Study Finds that Hormone Keys Plant Growth or Stress Tolerance, But Not Both

Plants that grow well are sensitive to heat and drought, and plants that can handle these stresses often have stunted growth. Purdue University researcher Jian-Kang-Zhu has found the switch that creates this antagonism, opening opportunities to develop plants that exhibit both characteristics.

Using the model plant Arabidopsis, Zhu found that the plant hormone abscisic acid (ABA) is activated in plants that can tolerate stresses such as salt and drought, but also sets off a chain reaction that stymies plant growth. Zhu calls this "the key to the antagonism between stress and growth."

In stressed plants, the ABA pathway is activated and leads to phosphorylation of the Target of Rapamycin (TOR) kinase. This process turns off the TOR kinase, which is essential for plant growth. In unstressed plants, however, the opposite happens. TOR disrupts ABA perception, shutting down the plant's stress responses. Those plants tend to exhibit strong growth.

For more details, read the Purdue University Agriculture News.