Brazilian researchers identify genes in sorghum that potentiate tolerance to aluminum

Researchers from the Brazilian Agricultural Research Corporation (Embrapa), in partnership with the Federal University of Viçosa (UFV), identified two new genes that potentiate plant tolerance to aluminum in sorghum.

The Brazilian discovery was revealed in an article published in the Proceedings of the National Academy of Sciences of the USA (PNAS) of the United States Academy of Sciences, titled, "Repeat variants for the SbMATE transporter protect sorghum roots from aluminum toxicity by transcriptional interplay in cis and trans”.

The two genes identified increase the effect of another gene, known as “SbMATE,” which causes plants to tolerate toxic aluminum in acidic soils.

These two isolated genes, called transcription factors, sense the presence of aluminum, and their effects increase when tolerance is required. In the absence of the chemical, the effects of the two genes are reduced, which also decreases the action of the SbMATE gene.

"We believe that this is the result of an evolutionary mechanism to avoid loss of energy in the form of organic carbon, when there are no aluminum stresses," said Embrapa Milho and Sorgo (MG) investigator Jurandir Vieira de Magalhães, who led the research, in partnership with Professor Elizabeth Fontes from the Federal University of Viçosa (UFV).

This result is especially important, as the soil of the Brazilian Cerrado is acidic, due to the presence of aluminum, which damages the root system of plants and reduces crop productivity. As well as Brazil, this problem is also common in tropical regions, such as in Africa and Asia.

Greater drought tolerance

The tolerance of crops to aluminum is closely related to the plant's ability to tolerate drought, because when the roots of crops are damaged by aluminum, they do not go deep into the soil. A damaged root system reduces the absorption capacity of water and nutrients, which causes loss of crop productivity in. This problem is common during summer periods, which occur frequently in the Brazilian Cerrado region.

"Embrapa also conducted the research to identify drought-tolerant cultivars. For over 20 years, the first aluminium-tolerant crops were identified by researchers Robert Schaffert when improving sorghum, and Elton Gama and Ricardo Magnavacca in the breeding of corn," Magalhães said.

Advancement in the breeding process

The intention of the research was to create a technology that will make a molecular diagnosis of tolerance to aluminium, even in a germplasm bank with hundreds or even thousands of accesses, to facilitate the work of breeders in identifying tolerance.

This research can also be used in cross-breeding programs, to produce aluminium-tolerant cultivars. "The study will create a genetic information system. Now, with knowledge of these genes and by developing new molecular tests, we can help breeders cross-breed, with greater precision, aluminium-tolerant sorghum cultivars for acidic soils," Magalhães added.

For Magalhães, two outcomes of the research stand out. "Now, considering the new genes, we can more accurately predict if a genotype is going to be tolerant or sensitive to aluminium. And we can also maximize the efficiency of the SbMATE gene, to increase the yield of sorghum grown on acidic soils," he said in conclusion.