Combating Antimicrobial Resistance by Employing Antimicrobial Peptides: Immunomodulators and Therapeutic Agents against Infectious Diseases.

The rising prevalence of multiple-drug-resistant pathogens poses a formidable challenge to conventional antimicrobial treatments. The inability of potent antibiotics to combat these "superbugs" underscores the pressing need for alternative therapeutic agents. Antimicrobial peptides (AMPs) represent an alternative class of antibiotics. AMPs are essential immunomodulatory molecules that are found in various organisms. They play a pivotal role in managing microbial ecosystems and bolstering innate immunity by targeting and eliminating invading microorganisms. AMPs also have applications in the agriculture sector by combating animal as well as plant pathogens. AMPs can be exploited for the targeted therapy of various diseases and can also be used in drug-delivery systems. They can be used in synergy with current treatments like antibiotics and can potentially lead to a lower required dosage. AMPs also have huge potential in wound healing and regenerative medicine. Developing AMP-based strategies with improved safety, specificity, and efficacy is crucial in the battle against alarming global microbial resistance. This review will explore AMPs' increasing applicability, their mode of antimicrobial activity, and various delivery systems enhancing their stability and efficacy.

CRISPR/Cas, Multiomics, and RNA Interference in Virus Disease Management.

Plant viruses infect a wide range of commercially important crop plants and cause significant crop production losses worldwide. Numerous alterations in plant physiology related to the reprogramming of gene expression may result from viral infections. Although conventional integrated pest management-based strategies have been effective in reducing the impact of several viral diseases, continued emergence of new viruses and strains, expanding host ranges, and emergence of resistance-breaking strains necessitate a sustained effort toward the development and application of new approaches for virus management that would complement existing tactics. RNA interference-based techniques, and more recently, clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing technologies have paved the way for precise targeting of viral transcripts and manipulation of viral genomes and host factors. In-depth knowledge of the molecular mechanisms underlying the development of disease would further expand the applicability of these recent methods. Advances in next-generation/high-throughput sequencing have made possible more intensive studies into host-virus interactions. Utilizing the omics data and its application has the potential to expedite fast-tracking traditional plant breeding methods, as well as applying modern molecular tools for trait enhancement, including virus resistance. Here, we summarize the recent developments in the CRISPR/Cas system, transcriptomics, endogenous RNA interference, and exogenous application of dsRNA in virus disease management.

Viral metatranscriptomic approach to study the diversity of virus(es) associated with Common Bean (Phaseolus vulgaris L.) in the North-Western Himalayan region of India.

Plant viruses are a major threat to legume production worldwide. In recent years, new virus strains have emerged with increasing frequencies in various legume cropping systems, which demands the development of cutting-edge virus surveillance techniques. In this study, we surveyed the common bean fields of Kashmir valley for virus infection using a total of 140 symptomatic and non-symptomatic leaf samples collected from different locations. The genetic diversity of viruses was examined by high-throughput sequencing (HTS) with three viruses being identified, namely, Bean Common Mosaic Virus (BCMV), Bean Common Mosaic Necrosis Virus (BCMNV), and Clover Yellow Vein Virus (ClYVV). BCMNV and ClYVV are new reports from India. De novo assembly of transcriptome constructed near-complete genomes of these viruses. RT-PCR results confirmed the presence of these viruses with an emerge incidence of 56. 4% for BCMV, 27.1% for BCMNV and 16.4 for ClYVV in the valley. Several samples were found to contain multiple virus infections with BCMV being the most predominant. Recombination events were detected in the genomes of BCMV and ClYVV, but not BCMNV. Phylogenetic and pairwise identity matrix evidence suggests viral import from multiple countries. Our results demonstrate that HTS followed by multiplex PCR assay is a simple, rapid, and reliable approach for simultaneous diagnosis of plant viruses.

First report of powdery mildew caused by Phyllactinia pyri-serotinae Sawada on pear (Pyrus communis L.) from India.

In August 2020 powdery mildew was observed on pear cv. Fertility at the University research field in Shalimar, Srinagar (J&K), India (34° 08' 30.5'' N and 74° 51' 42.0'' E) with a disease incidence up to 30% (100 leaves observed from ten trees). White irregularly shaped fungal colonies were observed on the abaxial leaf surface which latter covered the whole leaf surface and developed black chasmothecia. The affected leaves appeared brittle, slightly curved upwards and dropped prematurely. Mycelium was hypophyllous, septate and measured 2.0 to 5.0 µm in width. Appressoria were nipple shaped, solitary or present in opposite pairs. Conidiophores were erect, up to 440.0 µm long (n=50), mostly centrally on upper surface of mother cells. Conidiophore foot-cells were filiform, followed by 1 to 3 shorter cells, producing single conidia at the tip. Conidia were hyaline, lanceolate, with a non-papillate rounded apex, measuring55.5 to 81.4 × 14.8 to 22.5 µm (n=50) and devoid of any conspicuous fibrosin bodies. Germ tube was, filiform, twisted, arose basally and measured 2.0 to 5.0 µm in width. Chasmothecia were hypophyllous, black, scattered, globose and measured 195.0 to 255.0 µm in diameter (n=50) having 8 to 12 equatorial, acicular, up to 270.0 µm length appendages with 25.9 to 44.4 µm diameter bulbous base (n=50) and obtuse or subacute apex. Asci in a chasmothecium were clavate to saccate, 62.9 to 81.4 × 18.5 to 22.2 µm (n=50), stalked, and two- spored. Ascospores were 33.3 to 40.7 × 12.9 to 18.5 µm (n=50), pale yellowish or golden brown in color. All morphological features were consistent with Phyllactinia pyri-serotinae (Braun and Cook 2012). To confirm the fungus identity at molecular level, DNA of two isolates was extracted from chasmothecia. The internal transcribed spacer (ITS) sequence of ribosomal DNA was amplified with the primers ITS1 and ITS4 (White et al. 1990) and sequenced. The ITS sequences submitted to NCBI GenBank under Accession No. MZ505441 and MZ505442 have 97 (416/427) & 96 (424/440) per cent and 99 (424/430) & 98 (428/438) per cent base pair matching, with that of P. pyri-serotinae isolates from Japan (AB080521 and AB985507), respectively. Thus, the pathogen was identified as Phyllactinia pyri-serotinae Sawada based on morphological and molecular sequence analyses. The pathogenicity tests of both the isolates were carried out on one year old pear saplings (cv. Fertility) and repeated twice. The inoculum was prepared by collecting P. pyri-serotinae conidia in sterile distilled water from infected pear leaves. Three saplings were inoculated by spraying (15ml per sapling) the inoculum (3 x 105 spores ml-1) on leaf surfaces, while same number of saplings sprayed with sterile distilled water served as non-inoculated controls. After 15 days of incubation at 25oC in a green house, similar symptoms as observed on naturally infected plants were observed on inoculated plants and uninoculated plants remained symptomless. The pathogen of interest observed on inoculated plants was morphologically characterized and found to be similar to P. pyri-serotinae. The voucher specimen was deposited in the Herbarium Crytogamae Indiae Orientalis (HCIO), IARI, New Delhi under accession number 52213. Pear is the third most important temperate fruit grown in India (Chattopadhyay 2009) and our study reveal P. pyri-serotinae as the new causal agent of powdery mildew in addition to P. guttata (Dhar and Shah 1982) under Indian conditions.

Phylogenetics of tobacco rattle virus isolates from potato (Solanum tuberosum L.) in the USA: a multi-gene approach to evolutionary lineage.

Tobacco rattle virus (TRV) is an important soil-borne virus of potato that is transmitted by stubby-root nematodes. TRV causes corky ringspot, a tuber disease of economic importance to potato production. Utilizing protein-coding regions of the whole genome and a range of computational tools, the genetic diversity, and population structure of TRV isolates from several potato-growing regions (Colorado, Idaho, Indiana, Minnesota, Nebraska, North Dakota, and Washington State) in the USA were determined. Phylogenetic analyses based on RNA2 nucleotide sequences, the coat protein (CP) and nematode transmission (2b) genes, showed geographical clustering of USA isolates with previously known American isolates, while European isolates grouped in a distinct cluster. This was corroborated by the observed genetic differentiation and infrequent gene flow between American and European isolates. Low genetic diversity was revealed among American isolates compared to European isolates. Phylogenetic clustering based on RNA1 genes (RdRp, RdRp-RT, and 1a) were all largely incongruent to that of 1b gene (virus suppressor of RNA silencing). This genetic incongruence suggested the influence of recombination. Furthermore, the RdRp, RdRp-RT, and 1a genes were predicted to be more conserved and under negative selection, while the 1b gene was less constrained. Different evolutionary lineages between TRV RNA1 and RNA2 genomic segments were revealed.

Distribution and molecular characterization of potato virus Y (PVY) strains infecting potato (Solanum tuberosum) crop in Kashmir (India).

For breeding resistant cultivars, understanding the nature and distribution of PVY strains is indispensable. In present study, during the course of survey two hundred potato samples showing symptoms of vein clearing, mosaic, stunting, mottling, curling and vein banding were collected from 4 major potato growing districts of Kashmir valley. The disease incidence ranged from 16 to 27.33% with maximum in district Srinagar (27.33%). All the samples were serologically tested for PVY infection using DAS-ELISA and 74 tested positive for PVY infection. Out of 74 positive samples forty samples were re-confirmed by RT-PCR by amplifying 900 bp using coat protein (CP) gene specific primers. The PCR-positive samples were further characterized into different strains using strain specific primers. The strains NTN, N and O were reported and among them NTN strain was found to be most prevalent throughout the valley. The phylogenetic analysis of selected isolates carried out with known PVY strains also confirmed that the isolates belong to the N, NTN and O strains of PVY. The study will help in developing point of care strain specific diagnostics and also in devising the strategy for developing PVY resistant varieties, because when we have the complete information about the virus and its strains it will help us in screening the germplasm against each strain and, therefore, eventually development of a multi-strain resistant variety. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13337-021-00722-2.

Phylogeny and Optimization of Trichoderma harzianum for Chitinase Production: Evaluation of Their Antifungal Behaviour against the Prominent Soil Borne Phyto-Pathogens of Temperate India.

Trichoderma is the most commonly used fungal biocontrol agent throughout the world. In the present study, various Trichoderma isolates were isolated from different vegetable fields. In the isolated microflora, the colony edges varied from wavy to smooth. The mycelial forms were predominantly floccose with hyaline color and conidiophores among all the strains were highly branched. Based on morphological attributes, all the isolates were identified as Trichoderma harzianum. The molecular identification using multilocus sequencing ITS, rpb2 and tef1α, genes further confirmed the morphological identification. The average chitinase activity varied from 1.13 units/mL to 3.38 units/mL among the various isolates, which increased linearly with temperature from 15 to 30 °C. There was an amplified production in the chitinase production in the presence of Mg+ and Ca2+ and Na+ metal ions, but the presence of certain ions was found to cause the down-regulated chitinase activity, i.e., Zn2+, Hg2+, Fe2+, Ag+ and K+. All the chitinase producing Trichoderma isolates inhibited the growth of tested pathogens viz., Dematophora necatrix, Fusarium solani, Fusarium oxysporum and Pythium aphanidermatum at 25% culture-free filtrate concentration under in vitro conditions. Also, under in vivo conditions, the lowest wilt incidence and highest disease control on Fusarium oxysporum was observed in isolate BT4 with mean wilt incidence and disease control of 21% and 48%, respectively. The Trichoderma harzianum identified in this study will be further used in formulation development for the management of diseases under field conditions.

First report of Fusarium solani associated with the bulb rot of Tulip (Tulipa spp) in India.

Tulip is an ornamental bulbous flowering crop belonging to the Genus Tulipa and family Liliaceae. It is the first ranking bulbous ornamental plant in the world (Nayeem and Qayoom 2015). They are often the first flowers to witness the bloom in the spring. Kashmir valley is located in northern Himalayas in northwestern region of Indian subcontinent. It is the most alluring and fascinating place all over India and the home of famous "Indhra Gandhi Memorial Tulip garden", the largest tulip garden in the entire Asia. However there are number of constraints in tulip cultivation among which bulb rot occupy a prominent place (Piwoni 2000). Bulb rot is posing problem to all the tulip growers throughout the world (De Hertogh et al. 1983). Rot symptoms were observed on tulip bulbs in field as well as in storage conditions (20-22◦C temperature with a relative humidity of 65%) in the summers of 2018 and 2019 in Shalimar fields of Kashmir. The main disease symptoms are yellow sunken spots on bulbs, purple-yellow coloration of leaves. Causal agent was isolated using tissue bit technique (Pathak 1972) on potato dextrose agar plates which where incubated at 24±2◦C . Single spore technique was used to obtain the pure isolate (Johnston and Booth 1983). The isolate covered the full plate (90mm) in ten days. The colony was dull whitish in color, flat and smooth with concentric ring formation in the culture plate with inner ring having a creamy exudation. The mycelium was septate, branched and hyaline in color and measured 3.50-5.20 µm in width with an average of 4.4 µm. Micro-conidia were hyaline, cylindrical to oval, 0-1 septa and measured 7.50-11.00×2.80-3.75 µm in size. Macro conidia were hyaline with 3-4 septa, fusiform, moderately curved which measured 21.15- 32.00×3.80-4.75 µm in size with an average of 28.50±0.21× 4.30±0.2 µm. On the basis of these morphological and cultural characteristics of the fungus, it was identified as Fusarium solani (Mar.) Sacc.,. To confirm the identity the PCR amplification was carried out for two genes Internal Transcribed Spacer (ITS 1, ITS 4)and Translation Elongation factor1-alpha gene (tef1- alpha) (O'Donnell et al. 1998; White et al. 1990). BLAST analysis of the sequence obtained for both the genes showed 99% homology with F. solani sequences in GenBank and Fusarium -ID databases. The sequences were deposited in the GenBank (Accession No MN611433, MW995477). Pathogenicity test was conducted on variety orange emperor both in laboratory and polyhouse. Bulbs were divided into three sets, (three bulbs per set) one set was given injury and dipped in conidial suspension (106 conidia/ml) for 30 min, another set was kept uninjured and dipped in spore suspension of same concentration, the third set was served as control and dipped in sterilized distilled water. All the respective sets were incubated in a moist chamber maintained at a temperature of 22 ◦C to observe symptoms. The injured ones showed symptoms after 7-8 days of inoculation, whereas the uninjured bulbs showed symptoms after 11-12 days. No symptoms were observed in controlled set. A pot experiment was also conducted to carry the pathogenicity tests. Bulbs were injured with the help of sterile needle and were dipped in conidial suspension (106 conidia/ml) for 30 min (Pastrana et al. 2014). The bulbs kept for control were dipped in sterilized distilled water. Bulbs were then planted in pots maintained at 18◦C. The above ground parts of the inoculated bulbs showed symptoms like stunted growth which gradually turned yellow and did not produced flowers. The bulbs after harvesting were rotten .No symptoms were observed in controlled plants. To fulfill the Koch's postulates the fungal pathogen was re-isolated which was identified as F. solani. The pathogen is reported to cause disease in other crops (Gupta et al. 2012) but to our knowledge and on the basis of literature, this is the first report of F. solani causing bulb rot of tulip in India.

Molecular phylogeny, pathogenic variability and phytohormone production of Fusarium species associated with bakanae disease of rice in temperate agro-ecosystems.

Bakanae is the emerging disease threating the rice cultivation globally. Yield reduction of 4-70% is recorded in different parts of the world. A total of 119 Fusarium isolates were collected from rice plants at different geographical locations and seeds of different rice cultivars. The isolates were evaluated for morphological, biochemical and pathogenic diversity. The amplification of TEF-1α gene was carried out for exploring the species spectrum associated with the cultivated and pre-released rice varieties. The production of gibberellin varied from 0.53 to 2.26 µg/25 ml, while as that of Indole acetic acid varied from 0.60 to 3.15 µg/25 ml among the Fusarium isolates. The phylogenetic analysis identified 5 different species of the genus Fusarium viz. Fusarium fujikuroi, F. proliferatum, F. equiseti, F.oxysporum and F. persicinum after nucleotide blasting in NCBI. Only two Fusarium spp. F. fujikuroi and F. proliferatum were found to be pathogenic under virulence assays of the isolates. The isolates showed a considerable variation in morphological and pathogenic characters. The isolates were divided into different groups based on morphology and pathogenicity tests. The isolates showed a considerable variation in morphology, phytohormone profile and virulence indicative of population diversity. Three species F. equiseti, F.oxysporum and F. persicinum which have not been reported as pathogens of rice in India were found to be associated with bakanae disease of rice, however their pathogenicity could not be established.

Complete genome characterization and population dynamics of potato virus Y-NTN strain from India.

Potato virus Y (PVY) is a major threat to potato cultivation worldwide. PVY exists as biologically and genetically distinct strains and causes varying degrees of pathogenicity and a wide range of symptoms in potato. Knowledge of the nature of PVY strains is essential for breeding PVY resistant cultivars that are durable against a wide range of strains. We report the complete genome of a PVY potato isolate (JK12) characterised from the potato production areas of Jammu and Kashmir, India. Nucleotide sequence comparisons and phylogenetic analysis with known PVY strains revealed that the isolate belongs to the NTN strain of PVY. At the whole genome sequence level, the JK12 isolate shared the highest identity (99.42%) with PVY-NTN strains reported from Germany, followed by those from United Kingdom (99.34%) and Japan (99.33%). Recombination detection analysis identified two recombination break points and JK12 appeared to have originated from a recombination event between a PVY-N strain from Belgium as a major parent and a PVY-O strain from China as the minor parent. Our results suggest possible mutation and recombination could be the basis for the evolution and the subsequent establishment of NTN in this region. Furthermore, a global evolutionary lineage analysis of all the known PVY strains showed relatively low nucleotide diversity among the PVY-NTN strains. Neutrality tests showed that all the genotypes of PVY are undergoing purifying selection suggesting population expansion of PVY. This is the first report of complete genomic characterization of an NTN strain of PVY isolated from commercial potato fields in India. The implications of the emergence of this strain in the Indian context are discussed.