"The world's population stands at 6.5 billion people right now. By the year 2050, we will be 9.5 billion. So we will have a gap of about 3 billion people to feed in the next 35 years," said Prof. Heribert Hirt, Director of KAUST's Center for Desert Agriculture. An upcoming international conference at KAUST, titled Desert Rhizosphere Microbes for Future Sustainable Agriculture, to be held on November 3-5, 2014, will focus on examining ways to help plants and crops survive and thrive in extreme environmental conditions.

"We try and understand how these plants can actually live under these extreme conditions and determine how we can use this knowledge from these plants," as Prof. Hirt expounds. "We are looking into the microbes that are living with these plants and try to help them to establish themselves under these conditions of heat, drought and salt which are the three key factors in agriculture."

As we face the growing reality of global warming, this knowledge is of primal importance. We will have more heat and resulting droughts, so our agricultural system will need to adapt to these new realities -- since the plants and crops currently produced will have a hard time to survive.

"The problem is meeting our future challenges we will require an increase in food production by about 50 percent. With the current crops that we have we cannot do that. So the question is how can we achieve this?" Prof. Hirt said. "We need to actually improve their performance under these heightened drought and heat conditions."

Countering Adverse Environmental Conditions with Natural Microbes

Essentially, there are two ways to do this. One avenue is to experiment with genetic engineering to improve crops. The other option is to promote the use of natural microbes. Prof. Heribert Hirt is exploring answers that can be found through the capabilities of microbes. The upcoming conference will particularly focus on rhizosphere microbes.

Environmental conditions, ahead of the negative impact of insects or bad microbes eating up the plants, are in fact the major limiting factor in plant productivity nowadays. The particularity of rhizosphere microbes is that they can increase plants' abiotic stress tolerance (caused by heat, drought, and salt). All plants can adapt at some level to environmental changes but the more they are associated with these rhizosphere microbes, the greater is their stress tolerance.

The rhizosphere (from the Greek word "rhiza", meaning root), is a soil area around a plant's roots where the soil's microorganisms directly interact with secretions or chemicals released by the plant's roots.

As Prof. Hirt explains, in the past 15 years, thanks to sequencing technologies, scientists have come to realize that the soil is the richest source of microbes in the world. "People now have gotten more and more interested, also through this technology, to use microbes now to help plants grow," he said.

Making Current Plants Better

Given the fact that drought conditions alone are responsible for up to 60 percent of harvest losses, Prof. Hirt explains that: "Our concept is not to have plants that grow bigger and faster; but it's actually to preserve the capacity of the current crops to come to flower and to fruitfully produce without dying off due to a drought period."

As Prof. Hirt points out, we have evidence right here at KAUST of plants growing in the seawater with the surrounding mangroves and other vegetation growing along the shores of the Red Sea. "They are basically drinking seawater," said Hirt. "So the question is how do they do that? How can they live on that?"

Since this vegetation proves that it's possible to actually use seawater to grow crops, it means we could give current crops the ability to do the same.

"I've been working on plant stress biology for 25 years, with a focus on abiotic stress," said Prof. Hirt. In recent years, he came across an example of a remarkable fungus from a desert in Pakistan with the unique ability to interact with any kind of plant species – crops, cereals, and others – and actually help these plants to make them strongly resistant against drought stress.

This discovery then gave Hirt the conviction that there must exist other microbial organisms around the world that can do this.

An International Project to Discover the Deserts of the World

"Nobody has really gone in-depth to identify those microbes," said Prof. Hirt. So he thought that KAUST would be an ideal place to pursue this type of desert research. The Desert Rhizosphere Microbes Conference is in fact the kickoff for an international collaboration, helmed by Prof. Hirt and his colleague, extreme environments microbiologist, Dr. Daniele Daffonchio, as well as with the collaboration of KAUST's center for bioinformatics (CBRC), to go into different deserts of the world. This program will foster transnational collaborations among several institutions in Oman, the United Arab Emirates, Pakistan, Jordan, Africa and South America.

Aiming to become a global knowledge base of desert rhizosphere microbes, the DARWIN21 project was inspired by the scientific voyages undertaken by Charles Darwin, aboard the HMS Beagle, in the 19th century. This project now aspires to complete a similar voyage of discovery in the 21st century. The DARWIN21 project will go about exploring the various deserts on the planet and study the plants and microbes that grow there.

Saudi Arabia is itself an ideal place for prospecting different types of deserts since, as Prof. Hirt points out, "we already have very different types of deserts in Saudi Arabia: inland deserts, salty ones, less salty ones – so there are very different conditions."

His group of international scientists, many of whom will be present at KAUST for the conference, are seeking answers as to how these desert plants are able to survive. Are there different microbes that help them do that? What are the distinguishing factors tied to these microbes?

"We've got the tools to analyze spots on Earth that are yet to be discovered," said Prof. Hirt. "I think KAUST can be a great incubator to make this happen."

- by Meres J. Weche, KAUST News

Further Information

• Desert Rhizosphere Microbes Conference
• DARWIN21 Project