Microorganisms equivalent to bacteria and fungi help promote the health and performance of plant roots. It is usually believed that the composition of those microbes depends upon the soil properties. However, a world team of researchers led by the University of Bonn has now discovered that the genetic makeup of the plant also influences which microorganisms cluster across the roots, studying different local varieties of maize. . The findings, now published within the journal, could assist in future breeding of maize varieties which might be higher suited to drought and limited nutrients.
To grow properly, plants take up water and nutrients through their roots. But they've some little helpers: a layer of bacteria and fungi, just just a few millimeters thick, will be found directly across the roots. “These microorganisms are essential for plant health and fitness,” says Dr. Peng Yu, head of the junior research group “Root Functional Biology” on the Institute of Crop Science and Resource Conservation (INRES) on the University of Bonn. Microbes help absorb water and nutrients and protect plants against harmful organisms — just because the “microbiome” within the human gut helps determine whether we get sick. Or stay healthy.
The conventional view is that the composition of the microbiome—the sum total of all microorganisms—is decided primarily by soil properties. This includes things just like the kind of soil and whether it's more acidic or alkaline. However, a world team of researchers led by the University of Bonn has now demonstrated in maize plants that the genetic makeup of the host plant has a major effect on the composition of root microbes.
“Our studies also show that the microbiome around the roots has a significant impact on how maize plants respond to stressful conditions such as nutrient deficiency or How resilient they are when faced with water scarcity.” Department at INRES on the University of Bonn. Given global climate change and the limited supply of the nutrient phosphorus, drought and nutrient deficiency of those plants may play a fair greater role in the longer term.
Adaptation of regional maize varieties to environmental conditions
The genetic composition of various varieties of maize varies greatly. Regional varieties have adapted to very different environmental conditions depending on whether or not they are cultivated, for instance, within the cool highlands or hot lowlands of South America. “The fact that farmers have continued to select maize varieties for local climates over many centuries has led to the very different genotypes that we were able to use for our study,” says Dr. Yu, who heads Amy Noether. The junior research group is funded by the German Research Foundation and in addition a member of the Feinrobe Cluster of Excellence and the transdisciplinary research area “Sustainable Futures” on the University of Bonn.
The researchers, in collaboration with scientists from the Southwest University of Chongqing (China), studied a complete of 129 different varieties of corn. Some of them were cultivated under “normal” conditions while others suffered from phosphorus, nitrogen or water deficiency. Additionally, the team sequenced the DNA of microbes from 3,168 samples found directly across the roots, that are only just a few millimeters thick.
The role played by the genetic makeup of the roots was revealed in these plants grown under stress conditions. Interestingly, nutrient and water deficits had significant effects on microbial composition. Additionally, the team discovered significant trait differences within the microbiome between different maize varieties under the identical stress conditions. “We were able to prove that certain genes in maize are able to interact with certain bacteria,” says Dr. Yu, explaining an important findings. Using data on growing conditions and genetic makeup of a specific number of corn, the researchers were also in a position to predict which key organisms were present in the microbiome across the roots. will go.
Mycelia bacterium promotes lateral root growth.
The results for bacteria of the Mycelia genus stood out: “It was very noticeable that very few samples of this microbe were found when there was an abundance of nitrogen,” says Prof. Dr. Gabriel Schaaf of the Department of Ecophysiology of Plant Nutrition. From. at INRES and member of the PhenoRob Cluster of Excellence. If nitrogen was deficient, nonetheless, many mycelia clustered across the roots. The team then inoculated corn roots with the bacterium. This resulted within the plants growing more lateral roots and were subsequently in a position to significantly improve their nutrient and water uptake.
But how do corn plants use the tiny mycelia bacterium to grow these sorts of roots? After further studies, the researchers discovered that the roots actually use flavones to draw mycelia bacteria. This substance is one in all many secondary metabolites within the plant and stimulates lateral root growth with the assistance of bacteria. “However, it depended on whether the microtubule-binding gene was present in the maize plant,” says Dr. Peng Yu. If this gene was missing, the plant didn't produce many lateral roots.
Maize varieties with the missing gene come from an enormous database of maize mutations compiled by researchers led by Dr Caroline Marken at INRES. This database helps researchers define the functions of maize genes.
Maize varieties are higher adapted to drought and nutrient deficiency.
The international team of researchers hopes to give you the chance to forecast production within the medium term. “We're doing basic research,” says Hochholdinger. “However, these findings may serve as a basis for breeding maize varieties better suited to drought and phosphorus deficiency using genome and microbiome data.”