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The on-board attitude estimation represents a major task of the attitude and orbit determination and control subsystem as it is necessary to guarantee the spacecraft pointing accuracy as prescribed by the mission requirements. In a space mission each components requires a deep test campaign as well as the attitude estimation techniques where the Monte Carlo statistical approach represents the final step to fully validate the attitude determination algorithms. Motivated by this needs, a simulation tool suitable to develop, test and finally validate all the algorithms selected for the mission has been conceived and implemented in the ALMASat-EO context.

Research on soil microbial ecology is beginning to elucidate how and how much beneficial soil micro-organisms (i.e. plant-probiotics) contribute to plant integrity and plant environmental fitness. The differences so far highlighted among crop varieties show highly positive interactions with plant-probiotic microflora (PPM), and upgrade the role of soil PPM at the level of other essential factors for sustainable plant breeding. Current research efforts, aimed to rapidly achieve crop varieties fitting for low-input and organic production systems, finally take into account the capacity of each individual variety to efficiently exploit indigenous PPM.

In natural populations of plants, the ability to interact with beneficial rhizosphere micro-organisms like mycorrhizal fungi, associative N2 fixers, or biocontrol agents (globally named plant-probiotic micro-organisms, PPM) is a very well conserved genetic trait. In fact, during their evolution, terrestrial plants have not achieved the ability to grow independently of their own PPM, and all investigated natural plant genotypes show the biological need to find specific micro-organisms in their habitat to successfully complete their growth cycle. Selection of modern varieties has typically been performed in standardized, high fertility systems with a primary focus on yield. Under such conditions, rhizosphere microbial communities are faced with an environment that differs substantially from the one in which plants and plant-microbial interactions originally evolved. Benefits incurred through interactions between plants and PPM have been made obsolete by the excess provision of nutrients in readily plant-available forms. Studies comparing allelic diversity within landraces and modern varieties concluded that allele richness declined in modern varieties, and alleles contributing to PPM interactions were among the ones lost. In fact, wheat cultivars developed prior to 1950 were more reliant on mycorrhizal symbiosis than modern wheat cultivars. On the same way, landraces of mycorrhizal wheat grown in low-P soils produced a higher yield than modern varieties grown under the same conditions. The main present day challenges in agriculture can be summarized as the necessity to use scarce and increasingly costly fertilizer inputs more efficiently, while also raising productivity on poorer soils. Meeting these challenges will require to reintroduce genes regulating plant-PPM interactions into the gene pool of modern varieties. Despite the considerable effort devoted to the identification of suitable donors, and of genetic factors associated with these beneficial traits, progress in developing improved varieties has been slow and has so far largely been confined to modifications of traditional breeding procedures. Molecular biology, combined with Mendelian and quantitative genetics in quantitative trait locus (QTL) mapping and marker-assisted selection (MAS) are more and more used for revealing and evidence the inheritance of root association with PPM, and some examples will be given in this comunication. However, not much can be found in PPM literature about durum wheat. MAS for enhanced root-PPM association is not yet part of routine cultivar improvement programs, but this selection criterium begins to be used in experimental breeding schemes. In order to contribute to an efficient set-up of breeding programs for better durum wheat-PPM interactions, we are developing tools for the detection of plant genotypes best interacting with selected PPM, and we propose to narrow the gap between basic sciences and applied breeding, through a more interdisciplinary research. For example, if MAS for PPM-root interactions would be integrated into breeding programs that are already practicing MAS for other traits, this would avoid the necessity of additional selection methodologies purely for the determination of beneficial microbial-root associations.

A consortium of plant-probiotic microorganisms is under investigation in open field conditions, at the ICEA-certified Organic Farm “La Carioncella”, for its ability to ensure durable soil fertility while buffering nutritional inputs reduction. The primary objective of our QLIF-WP333 three-years-long project is to produce scientific data to help farmers in managing soil probiotics, as a way to reduce inputs, production costs, while keeping quality and sustainability of organic and low-input tomato production systems.

Recent breeding programs revealed that it is difficult to select varieties for low-input agriculture by starting from conventional varieties. One of the explanations given for this failing is that conventional varieties, selected under high-input conditions, would have lost genes coding for symbiotic competence. For example, conventional varieties generally show a lower capacity to sustain root symbiosis with naturally occurring arbuscular mycorrhizal fungi (AMF), than needed for low-input agriculture. Such loss in mycorrhizal competence was probably due to breeding in fully fertilized soils, which resulted in the selection for plant genotypes unable to exploit these beneficial microorganisms. Therefore, the goal of our research was to select, among ten mutant lines belonging to a tomato (cv Red Setter) EMS mutant collection, those presenting both a good mycorrhizal competence and a high level of productivity, in order to obtain tomato genotypes adapted to breeding in low-input cropping systems. The wild type line Red Setter, as well as all the 10 mutated ones, showed a characteristic AMF infection dynamics. Some differences were also found in the diversity of root-colonizing AMF taxa. One tomato mutant line was specially mycorrhizal competent, showed high symbiotic precocity and a highly structured symbiotic population. Other mutants were similar to wild type line, and more research is needed to clarify their actual position.

The use of plant-probiotic microorganisms (PPM) to control soil-borne pathogens and to improve plant nutrition is receiving increasing attention, since they may represent a sustainable alternative to chemical pesticides. We focus on recent data relating how differences in genotypic and phenotypic diversity within PPM communities can be attributed to soil type, soil management regime and plant hosts. Evidence shows that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PPM populations. [poster]

Among the genetic traits of plants, the ability to interact with plant-probiotic microorganisms (PPM, sensu Haas and Keel, 2003) is very well conserved in natural populations. In fact, during their evolution (more than 400 M years) terrestrial plants have not achieved the ability to grow independently of their own PPM, and most plant genotypes still show the biological need to find such microorganisms in their habitat to successfully complete their growth cycle. Indeed, well established knowledge on PPM, such as plant-growth-promoting-rhizobacteria (PGPR) (Kloepper et al., 1980) or arbuscular mycorrhizal fungi (AMF), tells how they positively and directly affect plant growth through several mechanisms, such as N2 fixation, P, K, microelements dissolution, biosynthesis of siderophores, plant hormones, and plant hormone regulators (Picard and Bosco, 2006). PPM can also indirectly promote plant growth by antagonizing the action of weeds, pests, and phytopathogenic organisms. All these mechanisms are regulated by the population density and biodiversity of PPM that are in direct contact with plant surfaces, or in the close rhizosphere, a habitat where there is the maximum microbial activity due to the release of organic compounds and microbial-growth regulators from plant roots. During the last decade, scientific literature has reported how breeding for conventional agriculture often resulted in modern crop varieties which are much less sensitive to PPM than needed for low-input and organic agriculture. Cultivar development in fully fertilized and parasite-protected environments has been proven to result in selection against genotypes that fully interact with AMF (Hetrick et al., 1995; Scholten et al., 2006), or PGPR (Smith et al., 1999; Engelhard et al., 2000; Germida and Siciliano, 2001; Mazzola et al., 2004). Since AMF actually reduce plant growth in environments where biotic and abiotic stresses are limited (i.e., when the cost of maintaining the AMF exceeds the benefit to the host), it is logical that selection under high input levels was highly biased towards non-mycorrhizal genotypes. In the same way, conventional breeding and crop improvement have resulted in the loss of host genes important in the PGPR-legume interaction, and thus in varieties that don’t maximize the benefits of root symbioses. As is already known for Rhizobium and AMF (Smith and Goodman, 1999), we recently proved the genetic basis of PGPR interactions with cereals (Picard and Bosco, 2006). Thus, future efforts of crop breeding in low-input and organic environments would indeed be able to take into account the biological need of plants to have broad-spectrum interactions with PPM. Here we propose and support the theoretical development, and the laboratory, field, and biostatistic assessment of a European breeding programme for crop genotypes genetically able to support broad populations of probiotic microorganisms (Picard et al., 2007). This could be done at different and parallel levels, by exploiting existing European-based knowledge on natural, local, and commercial (Bosco et al., 2006) PPM.

Research on soil microbial ecology is beginning to elucidate how and how much beneficial soil micro-organisms (i.e. plant-probiotics) contribute to plant integrity and plant environmental fitness. The differences so far highlighted among cereal varieties show highly positive interactions with plant-probiotic microflora, and upgrade the role of plant-probiotic soil micro-organisms at the level of other essential factors for sustainable plant breeding. Current European research efforts, aimed to rapidly achieve cereal varieties fitting for low-input and organic production systems, finally take into account the capacity of each individual variety to efficiently exploit indigenous probiotic micro-organisms. [invited oral keynote]

A co-operative (company, university) effort to develop a commercial PGPR-based product for sustainable production of orchard and field vegetable plants is described. Marketed probiotic microbial treatments were applied to all plants as follows: PGPR, arbuscular mycorrhizal fungi (AMF), mix of PGPR and AMF, control. Inoculation tests were performed both in microcosms (years 2002 and 2003) and in open fields (years 2003 and 2004), in conventional and organic systems, on a total of ten plant species (mostly vegetables), and up to two varieties. Plant productivity was affected by probiotic inocula according to species, and results were confirmed by molecular counts of microorganisms in the rhizospere. A clear tendency was detected for correlation between plant variety and probiotic inocula. This is in agreement with recent findings of other Authors and our own (Picard et al., this workshop), which are driving PGPR commercial research to the plant variety/genotype level.

By comparing the distribution of genomic and phenotypic markers among rhizospheric Pseudomonas strains recovered from two maize hybrids, with those of strains recovered from their four respective parental lines, we evidenced that both hybrids supported more elite probiotic strains than parents. Elite Pseudomonas strains showed potential for an appropriate in vitro 2,4-diacetylphloroglucinol (DAPG) and auxin (AIA) productivity, and a superior root-colonization ability. The actual biocontrol, root-stimulation and root-colonization abilities of these strains were confirmed by bioassays on five fungal strains and on axenic maize plants. Finally, results on the abundance and genetic diversity of resident probiotic Pseudomonas strains indicated that each hybrid was able to select its own specific probiotic population, while the four parental lines were not. The evidence that heterozygosis can drive maize plants to select elite probiotic rhizospheric DAPG+ -AIA+ Pseudomonas strains opens the way to a new strategy in the set up of plant breeding for low-input and organic agriculture.

Poster Abstract - D.06

In this study we present a novel silver complex of hyaluronan-lipoate (SHLS12) in a gel-state form. NMR analysis, conductometry and elemental analysis demonstrated stable non-covalent interactions between silver ions and the polysaccharide-lipoate backbone, whereas rheological investigations confirmed its gel-like physical-chemical behavior. Biological studies showed the ability of SHLS12 to exert a straightforward activity against different bacterial strains grown in sessile/planktonic state. The biocompatibility was also proved toward two eukaryotic cell lines. By considering both its ability to preserve antibacterial properties when exposed to the serum protein BSA and its low susceptibility to be degraded by hyaluronidase enzyme, this novel complex may be considered as a promising biomaterial for future in vivo applications.