The Agricultural Research Institute (INIA) La Platina seeks to detect, through a rapid technique, the presence of Agrobacterium species, which cause the disease known as Crown Gall, in order to provide new options to nurserymen and farmers when reproducing fruit trees, avoiding their dissemination and asymptomatic plants.
This bacterial disease, with a wide territorial distribution in temperate climates, affects woody plants throughout Chile, and is very common in fruit trees such as walnut, grape, raspberry, cherry, hazelnut and blueberry, among others. It is characterized by the presence of tumors or galls of different sizes, observed mainly in the root and neck, at the soil line, as well as aerial tumors in some hosts.
Infected plants show reduced development, smaller leaves, weakness and susceptibility to other pathogens, often losing their productive capacity when they are affected.
The spread of this pathogen occurs mainly in nurseries, from mother plants and infected soils, moving through irrigation water. In the presence of a wound in the neck area, this bacteria is attracted by compounds released from the plant, infecting and inducing the formation of tumors.
In the absence of hosts, these bacteria can remain in the soil for long periods waiting for ideal conditions to infect, which occurs when grafting tools are used or through damage caused by insects, nematodes or natural wounds.
For the species of Agrobacterium In order to produce the disease, they must contain the virulence gene and to detect this condition, laboratory culture studies are currently carried out to obtain colonies from plants with galls, to which the PCR technique is applied. However, in laboratory analysis it has been observed that even in symptomatic plants false negatives have occurred, which implies resorting to pathogenicity tests, lengthening the detection and diagnosis process.
For Danae Riquelme, Plant Pathologist at INIA La Platina, there is concern about the scientific evidence that shows the rapid evolution of these bacteria, reducing the effectiveness of traditional detection techniques. “For this reason, we have decided to include a new type of molecular analysis, through the Isothermal Amplification of Nucleic Acids (LAMP) technique, which has the advantage of being applied in the field, without the need for sophisticated equipment or qualified personnel. To make this possible, we are studying the genome of the main species of Agrobacterium that are present in Chile, for a highly sensitive detection, which would determine even if a plant that appears healthy could develop the disease in the future,” he pointed out.
The central idea of the study being carried out in the INIA La Platina Phytopathology Laboratory, in collaboration with the Phytovirology Laboratory of the University of Chile, is to directly observe, from the tissues of asymptomatic and symptomatic plants, the presence of the bacteria, in a fast and effective way, which can even be applied in nurseries, which would allow stopping the spread of species of Agrobacterium, before it manifests itself in symptomatic tumors, at which time its system and the soil have already become a reservoir for the pathogen, contributing to preventive control.
About INIA
The Agricultural Research Institute (INIA) is the main institution for agri-food research, development and innovation in Chile. Linked to the Ministry of Agriculture, it has a national presence and a team of more than 1,000 highly qualified people. It executes an average of 400 projects per year around 5 strategic areas: Climate Change, Sustainability, Foods of the Future, Emerging Technologies, and Outreach and Capacity Building. These initiatives contribute to the sustainable agri-food development of the country, creating value and proposing innovative solutions to farmers, strategic partners and society, generating a social return that varies between 15% and 25%, for each peso invested in each of its projects.
