Bt cotton producing Cry1Ac and Cry2Ab does not harm the parasitoid Aenasius arizonensis (Girault): a host-mediated tritrophic assay

Phytoparasitica - Transgenic crops with genes from Bacillus thuringiensis (Bt) Berliner, a soil bacterium producing δ-endotoxin that is lethal to several phytophagous insects. Concerns related...     

Screening Luffa germplasm and advanced breeding lines for resistance to Tomato leaf curl New Delhi virus

The two cultivated Luffa species can be severely infected by Tomato leaf curl New Delhi virus (ToLCNDV) with up to 100% yield loss. Here, 52 Luffa genotypes were screened for ToLCNDV resistance after natural field infection. Mean vulnerability index (VI) ranged from 0.00 to 75.33; genotypes IIHR-137 and IIHR-138 had no symptoms (VI 0), 16 genotypes were resistant (VI 0–25), 15 were moderately resistant (VI 26–50), and 19 were moderate to susceptible (VI?>?50). Ten of the most resistant genotypes and five susceptible checks were then challenge-inoculated using whiteflies or sap in an insect-proof net house; only IIHR-137 [L. cylindrica (L.) Roem.] was symptomless (VI 0.00), and 3–5% of plants of IIHR-138 [L. cylindrica (L.) Roem.] and IIHR-Sel-1 [L. acutangula (L.) Roxb.] had only mild symptoms; genotype Arka Prasan was most susceptible (VI 80.96). Asymptomatic plants were confirmed as infected using polymerase chain reaction. Susceptible genotypes rapidly developed leaf curling, then a severe mosaic 10 days post-inoculation. The resistant inbred lines identified are good candidates for a breeding program for ToLCNDV-resistant cultivars.

     

Enzymatic Process for Corn Dry‐Grind High‐Solids Fermentation

A modified dry‐grind process that combined the use of conventional amylases (glucoamylase [GA]), phytase, and granular starch hydrolyzing enzymes (GSHE) to achieve low liquefaction viscosities and low glucose concentrations during simultaneous saccharification and fermentation (SSF) with a high slurry solids content (>33% w/w) was developed. Doses of GSHE and GA were optimized for the modified process. At 35% solids content, the modified process had 80% lower slurry viscosity, 24% lower peak glucose concentration, 7.5% higher final ethanol concentration, and 51% higher fermentation rate compared with the conventional dry‐grind process. At 40% solids content, the modified process had lower viscosities, lower peak and residual glucose concentrations, and higher ethanol concentrations than the conventional process; however, the results were in contrast to those for 35% solids content. At 40% solids content, SSF did not run to completion for conventional or modified processes, and more than 2.5% w/v of residual glucose was left in the fermentation broth. Final ethanol concentration achieved with the modified process at 40% solids content was 19.5% v/v, similar to the ethanol concentration achieved with the modified process at 35% solids content. At 35% slurry solids content, a GSHE level of 1.25 μL/g db of corn and a GA level of 0.25 μL/g db of corn were selected as optimum enzyme doses for the modified process.     

α-Amylase inhibitor in local Himalyan collections of Colocasia: Isolation, purification, characterization and selectivity towards α-amylases from various sources

The α-amylase inhibitor from corms of Colocasia collected from Bhota village of Hamirpur district, Himachal Pradesh was purified to 17.21 folds with 61.61% recovery using ammonium sulfate precipitation, gel filtration chromatography (sephadex G-200) and ion exchange chromatography (DEAE-sephadex). A single band of the purified inhibitor was obtained by Native-PAGE. SDS-PAGE revealed the purified inhibitor to be a monomer with molecular weight of 13,900 daltons. The nature of inhibition was found to be of non-competitive type as determined by Lineweaver-Burk plot and a K_i value of 0.54 nmole was obtained by Dixon’s plot. The inhibitor was found to be heat stable and retained 81.50% activity at 70 °C temperature. Inhibitor was found to have pH optima of 6.9. The purified inhibitor was found to have inhibitory activity against α-amylases extracted from the larvae of Callosobruchus chinensis, Tribolium castaneum, Corcyra cephalonica and midgut α-amylase of Spodoptera littoralis. 100% larval mortality of C. cephalonica was observed when fed on wheat flour mixed with 0.0036% (w/w) of purified inhibitor. Purified α-amylase inhibitor was found to inhibit the activity of human salivary α-amylase. It also had inhibitory activity against potato α-amylases and reduced sugar content in treated potato slices. The purified inhibitor was found to be a glycoprotein. In the present study, the ability of the inhibitor to inhibit insect amylases highlights its possible role in pest resistance and post harvest decay of crop plants. Inhibitory activity of α-amylase inhibitor against mammalian amylases could suggest its potential in treatment of diabetes and cure of nutritional problems, which result in obesity.     

Embryo rescue in plants—a review

Summary The plant breeders usually rescue inherently weak, immature or hybrid embryos to prevent degeneration. The successful production of plants from the cultured embryos largely depends upon the maturation stage and the composition of the medium. Abortion of embryos at one or the other stage of development is a characteristic feature of distant hybridization. For the first time successful embryo culture to obtain an interspecific cross between Linum perenne × L. austriacum was demonstrated by Laibach (1925, 1929). Since then several refinements have been made in embryo culture/embryo rescue techniques which have been a popular approach for raising hybrids from a number of incompatible crosses. Currently embryo rescue holds great promise not only for effecting wide crosses, but also for obtaining plants from inherently weak embryos, obtaining haploid plants as well as for shortening the breeding cycle.     

Phytotoxic Interference of Ageratum conyzoides with Wheat (Triticum aestivum)

A study was conducted to assess the phytotoxicity of Ageratum conyzoides, a weed of cultivated areas, to the growth and establishment of wheat (Triticum aestivum). The lengths of the radicle and coleoptile and the seedling dry weight of wheat were significantly reduced when wheat was grown in field soil previously infested with A. conyzoides, compared to control soil collected from an area devoid of this weed. Even extracts prepared from A. conyzoides soil were inhibitory, indicating the presence of some water‐soluble phytotoxins in the soil. To determine the possible contribution of the weed in releasing these phytotoxins, growth studies involving leaf residues and their extracts and amended soils (prepared by incorporating leaf residues and residue extracts) were also performed on wheat. With all treatments, an inhibitory effect of A. conyzoides was found, compared to respective controls. A significant amount of water‐soluble phytotoxins (the phenolics) was found to be present in the soil infested with A. conyzoides, leaf residues and the amended soils. The amount of phenolics correlated well with growth performance in the respective treatments. This study establishes the phytotoxicity of leaf residues of A. conyzoides to wheat through the release of phenolics into the soil, which may serve as possible tools in establishing its allelopathy.     

Water Stress-induced Injury to Reproductive Phase in Chickpea: Evaluation of Stress Sensitivity in Wild and Cultivated Species in Relation to Abscisic Acid and Polyamines

Chickpea (Cicer arietinum L.) is more sensitive to water stress during its reproductive growth and consequently experiences substantial yield loss. Wild species being relatively tolerant to abiotic stresses offer a potential gene source for incorporation of drought tolerance in cultivated species. In the present study, the differential stress sensitivity of wild (Cicer reticulatum Ladiz.) and cultivated species (C. arietinum) was evaluated by subjecting the plants of both the species to water stress for 14 days during the reproductive phase and examined for stress injury, endogenous status of polyamines (PA) and abscisic acid (ABA). Comparatively, the cultivated species experienced higher stress injury (assessed as electrolyte leakage, 2,3,5‐triphenyl tetrazolium chloride reduction ability, chlorophyll loss) as well as decreased leaf water potential (Ψ_w; ?2.48 MPa) than the wild species (?1.98 MPa). The stressed plants of cultivated species lost more number of flowers (62 %) and pods (65 %) when compared with the unstressed ones while those of wild species showed 30 % and 44 % loss, respectively. The number of infertile pods was significantly more in stressed plants of cultivated species than in those of wild species. The endogenous status of PA revealed that putrescine (PUT), spermidine (SPD) and spermine (SPM) levels accumulated to a higher extent in the cultivated species relative to the wild species until the eighth day of stress, and thereafter, the wild species had significantly higher levels of PA. In contrast, ABA levels increased to a higher extent in the wild species until the eighth day of stress and declined subsequently to a greater degree than the cultivated species. The injury to reproductive growth appeared to accentuate with reduction in leaf Ψ_w that was coupled with depletion of PA in both the species, especially in the cultivated one. Exogenous application of 10 mm PUT partially alleviated the damage to reproductive growth by increasing the leaf water status and chlorophyll content while decreasing the ABA content, which resulted in improvement of retention of flowers and pods, particularly in the cultivated species.     

Long-term effects of various crop rotations for managing salt-affected soils through a field scale decision support system – a case study

Appropriate crop rotations coupled to water use plans are the basic means of managing salt‐affected soils. Recommendation of suitable crop rotations for salt‐affected land requires prediction of their long‐term impact on soil salinity/sodicity build‐up and consequent crop yield reduction. This is conventionally achieved through long‐term field experiments. However, such evaluations are site specific, expensive and time consuming. Appropriate decision support systems (DSS) can be a cost‐effective means in such cases. This study demonstrates the application of one such DSS for recommending the best crop rotation for a salt‐affected field in Gurgaon district of Haryana (India). Before application, the DSS was extensively validated on 11 farmer's fields and one experimental field in Gurgaon and Karnal districts of Haryana. The DSS gave realistic estimates of root zone soil salinity/sodicity and relative crop yield reductions under the local management practices. These estimates were associated with absolute mean relative errors ranging between 0.02 and 0.24. Ten‐year impact assessments of existing (i.e. paddy–wheat, P‐W) and 10 alternative crop rotation plans with the validated DSS showed that pearl millet‐based sequences were, environmentally and agronomically, the most suitable options for the test field. However, a cost–benefit analysis of DSS‐simulated average annual crop yields, under various crop rotations, showed that the economic return of pearl millet‐based sequences was about 13% less than fallow–wheat (F‐W) rotations and 4% less than P‐W rotations. Hence F‐W was recommended as the most beneficial environmental choice and economically the most robust alternative crop sequence for the salt‐affected field.     

Effect of dietary amino acids on in vitro rumen bacterial protein synthesis in buffaloes.

The effect of different ratios of urea to amino acid N at a fixed concentration of soluble sugars as energy source and varying levels of soluble sugars at optimum urea cell suspension was obtained from the rumen fluid of buffalo (Bubalus bubalis) calves fed on a growth ration. Under glucose fermentation, the bacterial protein content of the incubation mixture (I. M.) was increased to 3.91, 6.31 and 5.08 times the control value (urea alone) when 25, 50 and 75% of urea-N was replaced with amino acid N, respectively. With cellobiose, the corresponding increase was 4.06, 5.29 and 5.63 times. At 50% urea-N replacement with amino acid N (a ratio for maximum protein synthesis), the bacterial content was maximum when 1 g glucose or cellobiose per 100 ml of I. M. was added. Per cent incorporation of radioactivity from amino acids into bacterial protein was maximum at 25% amino acid N level with both the soluble sugar sources. The total amino acids incorporated into bacterial protein were, however, more at 50% than at 25% amino acid N level.     

Identification of sperm-specific proteins associated with high fertility of Punjab Red and RIR x Local cross roosters with SDS-PAGE and Immunoblotting

The present study aimed at characterization of fertility-associated proteins in PR and RIR x Local roosters and was conducted on two generations of birds. Roosters were divided into high- (>50%) and low-fertility groups (<50%) based on sperm function tests and fertility rate in both the generations. Polyclonal antibodies were raised in rabbits against sperm proteins of first generation highly fertile roosters and tested for characterization of fertility-associated sperm proteins in the second generation of same roosters. IgG fraction against proteins (anti-SP IgG) was reacted with sperm proteins of both high and low fertile roosters of second generation on immunoblots. SDS-PAGE of sperm extracts of PR and RIR x Local cross breeds resulted in resolution of 12 and 23 proteins on 12% acrylamide gels and anti-SP IgG reacted only with 8 and 9 sperm proteins of PR and RIR x Local cross roosters on immunoblots. The SDS-PAGE and immunoblotting analysis also indicated a variation in sperm proteins among two breeds and high/low fertile roosters. It can be concluded that the selection of roosters on the based on proteins of 65/ 25; 70/ 46/ 30 kDa may be specifically associated with high fertility of PR and RIR x Local cross, respectively. The proteins 62 kDa (PR) and 40kDa (RIR x Local cross) may be specifically responsible for low fertility.