Ionomic Profile of Rice Seedlings after Foliar Application of Selenium Nanoparticles.

Nanotechnology has been increasingly used in plant sciences, with engineered nanoparticles showing promising results as fertilizers or pesticides. The present study compared the effects in the foliar application of Se nanoparticles (SeNPs) or sodium selenite-Se(IV) on rice seedlings. The degree of plant growth, photosynthetic pigment content, and concentrations of Se, Na, Mg, K, Ca, Mn, Co, Cu, Zn, As, Cd, and Pb were evaluated. The results showed that the application of SeNPs at high concentrations (5 mg L-1), as well as the application of Se(IV), inhibited plant growth and increased the root concentrations of As and Pb. The application of SeNPs at 0.5 mg L-1 significantly increased Se accumulation in the aerial part from 0.161 ± 0.028 mg kg-1 to 0.836 ± 0.097 mg kg-1 without influencing physiological, chemical, or biochemical parameters. When applied to leaves, SeNPs tended to remain in the aerial part, while the application of Se(IV) caused a higher Se translocation from the shoots to the roots. This study provides useful information concerning the uptake, accumulation, and translocation of different Se formulations in rice seedlings and their effect on plant ionomic profiles, thus showing that the foliar application of SeNPs at low concentrations can be an effective and safe alternative for rice biofortification.

Selenium mitigates the loss of nutritional quality in rice grown at an elevated concentration of carbon dioxide.

Atmospheric CO2 enrichment has the potential to improve rice (Oryza sativa L.) yield, but it may also reduce grain nutritional quality, by reducing mineral and protein concentrations. Selenium (Se) fertilization may improve rice grain nutritional composition, but it is not known if this response extends to plants grown in elevated carbon dioxide concentration (eCO2). We conducted experiments to identify the impacts of Se fertilization on yield and quality of rice grains in response to eCO2. The effect of the Se treatment was not significant for the grain yield within each CO2 condition. However, the reduction in macronutrients and micronutrients under eCO2 was mitigated in grains of plants fertilized with Se. Fertilization with Se increased the concentration of Se in roots, flag leaves, and grains independently of atmospheric CO2 concentrations. Elevation of the transcripts of ion transport-related genes could, at least partially, explain the positive relationship between mineral concentrations and grain mass resulting from Se fertilization under eCO2. Treatment with Se also increased the accumulation of total protein in grains under eCO2. Overall, our results revealed that Se fertilization represents a potential asset to maintain rice grain nutritional quality in a future with rising atmospheric CO2 concentration.

Silicon applications in rice plants alter the stylet probing behaviors of Glyphepomis spinosa (Hemiptera: Pentatomidae).

The stink bug Glyphepomis spinosa Campos & Grazia (Hemiptera: Pentatomidae) is a potential rice pest in Brazil. This study evaluates the interaction between silicon sources and 3 rice cultivars (BRS Esmeralda, Canela de Ferro, and IRGA 417) and examines how increasing silicon levels affect the stylet probing behavior of G. spinosa. The experiment was set up in a completely randomized design with a 3 × 3 factorial scheme (silicon sources: calcium silicate, potassium silicate, a control, and 3 rice cultivars). Fertilizing rice plants with Si altered the probing behavior of the stink bug G. spinosa. The cultivar interaction by Si source was significant in a few variables. This was evidenced by longer periods without ingestion, prolonged time to the first stylet probe (initial probing), and less time spent in cellular maceration. This result supports the use of electropenetrography as a tool to evaluate resistance inducers in plants.

The Potential of Crude and Partially Purified Black Rice Bran Extracts Obtained by Ultrasound-Assisted Extraction: Anti-Glycemic, Cytotoxicity, Cytoprotective, and Antitumoral Effects.

Recovering anthocyanins from black rice bran is a way of valuing this byproduct, by obtaining an extract with biological potential. The objective of this study was to recover anthocyanins using ultrasound-assisted extraction. Some of the extract was partially purified, and both (crude and partially purified) extracts were evaluated for their anthocyanin content, antioxidant activity, antidiabetic and antitumoral activities, cytotoxicity, and oxidative stress. An increase in the laboratory scale was also achieved, making possible to increase the extraction volume up to 20 times without significantly changing the content of anthocyanins (1.85 mg C3G/g DW). It was found that the purified sample presented a 4.2 times higher value of total anthocyanins compared to the crude sample. The best IC50 values for the purified sample were verified by DPPH and ABTS (0.76 and 0.33 mg/mL). The best results for antidiabetic activity were obtained for the partially purified sample: 0.82 µM C3G for α-glucosidase and 12.5 µM C3G for α-amylase. The extracts demonstrated protection (~70%) when subjected to the oxidative stress of L929 cells. An antitumoral effect of 25-30% for both extracts was found in A459 cells. The crude and partially purified extracts of black rice have antidiabetic and anticancer effects and more studies are needed to explore their potential.

Gene regulatory networks underlying sulfate deficiency responses in plants.

Sulfur (S) is an essential macronutrient for plants and its availability in soils is an important determinant for growth and development. Current regulatory policies aimed at reducing industrial S emissions together with changes in agronomical practices have led to a decline in S contents in soils worldwide. Deficiency of sulfate-the primary form of S accessible to plants in soil-has adverse effects on both crop yield and nutritional quality. Hence, recent research has increasingly focused on unraveling the molecular mechanisms through which plants detect and adapt to a limiting supply of sulfate. A significant part of these studies involves the use of omics technologies and has generated comprehensive catalogs of sulfate deficiency-responsive genes and processes, principally in Arabidopsis together with a few studies centering on crop species such as wheat, rice, or members of the Brassica genus. Although we know that sulfate deficiency elicits an important reprogramming of the transcriptome, the transcriptional regulators orchestrating this response are not yet well understood. In this review, we summarize our current knowledge of gene expression responses to sulfate deficiency and recent efforts towards the identification of the transcription factors that are involved in controlling these responses. We further compare the transcriptional response and putative regulators between Arabidopsis and two important crop species, rice and tomato, to gain insights into common mechanisms of the response to sulfate deficiency.

Osmotin1 is involved in rice resistance to Schizotetranychus oryzae (Acari: Tetranychidae) infestation.

BACKGROUND: Rice is one of the most consumed cereals in the world. Productivity losses are caused by different biotic stresses. One of the most common is the phytophagous mite Schizotetranychus oryzae Rossi de Simons (Acari: Tetranychidae), which inhibits plant development and seed production. The identification of plant defense proteins is important for a better understanding of the mite-plant interaction. We previously detected a high expression of Osmotin1 protein in mite-resistant rice cultivars, under infested conditions, suggesting it could be involved in plant defense against mite attack. We therefore aimed to evaluate the responses of three rice lines overexpressing Osmotin1 (OSM1-OE) and three lines lacking the Osmotin1 gene (osm1-ko) to mite attack. RESULTS: The numbers of individuals (adults, immature stages, and eggs) were significantly lower in OSM1-OE lines than those in wild-type (WT) plants. On the other hand, the osm1-ko lines showed larger numbers of mites per leaf than WT plants. When plants reached the full maturity stage, two out of the three infested OSM1-OE lines presented lower plant height than WT, while the three osm1-ko lines (infested or not) presented higher plant height than WT. The reduction in seed number caused by mite infestation was lower in OSM1-OE lines (12-19%) than in WT plants (34%), while osm1-ko lines presented higher reduction (24-54%) in seed number than WT plants (13%). CONCLUSION: These data suggest that Osmotin1 is involved in rice resistance to S. oryzae infestation. This is the first work showing increased plant resistance to herbivory overexpressing an Osmotin gene. © 2023 Society of Chemical Industry.

Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach / Introdução do gene resistente à ferragem da folha bacteriana (BLB), xa7 na variedade MARDI elite, MR219 por abordagem de backcrossing assistida por marcador (MABC)

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

New species of Hexacladia Ashmead (Hymenoptera: Encyrtidae), a parasitoid of Tibraca limbativentris Stål (Hemiptera: Pentatomidae)

ABSTRACT The rice stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is a significant pest of rice cultivation in Brazil and attacks plants during both vegetative and reproductive phases. Natural enemy surveys conducted in plantations located in Arari, Miranda do Norte, Matões do Norte, Santa Rita, and Viana (state of Maranhão, Brazil) led to the discovery of a new species of parasitoid, which is described in this study. Hexacladia lemosae Costa, Noyes & Machado sp. nov. (Hymenoptera: Encyrtidae) is the first species of its genus associated with T. limbativentris and develops as a gregarious endoparasitoid in adult stink bugs, occasionally in nymphs. The parasitoid emerges from the host while host is still alive.

Water footprint of irrigated rice in the state of Rio Grande do Sul, 2019/2020 crop.

Agricultural production is the practice that uses the most water on the planet, especially the irrigated agriculture, which represents a large part of this demand. As well as the quantitative issue, adequate quality is essential to meet the demands of the crop and its return to the water sources, in a way that does not cause damage to the environment. To measure this consumption, the expression "water footprint" emerged. The water footprint seeks to quantify the demand for water incorporated into products. This paper aims to determine the amount of water used to produce irrigated rice in six rice growing regions in the state of Rio Grande do Sul (RS), in the 2019/2020 crop. The mentioned regions are represented the municipalities of Uruguaiana (West Border), Dom Pedrito (Campanha), Santa Maria (Central Region), Camaquã (Internal Coastal Plain), Porto Alegre (External Coastal Plain), and Rio Grande (South Zone). Climate data from the analyzed regions, during the plant cycle, and productivity values in the crop in question were used. Values of 1187 m3 t-1 were found for WB, 1347 m3 t-1 for CA, 1058 m3 t-1 for CR, 783 m3 t-1 for ICP, 1115 m3 t-1 for ECP, and 1066 m3 t-1 for SZ. For the state of Rio Grande do Sul, an average water footprint was obtained in the 2019/2020 crop of 1093 m3 t-1.

Impairment in photosynthesis induced by CAT inhibition depends on the intensity of photorespiration and peroxisomal APX expression in rice.

We have previously shown that rice plants silenced for peroxisomal ascorbate peroxidase (OsAPX4-RNAi) display higher resilience to photosynthesis under oxidative stress and photorespiratory conditions. However, the redox mechanisms underlying that intriguing response remain unknown. Here, we tested the hypothesis that favorable effects triggered by peroxisomal APX deficiency on photosynthesis resilience under CAT inhibition are dependent on the intensity of photorespiration associated with the abundance of photosynthetic and redox proteins. Non-transformed (NT) and OsAPX4-RNAi silenced rice plants were grown under ambient (AC) or high CO2 (HC) conditions and subjected to 3-amino-1,2,4-triazole (3-AT)-mediated CAT activity inhibition. Photosynthetic measurements evidenced that OsAPX4-RNAi plants simultaneously exposed to CAT inhibition and HC lost the previously acquired advantage in photosynthesis resilience displayed under AC. Silenced plants exposed to environment photorespiration and CAT inhibition presented lower photorespiration as indicated by smaller Gly/Ser and Jo/Jc ratios and glycolate oxidase activity. Interestingly, when these silenced plants were exposed to HC and CAT-inhibition, they exhibited an inverse response compared to AC in terms of photorespiration indicators, associated with higher accumulation of proteins. Multivariate and correlation network analyses suggest that the proteomics changes induced by HC combined with CAT inhibition are substantially different between NT and OsAPX4-RNAi plants. Our results suggest that the intensity of photorespiration and peroxisomal APX-mediated redox signaling are tightly regulated under CAT inhibition induced oxidative stress, which can modulate the photosynthetic efficiency, possibly via a coordinated regulation of protein abundance and rearrangement, ultimately triggered by crosstalk involving H2O2 levels related to CAT and APX activities in peroxisomes.

Water Deficit at Vegetative Stage Induces Tolerance to High Temperature during Anthesis in Rice.

BACKGROUND: Crop yields have been affected by many different biotic and abiotic factors. Generally, plants experience more than one stress during their life cycle, and plants can tolerate multiple stresses and develop cross-tolerance. The expected rise in atmospheric CO2 concentration ([CO2]) can contribute to cross-tolerance. Priming is a strategy to increase yield or to maintain yield under stress conditions. Thus, our objective was to evaluate if priming the rice plants with water deficit during the vegetative stage can induce tolerance to heat stress at anthesis and to evaluate the contribution of e[CO2]. METHODS: The experiment was arranged in a completely randomized design in a factorial arrangement. Factor A consisted of the following treatments: water deficit at four-leaf stage (no-stress, and drought stress), heat at anthesis (normal temperature, high temperature), and priming with water deficit at four-leaf stage and heat stress at anthesis; and Factor B was two [CO2] treatments: a[CO2] = 400 ± 40 µmol mol-1 and e[CO2] = 700 ± 40 µmol mol-1. We assessed the effect of the treatments on plant growth, yield, biochemical, and transcriptome alterations. RESULTS: Although e[CO2] affected rice growth parameters, it did not affect the priming effect. Primed plants showed an increase in yield and number of panicles per plant. Primed plants showed upregulation of OsHSP16.9A, OsHSP70.1, and OsHSP70.6. These results showed induced cross-tolerance. CONCLUSIONS: Water deficit at the rice vegetative stage reduces the effect of heat stress at the reproductive stage. Water deficit at the vegetative stage can be used, after further testing in field conditions, to reduce the effect of heat stress during flowering in rice.

Yield and Technological Quality of Pirarucu Trimming Surimi According to the Number of Washing Cycles, Rice Flour Content, and Cooking Temperature.

This research aimed to optimize surimi production with innovative raw materials called pirarucu trimmings and broken rice grains, which are by-products from food industries. The effects of three independent variables (number of washing cycles, content, and cooking temperature of rice flour-RF) on surimi's physical, chemical, and technological qualities were investigated through a Box-Behnken design. The number of washing cycles affected yield (77-93%), moisture (55-67%), lipids (18-35%), protein (7.15-11.88%), whiteness (46.73-64.45), chroma (8.86-13.18), hue angle (80.79-93.12°), cohesiveness (0.40-0.61), springiness (0.51-0.99), and freeze stability after 4 weeks (85.16-96.53%). RF concentration affected moisture, lipids, cohesiveness, springiness, and freeze-thaw stability after 4 weeks. RF cooking temperature affected moisture, chroma, cohesiveness, and springiness. The optimal conditions for surimi production with high yield and overall quality were three washing cycles, 6% of RF, and RF cooking temperature at 85 °C. It reveals the promising potential of both by-products to be used as an ingredient in restructured products and contribute to improving agri-industry sustainability.

Screening bacterial isolates for biocontrol of sheath blight in rice plants.

Sheath blight (Rhizoctonia solani) causes significant yield losses in rice (Oryza sativa L.). Its sustainable management needs an efficient biocontrol agent. The objective was to screen bacterial isolates as an antagonist to R. solani and identify the most efficient ones as sheath blight suppressors under greenhouse conditions. Two assays (E1 and E2) were performed in a completely randomized design with three replications. E1 tested 21 bacterial isolates antagonists to R. solani in vitro. E2 was conducted under greenhouse conditions, with rice cultivar BRS Pampeira sown in plastic pots (7 kg) containing fertilized soil. Sixty old plants were inoculated with a segment of a toothpick containing fragments of R. solani, followed by spray inoculation of a bacterial suspension (108 CFU/mL). The severity of the disease was determined by calculating the relative lesion size formed on the colm. Isolates BRM32112 (Pseudomonas nitroreducens), BRM65929 (Priestia megaterium), and BRM65919 (Bacillus cereus) reduced R. solani colony radial growth by 92.8, 77.56, and 75.56%, respectively while BRM63523 (Serratia marcescens), BRM65923 and BRM65916 (P. megaterium) and BRM65919 (B. cereus) with 23.45, 23.37, 23.62, and 20.17 cm, respectively were effective at suppressing sheath blight in greenhouse, indicating their potential as a biofungicide for sheath blight suppression.

Resposta do arroz irrigado a herbicidas em função do sombreamento e da inundação do solo / Paddy rice response to herbicides due to shadowing and soil flooding

A existência de uma ampla diversidade de plantas daninhas faz com que seja necessário a utilização de manejo adequado, a fim de não comprometer a produtividade da cultura do arroz irrigado. Em anos onde há ocorrência de El Niño, a saturação do solo é favorecida e a nebulosidade frequente pode afetar diretamente a eficiência de controle das plantas daninhas e/ou aumentar a fitotoxicidade a cultura após a aplicação dos herbicidas. Deste modo, o objetivo deste trabalho foi avaliar a resposta do arroz irrigado aherbicidas em função do sombreamento e da inundação do solo. Para isto utilizaram-se dois regimes de saturação do solo após a aplicação dos herbicidas (sem ou com inundação do solo) e a exposição das plantas a duas condições de luminosidade, desde a emergência até a aplicação dos herbicidas (sem ou com sombreamento) e quatro tratamentos herbicidas: 1) testemunha sem herbicida, 2) [imazapyr + imazapic], 3) [imazapyr + imazapic] + saflufenacil e 4) [imazapyr +imazapic] + carfentrazone-ethyl. As variáveis avaliadas foram fitotoxicidade, teor de clorofila, altura de plantas e massa seca da parte aérea. Os herbicidas causaram fitotoxicidade nicial, entretanto houve a recuperação da culturaao longo das avaliações. O crescimentodo arroz irrigado, cultivar SCS121 CL, foi afetado pelos herbicidas, principalmente pelas misturas de [imazapyr + imazapic] + saflufenacil ou carfentrazone-ethyl. A inundação do solo e o sombreamento pouco influenciaram a seletividade dos tratamentos herbicidas para o arroz irrigado.(AU)

A wide weed diversity requires efficient weed management to avoid weed interference and decrease grain yield. In season that El Niño is prevalent, the soil flooding is usually in paddy fields, and the cloudy time is frequent. This combination can directly decrease the weed control and to rise the crop injury after the herbicide spraying. So, the objective of this researchwas to evaluate the paddy rice response to herbicide to shadowing and soil flooding. For that were assessed two conditions of soil saturation (with or without soil flooding) and the exposition of plant rice to two light conditions, since deemergence until herbicide application (with or without shadowing) and four herbicide treatments: 1) check without herbicide, 2) [imazapyr + imazapic], 3) [imazapyr + imazapic] + saflufenacil and 4) [imazapyr + imazapic] + carfentrazone-ethyl. The assessedvariables wererice injury, chlorophyll content, plant height and aboveground biomass. The herbicides caused initial injury, however there was recovery of rice plants at long of the evaluations. The paddy rice growth, of cultivar SCS121 CL, were affected by herbicide application, mainly when the tank mixture of [imazapyr + imazapic] plus saflufenacil or carfentrazone-ethyl. The soil flooding and the shadowing little affected the herbicide selectivity to paddy rice.(AU)

New Insights into rice pyrimidine catabolic enzymes.

Introduction: Rice is a primary global food source, and its production is affected by abiotic stress, caused by climate change and other factors. Recently, the pyrimidine reductive catabolic pathway, catalyzed by dihydropyrimidine dehydrogenase (DHPD), dihydropyrimidinase (DHP) and ß-ureidopropionase (ß-UP), has emerged as a potential participant in the abiotic stress response of rice. Methods: The rice enzymes were produced as recombinant proteins, and two were kinetically characterized. Rice dihydroorotate dehydrogenase (DHODH), an enzyme of pyrimidine biosynthesis often confused with DHPD, was also characterized. Salt-sensitive and salt-resistant rice seedlings were subjected to salt stress (24 h) and metabolites in leaves were determined by mass spectrometry. Results: The OsDHPD sequence was homologous to the C-terminal half of mammalian DHPD, conserving FMN and uracil binding sites, but lacked sites for Fe/S clusters, FAD, and NADPH. OsDHPD, truncated to eliminate the chloroplast targeting peptide, was soluble, but inactive. Database searches for polypeptides homologous to the N-terminal half of mammalian DHPD, that could act as co-reductants, were unsuccessful. OsDHODH exhibited kinetic parameters similar to those of other plant DHODHs. OsDHP, truncated to remove a signal sequence, exhibited a kcat/Km = 3.6 x 103 s-1M-1. Osb-UP exhibited a kcat/Km = 1.8 x 104 s-1M-1. Short-term salt exposure caused insignificant differences in the levels of the ureide intermediates dihydrouracil and ureidopropionate in leaves of salt-sensitive and salt-resistant plants. Allantoin, a ureide metabolite of purine catabolism, was found to be significantly higher in the resistant cultivar compared to one of the sensitive cultivars. Discussion: OsDHP, the first plant enzyme to be characterized, showed low kinetic efficiency, but its activity may have been affected by truncation. Osb-UP exhibited kinetic parameters in the range of enzymes of secondary metabolism. Levels of two pathway metabolites were similar in sensitive and resistant cultivars and appeared to be unaffected by short-term salt exposure."

Initial development of upland rice inoculated and co-inoculated with multifunctional rhizobacteria / Desenvolvimento inicial de arroz de terras altas inoculado e coinoculado com rizobactérias multifuncionais

Inoculation and co-inoculation of upland rice with multifunctional rhizobacteria can promote plant growth, especially the root system. Thus, this study aimed to evaluate the effect of inoculation and co-inoculation with Azospirillum sp. and Bacillus sp. in the early development of upland rice. The experiment was conducted using a completely randomized design with 4 treatments and 10 replications, totaling 40 plots. The treatments were: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) co-inoculation of Ab-V5 + BRM 63573, and 4) control (without rhizobacteria). Inoculation and co-inoculation with the multifunctional rhizobacteria Ab-V5 and BRM 63573 provided positive effects on the initial development of upland rice. Inoculation with isolate BRM 63573 had significant effects on root length, shoot, and total biomass, while inoculation with isolate Ab-V5 had significant effects on root length and production of root and total biomass. Co-inoculation treatment had significant effects on variables such as diameter, volume, total surface, root biomass, and total biomass. The control treatment (without multifunctional rhizobacteria) had the worst results for most of the analyzed variables.

A inoculação e coinoculação do arroz de terras altas com rizobactérias multifuncionais pode promover o crescimento das plantas, especialmente do sistema radicular. Assim, este estudo teve como objetivo avaliar o efeito da inoculação e coinoculação com Azospirillum sp. e Bacillus sp. no desenvolvimento inicial do arroz de terras altas. O experimento foi conduzido em delineamento inteiramente casualizado com 4 tratamentos e 10 repetições, totalizando 40 parcelas. Os tratamentos foram: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) coinoculação de Ab-V5 + BRM 63573 e 4) controle (sem rizobactérias). A inoculação e coinoculação com as rizobactérias multifuncionais Ab-V5 e BRM 63573 proporcionaram efeitos positivos no desenvolvimento inicial do arroz de terras altas. A inoculação com o isolado BRM 63573 teve efeitos significativos no comprimento da raiz, parte aérea e biomassa total, enquanto a inoculação com o isolado Ab-V5 teve efeitos significativos no comprimento da raiz e produção de raiz e biomassa total. O tratamento com coinoculação teve efeitos significativos em variáveis como diâmetro, volume e superfície total de raiz e biomassa de raiz e total. O tratamento controle (sem rizobactérias multifuncionais) apresentou os piores resultados para a maioria das variáveis analisadas.

Biosynthesis of silver nanoparticles using actinomycetes, phytotoxicity on rice seeds, and potential application in the biocontrol of phytopathogens.

To find effective silver nanoparticles (AgNPs) for control of phytopathogens, in this study, two strains of actinomycetes isolated from the soil of the Brazilian biome Caatinga (Caat5-35) and from mangrove sediment (Canv1-58) were utilized. The strains were identified by using the 16S rRNA gene sequencing as Streptomyces sp., related to Streptomyces mimosus species. The obtained AgNPs were coded as AgNPs 35 and AgNPs58 and characterized by size and morphology using dynamic light scattering, zeta potential, transmission electron microscopy, and Fourier transformed infrared (FTIR). The antifungal activity of the AgNPs35 and AgNPs58 was evaluated in vitro by the minimal inhibitory concentration (MIC) assay on the phytopathogens, Alternaria solani, Alternaria alternata, and Colletotrichum gloeosporioides. The phytotoxic effect was evaluated by the germination rate and seedling growth of rice (Oryza sativa). AgNPs35 and AgNPs58 showed surface plasmon resonance and average sizes of 30 and 60 nm, respectively. Both AgNPs presented spherical shape and the FTIR analysis confirmed the presence of functional groups such as free amines and hydroxyls of biomolecules bounded to the external layer of the nanoparticles. Both AgNPs inhibited the growth of the three phytopathogens tested, and A. alternate was the most sensible (MIC ≤ 4 µM). Moreover, the AgNPs35 and AgNPs58 did not induce phytotoxic effects on the germination and development of rice seedlings. In conclusion, these AgNPs are promising candidates to biocontrol of these phytopathogens without endangering rice plants.

Characterization and Evaluation of Heat-Moisture-Modified Black and Red Rice Starch: Physicochemical, Microstructural, and Functional Properties.

This study sought to evaluate starch from black and red rice modified by heat-moisture, investigating the extraction yield, starch and amylose content, color, and phenolic compounds. The water and oil absorption capacity, whole milk and zero lactose absorption index, syneresis index, and texture were also analyzed. Microstructural analysis included Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The heat-moisture treatment (HMT) reduced the extraction yield and the starch and amylose content, with native black rice starch having the highest values for these parameters. The modification also affected the color and phenolic compounds of the starch, making it darker and changing its appearance. The modification improved the absorption of water, oil, and milk, reducing syneresis and increasing stability during storage. The starch surface was altered, especially for modified black rice starch, with larger agglomerates. The type of starch also changed from A to Vh, with lower relative crystallinity. The textural properties of modified red rice starch were also significantly altered. The HMT proved to be a viable and economical option to modify the analyzed parameters, influencing the texture and physicochemical properties of pigmented rice starch, expanding its applications, and improving its stability during storage at temperatures above 100 °C.

Biology of Glyphepomis dubia Campos & Souza, 2016 (Hemiptera: Pentatomidae) and the parasitoids Telenomus podisi Ashmead, 1893 and Trissolcus basalis (Wollaston, 1858) (Hymenoptera: Platygastridae) on rice / Biologia de Glyphepomis dubia Campos & Souza, 2016 (Hemiptera: Pentatomidae) e dos parasitoides Telenomus podisi Ashmead, 1893 e Trissolcus basalis (Wollaston, 1858) (Hymenoptera: Platygastridae) em arroz

The life cycle of stink bug, Glyphepomis dubia and the development of two egg parasitoids (Telenomus podisi and Trissolcus basalis) were studied at the Federal University of Maranhão, at 26 ± 2oC, relative humidity (RH) of 60 ± 10% and 12h photophase. Individuals used in the study were collected from seven rice fields located around the municipality of Arari, Maranhão, Brazil, and maintained in greenhouse and laboratory for the life cycle studies. From egg to adult, G. dubia took 35.2 days to complete the life cycle. The oviposition period was 37 days, with egg masses of about 12 eggs each and viability of 93.1%. Longevity was 53 and 65 days for females and males, respectively. The egg parasitoids Te. podisi and Tr. basalis parasitized and developed in G. dubia eggs; however, the biological characteristics of Tr. basalis were affected. Emergence of the parasitoids was higher for Te. podisi (83.5%) compared to the records for Tr. basalis (50.4%). Therefore, G. dubia may potentially achieve a pest status and Te. podisi is a promising biological control agent for G. dubia management in Brazil due to its higher longevity and better reproductive parameters.

O ciclo de vida do percevejo, Glyphepomis dubia e a biologia de dois parasitoides de ovos (Telenomus podisi e Trissolcus basalis) foram estudados na Universidade Federal do Maranhão, a 26 ± 2oC, umidade relativa (UR) de 60 ± 10% e fotofase de 12h. Sete indivíduos de G. dubia foram coletados em lavoura de arroz localizada no município de Arari, Maranhão, Brasil e mantidos em casa de vegetação e laboratório para estudos de ciclo de vida. Do ovo ao adulto, G. dubia levou 35.2 dias para completar o ciclo de vida. O período de oviposição foi de 37 dias com massas de ovos com cerca de 12 ovos/massa e viabilidade de 93.1%. A longevidade foi de 53 e 65 dias, respectivamente, para fêmeas e machos. Os parasitoides de ovos, Te. podisi e Tr. basalis parasitaram e se desenvolveram em ovos de G. dubia, no entanto as características biológicas de Tr. basalis foi afetada. A emergência dos parasitoides foi maior para Te. podisi (83.5%) em comparação com o registrado para Tr. basalis (50.4%). Portanto, G. dubia poderá apresentar potencial para atingir o status de praga e Te. podisi é um promissor agente de controle biológico para ser utilizado no manejo de G. dubia no Brasil, pois apresentou maior longevidade e os melhores parâmetros reprodutivos.