VvCCD7, a novel strigolactone synthesis gene in grapevine (Vitis vinifera L.), increases sensitivity to drought and low-phosphorus stress in transgenic Arabidopsis

As a new plant hormone, strigolactone not only promotes leaf senescence, inhibits plant branching and regulates root structure, but also plays an important role in abiotic stress resistance. However, little is known about the function of VvCCD7 under abiotic stress, a key gene for the synthesis of strigolactone in grapevine. In this study, VvCCD7 gene was cloned from grape leaves of 'Cabernet Sauvignon'. In Arabidopsis, the function of VvCCD7 was verified under drought and low phosphorus stress. The open reading frame of VvCCD7 is 1833 bp in length, encoding 610 amino acids, and the expression level was the highest in the old leaves. Under drought stress, the leaves of wild-type Arabidopsis yellowed and withered, the leaves of overexpressed Arabidopsis shrank slightly, and the peroxidase activity and proline content were significantly higher than those of wild-type Arabidopsis. The expression of AtBzip17 and AtVOZ2 in overexpressed Arabidopsis was significantly higher than that in the wild type, and the expression of AtCOR15A was significantly lower than that in the wild type. Under low phosphorus stress, the growth of wild-type Arabidopsis was slowed down and its root elongation was inhibited. The growth of overexpressed Arabidopsis was healthy and its root elongation was normal. In conclusion, VvCCD7 gene enhanced the tolerance of Arabidopsis to drought and low phosphorus stress, which laid a foundation for further study on the abiotic stress-relieving mechanism of strigolactone.