Scientists develop protein against sugarcane disease

With the use of bioinformatics, researchers from Embrapa Agrobiology (RJ) managed to produce a recombinant protein that has antimicrobial action against the bacteria xanthomonas albilineans and other microorganisms that cause plant diseases. Recombinant proteins are those produced by organisms other than those that normally generate them. A X. albilineans It is the cause of leaf scald, a disease that can cause losses of up to 100% in a sugarcane field when it affects susceptible varieties.

Using the recombinant protein called Gluconacin, researchers intend to arrive, in the coming years, at a biotechnological formulation to be applied in the field to prevent diseases. “The objective is to have a product with a large amount of bacteriocin to be used directly on the plant through spraying”, says the Embrapa researcher Márcia Vidal, who is part of the team involved in this study.

Sugarcane with less chemicals The development of bioinputs for sugarcane is in line with a global trend, with consumers increasingly concerned about the increased use of chemical pesticides and preferably consuming products that use biological methods of controlling pests and diseases. Added to this is the fact that 40 of the 177 diseases identified in the crop have been reported in Brazil, with the most important for the national sugar and alcohol sector being red streak, false red streak, leaf scald, gummosis , red rot and rot Fusarium.

Sugarcane with less chemicals

The development of bioinputs for sugarcane is in line with a global trend, with consumers increasingly concerned about the increased use of chemical pesticides and preferably consuming products that use biological methods of controlling pests and diseases. Added to this is the fact that 40 of the 177 diseases identified in the crop have been reported in Brazil, with the most important for the national sugar and alcohol sector being red streak, false red streak, leaf scald, gummosis , red rot and rot Fusarium.

Gluconacin is a bacteriocin (protein that acts against disease-causing agents) naturally produced by bacteria Gluconacetobacter diazotrophicus, very common in sugarcane and with recognized control potential against some microorganisms that cause diseases in the crop. However, it is only produced when the bacteria is subjected to a stressful situation.

The researcher explains that through bioinformatics tools it was possible to identify the gene that encodes the bacteriocin and insert it into another bacterium, which works like a test tube and allows large quantities to be produced. “In addition to overexpressing it in another organism, our objective was also to express the bacteriocin regardless of the condition of the bacteria to which it is being subjected”, explains Vidal.

How does protein work?

Through in vitro and greenhouse tests, researchers found that Gluconacin attacks bacteria, causes the membrane to rupture and kills pathogenic microorganisms. The stability of the protein was tested at high temperatures, in acidic environments and against other substances such as, for example, adhesive agents widely used as a vehicle for products applied to crops.

Recombinant proteins They are proteins artificially produced from cloned genes. The gene is a segment of a DNA molecule (deoxyribonucleic acid), responsible for genetically inherited characteristics. Each gene is made up of a specific sequence of DNA that contains a code (instructions) to produce a protein that performs a specific function in the organism.

Recombinant proteins

They are proteins artificially produced from cloned genes. The gene is a segment of a DNA molecule (deoxyribonucleic acid), responsible for genetically inherited characteristics.

Each gene is made up of a specific sequence of DNA that contains a code (instructions) to produce a protein that performs a specific function in the organism.

In all simulations, the protein maintained its characteristics and antimicrobial action. During the tests, the researchers were also able to define the minimum inhibitory concentration for controlling the scalding of sugarcane leaves.

The medicine that comes from the bacteria of the plant itself

The bacterium Gluconacetobacter diazotrophicus it was isolated for the first time in 1988 by researchers from Embrapa Agrobiologia. Present in crops such as sugar cane, sweet potatoes, pineapple and elephant grass, it is essential for the growth of these plant species, as it is one of the main responsible for the process of biological nitrogen fixation, in which the chemical element is removed from the atmosphere and transferred to plants.

The bacteria also produces plant hormones that promote an increase in the area of ​​the root system and, consequently, increase the absorption capacity of some essential nutrients from the soil.

Studies involving molecular genetics with the G.diazotrophicus began in the 1990s. However, the complete sequencing of the bacteria's genome occurred in the first decade of the XNUMXst century and was carried out by a multidisciplinary team of Brazilian scientists from different institutions, including Embrapa Agrobiologia. With sequencing, it was possible to identify genes with agrobiotechnological potential and arrive at Gluconacin.

Leaf scald

caused by bacteria Xanthomonas albilineans, the disease presents three basic types of symptoms that can make identification difficult:

• Latency: no external symptoms are observed. Internally, in mature culms, there is a change in the color of the vessels that resembles that which occurs in plants with rickets;

• Chronic symptom: This is the classic scald system, made up of longitudinal white streaks, of variable width, that extend across the entire leaf blade and may descend through the sheath. The beginning of the budding of basal buds in mature culms is often observed;

• Acute symptom: It only occurs under conditions that are extremely favorable to the disease and in susceptible varieties. The burning of leaves, intense lateral sprouting starting from the base to the apex and the large number of dead canes characterize this phase.

The bacteria spread through contaminated seedlings, cutting instruments and remnants of previous crops.