Within the framework of Agriculture 4.0 and new technologies applied to the sustainable management of crops, a group of researchers has developed an experimental variety of genetically modified tomato, capable of changing color in response to nitrogen deficiencies in the soil long before visible damage appears in the plant.

This biotechnological innovation for the early detection of nutritional deficiencies, inspired by previous studies carried out on vegetables such as tomatoes, could represent a qualitative leap in nutrient management and precision agriculture applied to the berry sector, specifically blueberries, one of the fastest growing and most competitive fruit industries worldwide.

A plant that “talks” to the farmer

The research would be applied to a modified blueberry variety, to express a natural anthocyanin-type pigment when the root system detects critical levels of available nitrogen.

Under normal conditions, the plant maintains its characteristic bluish-green color, but when the soil reaches a deficiency threshold, the leaves acquire reddish or purplish tones, an unmistakable sign that it requires fertilization.

The visual response is activated before stress symptoms such as chlorosis or necrosis appear, giving the grower a window of time to intervene precisely, avoiding losses in yield or fruit quality.

“The idea is to transform the crop into its own sensor. For the plant to visually communicate what is happening underground, before it’s too late,” explained one of the project’s leading researchers.

Sustainability and efficiency: two key objectives

The technology is based, among other factors, on the global problem caused by the excessive use of nitrogen fertilizers. In modern fruit farming, especially in intensive berry systems, farmers often apply between 30% and 50% more nitrogen than necessary, which raises production costs and generates significant environmental impacts, such as groundwater contamination, lake eutrophication, and greenhouse gas emissions.

Smart blueberries would allow fertilization to be adjusted to the crop's actual needs, reducing waste and improving nutrient use efficiency (NUE). This aligns with the sustainability goals promoted by international organizations and major export chains, which are seeking clean production certifications and environmental traceability.

A new paradigm in precision agriculture

Traditionally, the detection of nitrogen deficiencies is based on foliar or soil analysis, or on the use of specialized optical sensors.
While these tools are effective, they are expensive, technical, and not very accessible to small and medium-sized producers.

Instead, These sentinel plants function as living biosensors and low cost. They could be placed between crop rows or in strategic areas of the field, serving as visual indicators of the overall nutritional status of the crop. Producers, simply by observing the color changes, could decide when and where to apply fertilizers, without the need for complex equipment.

Furthermore, in technologically advanced systems, the chromatic signal can be detected by multispectral cameras installed on drones or tractors, allowing for the generation of real-time digital nutrition maps. In this way, the smart blueberry becomes a tool that can be integrated with digital agriculture platforms, promoting precision management adaptable to any production scale.

Potential impact on the blueberry industry

The blueberry is today one of the most dynamic fruits in international trade, with an area and production that is steadily growing in America, Europe and Asia.

Leading countries such as Peru, Chile, Mexico, Morocco, Poland, and China face the challenge of sustaining high yields without degrading the soil or overusing fertilizers.

The incorporation of living biosensors could represent a revolution in crop management, providing both economic and environmental advantages:

• Cost reduction in fertilization and monitoring.
• Increased productivity through balanced nutrition and less physiological stress.
• Reduction of the environmental footprint associated with nitrate leaching.
• Ease of technological adoption, even by small farmers.

Furthermore, the use of these sentinel plants could be extended to other critical nutrients, such as phosphorus or potassium, and even serve as a basis for integrated bio-alert systems against drought or heat stress conditions.

Democratization of smart agriculture

The team is also working on developing a mobile application that will correlate leaf color with available nitrogen levels, democratizing access to this technology and making it available to small producers and family farmers.

“The goal is to make precision agriculture more accessible, efficient, and sustainable. The smart blueberry could become a key tool for improving productivity and reducing the environmental impact of fruit farming,” the researchers state.

This type of innovation reinforces the global trend towards more sustainable and data-driven agricultural systems, where biotechnology and digitalization converge to optimize the management of the most limited resource of the 21st century: soil nutrients.