Unravelling the synergistic interaction of Thrips tabaci and newly recorded, Thrips parvispinus with Alternaria porri (Ellis.) Cif., inciting onion purple blotch.

Onion purple blotch is the most indispensable foliar disease of crop and has become a major concern for farmers and research fraternity. An attempt to investigate the role of injury in parasitism by Alternaria porri indicated that disease incidence and severity enhance considerably with injury. Thrips injured plants inoculated with A. porri presented 100% incidence and 52-72% severity while mechanically injured plants inoculated with A. porri showed 60-70% incidence and 28-34% severity. The uninjured plants showed considerably less disease incidence (30-40%) and severity (10-16%). Injured inoculated plants presented reduced leaf length and leaf area while the leaf diameter remained unaffected. The lesion number, lesion length and size was substantially enhanced with concomitant infestation of pest and pathogen. Thrips tabaci injury led to more pronounced symptoms of purple blotch compared to Thrips parvispinus injury. There was substantial decrease in photosynthetic rate and chlorophyll content with stress imposed on plant whilst the relative stress injury was enhanced. The induction of injury and inoculation of A. porri had an impact on the concentration of total phenolics, total soluble sugars, total proteins and hydrogen peroxide in onion leaves. A. porri combined with injury caused a more pronounced decrease in total soluble sugars and total protein content while enhancement in total phenolics and hydrogen peroxide content compared to uninjured plants. The dynamic nature of morpho-physiological and biochemical changes owing to stress conditions imposed on onion plant adds an extra layer of complexity in understanding the onion plant physiology and their ability to work out in response to challenging environment conditions.

Deciphering the Potential of Sulphur-Oxidizing Bacteria for Sulphate Production Correlating with pH Change.

Sulphur, available in the form of sulphate, is one of the essential nutrients that is required by plants. Bacteria capable of oxidizing reduced forms of sulphur to sulphate play an important role in sulphur nutrition for plants. The present study was conducted to isolate, screen, and characterize sulphur-oxidizing bacteria from different soil samples collected from mustard rhizosphere and fly ash mixed soil. A total of 33 sulphur-oxidizing bacterial isolates (HMSOB1-33) were retrieved from soil and further screened for sulphur-oxidizing ability. Maximum solubilization index (3.76), pH reduction (3.93), and sulphate production (173.61 µg/ml) were observed for the isolate HMSOB2 which on the basis of 16S rDNA sequencing was identified as Pantoea dispersa with sequence similarity 98.22%. Four other selected bacterial isolates were identified as Bacillus megaterium, Bacillus tropicus, Bacillus velezensis, and Bacillus cereus. Sulphate solubilization index (SSI) correlated positively (r = 0.91) with sulphate production; however, pH showed negative correlation (r = - 0.82) with SSI as well as sulphate production after 120 h of incubation. These promising bacterial isolates could be further explored as bioinoculant after assessing plant growth traits.

Actinobacteria Mediated Nanoparticles: A Pioneering Technology for Agriculture.

The induction of nanotechnology prevails against several issues threatening healthiness of plants and presents a powerful mean to defeat food crisis in a world of oversized inhabitants. Nanotechnology contributes numerous gadgets and constituents as nanostructures such as nano herbicides, pesticides, fertilizers and biosensors which play momentous roles in killing/suppression of weeds and pests, ingenious supply of nutrients and nourishing substances in soils. Actinobacteria, a class of microorganisms is known for production of antibiotics, growth promoting substances, hydrolytic enzymes and volatile compounds. Actinobacterial assisted synthesis of nanoparticles symbolizes an attractive technique as compared to traditional physico-chemical means as synthesis can be accomplished in assistance with bioremediation processes and can also diminish the utilization or manufacturing of hazardous matters having harmful effects on mankind and ecosystem as well. Therefore, this pioneering technology could carry out liable functions in agriculture by increasing food productivity in lucrative and environmental secured manner and could transfigure the agriculture system through employment of its tenets in adept ways.

Chickpea (Cicer arietinum L.) as model legume for decoding the co-existence of Pseudomonas fluorescens and Mesorhizobium sp. as bio-fertilizer under diverse agro-climatic zones.

Microbial co-inoculation strategy utilizes a combination of microbes to stimulate plant growth concomitant with an increased phytopathogen tolerance. In the present study, 15 endophytic bacterial isolates from rhizosphere and roots of wild chickpea accessions (Cicer pinnatifidum, C. judiacum, C. bijugum and C. reticulatum) were characterized for morphological, biochemical and physiological traits. Two promising isolates were identified as Pseudomonas fluorescens strain LRE-2 (KR303708.1) and Pseudomonas argentinensis LPGPR-1 (JX239745.1) based on 16S rRNA gene sequencing. Biocompatibility of selected endophytes with Mesorhizobium sp. CH1233, a standard isolate used as a national check in All India Coordinated Research Project (AICRP) was assessed to develop functional combinations capable of producing Indole acetic acid, gibberellins, siderophores and improving seed vigour (in vitro). In vivo synergistic effect of promising combinations was further evaluated under national AICRP, (Chickpea) at two different agro-climatic zones [North-West plain (Ludhiana and Hisar) and Central zones (Sehore)] for three consecutive Rabi seasons (2015-18) to elucidate their effect on symbiotic, soil quality and yield parameters. On the pooled mean basis across locations over the years, combination of Mrh+LRE-2 significantly enhanced symbiotic, soil quality traits and grain yield over Mrh alone and highly positive correlation was obtained between the nodulation traits and grain yield. Superior B: C ratio (1.12) and additional income of Rs 6,505.18 ha-1 was obtained by application of Mrh+LRE-2 over Mrh alone and un-inoculated control. The results demonstrate that dual combination of Mrh and Pseudomonas sp. from wild Cicer relatives can be exploited as a potential bio-fertilizer for increasing soil fertility and improving chickpea productivity under sustainable agriculture.

Ethanol production from Rice (Oryza sativa) straw by simultaneous saccharification and cofermentation.

Ethanol production from alkali treated rice straw was investigated by simultaneous saccharification and cofermentation (SSCF) using commercial cellulase and 3 different yeast strains viz., Saccharomyces cerevisiae HAU-1, Pachysolen tannophilus and Candida sp. individually as well as in combination at varied fermentation temperature and incubation time. Dilute alkali (2%) pretreatment of straw resulted in efficient delignification as observed by low residual lignin (12.52%) with 90.6% cellulose and 28.15% hemicellulose recovery. All the 3 yeast strains were able to produce ethanol form alkali treated rice straw and overall ethanol concentration varied from 5.30 to 24.94 g/L based on different fermentation time and temperature. Comparative analysis of ethanol production from different yeast strains combinations revealed maximum ethanol concentration of 23.48 g/L after 96 h incubation at 35ºC with P. tannophilus individually and 24.94 g/L when used as co-culture with Saccharomyces cerevisiae.