Genomic signatures and insights into host niche adaptation of the entomopathogenic fungus Metarhizium humberi.

The genus Metarhizium is composed of species used in biological control programs of agricultural pests worldwide. This genus includes common fungal pathogen of many insects and mites and endophytes that can increase plant growth. Metarhizium humberi was recently described as a new species. This species is highly virulent against some insect pests and promotes growth in sugarcane, strawberry, and soybean crops. In this study, we sequenced the genome of M. humberi, isolate ESALQ1638, and performed a functional analysis to determine its genomic signatures and highlight the genes and biological processes associated with its lifestyle. The genome annotation predicted 10633 genes in M. humberi, of which 92.0% are assigned putative functions, and ∼17% of the genome was annotated as repetitive sequences. We found that 18.5% of the M. humberi genome is similar to experimentally validated proteins associated with pathogen-host interaction. Compared to the genomes of eight Metarhizium species, the M. humberi ESALQ1638 genome revealed some unique traits that stood out, e.g., more genes functionally annotated as polyketide synthases (PKSs), overrepresended GO-terms associated to transport of ions, organic and amino acid, a higher percentage of repetitive elements, and higher levels of RIP-induced point mutations. The M. humberi genome will serve as a resource for promoting studies on genome structure and evolution that can contribute to research on biological control and plant biostimulation. Thus, the genomic data supported the broad host range of this species within the generalist PARB clade and suggested that M. humberi ESALQ1638 might be particularly good at producing secondary metabolites and might be more efficient in transporting amino acids and organic compounds.

Monitoring of the field application of Metarhizium anisopliae in Brazil revealed high molecular diversity of Metarhizium spp in insects, soil and sugarcane roots.

The use of Metarhizium against sugarcane spittlebugs in Brazil is one of the most successful and long lasting biological control programs using entomopathogenic fungus in the world. However, studies to monitor the fate of this fungus on the sugarcane agroecosystem are rare, especially with respect to its persistence, efficacy in pest control and impact on the local populations of Metarhizium. The present study aimed at documenting the efficacy and persistence of M. anisopliae strain ESALQ1604 in a sugarcane field by using microsatellite molecular markers. The species diversity of Metarhizium was characterized in insects, soil and sugarcane roots in a sprayed and an unsprayed plot. Although the infection rates were not very high (≤ 50%), the applied strain was recovered from spittlebugs after 7, 30 and 60 days' post-application, but accounted for only 50%, 50% and 70.5% of all insects killed by M. anisopliae, respectively. All haplotypes from spittlebug were associated with a single subclade of M. anisopliae. The highest haplotype diversity was found in soil (h = 0.989) and in the smallest in spittlebug (h = 0.779). Metarhizium robertsii, M. anisopliae, M. brunneum; one taxonomically unassigned lineage was found in soil and only M. brunneum and M. anisopliae were isolated from roots. This study revealed the great diversity of Metarhizium spp. in the sugarcane agroecosystem and the importance of the local population of M. anisopliae on spittlebugs management.

Control of Chrysodeixis includens (Lepidoptera: Noctuidae) using Chin-IA (I-A) isolate as integrate component of management in soybean crops / Controle de Chrysodeixis includens (Lepidoptera: Noctuidae) usando o isolado Chin-IA (I-A) como componente do manejo integrado da cultura da soja

Chrysodeixis includens is an important pest of soybean crop who has gained more visibility in the Brazilian Cerrado due to damage caused in this region. Foliar consumption, feeding period and mortality level of soybean loopers in laboratory, as well as their control in the field conditions, were evaluated after application of the ChinNPV virus in soybean plants. In the laboratory, were tested six concentrations of isolate Chin-IA (I-A) (1 × 1011, 2 × 1011, 4 × 1011, 6 × 1011, 8 × 1011 and 10 × 1011 PIB ha-1), one dose of methomyl chemical insecticide (172 g ai ha-1) and distilled water (control). The field experiment was carried out in the 2016/2017 season using the same cultivar and laboratory treatments, except for the lowest virus concentration. The population density of small and large larvae was evaluated before and at 5, 8 and 12 days after application (DAA) of the treatments in soybean plants. All concentrations of the isolate Chin-IA (I-A) have reduced the soybean loopers consumption and their feeding period, showing 100% of mortality after 3 ­ 4 days without differing from treatment with the chemical insecticide. After eight DAA of virus in the field, the population density of small and large larvae was reduced, providing satisfactory levels of control. These results showed the evident potential of ChinNPV in the reduction of defoliation power and maintenance the soybean loopers population under of control level, and thus may be used as complementary method in the integrated management of this pest in soybean crops.(AU)

Chrysodeixis includens é uma importante praga da cultura da soja que tem ganhado maior visibilidade na região do Cerrado brasileiro em razão do dano causado. Consumo foliar, período de alimentação e mortalidade de lagartas falsa-medideira foram avaliados em laboratório, assim como seu controle em condições de campo, após a aplicação do vírus ChinNPV em plantas de soja. Em laboratório, foram testadas seis concentrações do isolado Chin-IA (I-A) (1 × 1011, 2 × 1011, 4 × 1011, 6 × 1011, 8 × 1011 e 10 × 1011 CIP ha-1), uma dose do inseticida químico metomil (172 g i.a ha-1) e água destilada (controle). O ensaio de campo foi realizado na safra 2016/2017 utilizando o mesmo cultivar e tratamentos do ensaio em laboratório, exceto para a menor concentração do vírus. A densidade populacional de lagartas pequenas e grandes foi avaliada antes (pré-contagem) e 5, 8 e 12 dias após a aplicação dos tratamentos nas plantas de soja. Todas as concentrações do isolado Chin-IA (I-A) reduziram o consumo e o período de alimentação das lagartas falsa-medideira, mostrando 100% de mortalidade entre 3 ­ 4 dias, sem diferir do tratamento com o inseticida químico. Depois de oito dias após a aplicação do vírus no campo, a densidade populacional de lagartas pequenas e grandes foi reduzida, promovendo um controle satisfatório. Esses resultados mostram o evidente potencial de ChinNPV na redução do poder de desfolha, mantendo a população das lagartas falsa-medideira abaixo do nível de controle, e indicam o seu uso como um método complementar no manejo integrado dessa praga em culturas de soja.(AU)