Changes in jasmonate and gibberellin levels during development of potato plants (Solanum tuberosum)

Among the multiple environmental signals and hormonal factors regulating potato plant morphogenesis and controlling tuber induction, jasmonates (JAs) and gibberellins (GAs) are important components of the signalling pathways in these processes. In the present study, with Solanum tuberosum L. cv. Spunta, we followed the endogenous changes of JAs and GAs during the developmental stages of soil-grown potato plants. Foliage at initial growth showed the highest jasmonic acid (JA) concentration, while in roots the highest content was observed in the stage of tuber set. In stolons at the developmental stage of tuber set an important increase of JA was found; however, in tubers there was no change in this compound during tuber set and subsequent growth. Methyl jasmonate (Me-JA) in foliage did not show the same pattern as JA; Me-JA decreased during the developmental stages in which it was monitored, meanwhile JA increased during those stages. The highest total amount of JAs expressed as JA + Me-JA was found at tuber set. A very important peak of JA in roots was coincident with that observed in stolons at tuber set. Also, a progressive increase of this compound in roots was shown during the transition of stolons to tubers. Of the two GAs monitored, gibberellic acid (GA(3)) was the most abundant in all the organs. While GA(1) and GA(3) were also found in stolons at the time of tuber set, no other measurements of GAs were obtained for stolons at previous stages of plant development. Our results indicate that high levels of JA and GAs are found in different tissues, especially during stolon growth and tuber set.