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How plant roots change their growth pattern during 'puberty' has implications for climate-resilient agriculture

Understanding how roots grow can help us develop plants that—for example—are more resistant to drought. Research by Prof. Bert De Rybel's team (VIB-UGent), in collaboration with the VIB Screening Core and Ghent University, uncovers how roots go through a "puberty" phase, which could have important implications for developing climate-resilient agriculture. Their work in Science.

Plants, like all living organisms, transition through various developmental stages, starting as seeds, becoming shoots, and eventually full-grown, fertile plants. They even go through a sort of "puberty" during which a young shoot changes its growth patterns, which is vital for survival and adaptation to the environment. By altering the direction in which cells divide, plants can grow more in width than in height, or vice-versa.

What happens below the ground

Between the first and third week of development, roots undergo a lot of changes. Researchers from Prof. De Rybel's team (VIB-UGent Center for Plant Systems Biology) and the VIB Screening Core, together with the Department of Chemistry of the University of Ghent, now provide molecular details on "root puberty." Their findings highlight the crucial role of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 13 (SPL13) in regulating oriented cell divisions, a process essential for proper root growth and morphology.

"Our research provides molecular insights into the age-dependent changes occurring in the root during this crucial phase," says Prof. De Rybel. "We discovered that a change in gene expression of SPL transcription factors, particularly SPL13, is crucial for this transition by regulating the orientation of cell division."

Complexities of growth

The transition that results from SPL13 activity is characterized by distinct changes in the morphology and molecular profile of the roots, which are critical for the plant's overall development.

Dr. Dominique Audenaert, head of the VIB Screening Core (part of VIB Technologies), explains, "We provided advanced microscopy-based screening technology that allowed us to screen for molecules that alter cell division orientation in cell cultures. By assessing the mode-of-action of the identified compounds, we could demonstrate that altering SPL13 production in the cells makes the root systems grow steeper and deeper."

Changing expression levels of SPL13 even allowed the scientists to speed up or slow down root aging.

"Our research," explains Prof. De Rybel, "not only presents a previously unknown fundamental mechanism of plant development, but it also opens new avenues for improved crop yields and plant resilience in changing environmental conditions."

As the global population continues to grow, optimizing plant growth and development will be crucial for food security. The importance of SPL transcription factors in plant biology highlights their potential applications in agriculture through changing root growth patterns, which may make crops more resilient to drought, for example.

By revealing the previously hidden complexity of root development, this study also identifies a gap in current plant research. Most studies use root samples that are one week old, but it is now clear that roots go through significant changes in morphology and gene expression, which means the way we look at root growth in lab conditions will have to be reconsidered.