Current Status of Conventional and Molecular Interventions for Blast Resistance in Rice

Pyricularia oryzae anamorph of Magnaporthe oryzae is one of the most notorious fungal pathogens causing severe economic loss in rice production worldwide. Various methods, viz. cultural, biological and molecular approaches, are utilized to counteract this pathogen. Moreover, some tolerant or resistant rice varieties have been developed with the help of breeding programmes. Isolation and molecular characterization of different blast resistance genes now open the gate for new possibilities to elucidate the actual allelic variants of these genes via various molecular breeding and transgenic approaches. However, the behavioral pattern of this fungus breakups the resistance barriers in the resistant or tolerant rice varieties. This host-pathogen barrier will be possibly countered in future research by comparative genomics data from available genome sequence data of rice and M. oryzae for durable resistance. Present review emphasized fascinating recent updates, new molecular breeding approaches, transgenic and genomics approaches(i.e. mi RNA and genome editing) for the management of blast disease in rice. The updated information will be helpful for the durable, resistance breeding programme in rice against blast pathogen.

A randomized controlled trial of omega-3 fatty acids in dry eye syndrome

AIM:To evaluate the role of dietary supplementation of omega-3 fatty acids in dry eye syndrome.METHODS:A prospective,interventional,placebo controlled,double blind randomized trial was done at two referral eye centers.Two hundred and sixty-four eyes of patients with dry eye were randomized to receive one capsule(500mg)two times a day containing 325mg EPA and 175mg DHA for 3 months(omega-3 group).The omega-3 group was compared to a group of patients(n=254)who received a placebo(placebo group).There were 4 patient visits(at baseline,1 month,2 months and3 months).On each visit,recording of corrected distance visual acuity(CDVA),slit lamp examination and questionnaire based symptom evaluation and scoring was done.A symptomatic score of 0-6 was mild,6.1-12moderate and 12.1-18 severe dry eye.Response to intervention was monitored by routine tear function tests like Schirmer I test,tear film break-up time(TBUT),Rose Bengal staining and most notably,conjunctival impression cytology.RESULTS:Sixty-five percent of patients in the omega-3group and 33%of patients in placebo group had significant improvement in symptoms at 3 months(P=0.005).There was a significant change in both Schirmer’s test value and TBUT values in the omega-3group(P【0.001),both comparisons.However,there was a larger drift in TBUT values in omega-3 than the placebo group,in comparison to Schirmer’s test values.The mean TBUT score was 2.54±2.34 in the omega-3group and 0.13±0.16 in placebo group,respectively.The mean reduction in symptom score in omega-3 group was 2.02±0.96 as compared to 0.48±0.22 in placebogroup(P【0.001).Despite a slight increase mean score,the Schirmer scores did not correlate well with symptomatic improvement.CONCLUSION:Omega-3 fatty acids have a definite role for dry eye syndrome.The benefit seems to be more marked in conditions such as blepharitis and meibomian gland disease.The role of omega fatty acids in tear production and secretion needs further evaluation.

Disruption of NAD^+ binding site in glyceraldehyde 3-phosphate dehydrogenase affects its intranuclear interactions

AIM:To characterize phosphorylation of human glyceraldehyde 3-phosphate dehydrogenase(GAPDH),and mobility of GAPDH in cancer cells treated with chemotherapeutic agents. METHODS:We used proteomics analysis to detect and characterize phosphorylation sites within human GAPDH. Site-specific mutagenesis and alanine scanning was then performed to evaluate functional significance of phosphorylation sites in the GAPDH polypeptide chain. Enzymatic properties of mutated GAPDH variants were assessed using kinetic studies. Intranuclear dynamics parameters(diffusion coefficient and the immobile fraction) were estimated using fluorescence recovery after photobleaching(FRAP) experiments and confocal microscopy. Molecular modeling experiments were performed to estimate the effects of mutations on NAD+ cofactor binding.RESULTS:Using MALDI-TOF analysis,we identified novel phosphorylation sites within the NAD+ binding center of GAPDH at Y94,S98,and T99. Using polyclonal antibody specific to phospho-T99-containing peptide within GAPDH,we demonstrated accumulation of phospho-T99-GAPDH inthe nuclear fractions of A549,HCT116,and SW48 cancer cel s after cytotoxic stress. We performed site-mutagenesis,and estimated enzymatic properties,intranuclear distribution,and intranuclear mobility of GAPDH mutated variants. Site-mutagenesis at positions S98 and T99 in the NAD+ binding center reduced enzymatic activity of GAPDH due to decreased affinity to NAD+(Km = 741 ± 257 μmol/L in T99 I vs 57 ± 11.1 μmol/L in wild type GAPDH. Molecular modeling experiments revealed the effect of mutations on NAD+ binding with GAPDH. FRAP(fluorescence recovery after photo bleaching) analysis showed that mutations in NAD+ binding center of GAPDH abrogated its intranuclear interactions. CONCLUSION:Our results suggest an important functional role of phosphorylated amino acids in the NAD+ binding center in GAPDH interactions with its intranuclear partners.

Genotypic Variation in Spatial Distribution of Fe in Rice Grains in Relation to Phytic Acid Content and Ferritin Gene Expression

Rice varieties having high Fe concentration in the endospermic region can be used as a good source for Fe deficit population.In this study,303 Oryza sativa varieties and 1 Oryza rufipogon accession were assessed for spatial Fe accumulation in grains by Prussian blue staining method.Spatial ferritin protein distribution in grains was visualized by immunohistochemistry,and ferritin expression was assessed in selected rice varieties using semi-quantitative reverse transcription PCR.Three popular rice varieties,namely Sarjoo 52,Madhukar and Jalmagna,and the O.rufipogon variety showed Fe in all the regions of grains,and the highest Fe concentration was observed in the embryo region.Some high-yielding varieties like Swarna,Swarna Sub 1,CSR13 and NDRR359 had lower Fe concentration in the embryo region.The highest Fe concentration was detected in O.rufipogon(49.8μg/g),followed by Sarjoo 52(26.1μg/g)and Madhukar(25.7μg/g).Phytic acid concentration was the minimum in O.rufipogon(5.75 mg/g)followed by Sarjoo 52(5.83 mg/g).Western blot and semi-quantitative reverse transcription PCR showed higher expression of ferritin gene in O.rufipogon,Sarjoo 52 and Madhukar.In conclusion,O.rufipogon and Sarjoo 52 had higher Fe concentration in the embryo regions as well as endosperm and aleurone layer,whereas the other varieties had lower Fe concentration in the endosperm.Sarjoo 52 could be used as a donor in the rice breeding program for the generation of new varieties with elevated grain Fe concentration.

Synthesis and enhanced photoluminescence properties of red emitting divalent ion(Ca^(2+))doped Eu:Y_(2)O_(3)nanophosphors for optoelectronic applications

This work presents the synthesis of Y_(2)O_(3):Eu^(3+),χCa^(2+)(χ=0 mol%,1 mol%,3 mol%,5 mol%,7 mol%,9 mol%,11 mol%)nanophosphors with enhanced photoluminescence properties through a facile solution combustion method for optoelectronic,display,and lighting applications.The X-ray diffraction(XRD)patterns of the proposed nanophosphor reveal its structural properties and crystalline nature.The transmission electron microscope(TEM)results confirm the change in the shape of the particle and aggregation of particles after co-doping with Ca^(2+).Fourier transform infrared spectroscopy(FTIR)and Raman vibrations also confirm the presence of Y-O vibration and subsequently explain the crystalline nature,structural properties,and purity of the samples.All the synthesized nanophosphors samples emit intense red emission at 613 nm(~5D_(0)→~7 F_(2))under excitation with 235,394 and 466 nm wavelengths of Eu^(3+)ions.The photoluminescence(PL)emission spectra excited with 235 nm illustrate the highest emission peak with two other emission peaks excited with 466 and 394 nm that is 1.4 times higher than 466 nm and 1.9 times enhanced by 394 nm wavelength,respectively.The emission intensity of Y_(2)O_(3):Eu^(3+),χCa^(2+)(5 mol%)is increased 8-fold as compared to Eu:Y_(2)O_(3).Doping with Ca^(2+)ions enhances the emission intensity of Eu:Y_(2)O_(3)nanopho sphors due to an increase in energy transfer in Ca^(2+)→Eu^(3+)through asymmetry in the crystal field and by introduction of radiative defect centers through oxygen vacancies in the yttria matrix.It is also observed that the optical band gap and the lifetime of the~5D_(0)level of Eu^(3+)ions in Y_(2)O_(3):Eu^(3+),xCa^(2+)nanophosphor sample gets changed with a doping conce ntration of Ca^(2+)ions.Nanophosphor also reveals high thermal stability and quantum yield as estimating activation energy of 0.25 eV and 81%,respectively.CIE,CCT,and color purity values(>98%)show an improved red-emitting nanophosphor in the warm region of light,which makes this mate rial superior with a specific potential application for UV-based white LEDs with security ink,display devices,and various other optoelectronics devices.