Dynamics of reactive oxygen species and lignin biosynthesis during leaf spot disease of Withania somnifera (L.) Dunal

Withania somnifera is an important medicinal plant, however, its cultivation and quality are compromised due to infestation by leaf spot disease caused by the fungus Alternaria alternata. To decipher suitable strategies against the disease, studies on post-infectional changes are important. Reactive oxygen species (ROS) are critical as they cross-talk with other defense signaling pathways. Our study involved the analysis of ROS-generating and scavenging systems in the healthy and diseased leaf samples of W. somnifera and ROS-driven downstream defence pathways. DAB and NBT assays for ROS detection, spectrophotometric and in gel assays for ROS scavenging enzymes, thioglycolic acid (TGA) based assay and histochemical staining for lignin content and qRT-PCR for transcript-level expression studies were performed. Leaf spot infection in W. somnifera led to increased NADPH oxidase activity and ROS accumulation in the infected leaves which were supported by the enhanced antioxidant enzyme activities. Leaf spot infected leaves exhibited increased lignin content with higher expression of lignin biosynthesis genes. In addition, the transcript levels of defense-related genes, NPR1 and PR genes were also upregulated. The present work provides insights into the response of leaf spot disease in invoking the defense-related signaling in W. somnifera. It demonstrates the cross-talk between ROS and lignin biosynthesis. This work identifies potential targets for developing future strategies to confer disease resistance against leaf spot pathogen in W. somnifera.

Default distal radial approach for all coronary procedures – a prospective study

Background

Radial artery approach for coronary interventions has substantially improved the outcome especially in acute coronary syndrome patients. However, radial artery occlusion is the achilles' heel of such an approach.

Purpose

To obviate such problems, distal radial artery (DRA) approach is evolving but technical challenge is the small size of the artery. We looked at the feasibility, safety and advantages of it.

Methods

Patient population included any patient requiring a diagnostic or percutaneous coronary interventions (PCI) in our catheterization laoratory from March 2020 to March 2022. A primary operator performed all procedures as default, if the patient had a palpable DRA. After local anaesthesia infiltration, using seldinger technique and micropuncture kit, 5 to 7F hydrophilic sheaths were introduced and a cocktail of verapamil and heparin was given routinely. Sheaths were removed immediately after procedure but dedicated side specific compression devices were used but removed 45 min after diagnostic and 2 hours after PCI. Clinical patency of radial artery was assessed at discharge and follow up.

Results

A total of 682 procedures were performed (50% were diagnostic). Out of all PCIs 59% were for ACS). Elective PCIs included very complex cases including PCI for bifurcation, left main and rota assisted complex PCIs. 651 patients had right distal radial approach and 28 had left. Mean age of patients were 66.8±12.9 years (26 to 97). Females constituted 218 (32%). Mean time from 1st needle puncure to successful vascular access took 1.2±0.8 min (20 sec to 6 min). Average attempts to obtain successful vascular access was 1.3±0.7 (1 to7 attempts). There were 15 failures (2%) to obtain DRA access requiring change over to 6 ipsilateral radial, 2 ulnar, 4 contralateral distal radial, 2 femoral and 1 brachial access. Interestingly, in 5 different occaisions previous procedure related occluded radial arteries were recanalized through this access. Most importantly, no case of radial artery occlusion was encountered at discharge or at follow up by clinical examinations. No other vascular complications were encountered except mild transient bruising in 6 cases and early small hematoma in 3 cases. Patient's comfort, nursing staffs' satisfaction and trend towards early discharges were also noticed. There was a distinct improvement in obtaining faster access with lower failure rates by the operator after initial 90, especially after 150 procedures.

Conclusions

A default approach through distal radial artery in anatomical snuff box for all coronary interventions is feasible, safe and possibly superior to conventional radial access with better patient comfort and caring staff's satisfaction. Though learning curve is longer and more challenging, success rates were much higher and vascular access was faster after initial phase. Clinically radial artry occlusion was not seen but needs further study and more objective evidence.

Funding Acknowledgement

Type of funding sources: None.

Effect of dietary supplementation of prebiotic, probiotic, and synbiotic on growth performance and carcass characteristics of broiler chickens

Aim:

The aim was to investigate the effects of dietary supplementations of prebiotic, probiotic, and synbiotic on growth performance and carcass characteristics of broiler chickens.

Materials and Methods:

A total of 360 1-day-old Vencobb broiler chickens of either sex were randomly assigned to four dietary treatments each consisting of three replicates and each replicate having 30 birds for 6 weeks. The dietary treatments were (1) control group with basal diet, (2) basal diet supplemented with prebiotic (at 400 g/tonne of starter as well as finisher ration), (3) basal diet supplemented with probiotic (at 100 g/tonne of starter ration and 50 g/tonne of finisher ration), and (4) basal diet supplemented with synbiotic(at 500 g/tonne of starter as well as finisher ration). The birds were provided with ad-libitum feed and drinking water during the entire experimental period.

Results:

The highest body weight observed in asynbiotic group, which was non-significantly (p>0.05) higher than thecontrol group. Prebiotic and probiotic groups showed lower body weight than synbiotic and control groups. A total feed intake did not show any significant (p>0.05) difference between experimental groups. There were no significant (p>0.05) differences in feed conversion ratio of broiler chickens in prebiotic, probiotic, and synbiotic groups as compared with control group. There was no significant (p>0.05) difference in the carcass traits with respect to dressing percentage, carcass percentage, heart weight, liver weight and gizzard weight, wing percentage, breast percentage, back percentage, thigh percentage, and drumstick percentage in Cobb broilers under study.

Conclusion:

The growth performance and percentage of carcass yield did not show any significant increase by the dietary inclusion of prebiotic, probiotic, and synbiotic compared with unsupplemented control in a commercial broiler chicken.

First Report of Leaf Spot Disease in Withania coagulans Caused by Alternaria alternata in India

Withania coagulans (Paneer doddi) is a medicinal plant in the Solanaceae (1) that grows in northwestern India. An unknown disease appeared in the Amritsar district of Punjab, India on W. coagulans starting in 2009, and was noticed annually in the post-monsoon seasons through 2011. The plants were grown in a net house (74.82323 to 74.82332°E, 31.63678 to 31.63688°N, 221 m elevation), Guru Nanak Dev University, Amritsar. Symptoms first appeared as brown to black spots (2 to 10 mm in diameter) that were sometimes surrounded by a yellow halo, starting on the lower leaves and gradually spreading to the upper leaves. Spots were apparent on both the dorsal and ventral sides of the leaves. In the most severe outbreak of the disease, more than 90% of the leaf area was covered with the leaf spot symptoms. The pathogen was isolated by placing pieces of surface-sterilized leaf spots on potato dextrose agar (PDA), and the hyphae that emerged from the leaf pieces were sub-cultured to PDA. Initially, the fungal colony was white, and gradually turned olive-brown as it matured. Conidiophores were mostly simple, usually becoming geniculate by sympodial elongation. Conidiophores were mostly branched and conidia were arranged in acropetal chains of 6 to 10. Conidia were 15 to 25 μm long and 5 to 10 μm wide, with 3 to 4 transverse septa and 2 to 3 longitudinal septa, muriform, ovoid to ellipsoid, with a broadly rounded base and an apical beak. Based on these morphological characters, the pathogen was identified as Alternaria alternata (Fr.) Keissler (4). The identification of the pathogen was also confirmed by MTCC, Chandigarh, India and deposited in their culture collection with Accession No. MTCC-10939 ( http://mtcc.imtech.res.in ). During preliminary studies, the optimum temperature for its growth was 25 ± 2°C. Pathogenicity of the fungus was demonstrated on three potted W. coagulans plants after spray-inoculating leaves with a spore suspension of 3 × 10⁵ spores per ml. A batch of three plants sprayed with sterile distilled water served as controls. Both inoculated and control plants were incubated at 100% relative humidity for 5 days and transferred to a glasshouse at 25 ± 2°C. Initial symptoms developed on a few plants at 5 to 7 days post-inoculation, and the same leaf symptoms described above from field plants became apparent on all inoculated plants by 10 to 14 days. Control plants did not develop symptoms. The pathogen was recovered from leaf spots using the isolation technique described above, and was identified as A. alternata, thus fulfilling Koch's postulates. Although the leaf spot diseases caused by A. alternata and A. dianthicola were reported on W. somnifera (2,3), to the best of our knowledge, there is no report of either pathogen infecting W. coagulans. Thus, the identification of pathogen will facilitate the disease management program and for enhancing the commercial value of this important endangered medicinal plant. References: (1) S. A. Gilani et al. Afr. J. Biotechnol. 8:2948, 2009. (2) C. K. Maiti et al. Plant Dis. 91:467, 2007. (3) P. K. Pati et al. Indian J Microbiol. 48:432, 2008. (4) E. G. Simmons. Alternaria: An identification manual. American Phytopathological Society, St. Paul, MN, 2007.

Rose protoplast isolation and culture and heterokaryon selection by immobilization in extra thin alginate film

Somatic hybridization has been identified as one method for the genetic improvement of roses. The success of somatic hybridization programmes relies to a great extent upon efficient protoplast isolation and culture and selection of heterokaryons. This paper reports the isolation of rose cell suspension protoplasts by direct sucrose flotation and demonstrates their culture using extra thin alginate film. A comparative assessment of the efficiency of conventional culture techniques versus those with extra thin alginate film or thin alginate layer is also presented. A very high plating efficiency (80%) was obtained using thin alginate layer or extra thin alginate film techniques with improved media formulations. Protoplasts of Rosa damascena and R. bourboniana were fused by using polyethylene glycol as fusogen and later immobilized in the thin layer of alginate. The fused protoplasts were tracked on the basis of differential fluorescent staining, and the hybridity of heterokaryons following their development to callus was confirmed by molecular characterization. This novel selection strategy has general applicability and is faster and simpler to perform during somatic hybridization experiments.

Extra thin alginate film: an efficient technique for protoplast culture

This paper reports an efficient protoplast culture technique, the "extra thin alginate film" technique. The development of this improved method of protoplast culture was an outcome of an assessment of the efficiency and shortcomings of various protoplast culture techniques. The efficiency of this technique was evaluated with two model plant systems, viz., Nicotiana tabacum and Lotus corniculatus, and a comparison was made with the "thin alginate layer" technique, another efficient protoplast culture system. Results indicate that the culture technique with extra thin alginate film is as efficient as the technique with thin alginate layer, with many additional advantages. The present innovation overcomes most of the limitations of protoplast culture techniques described so far and can now be applied to a wide variety of crops to check its general applicability.