Pusa Komal Research Articles

Comparative Spatial Distribution of Sucking Insect-Pest-Complex in Summer and Monsoon Cowpea [Vigna unguiculata (L.) Walp.

Background: Pulse crops are known as an important dietary source of proteins for a major part of the vegetarian population across the globe; especially in India. Legume crops help restoration of soil fertility through symbiotic nitrogen fixation. Spatial distribution is an important aspect as it interprets the interaction between individuals of the species and their habitat. The biological reason of aggregation is highly unpredictable and it depends on behavioural pattern of the insect; therefore, spatial distribution accounts for informative description of organisms. Methods: In order to study the spatial distribution of sucking pests of cowpea, a field trial was laid out during Zaid and Kharif separately at the Instructional Farm of Rajasthan College of Agriculture, Udaipur in 2019 and 2020. Cowpea variety Pusa Komal was cultivated in 6 plots each of 3 m x 3 m with the row to row and plant to plant spacing of 50 cm and 10 cm, respectively. Different distribution pattern were used to determine spatial distribution pattern of species of insect fauna associated with cowpea during the summer and monsoon season. Result: The spatial distribution for most the insect pest complex was contagious during both the respective seasons. All positive IDM (index of clumping) values confirmed the clumping of the pest during the season. The mean crowding index was more than unity, indicated clumped interaction.

Assessment of genetic diversity in cowpea (Vigna unguiculata L.) genotypes by using RAPD markers

The present study was carried out at the department of Plant Biotechnology, College of Agricultural Biotechnology Latur, which aimed to study or assess the genetic diversity in eight different Cowpea genotypes by using the RAPD markers. This is important for cowpea genetic improvement and for the overall management of cowpea germplasm. Eight Cowpea genotypes namely GDVC-2, GC-3, GC-4, GC-6, Gangotri, Pusa Komal, Arka Garima, and VU-5 were assessed by using two RAPD markers (RPI-07 and RPI-08). In RAPD analysis, total of 20 amplicons were generated, among them 19 were polymorphic with 88.8% average polymorphism. RPI-7 and RPI-8 showed 88.8% and 100% polymorphism respectively. The similarity coefficient values ranged from 0.350% to 0.950% indicating high degree of genetic variation. The highest genetic similarity i.e. 0.857% was recorded between Pusa Komal and GC-6 and least genetic similarity i.e. 0.125% was observed in between VU-5 and GC-4. Two screened primers are found to be polymorphic (94.4%) with high polymorphic information content (PIC) which efficiently discriminating the varieties at molecular level.

Screening of Cowpea Genotypes for Growth, Yield and Cowpea Mosaic Virus Incidence

Eighteen cowpea genotypes against cowpea mosaic virus disease under zero tillage condition were screened during pre Kharif season of 2013, 2014 and 2015 at the field in Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal.Significant variation was observed for different genotypes with respect to cowpea mosaic virus, growth, yield and qualities. Highest pod yield was recorded in Kashi Kanchan (16.42 t/ha) which was statistically at par with Kanak (16.30 t/ha). Genotypes Bidhan Barbati 1, Bidhan Barbati 2, Kaberee and Pusa Komal were recorded without disease incidence i.e.immune while, Kanak, Pusa Phalguni Gold and Lafa Charulata exhibited highly resistance against cowpea mosaic virus. It was observed that cowpea mosaic virus incidence was negatively correlated with chlorophyll content, number of pods/plant, pod yield, leaf phenol content and leaf peroxidase content whereas, it was positively correlated with canopy temperature, days to flowering and first harvest. Bangladesh J. Bot. 51(4): 817-820, 2022 (December)

Growth, Yield and Phosphorus use Efficiency of Vegetable Cowpea (Vigna unguiculata) Varieties as Influenced by Phosphorus Levels under Rainfed Conditions of Semi-Arid Environment

Selection of a suitable variety and use of optimum level of phosphorous can significantly increase the productivity and profitability of vegetable cowpea under rainfed conditions in semi-arid tropics. However, application of appropriate level of phosphorus is of prime importance to realize higher yield, economics and phosphorus use efficiency. Hence, a field study was conducted at the Research Farm of Indian Agricultural Research Institute, New Delhi, India to find out the effect of different varieties and phosphorus levels on the growth, yield, economics and phosphorus use efficiency in two consecutive rainy seasons of 2018 and 2019 under semi-arid conditions. Three varieties of cowpea (Pusa Dharni, Pusa Komal and Kashi Kanchan) and four levels of phosphorus (0, 20, 40 and 60 kg P2O5 ha-1) were laid out in split plot design with three replications. The results revealed that variety Pusa Dharani recorded significantly higher green pod yield (5.12 t ha-1) with net returns of Rs. 40454 ha-1 and net B:C ratio of 1.27. The maximum nodules per plant, nodule weight per plant and nutrient uptake were also recorded with variety Pusa Dharni. Maximum increase in agronomic phosphorus use efficiency (33.73 kg pod yield per kg P applied) and P recovery (18.19%) were noted with Pusa Dharni. Phosphorus levels showed significant variation on all the growth and yield attributing parameters, and yield. Application of 60 kg P2O5 ha-1 resulted in highest green pod yield (5.38 t ha-1) but remained statistically comparable with 40 kg P2O5 ha-1. However, maximum net returns (Rs.41320 ha-1) and net B:C ratio (1.28) were obtained with 40 kg P2O5 ha-1, whereas 60 kg P2O5 ha-1 could fetched net returns of Rs. 41120 ha-1 and net B:C ratio of 1.22. Highest nodules per plant, nodules weight and N, P and K uptake were registered with 60 kg P2O5 ha-1 and was closely followed by 40 kg P2O5 ha-1. Application of 20 kg P2O5 ha-1 noted highest agronomic P use efficiency (39.72 kg pod yield per kg P applied) and P recovery (15.05%) followed by 40 kg P2O5 ha-1. The highest net returns (Rs. 41345 ha-1), net B:C ratio (1.28), economic efficiency (Rs. 516.81 per day per ha) and production efficiency (66.25 kg per day per ha) were obtained due to the application of 40 kg P2O5 ha-1. Increasing P levels showed positive correlation with nodules per plant, dry weight of nodules, nutrient uptake and pod yield. Hence, the results indicated that growing of cowpea variety Pusa Dharni along with the application of 40 kg P2O5 ha-1 registered to be most suitable to obtain higher net returns and net B:C ratio under rainfed condition of semi-arid regions.

Direct Foliar Application of dsRNA Derived From the Full-Length Gene of NSs of Groundnut Bud Necrosis Virus Limits Virus Accumulation and Symptom Expression.

Groundnut bud necrosis virus (GBNV) is the most significant member of the genus Orthotospovirus occurring in the Indian subcontinent. There is hardly any effective measure to prevent GBNV in crop plants. In order to develop GBNV infection prevention procedure, we examined the effect of the direct foliar application of double-stranded RNA (dsRNA) derived from the full-length NSs gene (1,320 nucleotides) of GBNV. The bacterially expressed dsRNA to the non-structural (dsNSs) gene of GBNV was purified and delivered to plants as an aqueous suspension containing 0.01% Celite for evaluating its efficacy in preventing GBNV infection in systemic host, Nicotiana benthamiana as well as in local lesion and systemic host, cowpea cv. Pusa Komal (Vigna unguiculata). The dsNSs application and challenge-inoculation were conducted in three different combinations, where plants were challenge-inoculated with GBNV a day after, immediately, and a day before the application of dsNSs. N. benthamiana plants, which were not treated with dsRNA showed severe systemic wilting and death by 9–16 days post-inoculation (dpi). The non-treated cowpea plants exhibited many chlorotic and necrotic lesions on the cotyledonary leaves followed by systemic necrosis and death of the plants by 14–16 dpi. The dsNSs treated plants in all the combinations showed significant reduction of disease severity index in both N. benthamiana and cowpea. The treatment combination where the GBNV inoculation was conducted immediately after the dsNSs treatment was found to be the most effective treatment in preventing symptom expression. The viral RNA analysis by real time PCR also showed 20 and 12.5 fold reduction of GBNV in cowpea and N. benthamiana, respectively. Our results suggest that the foliar application of dsRNA derived from the full-length NSs gene of GBNV through Celite is successful in delivering long dsRNA leading to effective prevention of GBNV infection.

Integrative small RNA and transcriptome analysis provides insight into key role of miR408 towards drought tolerance response in cowpea

Drought stress response studies and overexpression of vun-miR408 proved it to be essential for abiotic stress tolerance in cowpea. Small RNA and transcriptome sequencing of an elite high-yielding drought-tolerant Indian cowpea cultivar, Pusa Komal revealed a differential expression of 198 highly conserved, 21 legume-specific, 14 less-conserved, and 10 novel drought-responsive microRNAs (miRNAs) along with 3391 (up-regulated) and 3799 (down-regulated) genes, respectively, in the leaf and root libraries. Among the differentially expressed miRNAs, vun-miR408-3p, showed an up-regulation of 3.53-log2-fold change under drought stress. Furthermore, laccase 12 (LAC 12) was identified as the potential target of vun-miR408-3p using 5' RNA ligase-mediated rapid amplification of cDNA ends. The stable transgenic cowpea lines overexpressing artificial vun-miR408-3p (OX-amiR408) displayed enhanced drought and salinity tolerance as compared to the wild-type plants. An average increase of 30.17% in chlorophyll, 26.57% in proline, and 27.62% in relative water content along with lesser cellular H2O2 level was observed in the transgenic lines in comparison with the wild-type plants under drought stress. Additionally, the scanning electron microscopic study revealed a decrease in the stomatal aperture and an increase in the trichome density in the transgenic lines. The expression levels of laccase 3 and laccase 12, the potential targets of miR408, related to lipid catabolic processes showed a significant reduction in the wild-type plants under drought stress and the transgenic lines, indicating the regulation of lignin content as a plausibly essential trait related to the drought tolerance in cowpea. Taken together, this study primarily focused on identification of drought-responsive miRNAs and genes in cowpea, and functional validation of role of miR408 towards drought stress response in cowpea.

Insight into the cellular and physiological regulatory modulations of Class-I TCP9 to enhance drought and salinity stress tolerance in cowpea.

The Teosinte branched 1/Cycloidea/Proliferating cell factor (TCP) transcription factors are potent growth and developmental regulators in plants, also responsive to various hormonal and environmental stimuli. In this study, we primarily focused on the functional role of TCP9, a nuclear-localised Class-I TCP transcription factor in a drought and heat-tolerant legume crop, cowpea (Vigna unguiculata). Under drought stress, a higher protein expression level of TCP9 was observed in the leaves of the drought-tolerant cowpea cultivar Pusa Komal as compared to the drought-sensitive cultivar TVu-7778. Further, overexpression of VuTCP9 resulted in reduced cell and stomata size, aperture length and width while cell and overall stomatal density in the 35S::VuTCP9 transgenic cowpea lines increased. Phenotypic alterations, such as reduced leaf size and vigour, altered seed coats displaying extension pattern similar to the 'Watson pattern' and delayed senescence were prominent in the transgenic lines. Under normal conditions, the gas exchange and fluorescence measurements indicated reduction in transpiration rate (E), stomatal conductance (gs ) and photosynthetic efficiency (Φ PSII). However, water usage efficiency (WUE) remained unaltered in the transgenic lines as compared to the wild-type (WT) plants. Furthermore, the transgenic lines displayed higher tolerance to oxidative, drought and salinity stress, maintained relatively higher relative water content and lower occurrence of H2 O2 , as compared to the WT plants. Genes related to the jasmonic acid biosynthesis, stomatal development and abiotic stress responsiveness, such as TTG1, NAC25, SPCH and GRP1, increased and LOX2 decreased significantly in the transgenic lines.

First Report of Natural Infection by Capsicum Chlorosis Virus on Amaryllis (Hippeastrum hybridum) Plants from India

First Report of Natural Infection by Capsicum Chlorosis Virus on Amaryllis (<i>Hippeastrum hybridum</i>) Plants from India

Genetic analysis of pod yield and its contributing traits in cowpea (Vigna unguiculata L. Walp)

The present investigation was undertaken to study the type of gene action involved for green pod yield and its components in cowpea and to estimate the general combining ability and specific combining ability of parents and crosses, respectively. The significance of both gca and sca variance for most of the characters indicated that both additive as well as non-additive types of gene actions were involved in the inheritance of these traits. The gca effects of parents suggested that 2014/COPBVAR-4, 2012/COPBVAR-2, 2014/COPBVAR-5 and Kashi Kanchan were good combiners for different yield components like number of flowers per cluster, number of pods per cluster, per cent pod set, number of pods per plant and days to last harvest. The Arka Garima, 2014/COPBVAR-5 and 2014/COPBVAR-4 were good general combiner for days to 50% flowering and Kashi Kanchan, 2014/COPBVAR-5 and 2012/COPBVAR-2 for green pod yield per plant. No single parent was found to be good for all the traits. Based on specific combining ability effects of the hybrids, the cross combination2014/COPBVAR-5 x Gomti was found to be the best combination both for number of pods per plant and green pod yield per plant. The other best specific combinations were 2012/COPBVAR-3 x Pusa Komal, 2012/COPBVAR-5 x Pusa Komal and 2012/COPBVAR-2 x Arka Garima with high positive sca effects and high mean for green pod yield per plant. These promising parents can be used in future breeding programmes and the crosses may be exploited for isolation of transgressive segregants from the segregating generations of these crosses for further improvement of pod yield in cowpea.

Complete genome sequence and phylogenetic relationships of tobacco streak virus causing groundnut stem necrosis disease in India.

Tobacco streak virus (TSV, genus Ilarvirus family Bromoviridae) is known to cause stem necrosis disease (SND) in groundnut (Arachis hypogaea) since 2000 in Southern India. The TSV isolate infecting groundnut so far has not been characterized based on the complete genome sequence. In this study, TSV was isolated from a naturally infecting groundnut plant in Kadiri, the hot-spot of the SND in southern India. During the Kharif season of 2014, groundnut plants in an experimental field were affected with chlorosis and necrosis in leaf, stem and buds. The cent percent of the 48 samples with these symptoms collected from the field tested positive for TSV in ELISA samples in this context. One isolate, GN-Kad was established from a single lesion on cowpea cv. C-152 through successive sap inoculation. Cloning and sequencing of coat protein gene (717 nucleotides) of the isolate showed high sequence identity (98-99%) with the TSV isolates reported from different crops in India. The isolate produced local necrotic rings or veinal necrosis following sap inoculation to cowpea (cultivars C-152, Pusa Komal, Pusa Sukomal and Krishi Kanchan), French bean and sunflower; whereas, it produced systemic chlorotic mottling symptoms in Nicotiana benthamiana. The three segments of the virus genome (RNA 1, RNA 2 and RNA 3) contained 3523, 2903 and 2232 nucleotides, respectively. The overall genome sequence (8639 nt) of the present isolate shared 77-99% of nucleotide sequence identity with that of the other seven isolates reported from Australia, India and USA. The GN-Kad shared very close phylogenetic relationship with the okra and pumpkin isolates reported from India. The present report is the first comprehensive study of the molecular characterization of TSV associated with the stem necrosis disease of groundnut.

Use of sludge (a waste) as a resource for getting enhanced plant productivity

Experiments were carried out to check the utility of sludge, a waste generated from wastewater treatment as a soil supplement. Sludge collected from wastewater treatment plant was tested for presence of toxicants (if any) and supplemented in soil. Field experiments were conducted with crop plants vis. Brassica juncea var. Pusa Vijay (NPJ-93), Triticum aestivum var. HD-2967, Solanum lycopersicum var. Pusa hybrid 2 and Vigna unguiculata var. Pusa Komal. Results indicated that morphological growth was positively affected in plants raised in sludge supplemented soil in comparison to control. Plant growth parameters such as plant height, number of leaves, biomass showed enhancement, whereas biochemical attributes such as chlorophyll, soluble sugars and protein did not depict any significant alteration. Enhanced vegetative growth supported high yield. Present investigations suggested that sludge can be used as a partial substitute for fertiliser and hence can prove to be an effective soil supplement.

Impact assessment of silver nanoparticles on plant growth and soil bacterial diversity.

The present study was carried out to investigate the impact of silver nanoparticles (AgNPs) on the growth of three different crop species, wheat (Triticum aestivum, var. UP2338), cowpea (Vigna sinensis, var. Pusa Komal), and Brassica (Brassica juncea, var. Pusa Jai Kisan), along with their impact on the rhizospheric bacterial diversity. Three different concentrations (0, 50 and 75 ppm) of AgNPs were applied through foliar spray. After harvesting, shoot and root parameters were compared, and it was observed that wheat was relatively unaffected by all AgNP treatments. The optimum growth promotion and increased root nodulation were observed at 50 ppm treatment in cowpea, while improved shoot parameters were recorded at 75 ppm in Brassica. To observe the impact of AgNPs on soil bacterial community, sampling was carried out from the rhizosphere of these crops at 20 and 40 days after the spraying of AgNPS. The bacterial diversity of these samples was analyzed by both cultural and molecular techniques (denaturing gradient gel electrophoresis). It is clearly evident from the results that application of AgNPs changes the soil bacterial diversity and this is further influenced by the plant species grown in that soil. Also, the functional bacterial diversity differed with different concentrations of AgNPs.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-016-0567-7) contains supplementary material, which is available to authorized users.

Diagnostic assays for two closely related tospovirus species, Watermelon bud necrosis virus and Groundnut bud necrosis virus and identification of new natural hosts

Watermelon bud necrosis virus (WBNV) and Groundnut bud necrosis virus (GBNV) are two closely related tospovirus species infecting several crops in India. In the present study, specific diagnostic assays for these two most predominant tospoviruses were developed by comparing host reactions and genome sequence information. Bioassay was developed by sap transmission of both the viruses to a set of host plants, cowpea, groundnut and watermelon. WBNV induced only local symptoms including chlorotic spots on cowpea cv. Pusa Komal, typical chlorotic ring spots on cv. C-152, bud necrosis on watermelon and no symptoms on groundnut. Whereas, GBNV induced both local and systemic symptoms including chlorotic/necrotic spots and veinal necrosis on both the cowpea cultivars, systemic yellowing and bud necrosis on groundnut and no symptoms on watermelon. Single and duplex RT-PCR was developed for diagnosis of WBNV and GBNV by designing primers based on differential sequence from Gn/Gc genes located on M RNA and from nucleocapsid protein (NP) gene located on S RNA genome. The duplex RT-PCR using NP gene specific primers was successfully utilised for the diagnosis of natural infection of GBNV in dahlia and muskmelon and mixed infection of GBNV and WBNV in chrysanthemum. The amplified products of duplex RT-PCR were sequenced and phylogenetic analysis confirmed the authenticity of the RT-PCR assay as well as confirmed infection of WBNV and GBNV in the new natural hosts. The bioassay and RT-PCR developed in this study will be useful in detecting single and mixed infection of GBNV and WBNV strains in different crops.

Crop diversification with short-duration cassava (Manihot esculenta) in the humid tropics for agronomic and economic benefits

Presently cassava (Manihot esculenta Crantz) cultivation has shifted from the uplands to the lowlands, sequentially after main crop of rice, banana or vegetables and short-duration varieties (6-7 months) hold great promise. A three-year field experiment was carried out during 2007 to 2010 at Central Tuber Crops Research Institute, Thiruvananthapuram to develop feasible short-duration cassava-legume system in lowland situation akin to rice fallow. Two short-duration cassava varieties, Vellayani Hraswa and Sree Vijaya were evaluated in two cropping systems (sequential cropping and intercropping) involving two types of cowpea (vegetable (var. Pusa Komal) and grain types (var. C 152)) under two fertility levels based on soil testing (full and reduced) in split plot design. Vellayani Hraswa (24.55 tonnes/ha) produced significantly higher yield over Sree Vijaya (21.46 tonnes/ha) in systems involving cowpea. But the tuber and total biomass, crop growth rate, tuber bulking rate, mean tuber bulking rate, relative growth rate and harvest index of the varieties was comparable. Sequential cropping proved superior to intercropping as indicated by the significantly higher fresh tuber yield of 26.07 tonnes/ha under sequential cropping over 19.94 tonnes/ha in intercropping) and dry matter production. Both vegetable cowpea and grain cowpea were equally compatible with short-duration cassava under both the systems. Entire P and half N for short-duration cassava (N: P2O5: K2O @ 50:0:100 kg/ha) could be saved in both the systems involving cowpea by the third year. Sequential cropping of vegetable cowpea [Vigna unguiculata (L.) Walp.] followed by short-duration cassava (under full N) proved to be a profitable production system generating the highest net return (Rs. 97398/ha) and benefit: cost ratio (2.15).

Screening of cowpea [&lt;italic&gt;Vigna unguiculata&lt;/italic&gt; (L.) Walp.] accessions against pulse-beetle, &lt;italic&gt;Callosobruchus chinensis&lt;/italic&gt; (L.)

A total of 52 accessions of cowpea including two checks (Pusa Komal and Local variety) were screened for resistance to pulse beetle, &lt;italic&gt;Callosobruchus chinensis&lt;/italic&gt; under no-choice artificial infestation conditions. There were significant differences among the accessions in terms of number of eggs laid, development period, adult emergence, number of emergence holes, weight loss and growth index of &lt;italic&gt;C. chinensis&lt;/italic&gt; on cowpea. Based on growth indices, Pusa Komal (0.04081) and IC328859 (0.04112) were resistant while IC106033 (0.06819) and Local variety (0.06816) were most susceptible to &lt;italic&gt;C. chinensis&lt;/italic&gt;. Of the 52 accessions screeened, 11 accessions were resistant, 15 moderately resistant, 13 moderately susceptible, 8 susceptible and 5 were highly susceptible to &lt;italic&gt;C. chinensis.&lt;/italic&gt; Correlation between growth index and growth parameters of pulse beetle on different cowpea accessions indicated that growth index had significant negative relationship with mean development period (r = -0.68) and significant positive relationship with adult emergence(r = +0.80). Adult emergence had a positive relationship with weight loss (r = +0.22).

Heterosis for yield and yield contributing characters in cowpea genotypes

Fifteen F&lt;sub&gt;1&lt;/sub&gt; hybrids obtained by crossing 6 diverse parental lines of cowpea through diallel excluding reciprocals method was studied to investigate the extent of heterosis for yield and yield contributing characters during &lt;italic&gt;kharif&lt;/italic&gt;, 2007 and &lt;italic&gt;spring&lt;/italic&gt;&lt;italic&gt;summer&lt;/italic&gt;, 2008 season. Among the various components pods per plant and seeds per pods are important factor contributing to yield. IT-97K-1042 and IT-93K-452 were observed to be the top performing parents for total seed yield per plant. The crosses IT-97K-1042 X IT-98K-1111 and IT-97K-1042 X Pusa Komal were best heterotic crosses for seed yield and other characters.

Differential Response of Cowpea (&lt;i&gt;Vigna unguiculata &lt;/i&gt;L.&lt;i&gt;)&lt;/i&gt; Genotypes to Native Rhizobia in Tarai Region of Uttarakhand, India

Cowpea is an annual legume, rich in protein, which plays a critical role in the lives of millions of people in developing countries. Limited work has been done, especially on the symbiotic efficiency of cowpea against the native soil rhizobia. Therefore, our study was conducted to compare the effect of native rhizobia on nodulation, yield and protein content of eight cultivars and two control varieties in Tarai region of Uttarakhand, India. significant differences were observed among the cultivars tested in all the measured traits. Results of growth analysis indicated that ‘PGCP-4’ gave the highest number of nodules plant-1, nodule dry weight and protein content in grain, compared to both control varieties. Highest plant dry weight was recorded in ‘Pusa Komal’, while the highest grain yield was achieved in ‘PGCP-6’, followed by ‘PGCP-12’. This study hereby recommends ‘PGCP-6’ and ‘PGCP-12’ cultivars, as they are more suitable in terms of yield against the rhizobia.

Cowpea [Vigna unguiculata (L.) Walp

Agrobacterium tumefaciens-mediated transformation is an efficient method for incorporating genes and recovering stable transgenic plants in cowpea because this method offers several advantages such as the defined integration of transgenes, potentially low copy number, and preferential integration into transcriptional active regions of the chromosome. Cotyledonary node explants of cowpea present an attractive target for T-DNA delivery followed by regeneration of shoots via axillary proliferation without involvement of a de novo regeneration pathway. In this chapter, we describe a detailed protocol for Agrobacterium-mediated transformation of the cowpea variety Pusa Komal. The seedling cotyledonary node explants are used for cocultivation with an Agrobacterium strain EHA105 harboring standard binary vector, pCAMBIA2301 or pNOV2819, and putative transformed plants are selected using aminoglycoside antibiotic or mannose as sole carbon source, respectively. The entire process includes explant infection to transgenic seed generation in greenhouse.

Impact of ambient and supplemental ultraviolet-B stress on kidney bean plants: an insight into oxidative stress management.

In the present study, the response of kidney bean (Phaseolus vulgaris L. cv. Pusa Komal) plants was evaluated under three different levels of ultraviolet-B (UV-B), i.e., excluded UV-B (eUV-B), ambient UV-B (aUV-B; 5.8 kJ m(-2) day(-1)), and supplemental UV-B (sUV-B; 280-315 nm; ambient + 7.2 kJ m(-2) day(-1)), under near-natural conditions. eUV-B treatment clearly demonstrated that both aUV-B and sUV-B are capable of causing significant changes in the plant's growth, metabolism, economic yield, genome template stability, total protein, and antioxidative enzyme profiles. The experimental findings showed maximum plant height at eUV-B, but biomass accumulation was minimum. Significant reductions in quantum yield (Fv/Fm) were observed under both aUV-B and sUV-B, as compared to eUV-B. UV-B-absorbing flavonoids increased under higher UV-B exposures with consequent increments in phenylalanine ammonia lyase (PAL) activities. The final yield was significantly higher in plants grown under eUV-B, compared to those under aUV-B and sUV-B. Total protein profile through sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and analysis of isoenzymes, like superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR), through native PAGE revealed major changes in the leaf proteome under aUV-B and sUV-B, depicting induction of some major stress-related proteins. The random amplified polymorphic DNA (RAPD) profile of genomic DNA also indicated a significant reduction of genome template stability under UV-B exposure. Thus, it can be inferred that more energy is diverted for inducing protection mechanisms rather than utilizing it for growth under high UV-B level.

First Report of Tobacco streak virus Infecting Pigeon Pea (Cajanus cajan) in India

Pigeon pea is an important pulse crop grown in diversified cropping systems in India. In the rainy season of August 2011 and September 2012, pigeon pea cv. LRG 30 plants with leaf necrosis having wrinkled margin on one side were observed in Kadiri mandal of the Anantapuram district of Andhra Pradesh (A.P.), India. Symptoms included necrotic spots on young leaves followed by wilting of leaves, petiole and branch/axillary shoot proliferation, with small leaves having mosaic symptoms. Symptomatic leaves were sap-inoculated onto 10 seedlings of cowpea (cv. Pusa Komal) using 0.01 M phosphate buffer (pH 7.0). Localized necrotic lesions developed in all the inoculated plants after 2 days post inoculation. Field symptoms were reproduced on healthy pigeon pea upon back inoculation using single lesions of infected cowpea leaves. In direct antigen coating (DAC)-ELISA, all the infected pigeon pea and cowpea leaf samples were positive to a polyclonal antiserum specific to Tobacco streak virus (TSV) supplied by ICRISAT, India. Total RNA was extracted using infected pigeon pea and healthy leaf samples by TRI Reagent (Sigma). Reverse transcription (RT)-PCR was carried out using primers specific to the coat protein (CP) gene of TSV (1). A product of the 700-bp DNA fragment was obtained in field-infected pigeon pea samples but not in healthy controls. The amplicon was cloned into PTZ57R/T using the Ins TA clone PCR kit (Fermentas). Recombinant clone was sequenced in both directions and the CP gene sequence obtained was deposited in GenBank (KF220492). Sequence analysis of the CP gene of TSV from pigeon pea shared 98 to 100% identity with Indian TSV isolates originating from different hosts including groundnut (FJ355948), mung bean (FJ749259), and sunflower (DQ864448), and 88 to 92% similarity with TSV type isolate (white clover: X00435) both at nucleotide and amino acid levels. TSV belongs to the genus Ilarvirus of family Bromoviride and has a wide host range. TSV is pollen borne, assisted by thrips causing mechanical injury (2). To our knowledge, this is the first report of TSV on pigeon pea in India and was widespread in Anantapuram, Kadapa, Kurnool, and Mahbubnagar districts of A.P. Yield loss depends on the stage of infection as early infection resulted in complete failure of the crop. TSV was prevalent on many legume crops such as black gram, green gram, and groundnut in A.P, Tamil Nadu, Karnataka, and Maharashtra states (3). TSV infection of pigeon pea may pose a serious implication for pulse production.