Stress signaling convergence and nutrient crosstalk determine zinc-mediated amelioration against cadmium toxicity in rice

Consumption of rice (Oryza sativa L.) is one of the major pathways for heavy metal bioaccumulation in humans over time. Understanding the molecular responses of rice to heavy metal contamination in agriculture is useful for eco-toxicological assessment of cadmium (Cd) and its interaction with zinc (Zn). In certain crops, the impacts of Cd stress or Zn nutrition on the biophysical chemistry and gene expression have been widely investigated, but their molecular interactions at transcriptomic level, particularly in rice roots, are still elusive. Here, hydroponic investigations were carried out with two rice genotypes (Yinni-801 and Heizhan-43), varying in Cd contents in plant tissues to determine their transcriptomic responses upon Cd15 (15 µM) and Cd15+Zn50 (50 µM) treatments. High throughput RNA-sequencing analysis confirmed that 496 and 2407 DEGs were significantly affected by Cd15 and Cd15+Zn50, respectively, among which 1016 DEGs were commonly induced in both genotypes. Multitude of DEGs fell under the category of protein kinases, such as calmodulin (CaM) and calcineurin B-like protein-interacting protein kinases (CBL), indicating a dynamic shift in hormonal signal transduction and Ca2+ involvement with the onset of treatments. Both genotypes expressed a mutual regulation of transcription factors (TFs) such as WRKY, MYB, NAM, AP2, bHLH and ZFP families under both treatments, whereas genes econding ABC transporters (ABCs), high affinity K+ transporters (HAKs) and Glutathione-S-transferases (GSTs), were highly up-regulated under Cd15+Zn50 in both genotypes. Zinc addition triggered more signaling cascades and detoxification related genes in regulation of immunity along with the suppression of Cd-induced DEGs and restriction of Cd uptake. Conclusively, the effective integration of breeding techniques with candidate genes identified in this study as well as economically and technologically viable methods, such as Zn nutrient management, could pave the way for selecting cultivars with promising agronomic qualities and reduced Cd for sustainable rice production

Effets de doses croissantes des composts de fumiers de poules sur le rendement de chou de Chine (Brassica chinensis L.) installé sur un sol acide de Lubumbashi

Objective: A study was conducted on a ferralsol to assess the agronomic efficiency of manure from chickens and mineral fertilizers (NPK and urea) on the yield of Chinese cabbage. Methodology and Results: The experimental design was a completely randomized with six repetitions and six treatments: T0 (unfertilized control), T1 (175 kg NPK +87 kg urea per hectare), T2 (350 kg NPK+47.5 kg Urea per hectare), T3 (15 t.ha-1 manure of chicken compost), T4 (30 t.ha-1 manure of chicken compost), T5 (60 t.ha-1 manure of chicken compost). Manure of chicken, NPK and urea were incorporated into the soil, respectively, a week before the day of transplantation and 3 weeks after transplantation. Highly significant differences (p < 0.05) were found between treatments in terms of growth and yield of Chinese cabbage corn with yields ranging from 1.4 to 5.1 t.ha-1, the treatments T2 and T5 which gave similar yields and the highest and lowest T0 treatment. Conclusion and application: With reference to yields and agronomic efficiency, doses of manure at 15 t.ha-1 agree to address any use of mineral inputs. However, due to the low availability of manure nutrients, a mineral fertilizer supplement is recommended. The study showed that chicken manure under the conditions of this trial was a great potential for improving the availability of nutrients in soil and was able to provide the amount of nutrients needed to growing Chinese cabbage without the addition of mineral fertilizers.Keywords: Compost manure from chickens; mineral fertilizers; Chinese cabbage; acidic soil, agronomic efficiency; Lubumbash

Amélioration de la qualité des sols acides de Lubumbashi (Katanga, RD Congo) par l’application de différents niveaux de compost de fumiers de poules

Objectives: An experiment was conducted on an acidic soil to assess the influence of compost and mineral fertilizers on the chemical properties of this soil. Methodology and results: The test was installed to a completely randomized with six replicates of six treatment: T0 (unfertilized control), T1 (175 kg NPK+ 87 kg urea per hectare) T2 (double of T1, 350 kg NPK+175 kg urea) T3 (15t.ha-1 of compost), T4 (double of T3, 30 t.ha-1 of compost) T5 (quadruple of T3, 60 t.ha-1 of compost). Before installation of the test, composting chicken manure was carried out for 36 days. At the end of the experiment, chemical analyzes were performed on samples of soil and compost from manure of hens. The contents of exchangeable cations appear to be higher compared to the reference values found by other authors in the study area. The high values found for these parameters in the site of the present study could result from the contribution of fertilizers. For the witness, there was a low nutrient availability. In addition, the mean levels of K, P, C and pH are high in pots amended with plenty of compost. Significant differences were observed between the different doses of compost and mineral NPK fertilizer on soil characteristics studied. Conclusion and application: Recovery of waste as a source of organic matter is a practice to be encouraged in Lubumbashi urban horticulture, in given the high cost of mineral fertilizers and the low level of income of farmers.Keywords: Compost; mineral fertilizers; acid soil; urban and peri-urban agriculture; Lubumbashi

Unravelling the evolution of the Allatostatin-Type A, KISS and Galanin Peptide-Receptor gene families in Bilaterians: insights from Anopheles Mosquitoes

Allatostatin type A receptors (AST-ARs) are a group of G-protein coupled receptors activated by members of the FGL-amide (AST-A) peptide family that inhibit food intake and development in arthropods. Despite their physiological importance the evolution of the AST-A system is poorly described and relatively few receptors have been isolated and functionally characterised in insects. The present study provides a comprehensive analysis of the origin and comparative evolution of the AST-A system. To determine how evolution and feeding modified the function of AST-AR the duplicate receptors in Anopheles mosquitoes, were characterised. Phylogeny and gene synteny suggested that invertebrate AST-A receptors and peptide genes shared a common evolutionary origin with KISS/GAL receptors and ligands. AST-ARs and KISSR emerged from a common gene ancestor after the divergence of GALRs in the bilaterian genome. In arthropods, the AST-A system evolved through lineage-specific events and the maintenance of two receptors in the flies and mosquitoes (Diptera) was the result of a gene duplication event. Speciation of Anophelesmosquitoes affected receptor gene organisation and characterisation of AST-AR duplicates (GPRALS1 and 2) revealed that in common with other insects, the mosquito receptors were activated by insect AST-A peptides and the iCa(2+)-signalling pathway was stimulated. GPRALS1 and 2 were expressed mainly in mosquito midgut and ovaries and transcript abundance of both receptors was modified by feeding. A blood meal strongly up-regulated expression of both GPRALS in the midgut (p < 0.05) compared to glucose fed females. Based on the results we hypothesise that the AST-A system in insects shared a common origin with the vertebrate KISS system and may also share a common function as an integrator of metabolism and reproduction. Highlights: AST-A and KISS/GAL receptors and ligands shared common ancestry prior to the protostome-deuterostome divergence. Phylogeny and gene synteny revealed that AST-AR and KISSR emerged after GALR gene divergence. AST-AR genes were present in the hemichordates but were lost from the chordates. In protostomes, AST-ARs persisted and evolved through lineage-specific events and duplicated in the arthropod radiation. Diptera acquired and maintained functionally divergent duplicate AST-AR genes.Foundation for Science and Technology, Portugal (FCT) [PTDC/BIA-BCM/114395/2009]; European Regional Development Fund (ERDF) COMPETE - Operational Competitiveness Programme; Portuguese funds through FCT Foundation for Science and Technology [PEst-C/MAR/LA0015/2013, UID/Multi/04326/2013, PEst-OE/SAU/LA0018/2013]; FCT [SFRH/BPD/89811/2012, SFRH/BPD/80447/2011, SFRH/BPD/66742/2009]; auxiliary research contract FCT Pluriannual funds [PEst-C/MAR/LA0015/2013, UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

Zinc alleviates cadmium toxicity by modulating photosynthesis, ROS homeostasis, and cation flux kinetics in rice

Understanding of cadmium (Cd) uptake mechanism and development of lower Cd crop genotypes are crucial for combating its phytotoxicity and meeting 70% increase in food demand by 2050. Bio-accumulation of Cd continuously challenges quality of life specifically in regions without adequate environmental planning. Here, we investigated the mechanisms operating in Cd tolerance of two rice genotypes (Heizhan-43 and Yinni-801). Damage to chlorophyll contents and PSII, histochemical staining and quantification of reactive oxygen species (ROS), cell viability and osmolyte accumulation were studied to decipher the interactions between Cd and zinc (Zn) by applying two Cd and two Zn levels (alone as well as combined). Cd2+ and Ca2+ fluxes were also measured by employing sole Cd100 (100 μmol L−1) and Zn50 (50 μmol L−1), and their combination with microelectrode ion flux estimation (MIFE) technique. Cd toxicity substantially reduced chlorophyll contents and maximal photochemical efficiency (Fv/Fm) compared to control plants. Zn supplementation reverted the Cd-induced toxicity by augmenting osmoprotectants and interfering with ROS homeostasis under combined treatments, particularly in Yinni-801 genotype. Fluorescence microscopy indicated a unique pattern of live and dead root cells, depicting more damage with Cd10, Cd15 and Cd15+Zn50. Our results confer that Cd2+ impairs the uptake of Ca2+ whereas, Zn not only competes with Cd2+ but also Ca2+, thereby modifying ion homeostasis in rice plants. This study suggests that exogenous application of Zn is beneficial for rice plants in ameliorating Cd toxicity in a genotype and dose dependent manner by minimizing ROS generation and suppressing collective oxidative damage. The observations confer that Yinni-801 performed better than Heizhan-43 genotype mainly under combined Zn treatments with low-Cd, presenting Zn fortification as a solution to increase rice production