Esalq – This USP study evaluated a large number of cultivars and induced mutations in plants to select for tomato resistance to cadmium

A study to identify tomato plant tolerance to cadmium contamination

August 22, 2012

By Fábio de Castro

Agência FAPESP – A study carried outwas conducted at the Universidade de São Paulo (USP) to identified identify a tomato plant with high potential for tolerance to cadmium contamination by the heavy metal cadmium.

Professor Ricardo Antunes de Azevedo The advised and coordinated the doctoral thesis defended byof Fernando Angelo Piotto and the USP Genetics and Biochemical Laboratory in the Luiz de Queiroz Graduate School of Agriculture (Esalq) was advised by professor Ricardo Antunes as ade Azevedo and is part of the Thematic Project titled “Oxidative Stress Induced by metals—new approaches”, coordinated by Azevedo.

According to Azevedo, the The aim of this work consisted of the evaluation ofstudy was to characterize a large number of tomato cultivars and the analysis analyze of genetic variability induced by through mutagenesis, which is —an approach that consists ofrequires the introduction of mutations in DNA sequences by the actions ofusing chemical or physical agents.

The professor said that theThe results of this study contributed to the understandingprovide insight into of the genetic, physiological and biochemical changes brought aboutthat occur in the plants due to the exposureexposed to heavy metals. This understanding could lead to advances in the development of new means ofnovel contamination controls.

“Our laboratory has a bank of genetic material with cultivars of tomato plants from all over the world. In addition to analyzing these varieties, Piotto used mutagenesis to obtain mutant plants with enhanced tolerance to cadmium stress. This study identified at least one cultivar with enhanced tolerance and sensitivity to cadmium and a mutant plant that also showed enhanced tolerance for this metal,” Azevedo told Agência FAPESP.

FAPESP has approved funding for the Piotto’s Post-Doctoral work of Piotto to continue the study on determiningcharacterization of the parameters of cadmium tolerance in tomato plants.

“The Thematic Project involves studies on plant responses to the environmental stress caused by heavy metals such as cadmium and nickel. Plants commonly grow in environments contaminated with these metals, either due to the proximity to mining activities or to polluted water in rivers used for irrigation. This contamination could seriously impact plant development and exert a strong toxic effect on animal and human cells,” explained Azevedo.

As a genetically well-characterized fruit and a species of high economic importance, Tomatoes tomatoes are important models for this type of studytolerance studies because it is a genetically well-characterized fruit and a species of high economic importance.

“It is important to identify species tolerant to heavy metals for the development of a cultivar  that doesn’t absorb these contaminating agents into the parts of the plant that are consumed by humans and animals,” said Azevedo.

On the other handHowever, the researcher said that it is important to study the cultivars that are very sensitive to the heavy metals because they becometo generate important models for studies allowing us to understandcharacterizing the mechanisms that lead to contamination stress.

“Identifying these cultivars may also be useful for phytoremediation applications–--the use of plants for the recuperation of polluted areas. We can use plants that hyper-accumulate heavy metals to clean the soil in an area contaminated by these agents,” he saidstated Azevedo.

The cadmium-tolerant cultivar resulting fromgenerated using mutagenesis will now be genetically characterized and then studiedsubjected to physiologically and biochemical studiesly. “If we distinguish the cultivas as actually possessing this high tolerance, we will include the cultivar into our line of studies on the mechanisms, metabolic routes and genes involved in this tolerance,” said Azevedo.

While the methodology methodologies for mutagenesis isare quite dispersediverse, Azevedo said thatthe results of this the study helped will establishestablish  and optimize all the parameters and optimization of the procedures for applying the this approach in the specific case ofto study tomatoes.