Transcriptome profiles reveal the protective role of seed coating with zinc against boron toxicity in maize (Zea mays L.)

Despite its low abundance during biological growth, excessive boron (B) is potentially toxic to both plants and humans. Cultivation of maize (Zea mays L.), one of the most important crops worldwide, has been severely affected by B toxicity, thereby threatening human and animal food security. The effects of coating maize seed with B, zinc (Zn), and B+Zn were evaluated using transcriptome analysis. It was found that Zn coating signifi-cantly reduce B accumulation and toxicity in maize. Compared to the uncoated control, expression of 10871, 2844, and 1347 genes demonstrated alterations in response to coating with B, Zn, and B+Zn, respectively. Of the differentially expressed genes (DEGs), the expression of 7529, 1056, and 357 DEGs was found to be specific for coating with B, Zn, and B+Zn, respectively. Additionally, 132 co-modulated DEGs were found to primarily encode stress resistance- and membrane-related proteins. These genes were primarily involved in plant hormone signal transduction, ribosome assembly, carbon metabolism, phenylpropanoid biosynthesis, and oxidative phosphorylation pathways. Overall, our results suggested that seed coating with Zn significantly alleviates B accumulation and toxicity in maize by changing the expression of selected genes and constitutes a simple and effective strategy for alleviating B toxicity in high-B soils.