Sucrose Regulates Plant Responses to Phosphate Starvation

Plants require ample amounts of phosphate for their growth and development. When there is not enough amount of phosphate in the environment, plants show signs of developmental, biochemical, and physiological changes. To understand the molecular mechanism involved in phosphate starvation, Mingguang Lei of Tsinghua University, China, and a team of scientists isolated an Arabidopsis mutant (hypersensitive to phosphate starvation1 or hps1) with improved sensitivity in almost all aspects of plant responses to phosphate starvation.

Molecular and genetic analyses showed that the mutant phenotype is caused by overexpression of the SUCROSE TRANSPORTER2 (SUC2) gene. This led to increased sucrose levels in shoot and root tissues. On the other hand, the disruption of SUC2 functions led to inhibition of responses to phosphate starvation. Further analysis showed that 73% of the genes that are induced by phosphate starvation in wild-type plants can be induced by high levels of sucrose in hps1 mutants, even when grown in low phosphate conditions. These genes include a number of essential phosphate signaling components and those that are directly involved in phosphate transport, mobilization, and distribution between shoot and root.

Results of the study indicate that sucrose is a regulator of plant responses to phosphate deficiency. This finding contributes to the elucidation of signaling mechanism that manages plant responses to the nutritional stress of phosphate starvation.

Subscribers of Plant Physiology can download a copy of the study at http://www.plantphysiol.org/content/early/2011/02/23/pp.110.171736.abstract.