Scorpiurus muricatus L.: an interesting legume species for Mediterranean forage systems

Scorpiurus muricatus L. (prickly scorpion’s tail) is a legume species widely distributed as a spontaneous plant in Mediterranean pastures. In Sicily, farmers ascribe to this species a very high palatability and galactogogue effect, so that its abundance increases the value of the pasture. However, despite its worthy traits, the use of S. muricatus as a forage within cropping systems has not been well investigated. A field experiment was performed during two growing seasons in a semiarid Mediterranean environment to acquire information on the productivity of S. muricatus in comparison with other forage species grown in Mediterranean areas (e.g. berseem clover, burr medic, subterranean clover) and on its response to different cutting managements (cuts made in different phenological stages). Results showed that S. muricatus can provide biomass yield similar to, and in some cases higher than, that of the other forage legumes evaluated, differing from these species in its temporal distribution of the biomass accumulation. The findings contribute to define the role that S. muricatus could play in improving the productivity sustainability of the Mediterranean forage systems

Nitrogen uptake and nitrogen fertilizer recovery in old and modern wheat genotypes grown in the presence or absence of interspecific competition

Choosing genotypes with a high capacity for taking up nitrogen (N) from the soil and the ability to efficiently compete with weeds for this nutrient is essential to increasing the sustainability of cropping systems that are less dependent on auxiliary inputs. This research aimed to verify whether differences exist in N uptake and N fertilizer recovery capacity among wheat genotypes and, if so, whether these differences are related to a different competitive ability against weeds of wheat genotypes. To this end, 12 genotypes, varying widely in morphological traits and year of release, were grown in the presence or absence of interspecific competition (using Avena sativa L. as a surrogate weed). Isotopic tracer 15N was used to measure the fertilizer N uptake efficiencies of the wheat genotypes and weed. A field experiment, a split-plot design with four replications, was conducted during two consecutive growing seasons in a typical Mediterranean environment. In the absence of interspecific competition, few differences in either total N uptake (range: 98–112 kg N ha–1) or the 15N fertilizer recovery fraction (range: 30.0–36.7%) were observed among the wheat genotypes. The presence of competition, compared to competitor-free conditions, resulted in reductions in grain yield (49%), total N uptake (29%), and an 15N fertilizer recovery fraction (32%) that were on average markedly higher in modern varieties than in old ones. Both biomass and grain reductions were strongly related to the biomass of the competitor (correlation coefficients > 0.95), which ranged from 135 g m–2 to 573 g m–2. Variations in both grain and biomass yield due to interspecific competition were significantly correlated with percentage of soil cover and leaf area at tillering, plant height at heading, and total N uptake, thus highlighting that the ability to take up N from the soil played a certain role in determining the different competitive abilities against weed of the genotypes

Morpho-agronomic and genetic diversity among twelve Sicilian agro-ecotypes of lentil (Lens culinaris)

Although Sicily is relatively small (about 25000 km2), it accounts for several agro-ecotypes of lentil (Lens culinaris Medik.), for many of which no data on morphological, agronomic, and organoleptic characteristics are available to date. Thus, experiments were performed to characterize 12 lentil agro-ecotypes from different areas of Sicily, including some small islands surrounding the main island, and to assess the extent of genetic diversity (by means of six inter-simple sequence repeat [ISSR] primers). A famous agro-ecotype from central Italy (CastellucciodiNorcia) and two commercial varieties from Canada (Eston and Laird) were also included in the study. The results showed a large degree of genetic diversity (based on ISSR markers) and variability in pheno-morphological and agronomic traits. In contrast, the intra-accession variability was on average rather low. The agronomic (productivity, nitrogen fixation capacity) and qualitative (lipid content, hydration coefficient) attributes of several Sicilian agro-ecotypes were more pronounced than those of the controls. This fact certainly represents a prerequisite for their future economic valorization. Moreover, the observed variability may be of interest from the point of view of breeding

Molecular and agronomic responses to plant-growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi in durum wheat

Plant-growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal (AM) fungi contribute to plant nutrient uptake by increasing the availability of nutrients and the root adsorbing surface (Garg et al., 2006; Asghar et al. 2002). The first objective of this study was to determine the effects of these associations on plant total biomass and grain yield in durum wheat (cv. Anco Marzio). Secondly, we aimed to analyze the root transcriptomic and metabolomic changes in response to mychorrizal infections and the expression pattern of key genes involved in nutrient uptake and stress responses. Field analysis were carried out in inner Sicily, a typical Mediterranean area. Four types of biotic association in presence/absence of easily mineralizable organic nitrogen were studied: 1) not inoculated soil (control); 2) inoculated with a commercial mix of 8 AM fungal species; 3) inoculated with a commercial mix of 13 PGPR (Bacillus spp.); 4) inoculated of both AMF and PGPR mixes. Nitrogen content in aboveground biomass was determined at stem elongation stage. Quantitative RT-PCR assays were designed for nitrogen and phosphate transporter genes basing on sequence homologies with Triticum aestivum. An increase of total biomass when both PGPR and AM fungi were inoculated. In addition, PGPR inoculum determined a biomass increase when the organic fertilizer was supplied. Data showed a general downregulation of the 13 analyzed genes when crop is fertilized. In absence of fertilization, the co-inoculation of PGPR and AM fungi upregulated phosphate transporter genes (PT1, PT2, PT2.1). Mycorrizal inoculation seemed to contribute a greater extent. When organic fertilizer was supplied, similar trend was obserbed only for PT2.1. Transcript abundance of ammonium transporters were higher when crop was co-inoculated with AM fungi and PGPR. In unfertilized conditions, the inoculation of AM fungi significantly induced the expression of the nitrate transporter genes (NRT1.1; NRT2 and NAR2.2) irrespective of the inoculation of PGPR. Mycorrhizal and PGPR inoculation seemed to be synergistically efficient to increase the total durum wheat biomass. Preliminary results of durum wheat transcriptome and metabolome in response to mycorrhizal infections will be additionally presented. Gene expression analysis could lead to the identification of biomarkers usable to early select genotypes for an increased nutrient uptake efficiency

Aromatic and proteomic analyses corroborate the distinction between Mediterranean landraces and modern varieties of durum wheat

In this paper volatile organic compounds (VOCs) from durum wheat cultivars and landraces were analyzed using PTR-TOF-MS. The aim was to characterize the VOC’s profile of the wholemeal flour and of the kernel to find out if any VOCs were specific to varieties and sample matrices. The VOC data is accompanied by SDS-PAGE analyses of the storage proteins (gliadins and glutenins). Statistical analyses was carried out both on the signals obtained by MS and on the protein profiles. The difference between the VOC profile of two cultivars or two preparations of the same sample - matrices, in this case kernel vs wholemeal flour - can be very subtle; the high resolution of PTR-TOF-MS - down to levels as low as pptv - made it possible to recognize these differences. The effects of grinding on the VOC profiles were analyzed using SIMPER and Tanglegram statistical methods. Our results show that it is possible describe samples using VOC profiles and protein data

Aromatic and proteomic analyses corroborate the distinction between Mediterranean landraces and modern varieties of durum wheat

In this paper volatile organic compounds (VOCs) from durum wheat cultivars and landraces were analyzed using PTR-TOF-MS. The aim was to characterize the VOC's profile of the wholemeal flour and of the kernel to find out if any VOCs were specific to varieties and sample matrices. The VOC data is accompanied by SDS-PAGE analyses of the storage proteins (gliadins and glutenins). Statistical analyses was carried out both on the signals obtained by MS and on the protein profiles. The difference between the VOC profile of two cultivars or two preparations of the same sample - matrices, in this case kernel vs wholemeal flour - can be very subtle; the high resolution of PTR-TOF-MS - down to levels as low as pptv - made it possible to recognize these differences. The effects of grinding on the VOC profiles were analyzed using SIMPER and Tanglegram statistical methods. Our results show that it is possible describe samples using VOC profiles and protein data