The transcription factor AtHB5 is a negative regulator of carbohydrate transport

RAMINGER BETINA LORENA; ZAPATA, CARLOS A; MIGUEL, VIRGINIA N; CHAN, RAQUEL L.; CABELLO JULIETA V.

Santa Fe

Congreso; Reunión Argentina de Fiosiología Vegetal; 2021

AtHB5 is a transcription factor belonging to the homeodomain-leucine zipper I family. It was previously reported as repressed during stem maturation. To elucidate the role played by this protein, we obtained mutant (athb5) and overexpressor (OE) plants, as well as plants in which the AtHB5 promoter drives GUS expression. The reporter expression was evident in hypocotyls and vascular tissues. Mutants plants exhibited wider stems with increased lignification, phloem, and xylem vessels, a decrease in callose deposition and starch content in rosette leaves, whereas OE showed the opposite phenotype. In addition, mutant plants had longer roots, whereas OE shorter ones and revealed a lower transport speed compared with the WT.