First report of Colletotrichum siamense causing anthracnose in Oenocarpus bacaba in Brazil.

Bacaba (Oenocarpus bacaba Mart.) is a native palm tree from Brazilian Amazon and Cerrado biomes. This tree produces a small, rounded fruit with dark skin and approximately 1.5 mm thick pulp, extensively utilized for palm heart extraction, juices, and jellies (De Cól et al. 2021). However, several diseases can adversely impact fruit yield and quality. During the 2021 growing season, anthracnose symptoms were observed in Bacaba fruits, with a disease incidence of 58% in fruits collected from the Abreulândia (9°37'15″ S, 49°9'3″ W) and Gurupi (12°25'46" S; 49°16'42" W) municipalities in Tocantins state, Brazil. A total of 198 fruits exhibiting anthracnose symptoms, characterized by deep necrotic spots, were collected. In the laboratory, symptomatic fruits had their external surfaces sterilized for 30 seconds in 70% ethanol, 1 min in 1.5% NaOCl, and then rinsed with sterile distilled water. Sterilized pieces of the fruit tissue were transferred to PDA medium and incubated for 7 days at 28 ºC with a 12 h photoperiod. After this period, two isolates were obtained from the colonies and were identified both macroscopically and microscopically as Colletotrichum sp. The colonies grown at PDA showed a white to grey cottony mycelia, with straight and fusiform conidia, ranging from 14.0 to 21.0 (mean value of 15.8 ± 1.8) µm in length and 4.0 to 7.0 (mean value of 5.5 ± 0.7) µm in width, (n = 50). For species identification, the intergenic spacer between DNA lyase, mating-type locus MAT1-2-1 (APN2/MAT-IGS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutamine synthetase (GS), and ß-tubulin (TUB) loci were amplified and sequenced. Resulting sequences were deposited in GenBank (OR333843, OR333844, OR333845 and OR333846). BLAST analysis of the partial APN2/MAT-IGS (99%), GAPDH (99,48%), GS (99,32%) and TUB (99,48%) sequences showed highly similarity to C. siamense isolates (IIFT223 and CBS130147). Maximum likelihood multilocus analysis placed the isolate UFTC16 within the C. siamense clade with 98% bootstrap support, clearly assigning the isolate to this species. Morphological features were consistent with the description of C. siamense (Prihastuti et al., 2009). Inoculation of Bacaba fruits and seedlings was conducted to confirm pathogenicity. The surface of uninjured Bacaba fruits was inoculated with two drops (20 µL) of conidial suspension (106 conidia mL-1). The same methodology was adopted to placed healthy leaves of 35-day-old seedlings grown in plastic tubes. Two drops of sterile distilled water were inoculated on nonwounded healthy fruits and seedlings as a negative control. The fruits and seedlings were incubated for five days in a controlled chamber at 28 °C, 70-80% humidity and a "12-h photoperiod". The experiment was conducted with five replicates (five fruits and five seedlings inoculated per isolate) and repeated once. Typical symptoms of anthracnose were observed in the fruits and leaves of Bacaba seedlings five days after inoculation. No symptoms were observed in the negative control. The pathogen was reisolated from symptomatic fruits and leaves, showing similar morphological characteristics as the original isolate, fulfilling Koch's postulates. The identification of C. siamense as the causal agent of Bacaba anthracnose helps in the diagnosis and disease control strategies of the disease. Colletotrichum siamense is a cosmopolitan species and easily found in cultivated and non-cultivated species (Batista et al. 2023). However, to the best of our knowledge, this is the first report of C. siamense causing anthracnose on Bacaba.

Pseudomonas aeruginosa and Bacillus cereus Isolated from Brazilian Cerrado Soil Act as Phosphate-Solubilizing Bacteria.

The phosphate-solubilizing microorganism is essential for soil quality and plant development and can serve as an alternative to reduce such Brazilian needs for importing phosphate overseas. Here, we isolated and selected bacteria from Brazilian Cerrado soils capable of solubilize phosphate. We obtained 53 bacteria isolates, of which 23 could solubilize phosphate at a pH of 7.0, 17 could solubilize phosphate at a pH of 6.0, and 8 could solubilize at a pH of 5.5. Using 16S rRNA gene sequences, we identified nine bacteria species clustered in four groups: Bacillus sp., Pseudomonas sp., Priestia sp., and Klebsiella sp. Our results revealed that the UFT01 (P. aeruginosa) and UFT42 (B. cereus) isolates exhibited the best phosphate solubilization performance at all tested pH values. We further recorded higher levels of solubilization and phosphate availability six days after the soil inoculation with P. aeruginosa, and enzymatic analysis of the soil samples revealed that the P. aeruginosa-inoculated samples resulted in four-fold higher enzymatic activities when compared to non-inoculated soils. The B. cereus soil inoculation increased ß-glucosidase activities and resulted in reduced the activities of arylsulfatase. Altogether, our findings demonstrated that P. aeruginosa and B. cereus isolated from Cerrado soils showed high phosphate solubilization potential.

Efeito da adubação orgânica na produção de biomassa e bioatividade do óleo essencial do capim citronela / Effect of organic fertilization on biomass production and bioactivity of citronella grass essential oil

RESUMO Este trabalho teve como objetivo analisar o efeito da adubação orgânica no crescimento e na produção de biomassa do capim citronela (Cymbopogon nardus), assim como avaliar o efeito do óleo essencial do capim citronela e do composto citronelal na inibição do crescimento micelial do fungo Didymella bryoniae. Na avaliação do efeito da adubação orgânica no crescimento do capim citronela, foi utilizado o delineamento em blocos casualizados em esquema de parcela subdividida. As parcelas foram constituídas por quatro doses de adubação orgânica de esterco bovino curtido (0, 3, 6 e 9 Kg cova-1) e as subparcelas por cinco épocas de amostragem (80, 108, 136, 164, 192 dias após o transplante). Para avaliar a fungitoxicidade do óleo essencial do capim citronela na inibição do crescimento micelial do fungo D. bryoniae, foi instalado no delineamento inteiramente casualizado em esquema fatorial. Os tratamentos foram compostos por cinco alíquotas (5, 10, 15, 20 e 25 µL) do óleo essencial do capim citronela e do composto citronelal, em cinco épocas de amostragem. Verificou-se no tratamento de adubação orgânica de 9 Kg cova-1 os maiores valores em todas as variáveis analisadas na última época de amostragem. Constatou-se maior efeito de inibição do crescimento micelial utilizando o citronelal em comparação com o óleo essencial. Na alíquota de 25 µL do citronelal ocorreu inibição total do crescimento micelial do fungo D. bryoniae.

Midgut GPI-anchored proteins with alkaline phosphatase activity from the cotton boll weevil (Anthonomus grandis) are putative receptors for the Cry1B protein of Bacillus thuringiensis.

Cry toxins from Bacillus thuringiensis (Bt) are used for insect control. They interact with specific receptors located on the host cell surface and are activated by host proteases following receptor binding resulting in midgut epithelial cells lysis. In this work we had cloned, sequenced and expressed a cry1Ba toxin gene from the B thuringiensis S601 strain which was previously shown to be toxic to Anthonomus grandis, a cotton pest. The Cry1Ba6 protein expressed in an acrystaliferous B. thuringiensis strain was toxic to A. grandis in bioassays. The binding of Cry1Ba6 toxin to proteins located in the midgut brush border membrane of A. grandis was analyzed and we found that Cry1Ba6 binds to two proteins (62 and 65kDa) that showed alkaline phosphatase (ALP) activity. This work is the first report that shows the localization of Cry toxin receptors in the midgut cells of A. grandis.