Scientists finally learn what makes plants grow faster and stronger

Every seed begins life with a simple aim: to reach water, collect nutrients, and stay upright. Beneath the surface, root tips probe the soil and spread into branches that keep the plant alive.

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Getting those branches to appear at just the right spot and moment matters even more now that weather swings between long dry spells and sudden cloud-bursts.

Researchers have traced that timing to autophagy, the recycling pathway many people associate with health benefits from fasting.

By following a shape-shift-ing protein through Arabidopsis roots, the team uncovered how brief clean-up pulses let new branches form and help crops cope with tougher conditions.

Plant roots' cellular clean-up crew

Scientists at the University of Copenhagen mapped the pathway in living seedlings. They watched the transcription factor ARF7 vanish and return in predictable waves, each tied to a jump in the growth hormone auxin.

"Fasting has become popular as it seems to have a range of health-promoting effects in humans, as periods without food cause the body to activate clean-up processes to dispose of various waste products in cells," explains Assistant Professor Eleazar Rodriguez from the Department of Biology, who led the study.

"We have proven that the same mechanism, which also exists in the plant kingdom, plays a vital role in the ability of plant roots to grow and absorb water and nutrients for the rest of the plant."

The process relies on NBR1, a tag that guides used proteins toward a vacuole for breakdown. Each removal of ARF7 resets the signaling circuit so it can fire again a few hours later.

When autophagy slows, ARF7 accumulates, messages run long, and the root loses its usual rhythm.

Autophagy and auxin

Side branches normally form with steady precision. Roughly every four to six hours, auxin peaks at the root tip and switches on genes that mark a patch of tissue for future branching.