Plants balance responses to different stresses based on leaf age to survive in nature. Older leaves prioritize dealing with drought and salt stress over fighting off pests, while younger leaves can do both. A gene called PBS3 helps with this balance, but plants without it struggle with combined stresses. PBS3 also affects the types of bacteria that live on leaves under salt stress. This study shows how plants manage conflicting stresses and how a single gene can impact immunity, leaf bacteria, and stress tolerance.