Senescence and abiotic stress induce expression of autophagy-related genes in petunia

Abstract

Autophagy allows for the degradation and recycling of macromolecules and organelles. It plays a significant role in cellular homeostasis, nutrient remobilization during leaf senescence, and abiotic stress responses. Autophagosomes are the hallmark feature of autophagy, and their formation is regulated by the AuTophaGy-related (ATG) genes. The expression profiles of ATG genes have been reported in several agronomic and model plants. To gain insight into the role of autophagy in senescence and abiotic stress responses in floriculture crops, we investigated the regulation of petunia (Petunia ×·hybrida) ATG genes (PhATG4, PhATG5, PhATG6, PhATG7, PhATG8a, and PhATG13) during flower senescence and in response to low fertility, nutrient deficiency (-N, -P, and -K), and chronic (weeks) or acute (hours) salt stress using quantitative polymerase chain reaction (PCR). Age-induced corolla wilting coincided with the increased expression of all ATG genes. Petunia ATG genes were upregulated by low fertility and N and P deficiency. Acute salt stress rapidly increased the expression of the petunia ATG genes, but chronic salt stress treatments did not. This project provides insight into the role of autophagy in flower senescence and abiotic stress responses in floriculture crops.