Enhanced resistance to citrus canker in transgenic sweet orange expressing the sarcotoxin IA gene

Citrus canker, caused by the bacterial pathogen Xanthomonas citri subp. Citri (Xcc), is a serious disease reported in most citrus-producing areas around the world. Although different levels of field resistance to citrus canker have been reported in sweet oranges, they are usually not sufficient to provide adequate control of the disease. Ectopic over-expression of antibacterial genes is one of the potential strategies to increase plant resistance to bacterial diseases. Previous in vitro results showed that sarcotoxin IA, an antimicrobial peptide isolated from the flesh fly (Sarcophaga peregrina), can be efficient to control different plant pathogenic bacteria, including Xcc. Transgenic “Pera” sweet orange (Citrus sinensis [L.] Osbeck) plants constitutively expressing the sarcotoxin IA peptide fused to the PR1a signal peptide from Nicotiana tabacum for secretion in the intercellular space were obtained by Agrobacterium-mediated transformation using thin sections of mature explants. Citrus canker resistance evaluation in leaves of transgenic and non-transgenic plants was performed through inoculations with Xcc by infiltration and spraying. The Xcc population was up to 2 log unit lower in leaves of the transgenic plants compared to those of non-transgenic controls. Incidence of canker lesions was significantly higher in non-transformed controls (>10 lesions/cm²) than in the transgenic plants (<5 lesions/cm²) after injection infiltration or spraying with Xcc inoculum. Accumulation of sarcotoxin IA peptide in sweet orange tissue did not cause any deleterious effects on the growth and development of the transgenic plants, indicating this approach is suitable to provide resistance to citrus canker.     

Evaluation of oilseed rape seed yield losses caused by <Emphasis Type="Italic">Leptosphaeria biglobosa</Emphasis> in central China

Phoma stem canker of oilseed rape (Brassica napus), caused by Leptosphaeria maculans/L. biglobosa is a globally important disease. Severe phoma stem canker symptoms have been observed on winter oilseed rape in China but the seed yield loss caused by this disease remains unknown. In May 2012 and May 2013, 17 and 13 crops were surveyed, respectively, in seven counties of Hubei Province, central China. Stems with phoma stem canker disease symptoms were sampled for pathogen isolation and identification. Only L. biglobosa was identified by culture morphology and species-specific PCR; no L. maculans was found. To evaluate the yield losses, yield components (number of branches per plant, number of pods per plant, 1000-seed weight, number of seeds per pod) were assessed on healthy and diseased plants sampled from crops in four counties and on plants from inoculated pot experiments (plants of three cultivars were inoculated at the green bud stage by injecting L. biglobosa conidia into the stem between the first and second leaf scars). Results of the field surveys showed that diseased plants had 14–61% less branches and 32–83% less pods than healthy plants, respectively. The estimated seed yield loss varied from 10% to 21% and from 13% to 37% in 2012 and 2013, respectively. In the pot experiments, there were no differences in numbers of branches or pods but there were differences in number of seeds per pod between inoculated and control plants. For the three cultivars tested, the inoculated plants had yield losses of 29–56% compared with the control. This study indicates that L. biglobosa could cause substantial seed yield loss in China.     

Morphological and molecular characterization of <Emphasis Type="Italic">Diaporthe (</Emphasis>anamorph <Emphasis Type="Italic">Phomopsis)</Emphasis> complex and pathogenicity of <Emphasis Type="Italic">Diaporthe aspalathi</Emphasis> isolates causing stem canker in soybean

The complex of Diaporthe (asexual morph) species occurring on soybean constitutes an important pathogenic group associated with diseases such as pod and stem blight, seed decay and stem canker. Stem canker, caused by Diaporthe aspalathi, has been reported as the most aggressive form of canker and its occurrence has limited soybean crop productivity in the southern United States. The main form of pathogen control is the use of stem canker resistant soybean varieties. In this study, strains of Diaporthe and Phomopsis were isolated from stem and seeds of soybean in different locations in South America during the years 1989–2014. Genomic DNA from 26 isolates were analyzed by PCR-restriction fragment length polymorphism (RFLP) and Amplified Fragment Length Polymorphism (AFLP) techniques, and sequencing of internal transcribed spacer (ITS) regions of ribosomal DNA. The molecular analysis of ITS sequences by alignment with those of ex-type strains deposited in GenBank and morphological characteristics allowed the identification of Phomopsis longicolla, D. phaseolorum var. sojae, D. caulivora and D. aspalathi. An analysis of the pathogenicity of 13 isolates of D. aspalathi inoculated in soybean genotypes carrying different resistance genes to stem canker (Rdm1, Rdm2, Rdm3, Rdm4, Rdm5 and Rdm?) enabled us to identify the occurrence of at least three races of D. aspalathi occurring in Brazil. Among the isolates identified as D. aspalathi, both molecular and phenotypic analyses showed clustering depending on the date of collection and pathogenicity, which revealed the existence of variability of the pathogen.     

Rutin promoted resistance of tomato against <Emphasis Type="Italic">Xanthomonas perforans</Emphasis>

Xanthomonas perforans is the causal agent of bacterial spot, one of the most devastating diseases of tomato that results in considerable yield losses worldwide. Rutin, as a polyphenolic substance, was used to induce resistance in tomato against X. perforans. Rutin at concentration of 2 mM had ability to reduce the disease severity of bacterial spot. On the other hand, 2 mM rutin had no antibacterial activity in vitro. Expression profiling of pathogenesis-related gene 5 (PR-5), Phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX) was probed during the enhanced resistance by rutin. Pretreatment with rutin (rutin/ X. perforans) led to induction of PR-5, PAL and LOX compared to controls (water/ X. perforans). Our results suggest that rutin-induced resistance against X. perforans in tomato might be mediated through stimulation of some defense genes such as PR-5, PAL and LOX.     

<Emphasis Type="Italic">Ralstonia solanacearum</Emphasis> upregulates marker genes of the salicylic acid and ethylene signaling pathways but not those of the jasmonic acid pathway in leaflets of <Emphasis Type="Italic">Solanum</Emphasis> lines during early stage of infection

Real-Time PCR assay was used to quantify the expression of marker genes of the salicylic acid, jasmonic acid and ethylene signaling pathways in seven Solanum lines after inoculation with a Ralstonia solanacearum phylotype I strain, R008. Four Solanum lycopersicum lines (CRA 66, Hawaii 7996, MST 32/1, Quatre carrées), one S. tuberosum line (Spunta), the wild Lycopersicon cerasiforme and Solanum commersonii were used for this investigation. Results revealed very little activation of the jasmonic acid pathway marker genes, lipoxygenase A (LoxA) and protease inhibitor II (Pin2), with no significant difference (p > 0.05) in fold change expression among the Solanum lines. In contrast the salicylic acid pathway marker genes, glucanase A (GluA) and PR-1a, and the ethylene pathway marker genes, osmotin-like (Osm) and PR-1b, were expressed at higher levels with a statistically significant difference (p < 0.05) in fold change expression among the Solanum lines. The resistant lines L. cerasiforme, CRA 66, Hawaii 7996 and S. commersonii showed stronger activation of the salicylic acid and ethylene marker genes than the moderately resistant cultivar (MST 32/1) and the susceptible lines (Quatre carrées and Spunta). The marker genes reached their highest expression levels earlier (4 h.p.i) in the resistant and moderately resistant lines than in the susceptible lines (48 h.p.i.). These results indicate that salicylic acid and ethylene signaling pathways have a significant role in defense against R. solanacearum. The timing and magnitude of the upregulation of gene expression may determine the plant ability to put up a defense response against the pathogen.     

Seasonal progression of leaf rust in ‘Niagara Rosada’ grapevine in a biannual crop system in Brazil

The soil-borne fungus Fusarium oxysporum can cause both Fusarium yellows and Fusarium root rot diseases with severe yield losses in cultivated sugar beet. These two diseases cause similar foliar symptoms but different root response and have been proposed to be caused by two distinct F. oxysporum formae speciales. Fusarium yellows, caused by F. oxysporum f. sp. betae, presents vascular discoloration, whereas Fusarium root rot, due to F. oxysporum f. sp. radicis-betae, appears as black rot visible on the root surface. The aim of this work was to study the host-pathogen interaction between sugar beet lines and isolates originally characterized as Fusarium oxysporum f. sp. betae. Eight susceptible sugar beet lines, selected by the USDA-ARS (US) and UNIPD (University of Padova, Italy) breeding programs, were inoculated with three different isolates of F. oxysporum f. sp. betae, the causal agent of Fusarium yellows, representing different genetic groups. All inoculated lines developed symptoms, but severity, expressed as area under the disease progress curve (AUDPC), differed significantly (P < 0.05) among lines. Two lines from UNIPD, 6 and 9, were the most susceptible to the disease, whereas the other lines showed similar levels. The three isolates of F. oxysporum f. sp. betae differed significantly (P < 0.05) in disease severity. Five weeks after inoculation the plants were harvested and roots examined. Surprisingly, severe root rot was observed in the susceptible UNIPD lines when inoculated with all three isolates, while this symptom was never observed in the USDA germplasm. The development of this disease symptom obviously depends on the plant genotype.     

Search for reservoirs of ‘<Emphasis Type="Italic">Candidatus</Emphasis> Liberibacter solanacearum’ and mollicutes in weeds associated with carrot and celery crops

Currently, the main arthropod vectored pathogens associated with carrot and celery crop diseases are ˋCandidatus Liberibacter solanacearum´, Spiroplasma citri and different phytoplasma species. Mitigation strategies require elucidating whether these pathogens survive in the weeds of these Apiaceae crops, which can act as reservoirs. Weed surveys were conducted in a vegetative cycle (April to October 2012) in the spontaneous vegetation that surrounded crops affected by ˋCa. L. solanacearum´, S. citri and/or phytoplasmas. Sixty-three species of 53 genera that belong to 23 botanical families were collected in the main carrot and celery Spanish production area. Species were identified, estimating coverage and abundance, and conserved in herbarium. Samples were analysed by nested-PCR with universal primers for phytoplasmas detection, and were sequenced for identification purposes; by conventional PCR for S. citri and real-time PCR for ˋCa. L. solanacearum´. The only detected pathogens were ˋCa. Phytoplasma trifolii´ (clover proliferation group 16Sr VI-A) in Amaranthus blitoides and Setaria adhaerens and ˋCa. P. solani´ (stolbur group 16Sr XII-A) in Convolvulus arvensis. These pathogens were also sporadically detected in celery or carrot crops. Unexpectedly, neither ˋCa. L. solanacearum´ nor S. citri was detected in the weed samples, despite the relatively high prevalence of these pathogens (less than 66 % and 25 %, respectively) in the surveyed plots. This suggests that weeds do not play an epidemiological role as reservoirs in the spread of such organisms in the studied region. The use of pathogen-free seed lots and the control of vectors are crucial for preventing the introduction and spread of these economical important pathogens to new areas.     

Sequence variation in ribosomal DNA and in the nuclear <Emphasis Type="Italic">hsp</Emphasis>90 gene of <Emphasis Type="Italic">Pratylenchus penetrans</Emphasis> (Nematoda: Pratylenchidae) populations and phylogenetic analysis

Tomato bacterial canker and wilt disease caused by Clavibacter michiganensis subsp. michiganensis (Cmm) is among one of the major bacterial diseases associated with tomato (Solanum lycopersicum L.) in the western Mediterranean region of Turkey. A total of 118 Cmm isolates were obtained from the petiole and the main vein of leaves of different cultivars of diseased tomato plants, and these isolates were cultured in semiselective medium (mSCM). The identity of Cmm isolates was confirmed through gas chromatography-fatty acid methyl-esters (GC-FAME) analysis and polymerase chain reaction (PCR) using the primers, CMM5 and CMM6. The fatty acid analysis of all the Turkish isolates yielded major components that included anteisoheptadeconic acid (a15:0), palmitic acid (i16:0) and anteisoheptadeconic acid (a17:0); the analysis detected and categorized all the isolates into 10 different FAME groups. Among repetitive element sequence PCR (rep-PCR) analysis, Box primer yielded the most reproducible genomic profiles with band sizes that ranged from ~200 bp to 2 kb. The isolates were also separated into 12 groups by pulsed-field gel electrophoresis (PFGE) after digesting the total genomic DNA with SpeI, a rare cutting enzyme. The genome sizes of the different strains of Cmm were also determined after running unrestricted total genomic DNA, which yielded average values between 3.0 and 3.5 MB. All the Cmm isolates had pCM1 and pCM2 plasmids. This is the first report on the detailed characterization of the Cmm population in Turkey.     

Improved control of black rot of broccoli caused by <Emphasis Type="Italic">Xanthomonas campestris</Emphasis> pv. <Emphasis Type="Italic">campestris</Emphasis> using a bacteriophage and a nonpathogenic <Emphasis Type="Italic">Xanthomonas</Emphasis> sp. strain

We examined the potential for biological control of black rot of broccoli, caused by Xanthomonas campestris pv. campestris (Xcc), using nonpathogenic Xanthomonas sp. strain 11-100-01 (npX) mixed with bacteriophage XcpSFC211 (pXS). Inoculation of intact broccoli plants in greenhouse trials with either npX or pXS did not control black rot. After injured plant inoculation, however, npX alone or npX with pXS significantly controlled black rot. When a mixed suspension of npX with pXS was placed on a membrane filter, then washed with distilled water and air-dried, a substantial amount of pXS adsorbed to the surface of npX. In a field trial, broccoli plants were sprayed with a suspension of npX with pXS, then inoculated with Xcc. A meta-analysis of the results from five field trials showed an integrated risk ratio (IRR, the ratio of disease incidence in inoculated broccoli plants to the incidence in control plants) of 0.69 after treatment with only npX and 0.59 with npX with pXS, indicating that black rot incidence was significantly reduced by each treatment. The difference between these two treatments was also significant. IRR was 1.24 when comparing suppression by npX with pXS and that by basic copper sulfate wettable powder; thus, their control was comparable. The combination of npX with pXS improved the preventive effect against black rot. This is the first report describing that a nonpathogenic Xanthomonas sp. strain mixed with a bacteriophage effectively controlled black rot of broccoli in field trials.     

Root-specific expression of defensin in transgenic tobacco results in enhanced resistance against <Emphasis Type="Italic">Phytophthora parasitica</Emphasis> var. <Emphasis Type="Italic">nicotianae</Emphasis>

Phytophthora species are soil-borne pathogens that damage plants in both agro- and natural ecosystems. To suppress the devastating pathogen, we generated a root-specific expression system using a specific promoter (pPRP3) conferring elevated expression of the target gene in roots that are very susceptible to soil-borne pathogens. To verify root-specific expression, we compared β-glucuronidase (GUS) expression driven by a constitutive or root-specific promoters in shoots and roots. In histochemical and fluorometric assays, GUS activity was detected in whole tobacco plants when GUS expression was driven by p35S, but was detected only in the roots by pPRP3. We then expressed a pepper defensin (J1–1) gene in tobacco to elucidate its effect on plant resistance. The accumulation of J1–1 was also tissue-specific in transgenic tobacco plants. Finally, transgenic plants carrying GUS or J1–1 genes in combination with p35S or pPRP3 were inoculated with Phytophthora parasitica var. nicotianae and Pythium aphanidermatum. Disease symptoms were significantly suppressed in transgenic plants that accumulated J1–1, regardless of the promoter used. Furthermore, the expression of PR genes was induced in J1–1 transgenic plants, exhibiting much higher levels in p35S-driven J1–1 plants than in pPRP3::J1–1 plants. These results demonstrated that J1–1 transgenic plants were primed for enhanced expression of PR genes, which provided synergistic effects with the defensin for disease resistance.     

Histopathology of the infection on resistant and susceptible lentil accessions by two contrasting pathotypes of <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f.sp. <Emphasis Type="Italic">lentis</Emphasis>

Wilt disease of lentil caused by Fusarium oxysporum f.sp. lentis (Fol) is one of the most important diseases affecting lentil worldwide. Differential response of six lentil accessions with reported differences in the level of resistance to Fol was studied micro and macroscopically. Penetration took place through root epidermal cells without formation of any specific structure. Hyphae reached the stele within two days after inoculation (dai) and subsequently invaded xylem bundles having colonised the endodermis, vascular system and even vascular parenchyma phloem already by 4 dai. Resistance was observed as a quantitative trait in all studied accessions resulting from varying levels of xylem occlusion with gum-like substances and of degree of colonization observed only after 4 dai. An indication of a qualitative resistance was detected in accession BGE019696 inoculated with pathotype 1 as a fast secretion of phenolic compounds at 4 dai. Plasmolysis of cytoplasm, lignification and accumulation of phenolic compounds, gum-like substances and/or tyloses were observed from 15 to 30 dai. As a result of the various operative mechanisms, significantly lower numbers of propagules were recovered from roots by 15 dai, and a retardation of disease was measured as lower disease index by 30 dai in plants inoculated with pathotype 1, but not in those inoculated with pathotype 7.     

Increased susceptibility of potato to <Emphasis Type="Italic">Rhizoctonia</Emphasis> diseases in <Emphasis Type="Italic">Potato leafroll virus</Emphasis>-infected plants

In Hokkaido potato fields, tubers produced from the plants with leaf curl symptoms caused by potato leaf roll virus (PLRV) were noted to be more densely covered with Rhizoctonia sclerotia. This observation led us to hypothesize that potato infected with PLRV would have an increased susceptibility to Rhizoctonia solani. To test this hypothesis, in a pot experiment, we inoculated PLRV-infected mother tubers with Rhizoctonia. As a result, PLRV-infected plants produced significantly fewer and smaller tubers than virus-free plants did, suggesting that PLRV-infected plants are more susceptible than virus-free plants to R. solani. Virus-free seed tubers should thus be used to reduce Rhizoctonia diseases.     

Unique clones of the pitch canker fungus, <Emphasis Type="Italic">Fusarium circinatum,</Emphasis> associated with a new disease outbreak in South Africa

Pitch canker of pines is caused by the fungus Fusarium circinatum. In South Africa, this pathogen has mostly been a nursery problem. From 2005, however, outbreaks of pitch canker have been reported from established Pinus radiata and P. greggii in the Western and Eastern Cape Provinces. Most recently, pitch canker-like symptoms were observed on 10-year-old P. greggii trees in a plantation in the midlands of the KwaZulu-Natal (KZN) Province. The aim of this study was to: (i) identify the causal agent of the observed symptoms, (ii) determine the genetic diversity, and (iii) the mode of reproduction of this fungal population. Furthermore, the aggressiveness of isolates from these trees was compared with that of isolates obtained previously from P. patula in South Africa. Isolates from the P. greggii trees in KZN were confirmed as F. circinatum based on both morphology and DNA sequence analyses. Microsatellite marker analyses revealed the presence of five genotypes of F. circinatum, not previously reported from other plantations in South Africa, with one of these genotypes being dominant. These genotypes were all pathogenic to P. patula and P. elliottii. No evidence of sexual reproduction was detected in the KZN population of the fungus. This was consistent with the fact that isolates from P. greggii were all of the MAT-2 mating type, in contrast to previously collected isolates from across South Africa that included both mating types. The results suggest that the outbreak of pitch canker on P. greggii in KZN represents a separate introduction of F. circinatum into the region with important implications for managing the disease.     

<Emphasis Type="Italic">Alternaria alternata</Emphasis>: A new seed-transmitted disease of coriander in South Africa

This is the first report of Alternaria leaf spot disease on coriander (Coriandrum sativum L.) in South Africa. Using the agar plate method, Alternaria alternata was isolated from coriander seed lots together with four other fungal genera, which included Aspergillus, Fusarium, Penicillium and Rhizopus. Standard seed germination tests of coriander seed lots infected with seed-borne mycoflora showed a positive correlation with the number of diseased seedlings (r?=?0.239, p?<?0.01). Pathogenicity tests demonstrated that this seed-borne A. alternata was pathogenic on coriander and symptoms on leaves first appeared as small, dark brown to black, circular lesions (<5 mm diam.) that enlarged and coalesced to form dark brown blotches as time progressed. Leaf spot disease was most severe (64%) on wounded leaves inoculated with A. alternata. Re-isolation of A. alternata from diseased coriander plants satisfied the Koch’s postulates, thus confirming it as the causal agent of Alternaria leaf spot disease. Parsimony analysis based on rpb2 (GenBank Accession No. KT895947), gapdh (KT895949) and tef-1α (KT895945) sequences confirmed identity of the Alternaria isolate, which grouped within the A. alternata clade. Alternaria alternata was shown to be transmitted from infected coriander seed to the developing plants.     

Biological control of four homopterans in Israeli horticulture: achievements and problems

Biological control of four phloem-feeding homopterans on citrus and avocado is discussed. Examples of successful control are those achieved withParabemisia myricae andIcerya purchasi; only partial control was obtained withProtopulvinaria pyriformis (nonspecific parasitoid complex) and withPlanococcus citri (climatic conditions unfavourable for its natural enemies).     

Management of laurel wilt of avocado,caused by <Emphasis Type="Italic">Raffaelea lauricola</Emphasis>

Laurel wilt is caused by Raffaelea lauricola, a nutritional symbiont of an Asian ambrosia beetle, Xyleborus glabratus. American members of the Lauraceae plant family are most susceptible and 300 million trees have been killed by the disease in the southeastern USA since 2003. Recently, commercial production of an important crop in the laurel family, avocado (Persea americana), has been affected in southern Florida. We summarize studies in which diverse measures were tested for managing the disease. In all studies, trees were treated with potential laurel wilt control measures and subsequently inoculated with R. lauricola. On potted plants in greenhouse experiments, commercial nutritional products (Greenstim and Keyplex 350) and SAR products (Agri-Fos and Nutri-Phite), when applied as soil drenches or foliar sprays, had either no impact on, or increased laurel wilt symptom development compared to non-treated control treatments. Bark applications of Tilt (a propiconazole fungicide for which emergency registration had been obtained in 2010) in a surfactant (Pentrabark) enabled significant laurel wilt protection in greenhouse studies on small potted plants, but Pentrabark and other surfactants moved little propiconazole into the xylem of fruit-bearing trees in field studies. In efficacy studies in the field, Propiconazole Pro (an injectable formulation of propiconazole), Tilt, and two experimental formulations of another triazole fungicide, tebuconazole, decreased the development of laurel wilt compared to nontreated control trees when applied as undiluted injections into branches and scaffold limbs (microinjection), or injection of dilute fungicide into tree flare roots (macroinfusion). However, symptoms developed in all treated trees by 10–11 months after inoculation with R. lauricola, indicating that trees would need to be re-treated at least on an annual basis. Regardless of how fungicides were applied, insignificant levels of different active ingredients entered fruit. Although fungicide treatment of fruit-bearing avocado trees is not a concern for food safety and several triazole and DMI fungicides can protect avocado trees from laurel wilt, cost-effective measures with which the xylem could be loaded with and protected by these products remains a challenge. Management of laurel wilt in commercial avocado production areas is discussed.     

Mitigation of Salt Stress Negative Effects on Sweet Pepper Using Arbuscular Mycorrhizal Fungi (AMF), <Emphasis Type="Italic">Bacillus megaterium</Emphasis> and Brassinosteroids (BRs)

A study was conducted at the experimental farm of Faculty of Agriculture, Ain Shams University, Cairo, Egypt, during two successive summer seasons (2014 and 2015) to investigate the effects of arbuscular mycorrhizal fungi (Glomus irradicans 10% w/w), Bacillus megaterium (10?ml/pot) and brassinosteroids (24-EBL, C₂₈H₄₈O_6; 2?µM) on growth, nutrient absorption, chlorophyll, proline content, antioxidant enzymes activity and fruit yield of sweet pepper plants (Capsicum annuum L.) cv. Marconi. Plants were grown under three levels of salinity (0, 25 and 50?mM). The obtained results showed that plants grown under non-saline water (0?mM NaCl), with or without treatments, significantly gave the most vigorous vegetative growth and had the highest fruit yield compared with those grown under salt stress conditions. All anti-salinity treatments (Mycorrhiza, Bacillus and Brassinosteroids) improved growth when compared with untreated plants (control). Plants inoculated with mycorrhiza or treated with brassinosteroids showed better vegetative growth and shoot biomass (total fresh and dry weight per plant), chlorophyll a and b concentrations, antioxidant content expressed as total soluble phenols and proline concentrations at all studied salinity levels followed by plants inoculated with Bacillus megaterium compared with control plants which showed severe growth retardant especially under higher salt concentration (50?mM). Carotenoids concentration increased proportionally with the increase of salinity concentration. The maximum leaf relative water content (LRWC) and lowest values of membrane permeability (MP) were significantly observed with mychorhiza inoculated plants and brassinosteroid application respectively, followed by Bacillus inoculated plants. Antioxidant enzyme activity were highest in plants irrigated with moderate saline water (25?mM) than plants under high salinity irrigation water (50?mM) except polyphenol oxidase (PPO) as compared with unstressed plants (0?mM). Mycorrhizal inoculated plants accumulated higher K and lower Na and Cl followed by plants treated with brassinosteroids and then plants inoculated with Bacillus megaterium. Anti-salinity treatments positively enhanced fruit yield of sweet pepper plants under all salinity stress levels and the highest fruit yield were significantly observed with brassinosteroid application followed by mychorhiza inoculated plants and then Bacillus inoculated plants.