PROTECTIVE TOUCH: After 4 weeks of being gently bent back and forth 10 times, twice a day, Arabidopsis plants unable to produce the hormone jasmonate exhibited normal growth (left), while the plants that could produce jasmonate when touched had delayed flowering, shorter flower stems, and smaller leaf clusters (right). Plants that were touched also had smaller wounds from a fungal infection, and moth larvae that fed on touched plants did not grow as large.© JOELLE BOLT
THE PAPER
E.W. Chehab et al., “Arabidopsis touch-induced morphogenesis is jasmonate mediated and protects against pests,” Cur Biol, 22:701-06, 2012.
Although it’s known that plants can detect and respond to touch, how they relay information from physical contact has been less clear. Janet Braam’s group at Rice University and other labs had previously shown that the expression levels of many genes are upregulated in response to touch and that plants develop stockier builds if they are routinely perturbed. In their latest work, Braam’s team set out to identify how the physical perturbation was translated into growth changes. They found that a plant hormone called jasmonate is essential for the developmental responses to touch in Arabidopsis, and that touch itself, via jasmonate, can boost pest resistance.
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