Role of ribosomal proteins in salt-stress regulation of gravitropism in Arabidopsis thaliana

Abstract

High salinity is an important soil contaminant that is detrimental to plants and causes ionic and osmotic stress. In order to avoid these harmful stimuli, plants have developed mechanisms to change growth patterns. Arabidopsis roots cope with high salinity by initiating salt stress responses like root bending and agravitropism. From previous studies, we know that ribosomal proteins are down-regulated in response to multiple stresses in the epidermis, a tissue that is important for gravitropism. We want to determine what role ribosomal proteins play in regulating gravitropism during the salt stress response. With the use of the rpl5b mutant, we found that RPL5B may be important for meristem maintenance and root gravitropic response. In addition, RPL5B may also be involved in the roots’ auxin response and/or transport, which facilitates root gravitropism. Furthermore, we provided visualised gene expression patterns of the salt-regulated ribosomal proteins by using GFP reporters. Lastly, we tested whether root bending and agravitropism can function as an avoidance mechanism.