Key role of the motor protein Kinesin 13B in the activity of homeodomain-leucine zipper I transcription factors

MIGUEL, VIRGINIA NATALI; RIBICHICH, KARINA FABIANA; GIACOMELLI, JORGE IGNACIO; CHAN, RAQUEL LIA

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Año: 2020 vol. 20 p. 6282 - 6296

0022-0957

The sunflowerhomeodomain-leucine zipper I transcription factor HaHB11 conferred differentialphenotypic features when it was expressed in Arabidopsis, alfalfa and maizeplants. Such differences were increased biomass, seed yield, and tolerance toflooding. To elucidate molecular mechanisms leading to such traits and identifyHaHB11-interacting proteins, a yeast two-hybrid screening of an ArabidopsiscDNA library, was carried out using HaHB11 as bait. The sole protein identifiedwith high confidence, as interacting with HaHB11, was Kinesin 13B. Theinteraction was confirmed by bimolecular fluorescence complementation, and byyeast two-hybrid assay. Kinesin 13B also interacted with AtHB7, the Arabidopsisclosest ortholog of HaHB11. Histochemical analyses revealed an overlap betweenthe expression patterns of the three genes in hypocotyls, apical meristems,young leaves, vascular tissue, axillary buds, cauline leaves, and cauline leafnodes at different developmental stages. AtKinesin 13B mutants did not exhibita differential phenotype when compared with controls; however, both HaHB11 andAtHB7 overexpressor plants lost, partially or totally, their differentialphenotypic characteristics when crossed with such mutants. Altogether, theresults indicated that Kinesin 13B is essential for the homeodomain-leucinezipper transcription factors I to exert their functions, likely via regulationof the intracellular distribution of these transcription factors by the motorprotein.