The Plant Short-Chain Dehydrogenase (SDR) superfamily:genome-wide inventory and diversification patterns

Background Short-chain dehydrogenases/reductases (SDRs) form one of the largest and oldest NAD(P)(H) dependent oxidoreductase families. Despite a conserved 'Rossmann-fold' structure, members of the SDR superfamily exhibit low sequence similarities, which constituted a bottleneck in terms of identification. Recent classification methods, relying on hidden-Markov models (HMMs), improved identification and enabled the construction of a nomenclature. However, functional annotations of plant SDRs remain scarce. Results Wide-scale analyses were performed on ten plant genomes. The combination of hidden Markov model (HMM) based analyses and similarity searches led to the construction of an exhaustive inventory of plant SDR. With 68 to 315 members found in each analysed genome, the inventory confirmed the over-representation of SDRs in plants compared to animals, fungi and prokaryotes. The plant SDRs were first classified into three major types --- 'classical', 'extended' and 'divergent' --- but a minority (10 % of the predicted SDRs) could not be classified into these general types ('unknown' or 'atypical' types). In a second step, we could categorize the vast majority of land plant SDRs into a set of 49 families. Out of these 49 families, 35 appeared early during evolution since they are commonly found through all the Green Lineage. Yet, some SDR families --- tropinone reductase-like proteins (SDR65C), 'ABA2-like'-NAD dehydrogenase (SDR110C), 'salutaridine/menthone-reductase-like' proteins (SDR114C), 'dihydroflavonol 4-reductase'-like proteins (SDR108E) and 'isoflavone-reductase-like' (SDR460A) proteins --- have undergone significant functional diversification within vascular plants since they diverged from Bryophytes. Interestingly, these diversified families are either involved in the secondary metabolism routes (terpenoids, alkaloids, phenolics) or participate in developmental processes (hormone biosynthesis or catabolism, flower development), in opposition to SDR families involved in primary metabolism which are poorly diversified. Conclusion The application of HMMs to plant genomes enabled us to identify 49 families that encompass all Angiosperms ('higher plants') SDRs, each family being sufficiently conserved to enable simpler analyses based only on overall sequence similarity. The multiplicity of SDRs in plant kingdom is mainly explained by the diversification of large families involved in different secondary metabolism pathways, suggesting that the chemical diversification that accompanied the emergence of vascular plants acted as a driving force for SDR evolution

Impact of organic and inorganic fertilizers on tomato vigor, yield and fruit composition under tropical andosol soil conditions

Introduction. Little is known about the impact of organic manure on andosol. Materials and methods. Two varieties of Solanum lycopersicum L. (cvs. ‘Rio grande’ and ‘Rossol VFN’) were grown under tropical andosol. The soil was silty, acidic and very poor in Bray P (3 mg·kg–1) with a strong imbalance in the (Ca:Mg:K) ratio of (74.0:25.0:0.7). Five fertilization treatments were used: (i) control with no fertilizer, (ii) minerals, with a (Ca:Mg:K) ratio of (76:18:6) and 75 mg P·kg–1 of soil; (iii) poultry manure with a (Ca:Mg:K) ratio of (68:24:7) and 450 mg P·kg–1 of soil; (iv) a combination of (ii) and (iii), and (v) mineral fertilization as applied by local farmers, with a (Ca:Mg:K) ratio of (73:25:1) and 54 mg P·kg–1 of soil. Results. All cation-balanced treatments (organic, mineral or a combination of both) significantly improved plant growth, the number of trusses and fruits per plant, the marketable fruit yield and fruit P, K, Ca and Na contents of both tomato varieties considered. The ‘Rio grande’ variety was the most productive (32–44 t·ha–1) compared with the ‘Rossol’ variety (20–22 t·ha–1). There was no major difference between the organic fertilizer and the cation-balanced mineral fertilizer. There was no effect of mineral fertilizer with an unbalanced cation composition on tomato plant growth and production as compared with unfertilized control. Conclusion. In tropical andosol poor in potassium and phosphorous and with excess of Mg, application of poultry manure in adequate dosage and at the right time is capable of sustaining tomato fruit production, as well as the application of calculated inorganic fertilizer

Field management of Taro (Colocasia esculenta (L.) Schott) leaf blight via fungicidal spray of foliage

Taro leaf blight (TLB) epidemic hit Cameroon for the first time in 2009. Since then, the disease is persistent and its typical devastating legacy is threatening Taro (Colocasia esculenta) in the North and South West Regions of Cameroon. This study was initiated with the objective to determine the potentials of some fungicides to control TLB. The experimental design was completely randomized with a 3x15x2 factorial, including 3 treatments: T1 (Callomil plus72WP), T2 (Mancoxyl plus 720WP) and T3, 1:1 ratio T1 + T2 all applied at concentrations of 4g/L; 15 repetitions and 2 planting seasons (dry season i.e. October 2014 – March 2015 and rainy season i.e. April-October 2015). Disease incidence and disease severity were used to evaluate the disease progression while corm yield was used to appraise the economic injury. The results revealed disease incidence of 0% during the dry season and 18.2%, 27.3% and 100%, for T1, T2 and T3 and control during rainy season respectively. Disease severity was 75% in control and only 1% for the different treatments. Corm yield in the rainy season was 17.4kg, 15.08kg, 14.27kg and 5.89kg for T1, T2, T3 and control respectively. This study suggests that TLB epidemic can effectively be managed by foliage spray with Metalaxyl containing fungicides at a weekly dosage of 4g/L. Key words: Chemical control, Colocasia esculenta, Epidemic, Phytopathology, Phytophthora colocasia

Cold stress affects antioxidative response and accumulation of medicinally important withanolides in Withania somnifera (L.) Dunal

Withania somnifera (L.) Dunal (Indian ginseng) is a high value medicinal plant. It synthesizes a large array of biologically active withanolides. In this study, two month old seedlings of AGB002 (wild genotype) and AGB025 (cultivated genotype) of W. somnifera were subjected to cold stress (4 ◦C) under controlled envi-ronment. Plants were analyzed for three medicinally important secondary metabolites (withanolide A, withanone and withaferin A), lipid peroxidation (MDA), cell injury, superoxide radical (O2 •−) accumula-tion and anti-oxidative enzymes activities such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). Increases in the titers of superoxide anion and MDA were observed from day 1 to day 7 in both genotypes, although the increase on the first day of exposure was significantly higher. Enzymatic activities of SOD, CAT, APX and GR also showed an increasing trend in both genotypes and reached a maximum on day 7 of the cold temperature exposure; however, this increase was higher in AGB002 than AGB025. Withanolide A (WS-1) in the roots of both genotypes sig-nificantly decreased on the first day of cold exposure and then showed a recovery until day 7. WS-1 was not detected in the leaves of either genotype. Withanone (WS-2) content in the leaves also decreased towards the end of the cold period in both genotypes. Cold stress also elicited the accumulation of WS-2 in AGB025, but was not detectable in control seedlings. At maturity, WS-2 was also detected in control plants. Furthermore, a significant increase in the leaf withaferin A (WS-3) content was recorded from day 1 to day 7 of the cold exposure in both the genotypes, suggesting the possible involvement of with-anolides in cold-protection. AGB002 showed comparatively higher accumulation of antioxidant enzymes and selected marker withanolides than AGB025, indicating that AGB002 is better adapted to cold than AGB025. It could be inferred from these observations that cold stress induces bioactive withanolide accu-mulation in W. somnifera as a mechanism for scavenging reactive oxygen species (ROS). These studies also provide an impetus for enhancing the withanolide accumulation in W. somnifera using controlled environment technology.CSIR-Indian Institute of Integrative Medicine (CSIR-IIIM).http://www.elsevier.com/locate/indcrop2016-11-30hb2016BiochemistryChemistryGenetic

Functional characterization of SlscADH1, a fruit-ripening associated short-chain alcohol dehydrogenase of tomato

A tomato short-chain dehydrogenase-reductase (SlscADH1) is preferentially expressed in fruit with a maximum expression at the breaker stage while expression in roots, stems, leaves and flowers is very weak. It represents a potential candidate for the formation of aroma volatiles by interconverting alcohols and aldehydes. The SlscADH1 recombinant protein produced in Escherichia coli exhibited dehydrogenase-reductase activity towards several volatile compounds present in tomato flavour with a strong preference for the NAD/NADH co-factors. The strongest activity was observed for the reduction of hexanal (Km = 0.175 mM) and phenylacetaldehyde (Km = 0.375 mM) in the presence of NADH. The oxidation process of hexanol and 1-phenylethanol was much less efficient (Kms of 2.9 and 23.0 mM, respectively), indicating that the enzyme preferentially acts as a reductase. However activity was observed only for hexanal, phenylacetaldehyde, (E)-2-hexenal and acetaldehyde and the corresponding alcohols. No activity could be detected for other aroma volatiles important for tomato flavour, such as methyl-butanol/methyl-butanal, 5-methyl-6-hepten-2-one/5-methyl-6-hepten-2-ol, citronellal/citronellol, neral/nerol, geraniol. In order to assess the function of the SlscADH1 gene, transgenic plants have been generated using the technique of RNA interference (RNAi). Constitutive down-regulation using the 35S promoter resulted in the generation of dwarf plants, indicating that the SlscADH1 gene, although weakly expressed in vegetative tissues, had a function in regulating plant development. Fruitspecific down-regulation using the 2A11 promoter had no morphogenetic effect and did not alter the aldehyde/alcohol balance of the volatiles compounds produced by the fruit. Nevertheless, SlscADH1-inhibited fruit unexpectedly accumulated higher concentrations of C5 and C6 volatile compounds of the lipoxygenase pathway, possibly as an indirect effect of the suppression of SlscADH1 on the catabolism of phospholipids and/or integrity of membranes

Changements morphologiques et biochimiques au cours du développement et de la maturation des fruits de

Introduction. La pomme Cythère est un fruit économiquement sous-exploité au Cameroun par manque de connaissances sur les techniques de culture de l’espèce, la conservation post-récolte de son fruit et sa valeur nutritionnelle. L’objectif de notre étude a été d’analyser certains changements morphologiques et biochimiques qui se produisent au cours du développement de la pomme Cythère et de chercher à évaluer le temps s’écoulant entre la nouaison et la maturation des fruits, afin de prévoir une date probable de récolte au Centre Cameroun. Matériel et méthodes. Certains paramètres morphologiques (longueur, diamètre, volume et poids du fruit) et biochimiques (teneurs en eau, en sucres totaux, en lipides, protéines et en éléments minéraux, teneur en chlorophylles a et b) des fruits de S. cytherea ont été mesurés à partir de leur nouaison jusqu’à leur maturation. Résultats et discussion. Les valeurs des paramètres morphologiques mesurés sur le fruit ont augmenté au cours du temps et leur évolution a suivi une courbe à allure sigmoïdale. Les valeurs maximales ont été obtenues à la vingt-huitième semaine avec près de 128 g pour le poids frais, 19 g pour le poids sec, 69 mm pour la longueur, 58 mm pour le diamètre et 116 mL pour le volume. Les chlorophylles a et b ont diminué au cours du développement du fruit. La teneur des fruits en éléments minéraux a diminué avec le temps et le potassium a été l’élément le plus abondant. Sa teneur a varié de 1,6 % à 0,9 % entre la sixième et la trentième semaine après nouaison. Les sucres totaux ont augmenté avec le temps alors que les teneurs en lipides et les protéines diminuaient. Trente semaines après la nouaison, les valeurs ont été de 13,76 % de matière fraîche pour les sucres, de 0,47 % de matière sèche pour les lipides et de 0,43 % de matière sèche pour les protéines. Conclusion. La composition de la pomme Cythère donnerait à ce fruit une valeur nutritive aussi importante que celle de certains fruits tropicaux plus connus comme la banane, la mangue et l’ananas

Effect of Organic/Inorganic-Cation Balanced Fertilizers on Yield and Temporal Nutrient Allocation of Tomato Fruits under Andosol Soil Conditions in Sub-Saharan Africa

International audienceThe impact of organic fertilizers on plant behaviour under andosol conditions is not well understood. A field experiment was conducted on a silty and slightly acidic andosol, very poor in phosphorous (3 mg kg- 1of soil) and potassium (0.13 meq/100g of soil), with an imbalance Ca:Mg:K ratio of 74.0:25.0:0.7. The effect of integrated mineral fertilization (using N, P, K, Ca and Mg), dry poultry manure (organic), the association of the two (organo-mineral) fertilizers and non-integrated mineral fertilization has been studied on yield and nutrient allocation of two varieties of tomato (Solanum lycopersicum L. var. Roma VF and Tima). Yields of red tomatoes from organo-mineral fertilized plants (39.27-34.38 t ha-1) werethree times higher than the yields from plants fertilized with non-integrated minerals (12.97-11.59 t ha-1).Allocation of macronutrients (P, K and Ca) was high in fruits from plants fertilized with organic, organomineraland integrated mineral fertilizers. Fruit calcium increased mostly at the fruit ripening stage, while phosphorus and potassium accumulated mainly before the fruit ripening stage. This trend was by far more pronounced under organo-mineral and organic fertilization. Overall, the kinetics of nutrient allocation indicate a clear positive impact of poultry manure and organo-mineral fertilizers in improving tomato production on andosol

The Plant Short-Chain Dehydrogenase (SDR) superfamily: genome-wide inventory and diversification patterns

Abstract Background Short-chain dehydrogenases/reductases (SDRs) form one of the largest and oldest NAD(P)(H) dependent oxidoreductase families. Despite a conserved ‘Rossmann-fold’ structure, members of the SDR superfamily exhibit low sequence similarities, which constituted a bottleneck in terms of identification. Recent classification methods, relying on hidden-Markov models (HMMs), improved identification and enabled the construction of a nomenclature. However, functional annotations of plant SDRs remain scarce. Results Wide-scale analyses were performed on ten plant genomes. The combination of hidden Markov model (HMM) based analyses and similarity searches led to the construction of an exhaustive inventory of plant SDR. With 68 to 315 members found in each analysed genome, the inventory confirmed the over-representation of SDRs in plants compared to animals, fungi and prokaryotes. The plant SDRs were first classified into three major types — ‘classical’, ‘extended’ and ‘divergent’ — but a minority (10% of the predicted SDRs) could not be classified into these general types (‘unknown’ or ‘atypical’ types). In a second step, we could categorize the vast majority of land plant SDRs into a set of 49 families. Out of these 49 families, 35 appeared early during evolution since they are commonly found through all the Green Lineage. Yet, some SDR families — tropinone reductase-like proteins (SDR65C), ‘ABA2-like’-NAD dehydrogenase (SDR110C), ‘salutaridine/menthone-reductase-like’ proteins (SDR114C), ‘dihydroflavonol 4-reductase’-like proteins (SDR108E) and ‘isoflavone-reductase-like’ (SDR460A) proteins — have undergone significant functional diversification within vascular plants since they diverged from Bryophytes. Interestingly, these diversified families are either involved in the secondary metabolism routes (terpenoids, alkaloids, phenolics) or participate in developmental processes (hormone biosynthesis or catabolism, flower development), in opposition to SDR families involved in primary metabolism which are poorly diversified. Conclusion The application of HMMs to plant genomes enabled us to identify 49 families that encompass all Angiosperms (‘higher plants’) SDRs, each family being sufficiently conserved to enable simpler analyses based only on overall sequence similarity. The multiplicity of SDRs in plant kingdom is mainly explained by the diversification of large families involved in different secondary metabolism pathways, suggesting that the chemical diversification that accompanied the emergence of vascular plants acted as a driving force for SDR evolution.</p

Current status of strawberry (Fragaria spp.) cultivation and marketing in Cameroon

Background: Strawberries are among the most consumed fruits in the world, offering a multitude of health benefits. Their popularity has contributed to their economic value. However, in Cameroon, there is an insufficiency of strawberry yields, resulting in their importation and high market prices. Consequently, strawberries have become a luxury item, out of reach for the average citizen. This study carries out the inventory of the technique of production and marketing of strawberries in Cameroon. Method: In 2021, a survey of one hundred and one strawberry farmers in three regions: the Center, the West, and the South was conducted. The survey collected information on the socio-demographic characteristics of strawberry farmers, cultivation practices, and production. Additionally, we interviewed supermarkets, pastry chefs, and canvassers to gather data on strawberry marketing practices. Results: Male strawberry farmers (83.17%) outnumbered females (16.83%). The majority of farmers (65.35%) practiced mix cropping, especially with tomatoes, while 34.65% focused on monoculture. Back pain and pests were identified as the major constraints. The educational level and age were found to be influential factors in farmers' proposals for improving yields. On average, 1 kg of strawberries in Cameroon costs 10,000 XAF. The main customers are canvassers, supermarkets, and pastry chefs, who prioritize the size of the fruit when making purchases. Conclusion: The number of strawberry farmers is higher in the West region. It takes up to 1,000,000 XAF to initiate cultivation when the area is as from 1000 m2. The high cost of strawberries is due to their scarcity