankfully, my lab is filled with amazing people who are willing to help me whenever I need it.
