Lucas Nascimento de Almeida

Sclerotium rot, caused by Agroathelia rolfsii, is one of the main soil-borne diseases that limit tomato production. This study evaluates the efficacy of Amazonian Trichoderma species in controlling Sclerotium rot and stimulating plant development under field conditions in Manaus, Brazil. We used six Trichoderma isolates based on their previously evaluated performance under greenhouse conditions. The incidence of Sclerotium rot, tomato fruit production, and functional attributes of the isolates were evaluated. The isolates reduced the incidence of Sclerotium rot by up to 75 percentage points and also increased fruit production. T. rugulosum showed the best performance as it significantly reduced the incidence of Sclerotium rot and improved fruit yield. Although no differences were found in biomass allocation to plant organs, T. endophyticum, T. agriamazonicum, and T. asperelloides showed production of indolic compounds in vitro. The results highlight the potential of Amazonian Trichoderma isolates as biofungicides for use in sustainable tomato cultivation. In addition, we demonstrated the potential of Amazonian Trichoderma species both to reduce the incidence of Sclerotium rot and to increase fruit production. By reducing the use of synthetic agrochemicals, the use of Trichoderma promotes healthier and more sustainable agricultural practices.

Sclerotium rot, caused by Agroathelia rolfsii, is one of the main soilborne diseases that limit plant growth and tomato yield. This study evaluated the efficacy of Amazonian Trichoderma species to control sclerotium rot, and promote plant growth under field conditions, in Manaus, Brazil. We used six species (isolates) of Trichoderma based on their previously assessed performance in field trials. The incidence of sclerotium rot, tomato fruit yield and the production of indoleacetic acid (IAA) and siderophores were evaluated. The isolates reduced the incidence of sclerotium rot by up to 75% and also increased fruit yield. T. rugulosum had the best performance, as it greatly reduced sclerotium rot incidence and improved fruit yield. Although no differences were found in biomass allocation to plant organs, T. endophyticum, T. agriamazonicum, and T. asperelloides showed high production of IAA. The results highlight the potential of Amazonian Trichoderma isolates as bio fungicides to be used in sustainable cultivation of tomato. Furthermore, we show the potential of Amazonian species of Trichoderma to both reduce the incidence of sclerotium rot, and to increase the production of bioactive compounds that stimulate plant growth. By reducing the use of synthetic agrochemicals, the use of Trichoderma promotes healthier and more sustainable agricultural practices.

Guarana [Paullinia cupana var. sorbilis (Mart.) Ducke] is a species of great economic and social important in Brazil, as it is the only commercial guarana producer in the world. The vegetative propagation method indicated for the culture is stem cuttings, which aims at productivity, tolerance, and uniformity of clonal cultivars, because reproduction by seeds has slow germination and high genetic variability, which in traditional varieties is an undesirable factor. Genetic factors can interfere with the rooting capacity of the crop. Studies seek alternatives that can improve this condition and enhance the production system. Use of growth regulators, microorganisms that promote plant growth, variation of substrates and fertilization, have been strategies used. Preliminary tests on the rate of stem rooting and seed germination with the use of exogenous phytohormone did not demonstrate in relation to the non-application of these inducers. The use of rhizobacteria, which presents itself as a promising activity in many cultures, has not yet been demonstrated in the culture of guarana. On the other hand, the influence of different substrates on rooting has already shown consistent results as a function of rooting rate. Fertilizing the mother plants as recommended by the production system for the crop has proven to be an efficient procedure. There are still few studies aimed at improving the spread of guarana, demonstrating that new protocols need to be explored, or that the protocols already used are reviewed from another perspective.

Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.