Strigolactones: how far is their commercial use for agricultural purposes?

Strigolactones are a class of natural and synthetic compounds that in the past decade have been exciting the scientific community not only for their intriguing biological properties but also for their potential applications in agriculture. These applications range from their use as hormones to modify and/or manage plant architecture, to their use as stimulants to induce seed germination of parasitic weeds and thus control their infestation by a reduced seed bank, to their use as ‘biostimulants’ of plant root colonisation by arbuscular mycorrhizal fungi, improving plant nutritional capabilities, to other still unknown effects on microbial soil communities. More recently, these compounds have also been attracting the interest of agrochemical companies. In spite of their biological attractiveness, practical applications are still greatly hampered by the low product yields obtainable by plant root exudates, by the costs of their synthesis, by the lack of knowledge of their off‐target effects and by the not yet specified or properly identified legislation that could regulate the use of these compounds, depending on the agricultural purposes. The aim of this article is to discuss, in the light of current knowledge, the different scenarios that might play out in the near future with regard to the practical application of strigolactones. © 2016 Society of Chemical Industry     

Allelic variation of the ACCase gene and response to ACCase-inhibiting herbicides in pinoxaden-resistant Lolium spp

BACKGROUND: The repeated use of acetyl‐coenzyme A carboxylase (ACCase) inhibiting herbicides to control grass weeds has selected for resistance in Lolium spp. populations in Italy. The efficacy of pinoxaden, a recently marketed phenylpyrazoline herbicide, is of concern where resistance to ACCase inhibitors has already been ascertained. ACCase mutations associated with pinoxaden resistance were investigated, and the cross‐resistance pattern to clodinafop, haloxyfop, sethoxydim, clethodim and pinoxaden was established on homo/heterozygous plants for four mutant ACCase alleles. RESULTS: Seven different mutant ACCase alleles (1781‐Leu, 1999‐Leu, 2041‐Asn, 2041‐Val, 2078‐Gly, 2088‐Arg and 2096‐Ala) and 13 combinations with two types of mutation were detected in the pinoxaden‐resistant plants. The 1781‐Leu allele appears to confer a dominant resistance to pinoxaden, clodinafop, haloxyfop, sethoxydim and clethodim at 60 g AI ha^?1. The 2041‐Asn and 2041‐Val alleles are associated with dominant or partially dominant resistance to FOPs, no substantial resistance to DIMs and a moderate resistance to pinoxaden. The 2088‐Arg allele endows a partially dominant resistance to clodinafop, sethoxydim and most likely to pinoxaden. In addition, non‐target‐site resistance mechanisms seem to be involved in pinoxaden resistance. CONCLUSION: Almost all the ACCase mutations selected in the field by other ACCase inhibitors are likely to confer resistance to pinoxaden. Although pinoxaden is sometimes able to control FOP‐resistant populations, it should not be considered as a sustainable ACCase resistance management tool. The presence of non‐ACCase‐based resistance mechanisms that could confer resistance to herbicides with different modes of action further complicates the resistance management strategies. Copyright © 2011 Society of Chemical Industry     

A novel strategy to select Bifidobacterium strains and prebiotics as natural growth promoters in newly weaned pigs

The study addresses the first two weeks of piglet weaning and is aimed at i) identifying new probiotic strains of Bifidobacterium spp. and non-digestible oligosaccharides (NDO) able to increase the level of autochthonous bifidobacteria in the gut, and ii) finding the best probiotic doses, and probiotic-NDO combinations for piglet growth and gut health.Initially, on a total of 60 pigs we administered 12 strains of 4 bifidobacteria species taken from our collection of strains of different ecological origin. We found the most promising probiotic candidates to be two strains of B. animalis subsp. lactis (M 354 and Ra 18) and one strain of B. choerinum (Su 891), as these led to an increase in the number of viable bifidobacteria in the caecum. In a second trial, a different set of 64 piglets were fed a diet containing a galacto-oligosaccharide (1%) from milk whey, and two fructo-oligosaccharides (4%) from chicory inulin and sugar beet (SbFOS). There was virtually no effect on the hindgut microbiota, except for SbFOS at 4% which tended to increase the endogenous bifidobacteria. Then, in a third trial employing 128 weaning pigs, the probiotic strains Ra 18 and Su 891 were tested individually, at different doses (0; 10⁷; 10⁹; 10¹¹ per pig per day) and combined with 0% or 2% SbFOS supplementation. It was found that Ra 18 improved the live weight growth linearly, while the Su 891 did not. The FOS supplementation showed no interaction with the Ra 18 or Su 891 probiotics for growth performance and no effect on this response criterion.Our selection procedure has highlighted that B. animalis subsp. lactis Ra 18, at 10¹¹ CFU per pig per day, appears to be the best probiotic choice for improved growth performance in weaning piglets.     

Synthesis and antifungal action of new tricyclazole analogues

Melanins are very important pigments for the survival and longevity of fungi, so their biosynthesis inhibition is a new biochemical target aiming at the discovery of selective fungicides. In this work is described the synthesis of new pyrazolo-thiazolo-triazole compounds, analogues of tricyclazole (a commercial antifungal product that acts by inhibiting melanin synthesis), and their biological activity was studied on some dermatophytes and phytopathogens. The compounds poorly inhibited the growth and pigmentation of fungi tested and were less efficient than tricyclazole. Electron microscopy on Botrytis cinerea showed that treatment with the most active compound caused abnormally thickened and stratified walls in fungi, whose ultrastructure was, in contrast, generally normal. The fungus treated with tricyclazole, on the other hand, appeared to be drastically altered, so as to become completely disorganized. These results suggest that the new azole compounds employ an action mechanism similar to that of other azoles, but dissimilar to that of tricyclazole.     

Ageing and the Mediterranean diet: a review of the role of dietary fats

Consumers are becoming increasingly aware of the relationship between food and health. Concerns have been raised about dietary fats and their relative nutritional advantages or disadvantages. In investigations of the associations between health and fat intake, special emphasis has been placed on the benefits of virgin olive oil for counteracting certain neurodegenerative diseases and ageing. With respect to ageing, accumulating evidence indicates that an improvement in quality of life can be reached by modulation of the extrinsic factors that influence many ageing processes. Of the modifiable factors, nutrition appears to be one of the strongest elements known to influence the rate of ageing as well as the incidence of age-associated diseases such as atherosclerosis and neurodegenerative pathologies. This paper reviews the theory of ageing and the role of fatty acids in the mechanisms affecting its evolution. It also confirms that virgin olive oil, an essential component of the Mediterranean diet, provides large amounts of stable and not easily oxidizable fatty acids as well as remarkable quantities of powerful antioxidant molecules.     

Efficiency of controlled drainage and subirrigation in reducing nitrogen losses from agricultural fields

In northeast Italy, a regimen of controlled drainage in winter and subirrigation in summer was tested as a strategy for continuous water table management with the benefits of optimizing water use and reducing unnecessary drainage and nitrogen losses from agricultural fields.To study the feasibility and performance of water table management, an experimental facility was set up in 1996 to reproduce a hypothetical 6-ha agricultural basin with different land drainage systems existing in the region. Four treatments were compared: open ditches with free drainage and no irrigation (O), open ditches with controlled drainage and subirrigation (O-CI), subsurface corrugated drains with free drainage and no irrigation (S), subsurface corrugated drains with controlled drainage and subirrigation (S-CI). As typically in the region free drainage ditches were spaced 30 m apart, and subsurface corrugated drains were spaced 8 m apart.Data were collected from 1997 to 2003 on water table depth, drained volume, nitrate-nitrogen concentration in the drainage water, and nitrate-nitrogen concentration in the groundwater at various depths up to 3 m.Subsurface corrugated drains with free drainage (S) gave the highest measured drainage volume of the four regimes, discharging, on average, more than 50% of annual rainfall, the second-highest concentration of nitrate-nitrogen in the drainage water, and the highest nitrate-nitrogen losses at 236 k ha⁻¹.Open ditches with free drainage (O) showed 18% drainage return of rainfall, relatively low concentration of nitrate-nitrogen in the drainage water, the highest nitrate-nitrogen concentration in the shallow groundwater, and 51 kg ha⁻¹ nitrate-nitrogen losses.Both treatments with controlled drainage and subirrigation (O-CI and S-CI) showed annual rainfall drainage of approximately 10%. O-CI showed the lowest nitrate-nitrogen concentration in the drainage water, and the lowest nitrogen losses (15 kg ha⁻¹). S-CI showed the highest nitrate-nitrogen concentration in the drainage water, and 70 kg ha⁻¹ nitrate-nitrogen losses. Reduced drained volumes resulted from the combined effects of reduced peak flow and reduced number of days with drainage.A linear relationship between daily cumulative nitrate-nitrogen losses and daily cumulative drainage volumes was found, with slopes of 0.16, 0.12, 0.07, and 0.04 kg ha⁻¹ of nitrate-nitrogen lost per mm of drained water in S-CI, S, O, and O-CI respectively.These data suggest that controlled drainage and subirrigation can be applied at farm scale in northeast Italy, with advantages for water conservation.     

Fluorescence of vegetable oils: olive oils

Fluorescence spectra of undiluted extra virgin olive oil obtained with the traditional setup (right-angle fluorescence) show considerable artifacts and deformations due to self-absorption phenomena, even when the spectra are corrected for inner filter effects. On the other side, front-face fluorescence spectra are much less affected by self-absorption. Front-face fluorescence of native olive oil reveals the presence of different fluorophores and can provide information about their amount. From the intense emission at ca. 315-330 nm, it is possible to detect fluorescent polyphenols and pherols and to evaluate their overall content. Low-intensity emission bands at 350-600 nm are correlated to vitamins and other important molecules. Among them, the fluorescence of the riboflavin fluorophore can be used to evaluate its concentration. The intense emission of chlorophyll derivatives, measured in the 640-800 nm spectral region, can provide information on their concentration.     

C, N and their Stable Isotopes in Suspended and Sedimented Matter from the PO Estuary (Italy)

C and N content, C/N (atomic) ratio, and C and N isotopic composition (δ¹³C and δ¹⁵N) were determined on suspended particulate matter and sediment samples obtained from riverine, estuarine and marine environments in two cruises (September 1995 and March 1996) in the Po estuary (Italy). Isotopic tracers of C and N, reported for the first time for this environment, gave information on sources of organic matter and their distributions. An end-member mixing model based on δ¹³C values was applied to estimate the relative importance of riverine and marine sources of organic matter in suspended particulate matter and sediments.