Developmental transitions in plants require adequate carbon resources, and organ abscission often occurs due to competition for carbohydrates/assimilates. Physiological studies have indicated that organ abscission may be activated by Suc deprivation; however, an underlying regulatory mechanism that links Suc transport to organ shedding has yet to be identified. Here, we report that transport of Suc and the phytohormone auxin to petals through the phloem of the abscission zone (AZ) decreases during petal abscission in rose (Rosa hybrida), and that auxin regulates Suc transport into the petals. Expression of the Suc transporter RhSUC2 decreased in the AZ during rose petal abscission. Similarly, silencing of RhSUC2 reduced the Suc content in the petals and promotes petal abscission. We established that the auxin signaling protein RhARF7 binds to the promoter of RhSUC2, and that silencing of RhARF7 reduces petal Suc contents and promotes petal abscission. Overexpression of RhSUC2 in the petal AZ restored accelerated petal abscission caused by RhARF7 silencing. Moreover, treatment of rose petals with auxin and Suc delayed ethylene-induced abscission, whereas silencing of RhARF7 and RhSUC2 accelerated ethylene-induced petal abscission. Our results demonstrate that auxin modulates Suc transport during petal abscission, and that this process is regulated by a RhARF7-RhSUC2 module in the AZ.

植物的发育转变需要足够的碳资源，并且由于碳水化合物/同化物的竞争而经常发生器官脱落。生理学研究表明，Suc 剥夺可能会激活器官脱落；然而，将 Suc 运输与器官脱落联系起来的潜在调控机制尚未确定。在这里，我们报道了在玫瑰（ Rosahyda）花瓣脱落过程中，Suc 和植物激素生长素通过脱落区（AZ）韧皮部向花瓣的运输减少，并且生长素调节 Suc 向花瓣的运输。玫瑰花瓣脱落期间，AZ 中Suc 转运蛋白 Rh SUC2的表达下降。同样，Rh SUC2的沉默降低花瓣中Suc含量，促进花瓣脱落。我们确定生长素信号蛋白Rh ARF7 与 Rh SUC2的启动子结合，并且沉默 Rh ARF7会降低花瓣 Suc 含量并促进花瓣脱落。花瓣 AZ 中Rh SUC2的过度表达恢复了由 Rh ARF7沉默引起的加速花瓣脱落。此外，用生长素和 Suc 处理玫瑰花瓣可延迟乙烯诱导的花瓣脱落，而沉默 Rh ARF7和 Rh SUC2则加速乙烯诱导的花瓣脱落。我们的结果表明，生长素在花瓣脱落过程中调节 Suc 运输，并且该过程受到Rh ARF7- AZ 中的Rh SUC2 模块。