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Understanding Nitrogen Use Efficiency (NUE) physiological and molecular mechanisms in high N demanding crops has become decisive for improving NUE in sustainable cropping systems. How the Nitrogen Utilization Efficiency (NUtE) component contributes to the NUE enhancement under nitrate limiting conditions in tomato remains to be elucidated. This study deals with the changes in several important nitrate metabolism related gene expressions (nitrate assimilation, transport, remobilization and storage/sequestration) engendered by short and long-term limiting nitrate exposure in two selected NUE-contrasting genotypes, Regina Ostuni (RO) and UC82, efficient and inefficient, respectively. At short-term, nitrate limiting supply triggered higher SlCLCa and SlNRT1.7 expressions in RO root and shoot, respectively, suggesting a higher nitrate storage and remobilization compared to UC82, explaining how RO withstood the nitrate deficiency better than UC82. At long-term, nitrate reductase (SlNR) and nitrite reductase (SlNIR) expression were not significantly different between nitrate treatments in RO, while significantly down-regulated under nitrate limiting treatment in UC82. In addition, SlCLCa and SlNRT1.8 transcript levels were significantly lower in RO, while those of SlNRT1.5 and SlNR appeared significantly higher. This suggested that the efficient genotype stored less nitrate compared to UC82, which was allocated and assimilated to the shoot. More interestingly, the expression of SlNRT2.7 was significantly higher in RO shoot compared to UC82 and strongly correlated to RO higher growth as well as to NUE and NUtE component. Our findings underlined the differential regulation of N-metabolism genes that may confer to NUtE component a pivotal role in NUE enhancement in tomato. • The physiological and molecular mechanisms contributing to high NUE in tomato were highlighted. • The major role of the Nitrogen Utilization Efficiency (NUtE) component was emphasized. • Differential regulation of main N-metabolism related genes was assessed in NUE-contrasting genotypes under limiting N-supply. • High NUE was correlated to lower SlCLCa and SlNRT1.8 transcript levels in the root of the efficient genotype. • High NUE was correlated to higher SlNRT1.5 expression in root, and to SlNR and SlNRT2.7 in shoot of the efficient genotype. [ABSTRACT FROM AUTHOR]

Abstract Essential oils (EOs) have been extensively studied as valuable eco-friendly compounds with herbicidal activity for weed management. Phytotoxic potential of EOs, extracted from a wild population of Origanum vulgare ssp. hirtum (Link) Ietswaart, has been here evaluated on plant model Arabidopsis, through a physiological and metabolomic approach. The EOs composition was mainly characterized by monoterpenes and sesquiterpenes, with a strong abundance of two monoterpenic phenols, namely carvacrol and thymol, and the monoterpene o -cymene. The in vitro bioassay confirmed a strong phytotoxic effect of EOs on Arabidopsis rosettes, showing by both a strong growth reduction and highly chlorotic leaves. In well-developed seedlings, EOs firstly caused growth reduction and leaf chlorosis, together with a series of interconnected metabolic alterations: i) impairing the nitrogen assimilation into amino acids, which affects in particular the glutamine metabolism; and as consequence ii) excessive accumulation of toxic ammonia into the leaves, associated with oxidative stress and damage; iii) declining the efficiency of the photosynthetic apparatus, connected to the reduced CO 2 fixation and photooxidation protection; iv) impairing the photorespiratory pathway. Overall, the results highlights that EOs alters principally the ability of Arabidopsis seedlings to incorporate inorganic nitrogen into amino acids, principally glutamine, leading to a dramatic accumulation of ammonia in leaf cells. This primary effect induces, in turn, a cascade of reactions that limits the efficiency of PSII, inducing oxidative stress and finally causing a strong plant growth reduction, leaf necrosis and eventually plant death. These findings suggest that O. vulgare EOs might be proficiently exploited as a potential bioherbicide in an ecofriendly agriculture. Moreover, its multitarget activity could be advantageous in limiting weed resistance phenomenon. [ABSTRACT FROM AUTHOR]

Abstract: Eggplant cultivations are severely damaged by Colorado potato beetle (CPB) attacks. Two transgenic eggplant hybrids bearing a mutagenized Bacillus thuringiensis Berl. Cry3B gene were tested to assess their resistance to this insect pest. Field trials were performed at two locations for two consecutive years. Transgenic hybrids were deployed as pure stands (100% transgenic plants) and as mixed plot with 20% of non-toxic wild-type plants. Samples were taken bi-weekly to assess insect abundance; at harvest, total yield was recorded. In both locations, CPB infestation was relevant only in 1 of the 2 years. Field observations confirmed that Bt-expressing eggplant hybrids were able to control insect infestation both as pure stands and as the mixed ones. When insect infestation was massive, transgenic hybrids gave a significantly higher yield than untransformed ones, regardless of their deployment method. Mixed deployment of Bt-expressing eggplants may well be considered as a useful means of CPB control, which could possibly help delaying insect adaptation to cry toxin. [Copyright &y& Elsevier]

• A set of nuclear microsatellites (nSSR) in cluster bean was isolated. • Interesting correlations between productive parameters were identified. • A significative relationship between morpho-productive and genetic traits was observed. • Integrated approach stands up as a powerful tool for future breeding programs in guar. Guar (Cyamopsis tetragonoloba (L.) Taub.) is mainly cultivated as an industrial crop due to its high-quality galactomannan gum used as a thickener, flocculant, emulsion stabilizer and gelling agent in many industrial activities. In the present study, carried out in Southern Italy, a core collection of 46 guar genotypes, collected across the natural distribution area of the species, was characterized through a multidisciplinary approach, focusing on morphological (plant, leaf, stem and branch), productive (1000-seed weight and seeds per plant) and genetic traits. Plant height ranged from 37.7 to 97.3 cm. Branch number ranged from 0 to 12; branching genotypes showed a lower height of insertion of the first cluster. Seed weight showed an average value of 40.1 g per 1000 seeds with a narrow CV (10.1%) and nine genotypes yielded more than 45 g of seeds per plant. Positive correlation was observed between seeds and clusters per plant (0.77), seeds and pods per plant (0.94) and seeds per plant and seeds per pod (0.44). The high-throughput sequencing allowed us to isolate a set (157) of nuclear microsatellite (nSSR) markers from guar. Fourteen out of 48 analyzed nSSR markers showed polymorphisms and a sizeable discrimination power (PIC = 0.399; PI = 0.380) and gene diversity (0.276 ≤ H e ≤ 0.728) within the germplasm collection. The Discriminant Analysis of Principal Components (DAPC) highlighted three main clusters, with a private group in which three accessions from Delhi-India were included. Interestingly, the DAPC and morphological (PCA) analyses appeared to be in agreement, but with a partial discrimination across samples on the basis of geographic origin. However, for the first time in guar, a relationship between morpho-productive and genetic traits was underlined, showing significant p values (p < 0.05) in the Mantel test. Therefore, the novel set of molecular markers (nSSR) proposed here could be adopted as a useful tool to characterize the guar accessions for future breeding programs, looking for morpho-productive and productive valuable genotypes. [ABSTRACT FROM AUTHOR]