Gene Expression Analysis of Oat Phytases During Malting Using RT-qPCR

Abstract

Oat grains contain high levels of phytic acid, an anti-nutritional compound that reduces nutrient bioavailability, along with notably low phytase activity, the enzymatic mechanism responsible for phytic acid degradation. Malting of oats prior to human consumption is a recognized method to reduce phytic acid content by inducing phytase expression, thereby enhancing the nutritional value of oats. This study aimed to investigate the temporal and spatial gene expression patterns of phytase genes in oats during malting. Oat grains were steeped, germinated and dried, with samples collected at different stages and from various tissues of the germinating grains. Gene expression analysis was performed using Reverse Transcription Quantitative real-time Polymerase Chain Reaction (RT-qPCR), targeting predicted phytase genes in the oat genome identified through sequence similarity to known phytases in the closely related species barley. Six candidate phytase genes, grouped into two sets of homoeologs, were identified in the oat genome and RT-qPCR showed positive amplification across all sample types, confirming gene expression during malting. Expression was initiated in the early stage of germination, peaked mid-germination, and declined in the later stage of germination. Preliminary evidence suggests tissue-specific expression patterns across the embryo, root and sprout tissues, although further investigation is required. Overall, this study advances our understanding of phytase gene expression in oats during malting and provides valuable insights for future research aimed at improving the nutritional quality of oats.

Popular Abstract

Unlocking the Full Nutritional Power of Oats: A Study of Genes During Malting
Oats are recognized as a super grain, but even so, they contain a hidden nutrient thief. Luckily, germination of oat grains in a process known as malting, wakes up genes able to defeat the nutrient thief and unlock the full nutritional power of oats.
Whether in porridge, granola or oat milk, oats are part of the daily diet of millions of people worldwide. They are recognized for their impressive list of health benefits, and their nutritional composition makes them a great source of carbohydrates, dietary fibers, proteins and healthy fats. The increased recognition of oats as part of a diet to prevent disease and promote health has led to a rise in the consumption of oats and oat-based products. But even this super grain has a weakness. In addition to the many health benefits associated with oats, there is one potential health concern, namely: the presence of a compound known as phytic acid. Phytic acid acts as a nutrient thief, latching onto important minerals such as calcium, iron and zinc, and prevents them from being taken up by the human body. Over time, this may contribute to nutrient deficiencies and potential health issues.
Luckily, the trapped nutrients can be released by breaking down the phytic acid by enzymes known as phytases. The catch? Oat grains naturally have very low levels of these phytases. That’s where malting comes to the rescue. Malting is a centuries-old process widely used in beer making, and involves soaking the grains in water, letting them germinate for a few days and then drying them. The germination wakes up the grains, kick-starting their natural production of enzymes, including phytases that break down phytic acid. The result? Oats with less phytic acid and higher nutritional value!
While an oat phytase has previously been isolated from malted oats, the specific genes responsible for its production and how these genes behave during malting remains to be discovered. This study set out to change that by identifying the phytase genes in oats and uncover how they work behind the scenes during the malting process. To find out, oat grains were soaked, germinated, and dried, with samples taken at different stages and from various parts of the germinating grains. Phytase genes in the oat genome were hunted down by their similarity to known phytases in the close relative barley. The identified oat phytase genes were targeted for gene expression analysis using an advanced experimental method that quantitatively measures how active certain genes are.
The results showed that the phytase genes were indeed awake during malting. They switched on in the early stages of germination, peaked mid-germination, and then faded out in the later stages of germination. The genes were more or less awake in different parts of the germinating grain, such as the embryo, root and sprout, however, this needs to be further explored.
In summary, this study improved the understanding of the phytase genes in oats and their awakening during malting and provided valuable insights for future research aimed at unlocking the full nutritional power of oats.

• author: Pehrsson, Johanna
• supervisor: Sofia Marmon; Lars Dahlgren
• organization: Pure and Applied Biochemistry; Computational Chemistry
• course: KBKM05 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Oats, Phytic acid, Phytase, Malting, Gene expression, RT-qPCR, Applied biochemistry
• language: English
• id: 9198014
• date added to LUP: 2025-06-18 10:23:55
• date last changed: 2025-06-18 10:23:55