How parts of a plant can 'talk' to one another for the benefit of the whole

February 17, 2016 by Stuart Gillespie, Oxford Science Blog

It has been known for some time that plant roots can communicate with plant shoots. Now, a new paper from Oxford researchers (working in collaboration with researchers from the Chinese Academy of Sciences in Beijing) tells us how.

Professor Nick Harberd, Sibthorpian Professor of Plant Sciences at Oxford, spoke to Science Blog about the work.

'The fact that plant roots communicate with plant shoots is in many ways not surprising. Plant shoots incorporate carbon (as CO2) from the air, while extract mineral nutrients (for example, nitrate or phosphate) from the soil. Coordination of these activities is likely to be selectively advantageous, because it enables the whole plant to optimize its metabolism and growth. But the mechanism of communication has, until recently, been relatively unknown.

'Our paper shows that communication is achieved via movement of an agent from shoot to root. This agent is a protein known as HY5, a kind of protein known as a "transcription factor" that can activate, or "switch on", genes. HY5 was already known to control rates of photosynthesis (CO2 capture) in the shoot. Our work shows that HY5 acts as an agent of communication between shoot and root by moving through the phloem vessels (part of the plant vascular system).

'HY5 travels from shoot to root, and when it reaches the root it activates a number of genes in , including those genes that encode the nitrate transporters that extract nitrate from the soil. This activation is also dependent upon sugars (a measure of CO2 capture) that also travel through the phloem from shoot to root. Thus, movement of HY5 and sugars from shoot to root increases nitrate uptake by the root.

'Our use of genetics in this research has enabled us to discover things previously unknown. We screened for mutants that had reduced shoot-root communication. The logic here is that the mutants would lack genes that controlled shoot-root communication, thus allowing us to identify the genes which, in normal plants, control that communication. One of our mutants identified a gene encoding the previously well-characterised HY5 protein. What we discovered using this technique was that HY5 moves from shoot to root, something new that hadn't previously been known to be a property of HY5.

'In terms of fundamental science, this new knowledge significantly advances our understanding of how plant shoots and roots communicate with one another, and especially how that communication coordinates whole-plant growth and metabolism. This is just the beginning of what is likely to become a major new area in fundamental plant biology.

'In terms of application, HY5 was first identified as a protein that regulates the growth of plants in response to light signals. Most crops (for example, wheat, rice or maize) are grown in relatively dense plantings in which individual plants tend to shade one another. Our findings mean that HY5 can now become a target for breeders to increase HY5 activity in the roots of shaded crop plants, thus improving uptake of nitrate from the soil.

'This is a major objective for plant breeders worldwide as it will increase the efficiency with which crops use fertilizer, reduce the damaging ecological impacts of fertilizer run-off from fields, and in general contribute to the environmentally sustainable increases in crop yields that we need to feed the growing world population.'

Explore further: Researchers uncover new mechanism controlling plant root development

More information: Xiangbin Chen et al. Shoot-to-Root Mobile Transcription Factor HY5 Coordinates Plant Carbon and Nitrogen Acquisition, Current Biology (2016). DOI: 10.1016/j.cub.2015.12.066

Related Stories

For legume plants, a new route from shoot to root

September 19, 2014

A new study shows that legume plants regulate their symbiotic relationship with soil bacteria by using cytokinins—signaling molecules— that are transmitted through the plant structure from leaves into the roots to control ...

Blossom end rot: Transport protein identified

November 23, 2011

Poor calcium distribution in agricultural crops causes substantial loss of income every year. Now a Korean-Swiss research team under the co-leadership of plant physiologists at the University of Zurich identified a protein ...

Rooting about with circadian rhythms

July 9, 2015

The circadian clock drives our physical, mental and behavioural changes. In fact most living things respond to the solar and lunar cycle – day and night. And plants are no different. But scientists at The University of ...

Getting to the root of nutrient sensing

June 14, 2010

New research published by Cell Press in the June 15th issue of the journal Developmental Cell, reveals how plants modify their root architecture based on nutrient availability in the soil.

Recommended for you

Study shows how giraffe assassin bugs outwit spider prey

October 26, 2016

(—A biologist at Macquarie University in Australia has discovered the secret behind the giraffe assassin's ability to catch and kill spiders in their webs. In his paper published on the open access site Royal Society ...

New analysis of big data sheds light on cell functions

October 26, 2016

Researchers have developed a new way of obtaining useful information from big data in biology to better understand—and predict—what goes on inside a cell. Using genome-scale models, researchers were able to integrate ...

Researchers identify genes for 'Help me!' aromas from corn

October 25, 2016

When corn seedlings are nibbled by caterpillars, they defend themselves by releasing scent compounds that attract parasitic wasps whose larvae consume the caterpillar—but not all corn varieties are equally effective at ...

Structure of key DNA replication protein solved

October 25, 2016

A research team led by scientists at the Icahn School of Medicine at Mount Sinai (ISMMS) has solved the three-dimensional structure of a key protein that helps damaged cellular DNA repair itself. Investigators say that knowing ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.