SUMMARY A virus with isometric particles c. 26–28 nm in diameter isolated from naturally infected lucerne (Medicago sativa) in Australia and reported there to be a strain of lucerne Australian latent virus (LALV), is shown to be a distinct virus. The virus, called lucerne Australian symptomless (LASV), was mechanically transmitted to 10 of 22 plant species inoculated, but only induced symptoms in three Chenopodium species and Gomphrena globosa. Virus particles occurred in relatively low concentrations in plant sap, and the virus could not be reliably maintained in culture by serial transmission to plants during winter (October‐April). During the summer, sap of infected C. quinoa remained infective after diluting 10‐2 but not 10‐3, after heating for 10 min at 50 but not 55 oC and after storage for 24 days (the longest period tested) at 20, 4 and ‐15 oC. LASV was seed‐borne to 6% of C. quinoa seedlings. Partially purified preparations of virus particles contained one nucleoprotein component with a sedimentation coefficient of c. BOS. Particles contained two polypeptide species of estimated mol. wts 26 000 and 40 000, and two ssRNA species which, when denatured in glyoxal, had apparent mol. wts of 2–5 times 106 and 1–4 times 106. The infectivity of virus RNA was abolished by incubation with proteinase K. Purified particles of LASV reacted with homologous antiserum (gel diffusion titre 1:256) but not with antiserum to LALV or to 13 other plant viruses with isometric particles including arracacha B (AVB), broad bean wilt, rubus Chinese seed‐borne (RCSV) and strawberry latent ringspot (SLRV) viruses, and five comoviruses. These properties distinguish LASV from LALV and from all recognised nepoviruses and comoviruses. Its closest affinities are with SLRV, RCSV and possibly AVB; these viruses may comprise a distinct virus group or nepovirus subgroup.

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In this study three Trichoderma species isolated from Moroccan soil (natural and agricultural habitats) were investigated for their biocontrol potential against virulent Verticillium dahliae on eggplant in green house conditions based on dipping root approach. Evaluation of biocontrol efficacy of Trichoderma spp. demonstrated effective potential of Trichoderma on reducing Verticilium disease on eggplant cultivars. Disease assessment was established by measuring disease incidence in root units (DI-RU) and in the above ground of eggplant cultivars (DI-AU). DI-RU% was recorded at 12.5%, 25.0%, 31.3% and 37.5% in T3, TC, T1 and T2 treatment respectively where DI-RU recorded in Tm2 controls; eggplants inoculated with Verticillium only was equal to 100.0%. Whereas, disease incidence outcomes in aerial part was DI-AU = 100.0% in treatments TC and T2, 87.5% in T1 and 96.0% in T3 treatment where Tm2 controls were assessed with 100.0%.

Common bean (Phaseolus vulgaris L.) is grown on approximately 1,500 ha in commercial greenhouses and is of major economic importance in the Souss-Massa Region, Agadir, Morocco. Since October 2003, symptoms resembling a viral disease, consisting of pod mosaic and distortion and mild to severe mosaic in leaves, have been observed on bean plants in several greenhouses. Mechanical inoculation with symptomatic leaf extracts produced necrotic local lesions on P. vulgaris ‘Pinto’ and systemic symptoms similar to those observed in the naturally infected bean plants P. vulgaris ‘Donna’ (five plants per cultivar). Inoculated and naturally infected samples reacted positively using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to Southern bean mosaic virus (SBMV) (DSMZ, Braunschweig, Germany), a member of the Sobemovirus genus that is transmitted by contact, soil, beetles, and seeds (1). Virions purified from a naturally infected ‘Donna’ plant contained a 30-kDa polypeptide that reacted positively using sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis with SBMV antiserum (DSMZ). Reverse transcription-polymerase chain reaction amplification with SMBV primers as described by Verhoeven et al. (2) produced an expected 870-bp band. The amplicon was cloned, sequenced (GenBank Accession No. AJ748276), and compared to those isolates available in GenBank and had a nucleotide sequence identity of 87% and a derived amino acid sequence identity of 95% with an SBMV isolate from Spain (2). During a survey in different areas of the Souss-Massa Region, 20 symptomatic leaf and pod samples were randomly collected from 12 greenhouses (50 ha) where significant commercial losses were suffered because of this virus disease, and all samples were positive using DAS-ELISA for SBMV. To our knowledge, this is the first report of SBMV in Morocco. References: (1) J. H. Tremaine and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983. (2) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 109:935, 2003.

In this chapter, the authors introduce two research axes: Part A, nano-biosensors as ad-hoc technologies designed to meet plant diagnostic sensitivity and specificity needs at point of care, and Part B, the study of the interaction of drought and infection stresses in crops investigating bio-control potential antagonists in developing integrated approach (IPM) for disease control measures in crops system. The first part will be revising most used nano-biosensors in plant pathogens detection using different platforms in greenhouses, on-field, and during postharvest. A special focus will be on optical and voltametric immuno/DNA sensors application in plant protection. The last part will present case studies of using nanoparticles functionalized with antibody/DNA for detecting pathogenic Pseudomonas sp, mosaic viruses, Botrytis cinereal, and Fusarium mycotoxins (DON). The second part will be interpreting experimental results of a case study on evaluating bio-control efficacy of local Trichoderma spp. using root dips treatment in Fusarium solani-green beans pathosystem as a model.