Gianluca Caruso

Establishment of Aster sedifolius and Aster caucasicus callus cultures as a potential source of antioxidants

Abstract Callus cultures were established for Aster sedifolius and Aster caucasicus, two Aster species used in natural medicine for their anticancer, antibacterial and antiviral activities attributed to the high content of antioxidant compounds such as polyphenols and ascorbate. The effects of growth medium and light condition on the induction and growth rate of callus from leaf, petiole and root explants are reported. Callus induction and proliferation depended on the genotype and the experimental conditions. In particular, a profuse callus culture was obtained from leaf explants grown in the light on medium supplemented with 2,4-D (0.1 mg l−1) for A. caucasicus and on medium supplemented with 2,4-D (0.44 mg l−1) plus 6-benzil-ammino-purine (BAP) (0.22 mg l−1) for A. sedifolius. The content of total polyphenol and ascorbic acid was estimated in leaf and petiole explants of in vivo plants and in the relative derived calli. In calli, polyphenol content was lower than in the corresponding in vivo organs. Furthermore, the total ascorbic acid content decreased in calli while the reduced ascorbic acid pool increased. These findings demonstrate that Aster callus cultures produce antioxidant compounds and as such might be a model system to investigate the regulation and production of these important metabolites.

Exploring tomato Solanum pennellii introgression lines for residual biomass and enzymatic digestibility traits

BackgroundResidual biomass production for fuel conversion represents a unique opportunity to avoid concerns about compromising food supply by using dedicated feedstock crops. Developing tomato varieties suitable for both food consumption and fuel conversion requires the establishment of new selection methods.ResultsA tomato Solanum pennellii introgression population was assessed for fruit yield, biomass phenotypic diversity, and for saccharification potential. Introgression lines 2–5, 2–6, 6–3, 7–2, 10–2 and 12–4 showed the best combination of fruit and residual biomass production. Lignin, cellulose, hemicellulose content and saccharification rate showed a wide variation in the tested lines. Within hemicellulose, xylose value was high in IL 6–3, IL 7–2 and IL 6–2, whereas arabinose showed a low content in IL 10–2, IL 6–3 and IL 2–6. The latter line showed also the highest ethanol potential production. Alkali pre-treatment resulted in the highest values of saccharification in most of lines tested, suggesting that chemical pretreatment is an important factor for improving biomass processability. Interestingly, extreme genotypes for more than one single trait were found, allowing the identification of better genotypes. Cell wall related genes mapping in genomic regions involved into tomato biomass production and digestibility variation highlighted potential candidate genes. Molecular expression profile of few of them provided useful information about challenged pathways.ConclusionsThe screening of S. pennellii introgression population resulted very useful for delving into complex traits such as biomass production and digestibility. The extreme genotypes identified could be fruitfully employed for both genetic studies and breeding.

Yield, Quality and Antioxidant Properties of Indian Mustard (Brassica juncea L.) in Response to Foliar Biofortification with Selenium and Iodine

One of the possible ways to challenge selenium (Se) and iodine (I) deficiency in human beings is the joint biofortification of plants with these elements. Though the relationship between Se and I is highly pronounced in mammals, little is known about their interactions in plants where Se and I are considered not to be essential. Peculiarities of Se and I assimilation by a natural Se accumulator, such as Brassica juncea L., cultivar Volnushka, were assessed upon joint and separate plant foliar supply with sodium selenate (50 mg Se L−1) and potassium iodide (100 mg I L−1), in two crop seasons (spring, summer). Conversely to the individual application of Se and I, their joint supply did not stimulate plant growth. Separate use of sodium selenate enhanced I accumulation by 2.64 times, while biofortification with I increased the Se content in plant leaves by 4.3 times; this phenomenon was also associated with significant increase of total soluble solids and ascorbic acid content in leaves. The joint supply of Se and I did not affect the mentioned parameters. Both joint and separate application of Se and I led to synergism between these elements in: inhibiting nitrate accumulation; stimulating flavonoids biosynthesis (2–2.3 times compared to control plants) as well as Al and B accumulation; decreasing Cd and Sr concentrations. Plant biofortification with I increased the content of Mn and decreased K and Li. The consumption of 100 g Brassica juncea leaves provided 100% of the adequate human requirement of Se and 15.5% of I.

Screening of giant reed (Arundo donax L.) ecotypes for biomass production under salt stress

Abstract Given its high biomass and plasticity, Arundo donax L. is a promising ligno-cellulosic crop for cultivation in marginal lands in temperate climates. In order to test for adaptation to salinity, growth parameters of several A. donax clones were evaluated under two salt regimes in hydroponics. Mild NaCl stress (50 mM NaCl, 5.6 mS cm−1 EC, for 10 days) failed to discriminate between ecotypes, while a more severe NaCl treatment (150 mM, 18.8 mS cm−1 EC, for 21 days) enabled the identification of ecotypes maintaining plant growth under high salinity. Among several biometric parameters, 4th leaf width, and shoot and root DW consistently highlighted differences between ecotypes. Gas-exchange parameters also responded to severe NaCl treatment, while the photosystem efficiency was good, regardless of treatment. The results confirm that A. donax can be considered moderately tolerant to NaCl stress, with variation between ecotypes. Our screening protocol identified ecotypes with higher biomass production under severe NaCl treatment and can be useful for preliminary evaluation of NaCl tolerant clones for increasing productivity under salinity. The detected inter-ecotype variability could also be investigated to identify suitable clones for different environments.