Plant cells communicate via microscopic channels called plasmodesmata that are embedded in their cell walls. For the stem cells in the plants' growing tips, called "meristems," the plasmodesmata are lifelines, allowing nutrients and genetic instructions for growth to flow in.
Developmental and environmental cues trigger changes in the structure of the tiny channels, thereby altering the flow of traffic through them. The genes and molecular pathways of the plant cell that respond to these cues, and the mechanisms that control channel structure and cell-to-cell traffic are, however, mostly unknown.
To identify these genes, a team of researchers led by Professor David Jackson, Ph.D., at Cold Spring Harbor Laboratory (CSHL), devised a method to find mutant cells whose channels were blocked to traffic. The experiments have revealed a gene called GAT1 (pronounced gate-one), which instructs cells to produce an enzyme found only in meristems, the stem-cell rich tip of the plant where new growth takes place. The enzyme improves the flow of traffic through plasmodesmata by acting as an antioxidant, a type of molecule that relieves cellular stress.
"This discovery is one of the first examples of using genetics to understand how plant cells communicate through plasmodesmata," says Jackson, whose lab at CSHL is devoted to the study of plant genetics. "Our study suggests a mechanism through which plant cells can adjust trafficking in these channels through the various stages of development." The team's findings will be published in the Feb 17th issue of Proceedings of the National Academy of Sciences.
GAT1 keeps callose at bay
As plants develop, growth signals and environmental cues such as damage or stress trigger overproduction of a substance called callose. Although callose is a normal structural component of cell walls in plants, excess callose accumulates and forms obstructive clumps that plug the plasmodesmata
|Contact: Hema Bashyam|
Cold Spring Harbor Laboratory