الفهرس 
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Abstract
Isolation trials carried out from lupine rotted roots and spotted/blighted foliar resulted in development of fungal and bacterial growth that was purified through single colony or single cell isolation techniques and maintained on agar slants. Representatives of the purified isolates that proved pathogenic were first identified tentatively according to their morphological and cultural characters and subsequently verified by Mycological center at Assuit Univ.
Six Fusarium sp and four Macrophomina phaseolina isolates were secured from the diseased root system. The pathogens caused damping-off and root rot symptoms to the subjected plants in pathogenicity tests. However, Fusarium isolates proved more virulent as they caused 46.67-76.67 % damping -off and 20.33-46.67 % root rot to the host plant while Macrophomina phaseolina isolates came next after Fusarium and caused about 16.67 – 63.33 % damping - off and 15.0-19.08 % root rot symptoms to lupine plants. The secured foliar pathogenic were one isolate each of Chaetomium globosum, Chaetomium sp, Alternaria alternata and Nigrospora oryzae. Also six bacterial isolates identified as Bacillus megaterium were virulent on lupine plants as the fungal isolates and caused blight on the leaves which soon developed to be more severe and included the whole plants which eventually collapsed.
Tissue extracts prepared from experimentally diseased root or shoot systems showed great pectolytic and cellulolytic activities while healthy tissue extracts of both organs showed slight activities of the enzymes.
In varietal response test, four lupine cultivars i.e. Australian, Balady, Giza 1 and Giza 2 were tested for their susceptibility to root and shoot pathogens. All the tested cultivars were susceptible to the used root isolates (Fusarium solani isolate R2 and Macrophomina phaseolina isolate R7) and showed great percentage of damping - off and root rot diseases being cv. Balady more sensitive than the other tested cvs.
On the other hand, foliage of the aforementioned cultivars were also tested for their relative susceptibility towards one isolate each of Alternaria alternata, Nigrospora oryzae and two Chaetomium spp together with six Bacillus megaterium isolates. All the tested cultivars showed great susceptibility towards the tested fungal pathogens with slight variation among them. In case of the bacterial isolates, the tested cultivars behaved similarly as in case of fungi to the six bacterial isolates and the cultivar Balady was most sensitive to all isolates. However, isolates B2 and B6 were more virulent than the others as they recorded disease severity means as high as 82.45% and 82.95 % on the subjected cvs.
Sowing date effect on foliar disease severity caused by two fungal isolates Nigrospora oryzae and Alternaria alternata and two Bacillus megaterium isolates showed that the infection by all tested bacterial and fungal isolates took place at all the tested sowing dates of 1 st Octeber, 1 st November and 1 st December. However the severity exhibited by the used pathogens was more active at sowing date of 1 st October as it recorded 85.0 - 86.83 % in case of the fungal isolates and was 88.40 – 89.10 % in case of the bacterial isolates. Disease severity showed marked decline at sowing date 1 st December as it recorded 27.0 -29.90% in case of the fungal isolates and 29.90-43.40% in case of bacterial infection isolates.
One isolate each of Alternaria alternata and Nigrospora oryzae and two Bacillus megaterium isolates that caused blight on lupine plants were subsequently tested on other foliar plants representatives of 17 plant species. The two fungal isolates could infect faba bean, common bean, pea, lentil, chickpea, Egyptian clover, alfalfa, fenugreek, cowpea and soybean causing symptoms varied from leaf spots to blight. However the other tested plants i.e. India melilot, medic, wheat, barley, spinach, sunflower and cocklebur were highly resistant. However, in case of the used two Bacillus megaterium isolates, none of which could infect any of the tested plants but produced small necrotic spots on faba bean leaves.
Nine antioxidant compounds i.e ascrorbic,. Benzoic, ferulic, fumaric, malic, oxalic, salicylic acids, hydroquinone and thiourea together with CaCl2 and K2HPO4 salts were applied on lupine plants in the frame of disease management study. All the tested chemicals clearly retarded disease development on lupine plants emerged from seeds previously soaked in solution of the compounds (especially in case of higher concentration, 200 ppm for the antioxidants and 4000 ppm for the salts). These treatments caused clear protection to lupine against damping-off and root rot diseases caused by Fusarium solani and Macrophomina phaseolina and greatly increase the percentage of survival plants.
In case of foliar disease, the tested chemicals varied greatly in their effect on the appearance of foliar diseases caused by the two foliar pathogens i.e. Alternaria alternata and Nigrospora oryzae and by two Bacillus megaterium isolates. Benzoic, ferulic, malic and oxalic acids were the most effective antioxidants as they greatly reduced disease severity caused by either fungi or bacteria when administered as a foliar spraying or seed soaking. On the other hand, ascorbic, fumaric acid, thiourea, CaCl2 and K2HPO4 were the least effective compounds. It was clear that seed soaking method proved superior than spraying except in case of benzoic acid. It is worthnoting that the seed treater Rhizolex- T and the foliar fungicide Ridomil- plus deposit their marked inhibitory effects against root and foliage diseases, they came next after the more effective antioxidants (benzoic, ferulic, malic and oxalic acids).
Also, the in vitro effect of these chemicals on the fungal and bacterial pathogens was weak or moderate at higher concentration when compared with the in vitro effect of the two fungicides Rhizolex- T or Ridomil- plus which achieved higher inhibitory effect at 50-200 ppm for the fungal and 200 ppm for the bacterial pathogens.
Effect of the most effective antioxidants i.e. benzoic, ferulic, malic and oxalic acids were subsequently tested on lupine vigour plants emerged from soaked seeds in solutions of these antioxidants. The compounds exhibited marked increase in plant growth parameters. Treated plants showed higher plant length, more branches/plant and increased pod and seed number/plant and eventually increased mean yield/ experimental unit compared with untreated plants (control). However, deposit such increase in the mentioned parameters of the antioxidant treated plants, marked decrease in protein contents was recorded in their seeds when compared with those of the control plants. Nevertheless such decrease in protein contents was not so clear in case of oxalic acid treated plants.
Assessment of chlorophyll and carotenoids in lupine leaves taken from antioxidant treated plants (two month-old) showed marked increase in each of chlorophyll a, b and carotenoids compared with the control.
Effect of aforementioned four antioxidants on the symbiotic process between lupine roots and the symbiotant bacterium Bradyrhizobium lupini showed that nodule formation on plants emerged from seeds soaked in benzoic, ferulic and malic acids solutions clearly reduced nodule formation. On the other hand, oxalic acid clearly increased nodule formation at 50 and 100 ppm. However, at the higher concentration (200ppm), the stimulatory effect of the compound was reversed and nodule number per plant was almost equal to the control.
Assessment of peroxidase, polyphenol oxidase and phenylalanine ammonia lyase in lupine treated plants indicated great increase in their activities in antioxidants treated plants (root and foliage). Slight to moderate increase in phenolic compound contents was recorded in antioxidant treated plants measured in root or shoot systems.
Isolation of antagonistic organisms was performed from lupine phylloplane microflora. From 12 bacteria colonies, only four of which showed great inhibitory effect on the tested fungal and bacterial pathogens in plates. The selected antagonists were identified as Bacillus subtilis. For biological control, broth cultures of the most active antagonist on the fungal pathogens (isolate AB1) and bacterial pathogen (isolate AB3) were sprayed onto lupine foliage. This treatment achieved good protection against the fungal and bacterial infection when subsequently inoculated (after 24 h.) with the foliar pathogens in greenhouse test.
Interaction between the lupine symbiotant Bradyrhizobium lupini and the two root pathogens Fusarium solani and Macrophomina phaseolina were studied in sterile soil in pots. The obtained data showed that presence of Bradyrhizobium greatly reduced incidence of damping-off of lupine plant from 54.71 and 48.82% in case of Fusarium and Macrophomina respectively to 5.88% due to presence of Bradyrhizobium in association with the pathogens. Also the same situation was true for root rot disease and the symbiotant bacterium reduced root rot disease from 45.29 and 51.18% in control plants to 6.88 and 8.80%.