Polyamines (PA) play an important role in the growth, development and stress resistance of plants, and arginine decarboxylase (ADC) is one of the key enzymes in the biosynthetic pathway of polyamines. Previously, the transcriptional regulation of the ‘Manaohong’ cherry under the shelter covering was carried out, and the PA synthase-related genes, particularly the ADC gene, were differentially expressed as exposure to drought stress. However, the mechanisms of how ADC is involved in the response of cherry to abiotic stress (especially drought stress) are still unknown. In the present work, the full-length coding sequence of this gene was isolated and named CpADC. Bioinformatics analysis indicated that the coding sequence of CpADC was 2529 bp in length. Cluster analysis showed that CpADC had the highest homologies with those of sweet cherry (Prunus avium, XP_021806331) and peach (Prunus persica, XP_007200307). Subcellular localization detected that the CpADC was localized in the plant nucleus. The qPCR quantification showed that CpADC was differentially expressed in roots, stems, leaves, flower buds, flowers, and fruits at different periods. Drought stress treatments were applied to both wild-type (WT) and transgenic Arabidopsis lines, and relevant physiological indicators were measured, and the results showed that the putrescine content of transgenic Arabidopsis was higher than that of WT under high-temperature treatment. The results showed that the MDA content of WT was consistently higher than that of transgenic plants and that the degree of stress in WT was more severe than in transgenic Arabidopsis, indicating that transgenic CpADC was able to enhance the stress resistance of the plants. Both the transgenic and WT plants had significantly higher levels of proline in their leaves after the stress treatment than before, but the WT plant had lower levels of proline than that of transgenic Arabidopsis in both cases. This shows that the accumulation of proline in the transgenic plants was higher than that in the wild type under drought and high and low-temperature stress, suggesting that the transgenic plants are more stress tolerant than the WT. Taken together, our results reveal that, under drought stress, the increase in both expressions of CpADC gene and Put (putrescine) accumulation regulates the activity of ADC, the content of MDA and Pro to enhance the drought resistance of Arabidopsis thaliana.

In this paper, an auxin-responsive transcription factor, CpARF7, was isolated from the roots of Chinese cherry (Cerasus pseudocerasus Lindl. Cv. “Manao Hong”). CpARF7 is highly homologous to AtARF7 or AtARF19 in Arabidopsis, and PavARF1 or PavARF14 in sweet cherry. However, in the phenotype of transgenic tomatoes, the root morphology changed, the main root elongated, and the lateral root increased. Both drought treatment and low-phosphorus conditions can elongate the roots of transgenic tomatoes. In addition, the drought resistance and low-phosphorus tolerance of the transgenic lines are improved, and the POD, SOD, and CAT activities under drought and low-phosphorus environments are increased. There is an effect on the tomato somatotropin suppressor gene, SlIAAs, in which SlIAA1/14/19/29 are up-regulated and SlIAA2/11/12/16 are down-regulated. These results indicate that CpARF7 plays an essential regulatory role in root formation and abiotic stress response, and deepens the understanding of auxin-responsive genes in root growth and abiotic stress.