Researchers at the University of Kentucky (UK) have discovered the function
and placement of another component in a pathway that triggers plant disease
resistance. The team, led by Pradeep Kachroo and Aardra Kachroo studied the
chemical signals involved in cell-to-cell communication.
The research team found that pipecolic acid, a small organic compound
derived from lysine, initiates the process by inducing the accumulation of
free radicals. Free radicals initiate a pathway that results in the
accumulation of the signaling chemicals salicylic acid and
glycerol-3-phosphate. Salicylic acid, glycerol-3-phosphate, and to a lesser
extent, pipecolic acid then travel within the plant as part of the defense
"preparedness" process. There, salicylic acid and glycerol-3-phosphate
initiate additional pipecolic acid synthesis to continue this signaling
Pradeep Kachroo said that scientists knew the importance of pipecolic acid
in systemic signaling, but did not understand how it related to the other
known systemic chemical signals. Now they do not only know how pipecolic
acid functions, but also how the chemical cooperates with other signals.