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Background Despite the importance of osmoprotectants, no previous in silico evaluation of high throughput data is available for higher plants. The present approach aimed at the identification and annotation of osmoprotectant-related sequences applied to short transcripts from a soybean HT-SuperSAGE (High Throughput Super Serial Analysis of Gene Expression; 26-bp tags) database, and also its comparison with other transcriptomic and genomic data available from different sources. Methods A curated set of osmoprotectants related sequences was generated using text mining and selected seed sequences for identification of the respective transcripts and proteins in higher plants. To test the efficiency of the seed sequences, these were aligned against four HT-SuperSAGE contrasting libraries generated by our group using soybean tolerant and sensible plants against water deficit, considering only differentially expressed transcripts (p ≤ 0.05). Identified transcripts from soybean and their respective tags were aligned and anchored against the soybean virtual genome. Results The workflow applied resulted in a set including 1,996 seed sequences that allowed the identification of 36 differentially expressed genes related to the biosynthesis of osmoprotectants [Proline ( P5CS : 4, P5CR : 2), Trehalose ( TPS1 : 9, TPPB : 1), Glycine betaine ( BADH : 4) and Myo- inositol ( MIPS : 7, INPS1 : 8)], also mapped in silico in the soybean genome (25 loci). Another approach considered matches using Arabidopsis full length sequences as seed sequences, and allowed the identification of 124 osmoprotectant-related sequences, matching ~10.500 tags anchored in the soybean virtual chromosomes. Osmoprotectant-related genes appeared clustered in all soybean chromosomes, with higher density in some subterminal regions and synteny among some chromosome pairs. Conclusions Soybean presents all searched osmoprotectant categories with some important members differentially expressed among the comparisons considered (drought tolerant or sensible vs . control; tolerant vs . sensible), allowing the identification of interesting candidates for biotechnological inferences. The identified tags aligned to corresponding genes that matched 19 soybean chromosomes. Osmoprotectant-related genes are not regularly distributed in the soybean genome, but clustered in some regions near the chromosome terminals, with some redundant clusters in different chromosomes indicating their involvement in previous duplication and rearrangements events. The seed sequences, transcripts and map represent the first transversal evaluation for osmoprotectant-related genes and may be easily applied to other plants of interest.

ABSTRACT Cassava wastewater is the liquid residue of the cassava flour processing and its application to the soil as fertilizer for agricultural crops is a good alternative to sources of nutrients for plants. In this context, the objective of this work was to evaluate the growth and seed yield of sunflower on soil fertilized with cassava wastewater. A randomized block experimental design with four replications was used, with six cassava wastewater rates (0, 8.5, 17, 34, 68 and 136 m3 ha-1) and six plant sampling times (15, 30, 45, 60, 75 and 90 days after sowing), using the sunflower cultivar Helio-250. The evaluated variables were total leaf area, leaf area index, leaf area ratio, specific leaf area, leaf weight ratio, shoot dry mass and sunflower seed yield. The use of cassava wastewater rate of 136 m3 ha-1 increases the seed yield, leaf area, leaf area index and shoot dry mass, and results in lower leaf area ratio, specific leaf area and leaf weight ratio of sunflower (cv. Helio-250) crops. RESUMO A aplicação da manipueira, resíduo liquido do processamento da mandioca, em cultivos agrícolas apresenta-se como uma boa alternativa como fonte de nutrientes para as plantas. Nesta perspectiva o objetivo desta pesquisa foi analisar o crescimento e a produtividade de plantas de girassol adubadas com manipueira. O delineamento experimental utilizado foi em blocos ao acaso, com seis doses de manipueira (0; 8,5; 17; 34; 68 e 136 m3ha-1) em quatro repetições, sendo avaliados em seis épocas de amostragens das plantas (15, 30, 45, 60, 75 e 90 dias após a semeadura - DAS), utilizando-se a cultivar de girassol, Helio 250. As variáveis avaliadas foram a área foliar, o índice de área foliar, a razão de área foliar, a área foliar específica, a razão de peso foliar, a massa seca da parte aérea das plantas e a produtividade. A dose de manipueira igual a 136 m3 ha-1 propiciou maiores produtividade, área foliar, índice de área foliar e massa seca da parte aérea. Os menores valores de razão de área foliar, área foliar específica e a razão de peso foliar foram obtidos quando se utilizou a dose de 136 m3 ha-1.

ABSTRACT Pulse irrigation may be more advantageous for peanut crops than continuous irrigation, when using brackish water. However, studies on pulse irrigation with brackish water considering the environmental conditions of the Northeast region of Brazil using are incipient. Therefore, the objective of this study was to evaluate the effect of using brackish water for pulse and continuous dripping irrigations on the grain yield and production characteristics of peanut (Arachis hypogaea L.) crops. A completely randomized block design with four repetitions was used, in a 6*2 factorial arrangement consisted of six electrical conductivities of the irrigation water (EC; 0.2, 1.6, 2.8, 4.0, 5.2, and 6.4 dS m-1) set by adding NaCl to the irrigation water, which originally had 0.2 dS m-1, until reaching the respective EC; and two irrigation methods (pulse and continuous). The evaluated variables were fresh and dry weights of shoot, 10 grains, pods, grains, and production; number of pods and grains; and percentages of empty pods (EP%) and perfect grains (PG%). The addition of salt to the irrigation water negatively affected all variables studied, except for EP% and PG%. The lowest EP% were found for the pulse irrigation, which increased the pod and grain yields, regardless of the EC of the irrigation water. Under the conditions of the present study, the use of brackish waters with electrical conductivities of up to 2.98 dS m-1 is viable for peanut production.

ABSTRACT Pulse irrigation may be more advantageous for peanut crops than continuous irrigation, when using brackish water. However, studies on pulse irrigation with brackish water considering the environmental conditions of the Northeast region of Brazil using are incipient. Therefore, the objective of this study was to evaluate the effect of using brackish water for pulse and continuous dripping irrigations on the grain yield and production characteristics of peanut (Arachis hypogaea L.) crops. A completely randomized block design with four repetitions was used, in a 6*2 factorial arrangement consisted of six electrical conductivities of the irrigation water (EC; 0.2, 1.6, 2.8, 4.0, 5.2, and 6.4 dS m-1) set by adding NaCl to the irrigation water, which originally had 0.2 dS m-1, until reaching the respective EC; and two irrigation methods (pulse and continuous). The evaluated variables were fresh and dry weights of shoot, 10 grains, pods, grains, and production; number of pods and grains; and percentages of empty pods (EP%) and perfect grains (PG%). The addition of salt to the irrigation water negatively affected all variables studied, except for EP% and PG%. The lowest EP% were found for the pulse irrigation, which increased the pod and grain yields, regardless of the EC of the irrigation water. Under the conditions of the present study, the use of brackish waters with electrical conductivities of up to 2.98 dS m-1 is viable for peanut production. RESUMO A irrigação por pulsos pode proporcionar maiores rendimentos para a cultura do amendoim em comparação a irrigação contínua com a utilização de águas salobras, contudo, estudos para as condições do Nordeste brasileiro utilizando esta técnica de manejo da irrigação associada ao uso de águas salobras são incipientes. Diante disso, objetivou-se com o trabalho avaliar o efeito do uso de águas salobras e da irrigação por gotejamento pulsado e contínuo sobre a produção de grãos e características produtivas do amendoim (Arachis hypogaea L.). O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial de 6 x 2, composto por seis condutividades elétricas da água de irrigação (CEa: 0,2; 1,6; 2,8; 4,0; 5,2 e 6,4 dS m-1), na qual foi adicionada NaCl a água de abastecimento (CEa: 0,2 dS m-1) até atingir as respectivas CEa, e duas formas de aplicação da irrigação por gotejamento (com pulsos e contínua), com quatro repetições. As variáveis analisadas foram: a massa fresca e seca da parte aérea de 10 grãos, das vagens, dos grãos e da produção, além do número de vagens, do número de grãos, da percentagem de vagens chochas (PerVC) e da percentagem de grãos perfeitos (PerGP). A salinidade influenciou negativamente todas as variáveis estudadas, com exceção do PerVC e da PerGP. As menores percentagens de vagens chochas foram obtidas com a irrigação pulsada que por sua vez demonstrou a maior produção de vagens e de grãos independentemente dos níveis de condutividade elétrica da água avaliados. Nas condições desta pesquisa, é viável produzir amendoim utilizando águas salobras com condutividade elétrica de até 2,98 dS m-1.

In this study, the authors analyzed the consequences of irrigation management strategies as an essential factor to save water and maintain high crop yields. The present research aimed at comparing coriander (Coriandrum sativum L.), cv. Verdão, yields under fertigation via drip irrigation with a continuous application and in pulses, with 40, 60, 80, 100 and 120% of the crop evapotranspiration (ETc) being recovered. These treatments were distributed in randomized blocks in a 2 × 5 factorial scheme, with three replications, in a greenhouse located at the Federal Rural University of Pernambuco, northeast Brazil (08°01′6.50″ S and 34°56′46″ W, average elevation 6.5 m). The continuous irrigation consisted of the application of water depth in a single daily event, while pulsed irrigation comprised the application of the same irrigation depth split up into five events with a 1-hour interval between pulses. Crop evapotranspiration (ETc) was determined via the water balance by lysimetric drainage. The fertilizers were applied in every watering. The biometric and productivity crop pointed that pulsed irrigation to a mean depth of 58% of the ETc corresponds to the results obtained with the application of the depth equivalent to 100% of the ETc by continuous irrigation, consequently with reduced input costs.

In irrigated areas around the world, the recommendation for the use of subsurface drainage is also associated with controlling salinity problems. Due to the high implementation cost, the search for solutions that make this requirement more flexible is necessary. Among the options to be investigated is the hypothesis that the height and salinity of the water table in plots located at the highest points of a toposequence are lower and do not compromise plant development, even without underground drainage systems. In this context, the present work was developed to monitor and evaluate the variation in water level or mottling over twelve months, as well as to measure and analyze the electrical conductivity and average pH of the water table during this period and its possible impact on plants. For this purpose, three lots in toposequence were selected in the Senador Nilo Coelho Public Irrigation Project, Petrolina—PE, with previously defined characteristics: soil classification (Plinthic Yellow—Ultisol), crop planted (Mangifera indica L.) and irrigation system used (micro-sprinkler). Precipitation, reference evapotranspiration and volume of water applied via irrigation were monitored by an automatic weather station and hydrometers in each lot. In each plot, nine observation wells were installed, distributed in a grid, with the aim of make monthly measurements of the water table level or mottling. The electrical conductivity and pH of the groundwater were also measured to obtain the average monthly value for each lot. Illustrative 3D maps of the water table level in relation to the ground surface were created using the simple kriging method, in the UTM SIRGAS 2000 24S projection system. The absence and presence of groundwater in the upper and lower hillslope lots, respectively, were favored by the toposequence. The decision to install underground drainage or not can be made on a case-by-case basis; this must take into account, among other aspects, changes in physical characteristics along the soil profile, possible occurrence of mottling, the quality of water for irrigation, the irrigation management adopted and the position of the lot in the toposequence.

Physic nut (Jatropha curcas L.), a small oleaginous tree spontaneously occurring in arid and semi-arid tropical regions, is a sustainable and renewable energy source for biodiesel. However, the J. curcas yield in such areas should consider soil salinity and its consequences. Transcription factor (TF) proteins recognize cis-regulatory elements in promoters of genes to be expressed. In the present work, differentially expressed genes (DEGs) encoding putative TFs from physic nut plants responding to NaCl (150 mM), after 3 h of exposition, covered 23 TF families. The expressed profiles of members from AP2/ERF and NAC families basically showed induction after the salt stimulus, while members of bHLH, FHY3-FAR1, and ARF families presented repression. Concerning the induced TF DEGs, the gene ontology (GO) enrichment analysis highlighted terms related to abiotic stress responses, while those terms representing the repressed TF DEGs stood out the basal metabolism. In turn, the TF enrichment analysis predicted those TFs targeting promoters of induced TF DEGs. Some of the enriched TFs may be good candidates as transgenes in transgenic events. Also, RT-qPCR analyses validated the up-regulation of six TF DEGs (RAV1, ERF9, ZAT12, PTI5, MYB340, and BZIP4) of eight candidates selected from the expressed TFome. The generated data could help breeders to better understand the molecular basis of physic nut plants responding to salinity, to select potential candidates for transgenic studies, as well as to develop functional molecular markers to assist selection steps in breeding programs.