Autophagy Is More Vital in Tomato and Citrus than in Arabidopsis

Autophagy is crucial for plant growth, development, and stress responses. While its core machinery is conserved across species, the differential regulation of autophagy in annual versus perennial plants, particularly with respect to resource allocation trade-offs, remains poorly understood. Here, we conducted a comparative study to investigate the function of autophagy in horticultural plants with different life cycles. Using autophagy-deficient materials targeting ATG7 in tomato (Solanum lycopersicum) and citrus (Fortunella hindsii), alongside Arabidopsis as a reference, we analysed the impact of autophagy on vegetative growth, reproductive development, and nutrient stress responses in annual and perennial plants. Autophagy deficiency consistently impaired growth across species, but F. hindsii exhibited more severe growth inhibition and premature leaf senescence, highlighting life-history-dependent differences in autophagy reliance. Comparative transcriptomic analysis of F. hindsii further revealed potential molecular networks underlying autophagy deficiency-induced leaf senescence. In conclusion, our study provides the first evidence on how autophagy differentially underpins annual and perennial life strategies, offering a theoretical foundation for future autophagy-based breeding approaches.