The Lateral Suppressor-Like Gene, DgLsL, Alternated the Axillary Branching in Transgenic Chrysanthemum (Chrysanthemum x morifolium) by Modulating IAA and GA Content

The lateral suppressor-like gene DgLsL was transformed by agroinfection into chrysanthemum in both the sense and antisense directions. Sense transformants branched more profusely than the wild-type nontransformant, while branching in the antisense transformants was significantly suppressed. An analysis of DgLsL transcript abundance in the shoot tips revealed that expression was enhanced in the sense transformants and suppressed in the antisense ones. The shoot tip content of indole-3-acetic acid (IAA) was reduced in the sense transformants but enhanced in the antisense ones. The sense transformants had a lower content and the antisense transformants had a higher content of gibberellic acid (GA). Cytokinin content was not affected by the variation in DgLsL expression. We conclude that DgLsL controls shoot branching through its effect on IAA and GA levels.