Pusa Jai Kisan Research Articles

Identification of lncRNAs regulating seed traits in Brassica juncea and development of a comprehensive seed omics database.

Brassica juncea is a crucial oilseed crop, and its seeds possess high economic value as they are a source of edible oil. In order to understand the role of long non coding RNAs (lncRNAs) in the regulation of seed development, we carried out computational analysis using transcriptome data of developing seeds of two contrasting genotypes of B. juncea, Pusajaikisan (PJK) and Early Heera 2 (EH2). The seeds were sampled at three stages, 15, 30, and 45 days after pollination. We identified 1,539 lncRNAs, of which 809 were differentially expressed. We also carried out extensive characterization and functional analysis of seed lncRNAome. The expression patterns were analysed using k-means clustering, and the targets were analysed using pathway, transcription factor, and GO enrichment, as well as ortholog information. We shortlisted a total of 25 robust lncRNA candidates for seed size, oil content, and seed coat color. We also identified 4 lncRNAs as putative precursors of miRNAs regulating seed development. Moreover, a total of 28 miRNA-lncRNA-mRNA regulatory networks regulating seed traits were identified. We also developed a comprehensive database, (BrassIca juncea database or "BIJ" ( https://bij.cuh.ac.in/ ), which provides seed omics as well as other functional genomics and genetics data in an easily accessible form. These candidate lncRNAs are suitable for including in crop improvement programs through molecular breeding, as well as for future validations through genome editing. Together, the knowledge of these candidate lncRNAs and availability of BIJ database shall leverage the crop improvement efforts in B. juncea.

Transcriptional, biochemical, and histochemical response of resistant and susceptible cultivars of Brassica juncea against Albugo candida infection.

White rust disease caused by a biotrophic oomycete Albugo candida is one of the most serious impediments in realizing the production potential of Brassica juncea. Due to the obligate nature of the pathogen, R-gene-based resistance is unstable as the newer virulent races emerge quickly. For this, a deep understanding of the molecular basis of resistance is essential for developing durable resistant varieties. In this study, we selected one susceptible cultivar, 'Pusa Jaikisan' and its single R gene based resistant NIL, 'Pusa Jaikisan WRR as the source of understanding the defense mechanism in B. juncea against A. candida. Comparative histochemical analysis at 12 dpi showed higher callose deposition in the resistant cultivar than in the susceptible which hints towards its possible role in defense mechanism. Based on the biochemical markers observation, total protein was found to have a negative correlation with the resistance. The antioxidant enzymes (POX, CAT, and SOD) and non-enzymatic ROS scavenging compounds such as polyphenols and proline showed a positive correlation with the white rust resistance. Polyphenol Oxidase (PPO) total chlorophyll and total carotenoids were also found to be more abundant in the 'Pusa Jaikisan WRR'. Based on the heat map analysis, PAL was identified to be the comparatively most induced enzyme involved in the defense mechanism. The polyphenol oxidase, total chlorophyll and total carotenoids were also found to show higher activity in the 'Pusa Jaikisan WRR'. Furthermore, to study the defense response of 'Pusa Jaikisan WRR' compared to 'Pusa Jaikisan' against A. candida infection, the gene expression analyses of salicylic acid (SA)-marker PR protein genes (PR1 and PR2) and jasmonic acid (JA)-marker PR protein genes (PR3 and PR12) were done by qRT-PCR. Based on the results, PR2 emerged as the best possible gene for defense against A. candida followed by PR1. PR3 and PR12 also showed positive correlation with the disease resistance which may be due to the JA pathway acting complementary to the SA pathway in case of B. juncea-A. candida interaction. This provides evidence for the JA-SA hormonal crosstalk to be synergistic in case of the white rust resistance.

COMPARATIVE ANALYSIS OF CHEMICAL FERTILIZERS, NANOPARTICLES AND BIOFERTILIZERS ON THE GROWTH AND YIELD RESPONSES OF MUSTARD CULTIVARS

The present research is based on the hypothesis that foliar spray of zinc oxide nanoparticles (ZnO NPs) or application of biofertilizers such as vascular arbuscular mycorrhiza (VAM) or arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSBs) are more efficient than generally used chemical fertilizers supplementation such as nitrogen (N), phosphorus (P) and supplementation of zinc (Zn).In this study, six mustard varieties, Brassica juncea var. Alankar, Pusa Jai Kisan, Varuna, Sakha, Rohini, and Pusa Bold were tested for their comparative growth responses. Out of the six tested varieties, only two screened varieties (Alankar and Rohini) were further tested for their comparative growth responses among the foliar spray of zinc oxide nanoparticles (ZnO NPs), soil-applied chemical fertilizers to supplement nitrogen (N) phosphorus (P) and zinc (Zn) as zinc sulfate and soil-applied biofertilizers as phosphate solubilizing bacteria (PSBs) and vascular arbuscular mycorrhiza (VAM) or arbuscular mycorrhizal fungi (AMF).The results revealed that out of these three treatments, ZnO NPs significantly (p≤0.05) increased the growth morphology of the two mustard varieties, followed by VAM/AMF and PSBs, which were followed by chemical supplementation of N, P, and Zn. The effects were more pronounced in Alankar than in the Rohini variety of mustard. From the present study, it is concluded thatfoliar spray of ZnO NPs and application of biofertilizers can be a potent alternative of costly chemical fertilizers in the cultivation of mustardcrops.

Reactive oxygen species (ROS) scavenging and methylglyoxal (MG) detoxification confers salinity tolerance in mustard cultivars inoculated with Piriformospora (Serendipita) indica

Salinization has become a major concern for the growth and development of plants, resulting in significant crop losses. Beneficial microbial symbionts are utilized as promising tools in alleviation of adverse effects of salt stress. Piriformospora (Serendipita) indica is one of the cost-effective, eco-friendly, and stress relieving biostimulant that positively regulates the growth of a broad host range of plants. The present study was to investigate the impact of P. indica on Indian mustard (Brassica juncea L.) cultivars (Pusa Jaikisan and Pusa Bold) under different levels of salinity stress (0, 50, 100, 150, 200 and 300 mM NaCl) by analyzing morphological, physiological and biochemical attributes. Results revealed that the plant biomass, chlorophyll content, and relative water content were reduced and Na+ and Cl‒ ions uptake increased with increasing NaCl concentrations. The maximum reduction in the measured traits was observed at 300 mM NaCl in both cultivars [tolerant (Pusa Jaikisan) and sensitive (Pusa Bold)]. Additionally, the oxidative stress markers (TBARS, MG, H2O2, and EL) accumulation were increased with increasing salt concentrations. However, P. indica colonization enhanced the plant performance by improving the biomass, chlorophyll, and water content, and reduced levels of oxidative stress markers (TBARS, MG, H2O2, and EL) in both cultivars comparatively more in Pusa Jaikisan than Pusa Bold under salinity stress. Additionally, the maximum activities of methyl glyoxal detoxifying enzymes (Gly I & Gly II) along with the components of ROS scavenging machinery (SOD, APX, GPX, GR, AsA, and GSH) in the P. indica colonized plants conferred salt tolerance in comparison to non-colonized cultivars under salinity stress. The results indicate that P. indica promotes the growth and tolerance of mustard plants under salinity stress, thus providing opportunity for further assessment in terms of use in sustainable agriculture.

Integrated analysis of transcriptomic and small RNA sequencing data provides miRNA candidates for engineering agronomically important seed traits in Brassica juncea

Brassica juncea L. is an important oilseed crop that yields edible oil and biofuel. Improving B. juncea seed traits is a primary breeding target, but these traits are genetically complex. MicroRNAs (miRNAs) regulate seed development by modulating gene expression at the post-transcriptional or translational level and are excellent candidates for improving seed traits. However, the roles of miRNAs in B. juncea seed development are yet to be investigated. Here, we report small RNA profiling and miRNA identification from developing seeds of two contrasting varieties of B. juncea, Early Heera2 (EH2) and Pusa Jaikisan (PJK). We identified 326 miRNAs, including 127 known and 199 novel miRNAs, of which 103 exhibited inter-varietal differential expression. Integrating miRNAome and our previous transcriptome data identified 13,683 putative miRNA-target modules. Segregation of differentially expressed miRNAs into different groups based on variety-wise upregulation, followed by comprehensive functional analysis of targets using pathway mapping, gene ontology, transcription factor mapping, and candidate gene analysis, revealed at least 11, 6, and 7 miRNAs as robust candidates for the regulation of seed size, seed coat color, and oil content, respectively. Further, co-localization with previously reported quantitative trait loci (QTL) proffered 29 and 15 miRNAs overlapping with seed weight and oil content QTLs, respectively. Our study is the first comprehensive report of miRNAome expression dynamics from developing seeds and provides candidate miRNAs and target genes for engineering seed traits in B. juncea.

Exploring salt tolerance in Indian mustard [Brassica juncea (L.) Czern. & Coss.] genotypes: A physiological and biochemical perspective

Salinity is a crucial problem affecting the productivity of crops across the globe and poses a serious threat to agricultural food production and food security. Salinity stress adversely affects the growth and development of plants by reducing growth attributes, chlorophyll content, and relative water content and further, led to nutritional toxicities and high osmotic stress. The present investigation was employed to assess the response of ten mustard [Brassica juncea (L.) Czern. & Coss.] genotypes under different regimes of salt concentrations (0, 50, 100, 150, 200, 300 mM NaCl) for tolerance potential using principal component analysis (PCA). The PCA analysis of studied attributes found that Pusa Jai Kisan was salt-tolerant and Pusa Bold was susceptible under different salt conditions compared to the rest of the mustard genotypes. The reduction in morphological attributes, the maximum quantum yield of PSII (Fv/Fm), total chlorophyll, and relative water content was lower in Pusa Jai Kisan and higher in Pusa Bold with increasing concentrations of salinity. In addition, the accumulation of Na+ and Cl‒ ions was increased with increasing salinity stress. Based on growth performance, ten genotypes of mustard were ranked depending on their tolerance to salinity stress: Pusa Jai Kisan > Pusa Mustard 30 > Pusa Jagannath > Pusa Mustard 28 > Pusa Vijay > Pusa Tarak > Pusa Mustard 25 > Pusa Mustard 27 > Pusa Mahak > Pusa Bold, respectively. Thus, PCA analysis can be used as a powerful tool for the identification of tolerant and susceptible genotypes under salinity stress. The understanding of mustard responses towards salinity stress could help in the selection of tolerant genotypes and this selection may play a crucial role in further improving the effectiveness of breeding.

Morpho-Biochemical Responses of Brassica Coenospecies to Glyphosate Exposure at Pre- and Post-Emergence Stages

Crop wild relatives (CWRs) belonging to the Brassicaceae family possess extensive genetic diversity and have frequently been utilized in the enhancement of cultivated Brassica species. However, their tolerance to glyphosate, a widely used herbicide, has remained unknown. Our study examined the glyphosate response of 20 genotypes from the Brassicaceae family, which included genotypes within the U triangle and their wild relatives. We evaluated their behaviour based on morpho-biochemical responses, specifically focusing on the traits of germination percentage, root length, and survival percentage. By calculating the mean membership function value (MFV) for each genotype’s response to these traits, we classified them into three distinct groups: susceptible, moderately tolerant, and tolerant. Among these genotypes, Brassica rapa (NRCPB rapa 8) demonstrated tolerance to glyphosate, as indicated by their mean MFV value of 0.68. Moderate tolerance to glyphosate was observed in Brassica juncea (Pusa Jaikisan) with a mean MFV of 0.52. Conversely, Diplotaxis catholica, Diplotaxis muralis, and Enarthrocarpus lyratus were susceptible, with mean MFV values of 0.37, 0.35, and 0.34, respectively. These findings revealed varying levels of response to glyphosate among these genotypes, with some displaying significant tolerance. The study provides valuable insights into the herbicide tolerance of Brassica CWRs and emphasizes the potential use of phenotypic and biochemical markers in evaluating herbicide tolerance.

Indexing Resilience to Heat and Drought Stress in the Wild Relatives of Rapeseed-Mustard.

Wild species are weedy relatives and progenitors of cultivated crops, usually maintained in their centres of origin. They are rich sources of diversity as they possess many agriculturally important traits. In this study, we analysed 25 wild species and 5 U triangle species of Brassica for their potential tolerance against heat and drought stress during germination and in order to examine the early seedling stage. We identified the germplasms based on the mean membership function value (MFV), which was calculated from the tolerance index of shoot length, root length, and biochemical analysis. The study revealed that B. napus (GSC-6) could withstand high temperatures and drought. Other genotypes that were tolerant to the impact of heat stress were B. tournefortii (RBT 2002), D. gomez-campoi, B. tournefortii (Rawa), L. sativum, and B. carinata (PC-6). C. sativa resisted drought but did not perform well when subjected to high temperatures. Tolerance to drought was observed in B. fruticulosa (Spain), B. tournefortii (RBT 2003), C. bursa-pastoris (late), D. muralis, C. abyssinica (EC694145), C. abyssinica (EC400058) and B. juncea (Pusa Jaikisan). This investigation contributes to germplasm characterization and the identification of the potential source of abiotic stress tolerance in the Brassica breeding programme. These identified genotypes can be potential sources for transferring the gene(s)/genomic regions that determine tolerance to the elite cultivars.

Transcriptome analysis reveals cell cycle-related transcripts as key determinants of varietal differences in seed size of Brassica juncea

Brassica juncea is an important oilseed crop, widely grown as a source of edible oil. Seed size is a pivotal agricultural trait in oilseed Brassicas. However, the regulatory mechanisms underlying seed size determination are poorly understood. To elucidate the transcriptional dynamics involved in the determination of seed size in B. juncea, we performed a comparative transcriptomic analysis using developing seeds of two varieties, small-seeded Early Heera2 (EH2) and bold-seeded Pusajaikisan (PJK), at three distinct stages (15, 30 and 45 days after pollination). We detected 112,550 transcripts, of which 27,186 and 19,522 were differentially expressed in the intra-variety comparisons and inter-variety comparisons, respectively. Functional analysis using pathway, gene ontology, and transcription factor enrichment revealed that cell cycle- and cell division-related transcripts stay upregulated during later stages of seed development in the bold-seeded variety but are downregulated at the same stage in the small-seeded variety, indicating that an extended period of cell proliferation in the later stages increased seed weight in PJK as compared to EH2. Further, k-means clustering and candidate genes-based analyses unravelled candidates for employing in seed size improvement of B. juncea. In addition, candidates involved in determining seed coat color, oil content, and other seed traits were also identified.

Impact of Ferrous Sulfate on Thylakoidal Multiprotein Complexes, Metabolism and Defence of Brassica juncea L. under Arsenic Stress.

Forty-day-old Brassica juncea (var. Pusa Jai Kisan) plants were exposed to arsenic (As, 250 µM Na2HAsO4·7H2O) stress. The ameliorative role of ferrous sulfate (2 mM, FeSO4·7H2O, herein FeSO4) was evaluated at 7 days after treatment (7 DAT) and 14 DAT. Whereas, As induced high magnitude oxidative stress, FeSO4 limited it. In general, As decreased the growth and photosynthetic parameters less when in the presence of FeSO4. Furthermore, components of the antioxidant system operated in better coordination with FeSO4. Contents of non-protein thiols and phytochelatins were higher with the supply of FeSO4. Blue-Native polyacrylamide gel electrophoresis revealed an As-induced decrease in almost every multi-protein-pigment complex (MPC), and an increase in PSII subcomplex, LHCII monomers and free proteins. FeSO4 supplication helped in the retention of a better stoichiometry of light-harvesting complexes and stabilized every MPC, including supra-molecular complexes, PSI/PSII core dimer/ATP Synthase, Cytochrome b6/f dimer and LHCII dimer. FeSO4 strengthened the plant defence, perhaps by channelizing iron (Fe) and sulfur (S) to biosynthetic and anabolic pathways. Such metabolism could improve levels of antioxidant enzymes, and the contents of glutathione, and phytochelatins. Important key support might be extended to the chloroplast through better supply of Fe-S clusters. Therefore, our results suggest the importance of both iron and sulfur to combat As-induced stress in the Indian mustard plant at biochemical and molecular levels through enhanced antioxidant potential and proteomic adjustments in the photosynthetic apparatus.

Cloning and structural elucidation of a brassinosteroids biosynthetic gene (Atdwarf4) and genetic transformation of Indian mustard (Brassica juncea L.)

Phytohormones play critical roles in plant growth and development. Brassinosteroids (BRs) are essential group of phytohormones required for optimum growth of plants and their deficiency causes distinctive dwarf phenotypes in plants. Homeostasis of BRs in plants is maintained by DWARF4 enzyme that mediates multiple 22α-hydroxylation steps in brassinosteroid biosynthesis. Arabidopsis plants over-expressing DWARF4 show increase in inflorescence, number of branches and siliques; thereby increased number of seeds/plant. This suggests that engineering DWARF4 biosynthesis in Brassica plant can be strategized to enhance yield in mustard. In the present study (i) we cloned dwarf4 gene from Arabidopsis using gene specific PCR strategy, (ii) elucidated the three-dimensional structure of DWARF4 protein at molecular level where it revealed presence of four beta sheets and 20 alpha-helices, and (iii) transformed mustard cultivar Pusa Jaikisan with an objective to develop transgenic mustard with enhanced number of siliques. We obtained several putative transgenics with an average transformation efficiency of 3.3%. Molecular characterization with nptII specific primers confirmed presence of transgene in six putative transgenic plants.

Refinement in Cultivar of Indian Mustard for Higher Yield Under Thermal Climatic Condition of Uttar Pradesh

The refinement and assessment based field experiment was laid out during Rabi season of 2002 and 2003 on farmers fields at Mainpuri district under National Agricultural Technology Project, Zonal Agricultural Research Station, Mainpuri. The main objective was to find out suitable variety of Indian mustard for sowing in early period under thermal condition and replace the local Indian mustard cultivar ‘chhapka’. The nutrient status of pilot area was low. Five high yielding varieties i.e. Rohani, Varuna, Kanti, Urvarshi, Pusa Jai Kisan were tested with local cultivar Chhapka. The tested varieties of Indian mustard did not much differ in growth parameters but cv. Urvarshi displayed the superiority over all varieties. The lowest seed weight/plant (15.85 /plant) and test weight (4.30 gram) were weighed in local cultivar Chhapka, while highest seed weight/plant (18.00 g/plant) and test weight (4.95 gram) were recorded in cv. Urvarshi. The highest seed yield of 30.80 q/ha was noted under tested cultivar Urvarshi and lowest noted under Chaapka(15.70 q/ha). The other tested varieties yielded seed between these two limits. The highest net return of Rs. 99667/ha and BCR (1:3.56) were computed under Urvarshi cultivar. The lowest net return of Rs. 31717/ha and BCR (1:1.81) were computed under local cultivar Chhapka. The cultivar Urvarshi also increased net income of famers by 3.15 fold, which was higher over other tested varieties.

Suitability of Indian mustard genotypes for phytoremediation of mercury-contaminated sites

Phytoremediation is an environment-friendly remediation technology, which has become widely accepted and is regarded as an easy and safe technique for removal of contaminants. Mercury (Hg) is one of the most toxic soil and water contaminants, which has not yet been widely treated via phytoremediation technology because Hg-accumulating plants were hitherto unknown. In the present study, ten genotypes (viz. Agrini, BTO, Kranti, Pusa Bahar, Pusa Basant, Pusa Bold, Pusa Jai Kisan, Vaibhav Vardhan and Varuna) of Indian mustard (Brassica juncea L.) were grown hydroponically under five different Hg concentrations (0–50 μM), and the changes in Hg uptake, plant growth and plant biomass were evaluated in order to determine the suitability of these genotypes, if any, for being used as Hg-phytoremediators. Genotype Pusa Jai Kisan was identified as the most Hg-tolerant genotype, accumulating up to 269.9 μg Hg g−1 dry weight (DW) in its subterranean parts and up to 61.7 μg Hg g−1 DW in its aerial parts. This genotype, therefore, seems to be quite suitable for use as a viable candidate for phytoremediation of Hg-contaminated sites.

Thermal requirement of mustard (Brassica juncea) at different phonological stages under Chhattisgarh plain climatic conditions: A review

Growth and yield of Brassica species largely depends upon change in environment during crop growth this change in environment can occur through many practices including sowing dates and water availability. For getting higher yield, sowing time of crop needs to be adjusted with suitable agro-climatic environment (Saha and Khan, 2008). Pradhan et al. (2014) reported that there was significant interaction between date of sowing and cultivars with respect to seed yield of mustard. It was concluded that normal or early sowing of Pusa Jai Kisan or Pusa Bold cultivar may be practiced for achieving higher seed yield, radiation and water use efficiency in semi-arid environment of north and north-western part of India. Indian-mustard is much sensitive to climatic variables; hence, climate change could have significant effect on its production. One month delay in sowing from mid of October resulted in 40.6% loss in seed yield (Lallu, et al., 2010). Gill and Bains (2008) observed a linear and positive relation between leaf area development and photosynthetically active radiation (PAR) interception, which leads to higher dry matter production. LAI plays an important role for crop growth based on its interception and utilization of PAR for producing dry matter and with the delay in planting date, the higher mean temperature was experienced during flowering which led to accelerate the decrease in LAI and reduction in the flowering period.

Frontline demonstrations on Indian mustard (Brassica juncea) for showcasing production potential and economics in hot sub humid (moist) eco-region

The production ofIndianmustard (Brassica juncea) islower due to non-adoption ofrecommended high yielding varieties and improved technologies by the farming community in eastern plains of Uttar Pradesh, India. To educate farmers on the improved technologies, 92 frontline demonstrations (FLDs) were conducted in farmers' fields by KVK, Deoria, Uttar Pradesh, India. The technologies demonstrated included improved varieties, thinning, irrigation, date of sowing, seed treatment, spacing, balanced use of fertilizers, intercultural operations and plant protection measures. The improved technology showed increase in the yield of mustard between 22.3-43.3% over local checks. Technology gap was highest in Pusa Jaikisan (1767 kg/ha) and lowest in Pusa Bold (341 kg/ha) variety. The extension gap was highest with Pusa Jaikisan (447 kg/ha) and lowest with Pusa Bold (434 kg/ha). Technology index was highest (50.5%) with Pusa Jaikisan and lowest (13.9 %) with Pusa Bold. Lower, values of technology index indicates higher feasibility of the technology in eastern plains of Uttar Pradesh.

Transcriptome and Co-Expression Network Analyses Identify Key Genes Regulating Nitrogen Use Efficiency in Brassica juncea L.

Nitrate is the main source of inorganic nitrogen for plants, which also act as signaling molecule. Present study was aimed to understand nitrate regulatory mechanism in Brassica juncea cultivars, with contrasting nitrogen-use-efficiency (NUE) viz. Pusa Bold (PB, high-NUE) and Pusa Jai Kisan (PJK, low-NUE), employing RNA-seq approach. A total of 4031, 3874 and 3667 genes in PB and 2982, 2481 and 2843 genes in PJK were differentially expressed in response to early, low (0.25 mM KNO3), medium (2 mM KNO3) and high (4 mM KNO3) nitrate treatments, respectively, as compared to control (0 mM KNO3). Genes of N-uptake (NRT1.1, NRT1.8, and NRT2.1), assimilation (NR1, NR2, NiR, GS1.3, and Fd-GOGAT) and remobilization (GDH2, ASN2–3 and ALaT) were highly-upregulated in PB than in PJK in response to early nitrate treatments. We have also identified transcription factors and protein kinases that were rapidly induced in response to nitrate, suggesting their involvement in nitrate-mediated signaling. Co-expression network analysis revealed four nitrate specific modules in PB, enriched with GO terms like, “Phenylpropanoid pathway”, “Nitrogen compound metabolic process” and “Carbohydrate metabolism”. The network analysis also identified HUB transcription factors like mTERF, FHA, Orphan, bZip and FAR1, which may be the key regulators of nitrate-mediated response in B. juncea.

EVALUATION OF DIFFERENT GERMPLASM OF BRASSICA JUNCEA AGAINST OROBANCHE AEGYPTIACA

Among the major weed groups that cause huge economic losses to important cropping systems, Orobanche species are greatly devastating. Egyptian broomrape (Orobanche aegyptiaca) is a parasitic weed causing major yield loss in many field and vegetable crops and is a serious threat to Indian mustard. In this study, severalgenotypes of Indian mustard were screened in order to identify resistant genotypes against O. aegyptiaca. In the greenhouse conditions, genotypes were different in the degree of susceptibility to Broomrape. Attachment number, emergence number, and dry matter of parasitic broomrape were affected by biomass of genotype. A significant impact of the parasitism onto the dry weight of all infected mustard genotype with variable degree was observed. Broomrape attachment was observed in all the cultivated genotypes with Pusa mustard 24 being the most susceptible with the greatest number of emerged Orobanche shoots. In contrast, no emergence shoots were observed in four out of the fifteen genotype viz., Pusa Jaikisan, Pusa bold, Pusa Vijay and Pusa mustard 26 which have less attachment number and emergence number. These genotype appear to be interesting for our objectives.

Inheritance and allelic relationship of white rust resistance gene in the crosses of exotic and indigenous germplasm lines of Indian mustard [Brassica juncea (L.) Czern. and Coss.

White rust caused by Albugo candida (Pers. ex Lev.) Kuntze is a destructive disease in many important Brassica species including Brassica juncea in India. It leads to massive yield losses with maximumdamage upto 89.8 per cent under late sown conditions due to staghead formation. Identification of diverse sources ofresistance is a prerequisite for proper cost effective and eco-friendly management of white rust in Indian mustard. Here, a combination of both exotic and indigenous sources of B. juncea was taken to study the genetics of white rust resistance. Five resistant genotypes viz., BEC144, BEC286, EC399299, Heera and BioYSR were crossed to Bio 902 (Pusa Jaikisan) an otherwise high-yielding popular variety of Indian mustard but susceptible to white rust. The F1 s of the ten crosses including reciprocals were resistant indicating the dominance nature of white rust resistance in Indian mustard. Segregation of 3 resistant: 1 susceptible plants in F2 generation showed the monogenic inheritance of white rust resistance. Further, backcross generations revealed segregation of 1 resistant: 1 susceptible plants confirming that white rust resistance is governed by a single dominant gene which can easily be transferred through backcrossing froma resistant donor to high yielding, well adapted susceptible genotypes. Crosses among the resistant donors have also been attempted to study the allelic relationship among the five resistant sources; and F2 population of all possible twenty crosses including reciprocals showed complete resistance indicating the genes for white rust resistance in these resistant sources were allelic to each other.

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.

Ethylene Potentiates Sulfur-Mediated Reversal of Cadmium Inhibited Photosynthetic Responses in Mustard.

The potential of exogenous ethylene and sulfur (S) in reversal of cadmium (Cd)-inhibited photosynthetic and growth responses in mustard (Brassica juncea L. cv. Pusa Jai Kisan) were studied. Plants grown with 50 μM Cd showed increased superoxide and H2O2 accumulation and lipid peroxidation together with increased activity of 1-aminocyclopropane carboxylic acid synthase (ACS) and ethylene production and inhibition of photosynthesis and growth. Application of 1 mM SO42- or 200 μL L-1 ethephon (ethylene source) influenced photosynthetic and growth performance equally in presence or absence of Cd. However, their combined application synergistically improved photosynthetic performance more in presence of Cd and reduced oxidative stress (lower superoxide and H2O2 accumulation) by decreasing ethylene and glucose sensitivity with the increase in cysteine and methionineand a non-proteinogenic thiol (reduced glutathione; GSH) contents. The central role of ethylene in potentiating S-mediated reversal of Cd-induced oxidative stress was evident with the use of ethylene action inhibitor, norbornadiene (NBD). The application of NBD resulted in decreased thiol production and photosynthetic responses. This suggests that ethylene promotes the effects of S in reversal of adverse effects of Cd, and thus, ethylene modulation may be considered as potential tool to substantiate the S effects in reversal of Cd inhibited photosynthesis and growth in mustard.