Genome-Wide Identification of Cassava Glyoxalase I Genes and the Potential Function of in Iron Toxicity Tolerance

Glyoxalase I (GLYI) is a key enzyme in the pathway of the glyoxalase system that degrades the toxic substance methylglyoxal, which plays a crucial part in plant growth, development, and stress response. A total of 19 genes were identified from the cassava genome, which distributed randomly on 11 chromosomes. These genes were named and were systematically characterized. Transcriptome data analysis showed that gene expression is tissue-specific, and is the dominant gene expressed in young tissues, while is the dominant gene expressed in mature tissues and organs. qRT-PCR analysis showed that is upregulated under 2 h excess iron stress, but downregulated under 6, 12, and 20 h iron stress. Overexpression of enhanced the growth ability of transgenic yeast under iron stress. The root growth of transgenic seedlings was less inhibited by iron toxicity than that of the wild type (WT). Potted transgenic blossomed and podded under iron stress, but flowering of the WT was significantly delayed. The GLYI activity in transgenic was improved under both non-iron stress and iron stress conditions compared to the WT. The SOD activity in transgenic plants was increased under iron stress, while the POD and CAT activity and MDA content were decreased compared to that in the WT. These results provide a basis for the selection of candidate genes for iron toxicity tolerance in cassava, and lay a theoretical foundation for further studies on the functions of these MeGLYI genes.