Transcriptional Analysis Reveals Different Fertilizer Treatments Improve the Yield and Quality of Tomato Fruits by Postponing Age-Triggered Senescence

Inappropriate fertilization has led to adverse environmental effects and food-safety issues. Biostimulants have been widely used to improve the growth, yield, and quality of crops. However, the effects of biostimulants on age-triggered senescence in plants, which affect the later yield and quality, have scarcely been reported. In this study, the fertilization formulas that were modified according to the requirements of plants in different growth stages, and adding yeast extract agents or microorganisms were respectively used in soilless tomato culture as three fertilization treatments. The Yamazaki formula was set as the control. As results, leaf senescence was delayed by the three fertilization treatments, and the yield and quality of the tomatoes were improved. RNA-seq analysis was used to identify the underlying regulatory mechanisms. The results showed that the genes expression levels remained unchanged in leaves in response to the three fertilization treatments. However, the “MAPK signaling pathway—plant” and “Plant-hormone signal transduction” processes between the roots and leaves were significantly affected, including auxin, gibberellin, ethylene, jasmonic acid, cytokinin, brassinosteroid, and the salicylic acid regulatory pathways. In addition, senescence-related transcription factors were significantly differentially expressed between roots and leaves, including WRKY, MYB, and AP2-EREBP. Our results confirm that using three fertilization formulas can improve the tomato yield and quality, and indicate that a close association exists between root and leaf senescence.