Tuber Development and Propagation Are Inhibited by GA3 on DELLA-dependent Pathway in Cyperus rotundus

Cyperus rotundus L. is a globally distributed noxious weed that poses a significant challenge for control due to its fast and efficient propagation through the tuber, which is the primary reproductive organ. Gibberellic acid (GA3) has proved to be crucial for tuberization in tuberous plants. Therefore, understanding the relationship between GA3 and tuber development and propagation of C.roundus will provide valuable information for controlling this weed. This study shows that the content of GA3 decreases with tuber development, which corresponds to lower expression of bioactive GA3 synthesis genes (CrGA20ox, two CrGA3oxs) and two up-regulated GA3 catabolism genes (CrGA2oxs), indicating that GA3 is involved in tuber development. Simultaneously, the expressions of CrDELLAs and CrGID1 decline with tuber growth and GA3 decreasing, and Yeast two-hybrid (Y2H) assays confirm that the GA3 signaling is DELLA-dependent. Furthermore, exogenous application of GA3 markedly reduces the number and the width of tuber, and represses the growth of tuber chain, further confirming the negative impact that GA3 has on tuber development and propagation. Taken together, these results demonstrate that GA3 is involved in tuber development and regulated by the DELLA-dependent pathway in C. rotundus, and plays a negative role in tuber development and propagation.