Genomics and food safety, study uncovers new genetic factors behind photosynthesis in maize

New genetic factors that can boost photosynthesis in the globally vital cereal crop maize have been discovered by researchers. The University of Essex study, the University of Cambridge and the Scuola Superiore Sant'Anna in Pisa, Italy, offer a valuable new approach to improving productivity in staple crops.
Maize is one of the world’s most important cereal crops, and even minimal increases in productivity can have significant impacts on global food security.
Photosynthesis is the process by which plants use solar energy to produce nutrients for their growth. Increasing the efficiency of this mechanism means making the plants we cultivate more productive and consequently increasing their yield. 

Co-first author of the study, Dr John Ferguson, from Essex’s School of Life Sciences, said: “It is critical that we begin to understand the genetics regulating photosynthesis in crops. This will enable us to fine-tune photosynthesis and improve crop productivity. In this study, we used a combination of genomics and high-throughput trait measurements to discover genes that regulate the response of photosynthesis to dynamic light. This is important because in a field setting, crops are exposed to variable light.
We discovered that the activity of one gene in particular (CP24) is central to regulating the response of photosynthesis to changing light. 
This has important implications for maize breeding and offers opportunities for designing strategies to optimize photosynthetic efficiency in maize.”

The study used approaches from genetics, genomics, and molecular biology to demonstrate that there is genetic diversity in the maize we cultivate, and that this can lead to substantial changes in how the crop can use energy from the sun. 
Specifically, the research identified genetic variants present in some types of maize from temperate regions that significantly limit their photosynthetic capacity.
The findings could be particularly useful for improving production in cooler climates like the UK and northern Europe where the amount of land given to growing maize has expanded considerably in recent decades and is likely to continue to rise.
The research is part of a major European project called CAPITALISE. 

The idea behind the study is to understand and optimise the processes that regulate the 'switching on and off' of certain components of the photosynthetic machinery. Dr Johannes Kromdijk, head of the Environmental Plant Physiology group at the University of Cambridge and senior author of the paper said: “Until now there was a view that photosynthesis didn’t vary that much within species. This project is challenging that idea. We’re now finding natural variation in photosynthetic traits in tomato, barley and in this case maize. Other yield factors have already been explored and are unlikely to give such big improvements. So photosynthetic efficiency is an area ripe for exploration" said Dr Kromdijk.

The results significantly contribute to defining objectives for the genetic improvement of maize, opening new perspectives in terms of the impact and sustainability for cultivation.

The project involved a team of researchers working over two years to measure a collection of around 300 specific genotypes of maize in a field trial at Niab just outside Cambridge. 

Leonardo Caproni, the author of the research for the Scuola Superiore Sant'Anna, said: "The results significantly contribute to defining the objectives for the genetic improvement of maize, opening new perspectives in terms of the impact and sustainability of its cultivation. Increasing photosynthetic efficiency means putting our crops in a position to yield more. In the case of maize even minimal increases in productivity can have significant impacts on global food security".