A Study of the Spatial Distribution of Gossypol and Other Terpenoids in Cotton Leaves and Ovules

User Benefits

- High spatial resolution (5 µm) of the integrated optical microscopy and MS imaging technique that enables observation of the spatial distribution of endogenous metabolites in tiny areas (e.g., in glands) - Uniform and fine matrix crystal (sub-microscale in size) coating by matrix sublimation that further supports the high spatial resolution - Highly-sensitive MS imaging that yields high definition and tissue-specific distribution images of gossypol and hemigossypolone in the glands in cotton ovule despite the MS signal intensity differs by a factor of more than 1000 between the two chemicals

Introduction

Terpenoids are a diverse group of metabolites. Plants synthesize different terpenoids in response to different environments, which can attract pollinators and seed dispersers, defend against pathogens and herbivores. Terpenoids are synthesized in specific organs of different cell types. Cotton plants possess lysigenous glands in their leaves, stems, and seeds, which accumulate various non-volatile terpenoids such as gossypol and hemigossypolone. But direct visual evidence is lacking. iMScope QT mainly consists of a high-resolution optical microscope, an atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI) ion source and an quadruple-time-of-flight (Q-TOF) analyzer. We can not only use iMScope QT to observe the morphology of the sample in detail, but also to obtain the distribution and content information of compounds in specific parts of the sample. The spatial distribution of gossypol and other terpenoids (hemigossypol and hemigossypolone) in cotton leaves and cotton ovules was studied using iMScope QT. It was found that gossypol, hemigossypol and hemigossypolone were mainly distributed in the glands, and the content of gossypol in cotton ovule was much higher than that in leaves, which was consistent with literature reports. In addition, the study also revealed that the distribution level of hemigossypolone is high in leaf but low in cotton ovule. The above findings provide a reference for the study of the synthesis and transformation mechanism of gossypol and other terpenoids, and also indicate that iMScope QT is a reliable method for both microscopic observation and MS imaging studies of various compounds.

May 7, 2025 GMT