Maldi-mass Spectrometry Imaging for Phytoalexins Detection in RD6 Thai Rice

Phytoalexin production has been extensively studied using multiple methods. However, this is the first report on the use of matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to detect diterpenoid phytoalexins in fungal-infected Thai rice plants. In this study, we successfully detected diterpenoid phytoalexins in RD6 Thai rice (Oryza sativa). Detection of phytoalexin production and distribution can be used to indicate the resistance properties of RD6 rice to blast disease. First, rice leaves were infected with Magnaporthe oryzae before analysis with MALDI-MSI. Results revealed 5 types of phytoalexins detected on leaf tissue, including momilactone-A (m/z 353.17), momilactone-B (m/z 369.16), phytocassane-A, D, or E (m/z 355.18), phytocassane-B (m/z 373.19) and phytocassane-C (m/z 357.20). MSI data correlated with the results from the MALDI-MS of rice leaf extraction. Finally, the structure of momilactone-A, phytocassane-A, D, or E and phytocassane-C was also determined using the MS/MS technique. Overall, MALDI-MSI is a useful and reliable technique for phytoalexin detection, representing new opportunities for agricultural applications in the future.

Automated summary

The study successfully detected diterpenoid phytoalexins in Thai rice using MALDI-MSI, revealing five types of phytoalexins in RD6 rice and demonstrating its resistance to blast disease. This technology offers new opportunities for agricultural applications in the future.