Chemical imaging reveals diverse functions of tricarboxylic acid metabolites in root growth and development

Understanding how plants grow is critical for agriculture and fundamental for illuminating principles of multicellular development. Here, we apply desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to the chemical mapping of the developing maize root. This technique reveals a range of small molecule distribution patterns across the gradient of stem cell differentiation in the root. To understand the developmental logic of these patterns, we examine tricarboxylic acid (TCA) cycle metabolites. In both Arabidopsis and maize, we find evidence that elements of the TCA cycle are enriched in developmentally opposing regions. We find that these metabolites, particularly succinate, aconitate, citrate, and alpha-ketoglutarate, control root development in diverse and distinct ways. Critically, the developmental effects of certain TCA metabolites on stem cell behavior do not correlate with changes in ATP production. These results present insights into development and suggest practical means for controlling plant growth. Chemical imaging of maize roots reveals differential patterns of TCA cycle metabolites along the axis of development. Root growth is affected in distinct ways by exogenous treatments and tissue-specific genetic manipulation of TCA metabolites.

Automated summary

Understanding the principles of plant growth is essential for agriculture and multicellular development research. Using DESI-MSI, we mapped the chemical distribution in developing maize roots and discovered various small molecule patterns across the stem cell differentiation gradient. Through the analysis of TCA cycle metabolites in Arabidopsis and maize, we found that these metabolites are enriched in developmentally opposing regions and control root development in distinct ways. These findings shed light on plant development and offer practical methods for regulating plant growth.