Objective A member of the MYB protein family closely related to plant growth, development, starch metabolism, and abiotic stress responses, MeLHY was cloned for a functional analysis.

Method MeLHY was cloned from the cassava cultivar, SC205, to study the structural characteristics by bioinformatics methods. Subcellular localization of the gene was determined through construction of the pNC-Green-SubC and pNC-Green-CherryC vectors. Infecting tobacco epidermal cells of the gene was achieved by agrobacterium transient transformation. Fluorescence signal was captured using laser confocal microscopy. Gene expressions in tissues at various root developmental stages were determined by qRT-PCR. And binding of the protein to the promoters of starch metabolism genes were studied by applying the yeast-one-hybrid method.

Result The coding region of MeLHY was 2,271bp in length encoding 756 amino acids. The unstable hydrophilic protein had a molecular weight of 83,717.14Da and a theoretical isoelectric point of 5.92. It contained a typical MYB DNA-binding domain and had the closest similarity of 83.73% with the protein from rubber tree. Its promoters consisted of responsive elements to light, auxin, jasmonic acid, and abiotic stress. Subcellularly localized in the nucleus, the gene was expressed relatively high in the tubers, leaves, and mid-veins and significantly higher in the early than in the late stages of tuber development. It could co-express with the starch metabolism genes, MeAPL1 and MeDPE1.

Conclusion Belonging to the MYB gene family, MeLHY of cassava was located in the nucleus, expressed differentially in tissues and tuber development stages, and could interact with the promoters of starch metabolic MeAPL1 and MeDPE1.