Biocontrol of sheath blight of rice (Oryza sativa L.) through alteration in expression dynamics of candidate effector genes of Rhizoctonia solani AG1-IA during pathogenesis.

In genome analyses of Rhizoctonia solani AG1-IA causing sheath blight (ShB) of rice, many genes were identified to have a hypothetical role in pathogenesis. To understand their roles in pathogenesis, their expressions during fungal infection were studied. An aggressive R. solani strain, RIRS-K, was first identified among six isolates, RIRS-K, RIRS-17, RIRS-S, RIRS-T, RIRS-MU and RIRS-FD, for inducing a maximum relative lesion height (RLH) of 32.7% on a ShB susceptible cultivar, Pusa Basmati-1. Hypothetical pathogenicity genes (52 nos) identified by in silico analyses of the publicly available genomic database of the pathogen strain were evaluated in Pathogen-Host Interaction (PHI) blast and RIRS-K. Though PHI blast identified 26 genes as potential ones, only 8 were constitutively expressive in RIRS-K cultured in a minimal broth. Among them, only expressions of AG1IA_06195, AG02692, AG04508, and AG05730 were induced in the rice plant inoculated with RIRS-K and, hence, were identified as the candidate ones. The candidate genes were highly expressed in the aggressive strain (RIRS-K) in comparison to the less aggressive one (RIRS-17). In further testing of their expressions in the highly aggressive fungal strain, RIRS-K infecting PB-1 pre-colonized by a potent biocontrol consortium comprising of Bacillus subtilis (S17TH), Pseudomonas putida (TEPF-Sungal-1), and Trichoderma harzianum (S17TH), the disease scoring and gene expression studies indicated that the candidate genes were downregulated. The studies, therefore, speculated that these genes might play a role in pathogen aggressiveness and ShB development.

Physiological race characterisation of Fusarium oxysporum strains infecting tomato employing candidate pathogenicity genes and host resistance.

Physiological races of 14 strains of Fusarium oxysporum f.sp. lycopersici were established by PCR profiling SIX gene expressions. No amplification of the SIX4 (Avr1) gene was observed in any of the 14 strains. Based on amplification of the SIX3 (Avr2) gene, 6 strains were distinguished as race 2. Race 2 strains are known to contain identical SIX3 sequences and differ from race 3 strains by single point mutations. Hence, based on polymorphic amplicons of the SIX3 gene detected by stringent PCR conditions, 8 strains were identified as race 3. The identity of the physiological races of the strains was validated by inoculating on three germplasm lines, EC-814916, FEB-2 and Pusa Rohini carrying I-2, I-3 and no I gene, respectively. The race 2 and race 3 strains were avirulent on EC-814916 and FEB-2 lines, respectively. All the 14 fungal strains were pathogenic on Pusa Rohini, the Fusarium wilt susceptible cultivar lacking R genes and exhibited different levels of virulence. In evaluating two other potential pathogenicity genes, Fow1 and Fow2 as markers for virulence, their expressions were observed among both the races of the Fol strains, and hence are not potential candidates for physiological race discrimination. However, strong expressions of the genes in the root tissues inoculated with the highly virulent strain, TOFU-IHBT in comparison to the uninoculated control indicated their roles in fungal pathogenicity. To understand the role of these pathogenicity genes in countering the host defence mechanisms, their expressions in response to ROS and phenolics, the earliest known defence mechanisms of host plants were assessed. In H2O2, the Fow2 gene expressed 1.4-fold greater than that of the control. On the contrary, in relation to the control, the expressions of Fow1 were strongly repressed exhibiting 0.7-to 0.8-fold lesser at 0.1 mM through 3 mM concentrations than that of the control indicating that the gene is modulated by the phenolic acid indicating the roles of Fow2 and Fow1 in alleviating oxidative stress and targeted by the phenolic acid, respectively.

Genome-Wide Identification and Characterisation of Cytokinin-O-Glucosyltransferase (CGT) Genes of Rice Specific to Potential Pathogens.

Cytokinin glucosyltransferases (CGTs) are key enzymes of plants for regulating the level and function of cytokinins. In a genomic identification of rice CGTs, 41 genes with the plant secondary product glycosyltransferases (PSPG) motif of 44-amino-acid consensus sequence characteristic of plant uridine diphosphate (UDP)-glycosyltransferases (UGTs) were identified. In-silico physicochemical characterisation revealed that, though the CGTs belong to the same subfamily, they display varying molecular weights, ranging from 19.6 kDa to 59.7 kDa. The proteins were primarily acidic (87.8%) and hydrophilic (58.6%) and were observed to be distributed in the plastids (16), plasma membrane (13), mitochondria (5), and cytosol (4). Phylogenetic analysis of the CGTs revealed that their evolutionary relatedness ranged from 70-100%, and they aligned themselves into two major clusters. In a comprehensive analysis of the available transcriptomics data of rice samples representing different growth stages only the CGT, Os04g25440.1 was significantly expressed at the vegetative stage, whereas 16 other genes were highly expressed only at the reproductive growth stage. On the contrary, six genes, LOC_Os07g30610.1, LOC_Os04g25440.1, LOC_Os07g30620.1, LOC_Os04g25490.1, LOC_Os04g37820.1, and LOC_Os04g25800.1, were significantly upregulated in rice plants inoculated with Rhizoctonia solani (RS), Xoo (Xanthomonas oryzae pv. oryzae) and Mor (Magnaporthe oryzae). In a qRT-PCR analysis of rice sheath tissue susceptible to Rhizoctonia solani, Mor, and Xoo pathogens, compared to the sterile distilled water control, at 24 h post-infection only two genes displayed significant upregulation in response to all the three pathogens: LOC_Os07g30620.1 and LOC_Os04g25820.1. On the other hand, the expression of genes LOC_Os07g30610.1, LOC_Os04g25440, LOC_Os04g25490, and LOC_Os04g25800 were observed to be pathogen-specific. These genes were identified as the candidate-responsive CGT genes and could serve as potential susceptibility genes for facilitating pathogen infection.

Pharmacodynamic effects of clopidogrel in pediatric cardiac patients: a comparative study of platelet aggregation response.

Little data on pediatric percent platelet aggregation (%PA) exist in the literature, particularly in cardiac patients and in response to clopidogrel. The objectives were to estimate the %PA range expected in pediatric patients and to measure the clopidogrel effect on %PA in the PICOLO (Platelet Inhibition in Children on Clopidogrel) trial. To estimate a neonatal/infant %PA response range, %PA induced by 5 µM adenosine diphosphate (ADP) was assessed using light transmission aggregometry in 16 cord and 11 normal adult blood samples and prior to clopidogrel therapy in 49 neonatal and 49 infant/toddler cardiac patients enrolled in PICOLO. The %PA induced by 5 µM thrombin receptor-activating peptide (TRAP) was also assessed for 10 neonates and 21 infants/toddlers enrolled in PICOLO and compared with 11 adult samples. Percent inhibition of platelet aggregation (%IPA) induced by 5 µM ADP at steady-state clopidogrel levels was assessed in 33 neonates and 39 infants/toddlers. ADP-induced %PA was lowest in cord blood samples, intermediate in study neonates and infants/toddlers, and highest in adults. Similarly, TRAP-induced platelet aggregation was lower in neonates and infants/toddlers than adults. For all groups, %PA and %IPA were highly variable, with 11% of neonates and 13% of infants/toddlers showing <10% IPA. In conclusion, ADP- and TRAP-induced %PA is lower in pediatric cardiac patients than normal adults, but highly variable in both. The lower baseline %PA may explain why the pediatric clopidogrel dose providing 30-50% IPA (0.20 mg/kg/day) is lower than a simple weight-based extrapolation of the adult dose (75 mg/day) providing similar inhibition.

The study of temporal and spatial trends of water qulity of river Kshipra using water quality index.

Water quality index (WQI) plays an important role in interpreting the information on water quality trends of a water body. In the present study, an attempt has been made to study the spatial and temporal water quality trends of one of the pristine river Kshipra (Madhya Pradesh) using water quality index. The importance of existing sampling sites has also been discussed.

Formation of an Air Pollution Index.

An air pollution index is a quantitative tool through which air pollution data can be reported uniformly. There have been efforts to describe overall air pollution by an aggregation of pollutant subindices. When ambiguous, these aggregations raise unnecessary alarm by declaring a less polluted air to be highly polluted. Similarly, when eclipsed, a false sense of security is provided by indicating highly polluted air as less polluted. Linear sum and root sum square forms in vogue suffer from ambiguity. Whereas the maximum operator aggregation does not consider change in the remaining pollutants, it is not a good tool for management purposes. In this paper, an ambiguity-and eclipsicity-free function has been presented for aggregation of air pollution subindices. For computer adaptation of the aggregation process, the subindices have been expressed as full range functions of the pollutant concentrations.