Molecular Confirmation of Intraspecific Tomato (<Emphasis Type="Italic">Solanum lycopersicum)</Emphasis> Hybrids and Their Evaluation Against Late Blight and Cucumber Mosaic Virus

Tomato is one of the most consumed vegetables in the world. Diseases are the number one concern in the development of high-yield and disease-resistant tomato hybrids which is the foremost priority of breeders. Present study was conducted (1) to develop DNA-based markers for genetic confirmation of tomato F₁ hybrids, (2) to utilize sequenced characterized amplified region (SCAR) marker linked to the Ph-3 gene for Phytophthora infestans resistance in tomato and (3) to evaluate male and female parental genotypes and their F₁ hybrids against late blight (LB) and cucumber mosaic virus (CMV). For molecular studies, 58 previously reported markers including RAPDs (10), SCAR (01), EST-SSR (01) and SSR (46) were applied. The SCAR marker clearly differentiated the LB3 and LB4 from Roma and T-1359 and provided evidence for Ph-3 gene. The SCAR marker was able to confirm the Ph-3 gene in the hybrids Roma × LB4, Roma × LB3, Riogrande × LB2, Riogrande × LB3 and Roma × LB7. Out of several tested primers, SSR-22 proved useful for genetic confirmation of F₁ hybrid TMS1 × Money Maker (MM). For LB, tested hybrids/genotypes were ranked as susceptible to highly susceptible with different infection percentage (IP). However, the pace of symptom development was slower in hybrid Rio × LB2, 45% IP after 10 days of inoculation compared with 85% disease in one of the parent genotypes (Riogrande). None of the tested genotypes was found resistant; however, TMS1 responded as tolerant against CMV using mechanical inoculation. Under natural field conditions, TMS1 was found resistant while hybrids TMS1 × Naqeeb and TMS1 × MM were tolerant where as others were found to be susceptible. In conclusion, all tomato hybrids were genetically confirmed using DNA-based markers. SCAR marker was useful for marker-assisted confirmation of the Ph-3 gene in parental lines and hybrids; however, this gene was unable to provide protection against the local population of P. infestans.     

Relationships between gas-exchange characteristics and stomatal structural modifications in some desert grasses under high salinity

Two populations, one from lesser saline Derawar Fort (DF) and the other from highly saline Ladam Sir (LS) in the Cholistan desert, for each of the five grass species, Aeluropus lagopoides, Cymbopogon jwarancusa, Lasiurus scindicus, Ochthochloa compressa, and Sporobolus ioclados were examined to investigate the influence of salinity on structural and functional characteristics of stomata. Salinity tolerance in A. lagopoides mainly depended on controlled transpiration rate (E) and high water-use efficiency (WUE), which was found to be regulated by fewer and smaller stomata on both leaf surfaces as well as stomatal encryption by epidermal invaginations. C. jwarancusa had sunken stomata on the abaxial surface only, which largely reflected a reduced E, but less affected stomatal conductance (g _s) or WUE. L. scindicus had fewer but larger stomata along with hairs/trichomes which may function to avoid water loss through transpiration, and hence, to attain a high WUE. In O. compressa stomata were found only on the abaxial surface and these were completely encrypted by epidermal invaginations as well as a dense covering of microhairs, which was associated with a low E and high WUE under salinity stress. In S. ioclados, the traits of increased stomatal density and decreased stomatal area may be critical for stomatal regulation under salt-prone environments. High stomatal regulation depended largely on stomatal density, area, and degree of encryption under salinity, which is of great ecophysiological significance for plants growing under osmotic stresses.     

Characterization and analysis of antibiotic activity of some aquatic actinomycetes

Nine different isolates of aquatic actinomycetes identified as Streptomyces spp. were studied for their morphological and cultural characteristics. One of these isolates (C4-S, Streptomyces violaceusniger) was extensively studied for its inhibitory effect against a wide range of Gram-positive, Gram-negative bacteria, Mycobacterium vaccae ATCC 29678, Candida albicans and several food associated filamentous fungi and yeasts. Most of these were characterized by flexous sporophore morphology and their inability to produce cultural pigments. Bioassay results indicated that S. violaceusniger of 10 days culture age was highly active against Gram-positive cocci and bacilli with an inhibition zone of 16-25 mm, and slightly active against M. vaccae ATCC 29678 with an inhibition zone of 5-10 mm. The inhibitory effect was slight against Escherichia coli, Aspergillus niger 1 and C. albicans with an inhibition zone of 8-10 mm for each of them. There was no inhibitory effect of S. violaceusniger against other Gram-negative bacteria, filamentous fungi and yeast. The nature of the active molecule produced by S. violaceusniger showed a maximum absorption in the UV region at 210-260 nm.     

Chromium-resistant bacteria and cyanobacteria: impact on Cr(VI) reduction potential and plant growth

Two chromium-resistant bacterial strains, Bacillus cereus S-6 and Ochrobactrum intermedium CrT-1, and two cyanobacterial strains, Oscillatoria sp. and Synechocystis sp., were used in this study. At initial chromate concentrations of 300 and 600 μg K₂CrO₄ mL⁻¹, and an inoculum size of 9.6×10⁷ cells mL⁻¹, B. cereus S-6 completely reduced Cr(VI), while O. intermedium CrT-1 reduced Cr(VI) by 98% and 70%, respectively after 96 h. At 100 μg K₂CrO₄ mL⁻¹, Synechocystis sp. MK(S) and Oscillatoria sp. BJ2 reduced 62.1% and 39.9% of Cr(VI), respectively, at 30°C and pH 8. Application of hexavalent chromate salts adversely affected wheat seedling growth and anatomical characters. However, bacterial inoculation alleviated the toxic effects, as reflected by significant improvements in growth as well as anatomical parameters. Cyanobacterial strains also led to some enhancement of various growth parameters in wheat seedlings.

     

FAIR: A server for internal sequence repeats

An Internet computing server has been developed to identify all the occurrences of the internal sequence repeats in a protein and DNA sequences. Further, an option is provided for the users to check the occurrence(s) of the resultant sequence repeats in the other sequence and structure (Protein Data Bank) databases. The databases deployed in the proposed computing engine are up-to-date and thus the users will get the latest information available in the respective databases. The server is freely accessible over the World Wide Web (WWW). AVAILABILITY: http://bioserver1.physics.iisc.ernet.in/fair/     

Molecular factors regulating E-cadherin expression in urothelial bladder cancer and their correlations with the clinicopathological features

This study aimed to assess the expression of S100A4, Twist and E-cadherin (mRNA and protein) in urothelial bladder cancer, investigate the correlation between them and evaluate their association with the clinicopathological features of the disease. The study included 54 patients diagnosed as urothelial bladder cancer of different stages and grades. The expression levels of S100A4, Twist and E-cadherin (mRNA and protein) in tissue samples were determined by quantitative RT-PCR and immunohistochemistry. The expression of S100A4 and Twist was significantly upregulated while E- cadherin was significantly downregulated in urothelial bladder cancer tissues compared to the adjacent surrounding normal bladder tissues at both mRNA and protein levels (p?<?0.001). Expression levels of S100A4 and Twist were significantly higher in recurrent tumor than in non-recurrent tumors (p?<?0.001) while the expression level of E-cadherin was significantly lower in recurrent tumors than in non-recurrent tumors at both mRNA and protein levels (p?<?0.001). There was a significant positive correlation between S100A4 and Twist expressions (r?=?0.875, p?<?0.001) while significant negative correlations were found between E- cadherin and S100A4 expressions(r=- 0.803, p?<?0.001) and between E-cadherin and Twist (r?=??0.809, p?<?0.001). Up-regulation of S100A4 and Twist and down-regulation of E-cadherin in urothelial bladder cancer tissues compared to adjacent normal tissues were observed. There was a significant negative correlation between S100A4 and E- cadherin and between E- cadherin and Twist expression. However, there was a significant positive correlation between S100A4 and Twist expressions. Furthermore, the alterations in the gene expression were associated with disease stage and grade.     

Effect of host plant on cornucopia of mango fruit flies (Diptera: Tephritidae) and their triumphant management in context of climate change

A study was performed to assess the preference of fourteen mango cultivars for fruit flies and their management by bagging. So the choice of Tephritid flies to mango cultivars during fruiting phase is crucial. Fourteen different cultivars of mango viz., ‘Dusehri’, ‘Malda’, ‘Langra’ early cultivars, ‘Chaunsa’, ‘Fajri Klan’, ‘Sensation’ medium whereas ‘Sanglakhi’, ‘Retaul-12’, ‘Mehmood Khan’, ‘Tukhmi’, ‘Kala Chaunsa’, ‘Chitta Chaunsa’, ‘Dai Wala’ and ‘Sobey De Ting’ late cultivars were assessed for their suitability for fruit flies. The results indicate that the population density of fruit flies was higher on late cultivars like ‘Sanglakhi’ (20.61 percent), ‘Mehmood Khan’ (20.22 percent) and ‘Reutal-12’ (19.92 percent) were proved to be highly susceptible to fruit flies. Among these the cultivar ‘Reutal-12’ was selected being commercial and future cultivar for the management of fruit flies through bagging. The results reported that the attack of tephritid fruit flies and other insect pests were zero in bagged fruits as compared with control. It was further recorded that the bagged fruits has maximum average fruit weight i.e. 203.50 and 197.83 g per fruit was noted in those treatments where butter paper bag and brown paper bag was wrapped with better coloration as compared with un-bagged fruit with 159.5 g per fruit. Similarly, on an average fruit length were more i.e. 90.17, 91.33 mm in bagged fruit and 85.33 in un-bagged fruits. Furthermore, bagged fruits have zero incidence of disease with reduced fruit crack, fruit sunburn, mechanical damage, bird damage, fruit blemished and agrochemical residues on the fruit. So, it is concluded that the special attention should be given on ‘Reutal-12’ for the management of fruit flies when devising an IPM program for the control of fruit flies. Further, bagging has proved to be the good agricultural practices for the production of quality mango.