Biotin supplementation alters root system architecture and development in Arabidopsis thaliana

Abstract

Biotin is a member of the vitamin B-complex family that acts as a cofactor of carboxyl-ases and is essential in the metabolism of all or-ganisms. In addition to its essential metabolic functions, biotin has been suggested to play a criti-cal role in regulating gene expression in plants and animals. However, all studies in plants have been conducted under biotin deficiency. Therefore, we hypothesized that exogenously supplied biotin also exerts non-enzymological functions similar to those reported in animals, regulating root growth and development in Arabidopsis thaliana. To test this hy-pothesis, we evaluated the effects of the biotin supply on seedlings and analyzed the root archi-tecture. Biotin supplementation inhibited root elongation and promoted lateral root formation in a concentration-dependent manner. Inhibited primary root elongation was correlated with decreased expression of the cell cycle genes CycB1;1:uidA and cell expansion gene pAtExp7::uidA, and depended on the concentration of biotin. Viability tests with AtHisH2B:YFP showed that the meristem was de-pleted. However, biotin supplementation did not af-fect the concentration of chlorophyll but had a slight inhibitory effect on foliage growth and increased the production of reactive oxygen species (ROS) at the apex of primary roots. Our study pro-vides the first evidence of functions of biotin sup-plementation in plants in addition to its catalytic role as an enzyme cofactor, likely advancing our understanding of the biological functions of biotin.