Characterization of Endophytic Microorganisms of Rice(Oryza sativa L.)Potentials for Blast Disease Biocontrol and Plant Growth Promoting Agents

One hundred twenty-five endophytic microorganisms were isolated from the roots,stems,and leaves of four prominent rice cultivars growing in temperate regions.Their potential to combat rice blast disease and promote plant growth was investigated.The dual culture tests highlighted the strong antagonistic activity of five fungal(ranging from 89%–70%)and five bacterial(72%–61%)endophytes.Subsequent examination focused on volatile compounds produced by selected isolates to counter the blast pathogen.Among these,the highest chitinase(13.76μg mL−1)and siderophore(56.64%),was exhibited by Aspergillus flavus,and the highest HCN production was shown by Stenotrophomonas maltophilia(36.15μM mL−1).In terms of growth promotion traits,Aspergillus flavus and Enterobacter cloacae excelled in activities viz,phosphorous solubilization,ammonia production,auxin and gibberellic acid production,and nitrogen fixation.The Identity of these endophytes was confirmed through molecular analysis as Trichoderma afroharzianum,Trichoderma harzianum,Penicillium rubens,Aspergillus flavus,Stenotrophomonas rhizophila,Stenotrophomonas maltophilia,Bacillus cereus,Enterobacter cloacae,and Bacillus licheniformis.Under greenhouse conditions,the highest disease control was shown by isolate Bacillus licheniformis and A.flavus with an inhibition of 79%,followed by S.rhizophila(77%)and T.afroharzianum(73%).The overall results of this study showed that Bacillus licheniformis and Stenotrophomonas rhizophila have great potential to be used as bio-stimulant and biocontrol agents to manage rice blast disease.

Integrated application of some compatible biocontrol agents along with mustard oil seed cake and furadan on Meloidogyne incognita infecting tomato plants

Experiments were carried out to study the effect of two fungal bioagents along with mustard oil cake and furadan against root knot nematode Meloidogyne incognita infecting tomato under greenhouse condition. Bioagents viz., Paecilomyces lilacinus and Trichoderma viride alone or in combination with mustard cake and furadan promoted plant growth, reduced number of galls/plant, egg masses/root system and eggs/egg mass. The fungal bioagents along with mustard cake and nematicide showed least nematodes reproduction factor as compared to untreated infested soil.

Synergistic Influence of Pre-Harvest Calcium Sprays and Postharvest Hot Water Treatment on Fruit Firmness, Decay, Bitter Pit Incidence and Postharvest Quality of Royal Delicious Apples (<i>Malus x domestica</i>Borkh)

Experiments were conducted to observe the effect of pre-harvest calcium (Ca) applied as calcium chloride (1% W/V) and postharvest hot water treatment (HWT) on “Royal Delicious” apples. For this, apples were divided in 4 lots viz., untreated (neither Ca nor HWT), Ca alone (pre-harvest 3 sprays of CaCl2 (1.0% w/v) in the orchard), HWT (42℃ for 2 h). Apples of all four lots were stored in cold storage maintained at 0℃ ± 1℃ and 90% - 95% relative humidity for 6 months. After storage, fruits were removed to ambient conditions for 5 days, and then observations on decay area and incidence, bitter pit incidence, fruit Ca content, lipoxygenase (LOX) and antioxidant (AOX) activity, fruit firmness and fruit quality parameters were recorded. After 6 months in cold storage plus 5 day at 22℃ ± 2℃ and 70% + 4% RH, apples, which received Ca as pre-harvest spray or those which received postharvest hot water treatment or Ca + HWT had significantly lesser decay area (decay lesions) caused by Penicillium expansum or Botrytis cinerea than untreated ones (control). Ca + HWT treatment was significantly more effective on B. cinerea than P. expansum. Untreated apples exhibited higher incidence of bitter pit (18.2%) than those treated with Ca or HWT or both. Fruit Ca content (2.92% DM) were significantly lower and conversely the LOX activity (6.9 μmoles min–1×g–1FW) was higher in untreated apples. Similarly, total phenolics and AOX activity were also lower in the untreated apples than Ca or HWT treated. HWT or Ca treated apples have beneficial effects on fruit firmness, peel colour and quality parameters like TSS and ascorbic acid content. Thus, it is concluded that pre-harvest sprays of calcium chloride with postharvest HWT is highly useful for “Royal Delicious” for reducing decay loss, maintaining firmness, high levels of antioxidants and fruit quality.

Floral Homeostasis Breakdown in Endangered Plant <i>Valeriana jatamansi</i>Jones (Valerianaceae) in North Eastern Himalayan Region

An inhabitant of north western Himalayan region and a gynodioceious plant having a lot of medicinal properties, Valeriana jatamansi Jones (Valerianaceae) is an enlisted endangered plant in the world. It was introduced in the research station of North Bengal Agricultural University (27.06&degN 88.47&degE) situated in north eastern Himalayan region of Darjeeling district in the state of West Bengal from Sikkim Sangtok (27&deg25'N 88&deg31'E) of north Sikkim area in India for the purpose of conservation. As we noticed some irregular development of floral organs, we investigated some pertinent questions regarding ecological aberrations found in plants. We found plants introduced in north eastern Himalayan region changed their homology of number flower petals and position of stamens seen naturally in north western Himalayan region as per the reports. Was there any genetic or extreme environmental stress condition caused a sudden change in floral structure as it is generally known as a rare phenomenon and frequently not seen? What were the correlations of different floral parts and fitness of population in different morphotypes? We predicted possible outcomes of seed setting by univariate regression models in a particular environment in addition to this investigation. We proposed three models of heterozygousity for answering the reasons of unstable floral form from a general known floral form, where silent mutations help the plants to survive in adverse conditions in spite of deformed or variable formed of floral morphology.

Validation of Molecular Tools for Monitoring the Entomopathogen Neozygites Tanajoae(Entomophthorales:Neozygitaceae) Used for Biological Control of Cassava Green Mite in Africa

Neozygites tanajoae is an entomopathogenic fungus which has been used for biocontrol of the cassava green mite(Mononychellus tanajoa,CGM)in Africa. Establishment and dispersal of Brazilian isolates which have been introduced into some African countries in recent years to improve CGM control was followed with specific PCR assays.Two primer pairs,

Management of needle blight (Lophodermium pinastri) disease in Blue pine trees in Kashmir,India

Evaluation of various fungicides against needle blight disease of pine was carried out at Shed Kashmir University of Agriculture Sciences and Technology of Kashmir （India） during the year 2008 and 2009. Applica- tion of various fungicides were evaluated in vivo at dif- ferent concentrations. However in both, mist-chamber and poly-chamber, the Blue pine （Pinus wallichiana Jackson） seedlings treated with hexaconazole 5EC （@ 0.03 %） or carbendazim 50WP （@ 0.1%） depicted significantly less disease incidence and intensity. The seedlings treated with mancozeb 75WP （@ 0.3 %） and chlorothalonil 75WP （@ 0.3 %） exhibited less disease incidence and intensity. Increase in relative humidity from 60 to 100 % signifi- cantly enhanced needle blight disease incidence and intensity. In field trial the fungitoxicants used either as single spray or protectant followed by systemic fungitoxi- cant spray significantly reduced disease incidence in Blue pine compared to check. The mean disease incidence in fungitoxicant treated plants varied from 11.82 to 25.51% as compared to 36.03 % in control.

Improvement of Bio-Efficacy to Reduce Bacterial Wilt Complex Disease in Tomatoes through Bacillus amyloliquefaciens and Pseudomonas fluorescens under Field Conditions

Bacterial wilt complex disease of tomato(Solanum lycopersicum L.)was incited jointly by bacterial wilt pathogen Ralstonia solanacearum and Meloidogyne incognita worldwide.Bio-efficacy of bacterial antagonists i.e.B.amyloliquefaciens DSBA-11 and P.fluorescens DTPF-3 was studied against the wilt disease complex in tomato at National Phytotran facility Indian Agricultural Research Institute(IARI),New Delhi,at 26±2°C.Minimum wilt disease incidence(26.00%)with the highest bio-control efficacy(64.15%),less juvenile population(19.33 J2/g of soil)of M.incognita was recorded in the combined application of DTPF-3+DSBA-11 after 30 d of inoculation under glasshouse conditions.In a field study,minimum bacterial wilt disease incidences 19.0%and 20.4%were recorded in the bleaching powder treatment followed by mixed application of DSBA-11+DTPF-3,19.6%and 21.2%wilt incidence in 2014 and 2015 respectively.However,a reduction of root-knot gall index was recorded a maximum of 59.76%and 69.62%in DSBA-11+DTPF-3 treated plants followed by 54.88%and 60.13%over control in DTPF-3 treatment in 2014 and 2015 respectively.The yield of tomato fruit was increased over control by 17.48%and 16.97%in 2014 and 2015 respectively under field conditions.A combination of P.fluorescens DTPF-3+B.amyloliquefaciens DSBA-11 suppressed bacterial wilt and root-knot diseases and also increased the yield of the tomato fruit significantly(p<0.05)under field conditions.

Identification of QTLs for Yield and Associated Traits in F_(2) Population of Rice

Identification of quantitative trait loci(QTLs)controlling yield and yield-related traits in rice was performed in the F_(2) mapping population derived from parental rice genotypes DHMAS and K343.A total of 30 QTLs governing nine different traits were identified using the composite interval mapping(CIM)method.Four QTLs were mapped for number of tillers per plant on chromosomes 1(2 QTLs),2 and 3;three QTLs for panicle number per plant on chromosomes 1(2 QTLs)and 3;four QTLs for plant height on chromosomes 2,4,5 and 6;one QTL for spikelet density on chromosome 5;four QTLs for spikelet fertility percentage(SFP)on chromosomes 2,3 and 5(2 QTLs);two QTLs for grain length on chromosomes 1 and 8;three QTLs for grain width on chromosomes1,3 and 8;three QTLs for 1000-grain weight(TGW)on chromosomes 1,4 and 8 and six QTLs for yield per plant(YPP)on chromosomes 2(3 QTLs),4,6 and 8.Most of the QTLs were detected on chromosome 2,so further studies on chromosome 2 could help unlock some new chapters of QTL for this cross of rice variety.Identified QTLs elucidating high phenotypic variance can be used for marker-assisted selection(MAS)breeding.Further,the exploitation of information regarding molecular markers tightly linked to QTLs governing these traits will facilitate future crop improvement strategies in rice.

Impact of Climate Change on Diseases of Crops and Their Management-A Review

Change in global climate is primarily due to rising concentrations of greenhouse gases in the atmosphere that is mostly caused by human activities.The important factors affecting the occurrence and spread of the plant diseases are temperature,moisture,light,and CO_(2) concentration.These factors cause physiological changes in plants that result in increase in intensity of crop diseases.Climate change causes a significant impact on germination,reproduction,sporulation and spore dispersal of pathogens.Climate change affects all life stages of the pathogen as well as its host to cause impact on host-pathogen interaction which facilitates the emergence of new races of the pathogen ultimately breakdowns the host resistance.It also affects the microbial community in the soil which is beneficial to the plants in various aspects.The minor diseases become major ones due to alteration in climatic parameters thus posing a threat to the food security.

Diversity of endophytic phosphate solubilising fungi associated with Pomatocalpa decipiens(Lindl.)J.J.Smith-an endangered orchid in Barbara forest of Odisha,India

Investigations were done to obtain potential phosphate solubilising strains from endophytic mycoflora isolated from the orchid,Pomatocalpa decipiens.928 endophytic phosphate solubilising fungal isolates were obtained from 2400 leaf segments(0.38%recovery)from rare epiphytic orchid Pomatocalpa decipiens present in the Barbara hills of Odisha(India).A number of isolates belonged to different genera such as Paecilomyces,Curvularia,Aspergillus,Cladosporium,Penicillium,Colletotrichum,while others,which were unidentified were classified as mycelia sterilia.Root sampling done from 25 different sites resulted in isolation of 20 endophytic phosphate solubilising fungal isolates from 300 segments(0.1%recovery).Aspergillus,Paecilomyces,Fusarium,Penicillium,and mycelia sterilia were mostly obtained.The qualitative and quantitative assessments of Phosphate(P)solubilisation were performed using TCP and Rock phosphate as P source for those strains.Aspergillus niger(leaf isolate)showed a maximum of 33.2 and 22.7%solubilisation in presence of TCP and Rock phosphate respectively whereas Aspergillus niger(Root isolate)showed a maximum of about 23.9%and 36.2%solubilisation in presence of TCP and Rock phosphate respectively.

Cryptic species composition and genetic diversity within Bemisia tabaci complex in soybean in India revealed by mtCOI DNA sequence

Bemisia tabaci is a cryptic species complex, causing signiifcant loss on many agricultural y important crops worldwide. Knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. Here we investigate the whitelfy species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1 (mtCOI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely Asia I, Asia II 1, and Asia II 7. Al the haplotypes detected in the study could be assigned to these three cryptic species fol owing the species demarcation criteria of 3.5%divergence threshold. Of these, Asia II 1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species Asia II 7 showed localized distribu-tion. The Asia II 1 exhibited the highest haplotype diversity and Asia I showed high level of nucleotide diversity. There was a signiifcantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitelfy species in India and yel ow mosaic disease observed during sampling survey.

Genotoxicity of ferric oxide nanoparticles in Raphanus sativus：Deciphering the role of signaling factors,oxidative stress and cell death

We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles（Fe_2O_3-NPs） in Raphanus sativus（radish）.Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs（1.0 mg/m L） treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species（ROS）,mitochondrial membrane potential（ΔΨm）,nitric oxide（NO） and Ca2＋influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione（GSH）,catalase（CAT）,superoxide dismutase（SOD） and lipid peroxidation（LPO） has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid（DNA） strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs（2.0 mg/m L） treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles（NPs） and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment.

Xanthomonas axonopodis pv. punicae uses XopL effector to suppress pomegranate immunity

Xanthomonas axonopodis pv. punicae （Xap） causing bacterial blight is an important pathogen that incurs significant losses to the exportability of pomegranate. Xap uses the Xop TTSS-effector, via the type three secretion system, to suppress pomegranate immunity. Here, we investigate the role of XopL during blight pathogenesis. We observed that XopL is essential for its in planta growth and full virulence. Leaves inoculated with Xap AxopL produced restricted water-soaked lesions compared to those inoculated with wild-type Xap. XopL supports Xap for its sustained multiplication in pomegranate by suppress- ing the plant cell death （PCD） event. We further demon- strated that XopL suppresses immune responses, such as callose deposition and production of reactive oxygen species （ROS）. RT-qPCR analysis revealed that immune responsive genes were upregulated when challenged with Xap AxopL, whereas upregulation of such genes was compromised in the complemented strain containing the xopL gene. The transiently expressed XopL：：EYFP fusion protein was local- ized to the plasma membrane, indicating the possible site of its action. Altogether, this study highlights that XopL is an important TTSS-effector of Xap that suppresses plant immune responses, including PCD, presumably to support the multiplication of Xap for a sufficient time-period during blight disease development.