Directed expression of R2R3 MYB transcription factors for ectopic suberin deposition
Date
2022
Authors
McKay Whiteman, Angel, author
Medford, June, advisor
Nishimura, Marc, committee member
Peebles, Christie, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
Plants are susceptible to many stresses, which can lead to reduced growth, decreased crop yield, or even plant death. Plants contain natural barriers to protect them from stresses, including the hydrophobic biopolymer suberin. Suberin protects plants against a variety of factors, including water loss, toxic ions, loss of essential nutrients, and entry of microorganisms. Plant roots contain a suberized barrier called the endodermis, which regulates the entry and exit of materials from the cortex to the vascular cylinder. While the endodermis protects the vascular cylinder, the cortex is left susceptible to stresses. Engineering a suberized barrier in the root epidermis could protect the cortex and provide an additional point of regulation. Multiple R2R3 type MYB transcription factors have been found to be involved in suberin biosynthesis. Expressing these transcription factors in the root epidermis could provide a suberin barrier for protection. I expressed five R2R3 MYB transcription factors in the root epidermis of Arabidopsis thaliana to determine whether their expression led to suberization of the root epidermis. Constitutive expression of one transcription factor, MYB84, led to increased epidermal suberin. Two homozygous lines were further analyzed and found to have decreased root growth. Gene expression results from one homozygous line suggest that MYB84 overexpression may lead to increased expression of suberin biosynthetic genes involved in synthesis of aliphatic suberin monomers and monomer transport. Further analysis of these transgenic plants could provide insight into the potential protective barrier the root epidermal suberin provides.