Written by Rugile Sestokaite. This is the report from a BSPP Undergraduate Summer Vacation Bursary. Click here to read more/apply for one yourself.
This summer, I was given a fantastic opportunity by the BSPP and my supervisor to gain experience in the laboratory at the University of Worcester. However, due to the COVID-19 situation, my practical research was changed into a desk-based study. This project investigated how small RNAs such as siRNAs and miRNAs are involved in plant-pathogen interactions and they are transferred from the plant into the fungi and vice versa.
Small RNA molecules such as small interfering RNAs (siRNAs) and microRNAs (miRNAs), which are 21 to 24 nucleotides in length emerged as essential regulators of gene expression in plants and fungi. Recent studies have shown that plants and pathogens are capable of exchanging small RNAs between each other. Trans-species sRNAs that occur naturally in many plants including the model plant Arabidopsis thaliana and crop plants such as tomato are used to silence genes in pathogens and, therefore, are beneficial for plants. Simultaneously, pathogenic fungal species such as Botrytis cinerea (grey mold) and Alternaria alternata (leaf spot) produce small RNAs to manipulate host defence system.
The spray-induced gene silencing (SIGS), which relies on RNA interference approach has been tested to protect crops against several pathogenic fungi such as Fusarium graminearum, B. cinerea and Verticillium dahilae. For example, in one study scientists sprayed barley leaves with CYP3-dsRNAs, which are long dsRNA 791 nucleotides in length, and this led to the growth inhibition of F. graminearum. The CYP3-dsRNAs spray contained sequence which was complementary to F. graminearum CYP51A, CYP15B and CYP61C genes. Another approach is known as host-induced gene silencing (HIGS), broadly used in plant-pathogen systems. HIGS also uses small RNA interference approach; however, unlike SIGS, HIGS use transgene expression.
During this project period, I was introduced to various bioinformatics tools such as Geneious software, which I used to analyse sequences of A. alternata genome. I also developed a better understanding of how to use both nucleotide and protein NCBI BLAST. Moreover, one of my tasks during this project was to produce a small RNA review. This was a fantastic opportunity not just to gain a deep understanding of small RNAs and their function of pathogen-plant interactions, but it also allowed me to improve my ability to search for information more effectively. In addition, my scientific writing skills and analytical skills improved enormously.
I certainly enjoyed every day of my summer studentship; this project inspired and encouraged me to pursue a research career. I am very grateful to the BSPP for providing me with the funding for this fantastic and valuable opportunity. I also would like to thank my supervisor Professor Mahmut Tör who helped and supported me through all my work. I look forward to learning more about small RNAs and plant-pathogen interactions and how we can minimise damages caused by fungi in agriculture.