Pigeonpea Plants Research Articles

Effect of nutrient supply system on biometry and rhizosphere microflora of soybean, pigeon pea and sorghum.

A field experiment was conducted at farm of Agriculture College, Latur (Maharashtra) to study the Effect of Nutrient Supply System on Biometry i.e. Plant height, functional leaves, grain yield and straw yield of Soybean, Pigeon pea and Sorghum as well as to study the azotobactor,phosphate solubilizing bacteria , fungi, actinomycetes and total microorganism in the rhizosphere microflora of soybean, pigeon pea and sorghum. The experiment was laid out in randomized block design with seven treatments combinations replicated two time. The treatments were - T1-organic ( 100% R.D.F.) ,T2-Inorganic nutrient supply system.(Rhizobium + PSB + Azotobactor + FYM ), T3—Integrated nutrient supply system.( 50% R.D.F. +50% FYM + Rhizobium PSB + Azotobactor ), T4- maximum yield nutrient supply system. T5- biodyamics or Ecofriendly nutrient supply system.. T6- natural (No fertilizer) ,T7-fallow . The fertilizer were applied as a basal dose as per the treatments. The observation on growth i.e. height of plant and number of functional leaves and yield were recorded by using five randomly selected plants of soybean,pigeon pea and sorghum in each treatment plot. The selected plants were labelled and all subsequent biometric observations were recorded on labelled plants during the course of investigation.The judicious use of biofertilizers like rhizobium, azotobactor ,phosohate solubilizing bacteria with organic manures helped in building up of soil microflora .It also help to augment the availabity of nutrient that could be easily assimilated by plants. The results revealed that the Maximum Yield nutrient supply system ( MYNSS ) is significantly superior to other system and it was at par with integrated nutrient supply system.

Comparative characterization of small RNAs derived from an emaravirus and a geminivirus infecting pigeonpea

High throughput sequencing technologies, supported by bioinformatics tools are employed to retrieve small RNA sequence information derived from the nucleic acids of plant infecting viruses. In addition to characterization of the small RNAs to understand the biology of the virus, the small RNA sequence can be assembled to reconstitute viral genome sequence. For the first time the semiconductor based Ion Proton sequencing technology is used to sequence the small RNAs from pigeonpea (Cajanus cajan) plants infected by two distinct viruses with RNA and DNA as their genomes. The reconstitution of the viral genome sequence revealed that the pigeonpea plant from Kalaburagi (erstwhile Gulbarga, Karnataka state) was infected by an emaravirus species Pigeonpea sterility mosaic emaravirus 1 (PPSMV-1) and another plant from New Delhi was infected by a begomovirus species Mungbean yellow mosaic India virus (MYMIV). Characterization and comparison of small RNA sequences derived from both the viruses showed vast differences in their pattern of accumulation and their size classes. In the case of PPSMV-1, the 21 nt sized siRNAs accumulated at far greater levels followed by 22 and 24 nt siRNAs. Whereas in MYMIV, the proportion of accumulation of each size class of siRNAs was similar. Further the distribution of small RNAs across the genomes of PPSMV-1 and MYMIV was mapped and the density of small RNA accumulation showed a positive correlation with the GC content of viral sequence.

English

Pigeon pea (Cajanus cajan (L.) Millsp.) is an important protein source grown in several tropical and sub-tropical countries, and is considered a multi-purpose plant that is resistant to the conditions where drought and salinity is a common phenomenon. The aim of this study was to evaluate the diversity of rhizobial isolates obtained from root nodules of pigeon pea plants grown in central and southern Ethiopia. A total of 116 nitrogen-fixing rhizobial strains were isolated. The bacterial isolates were characterized by 91 phenotypic traits including cultural characteristics, intrinsic antibiotic and heavy metal resistance, salt, pH and incubation temperature tolerance, and carbon and nitrogen sources utilization ability. Preliminary symbiotic properties of the isolates were also evaluated. The isolates were compared with seven reference strains of rhizobia by application of the unweighted pair group method with arithmetic means (UPGMA) using NTSYSpc Version 2.1 software program. The dendrogram constructed from cluster analysis of 91 phenotypic traits, grouped them into six clusters and eight un-clustered positions at 80% relative similarity. Cluster I contained 83% of the test isolates that were grouped together with the reference strains Bradyrhizobium japonicum (HAMBI 2314T) and Bradyrhizobium elkanii (LMG 6164), suggesting that pigeon pea is commonly nodulated by bradyrhizobia. Results from symbiotic effectiveness test revealed that majority of the isolates were found to be effective. Generally, this investigation demonstrated that rhizobial population nodulating C. cajan on the study area were phenotypically diverse and symbiotically effective. Furthermore, the result indicates the existence of strains in the collection, which can tolerate environmental stresses, thus can be developed into inoculant for pigeon pea inoculation and production in Ethiopia and beyond. Key words: Bradyrhizobium, Cajanus cajan, phenotypic characteristics, rhizobium.

Molecular characterization of emaraviruses associated with Pigeonpea sterility mosaic disease

Sterility Mosaic Disease (SMD) of pigeonpea (Cajanus cajan (L.) Millspaugh) is a complex disease due to various factors including the presence of a mixed infection. Comparison of dsRNA profile and small RNA (sRNA) deep sequencing analysis of samples from three locations revealed the presence of Pigeonpea sterility mosaic virus-I and II (PPSMV-I and II) from Chevella and only PPSMV-II from Bengaluru and Coimbatore. PPSMV-I genome consisted of four while PPSMV-II encompassed six RNAs. The two viruses have modest sequence homology between their corresponding RNA 1–4 encoding RdRp, glycoprotein precursor, nucleocapsid and movement proteins and the corresponding orthologs of other emaraviruses. However, PPSMV-II is more related to Fig mosaic virus (FMV) than to PPSMV-I. ELISA based detection methodology was standardized to identify these two viruses, uniquely. Mite inoculation of sub-isolate Chevella sometimes resulted in few- to- many pigeonpea plants containing PPSMV-I alone. The study shows that (i) the N-terminal region of RdRp (SRD-1) of both the viruses contain “cap-snatching” endonuclease domain and a 13 AA cap binding site at the C-terminal, essential for viral cap-dependent transcription similar to the members of Bunyaviridae family and (ii) P4 is the movement protein and may belong to ‘30 K superfamily’ of MPs.

In-Vivo and field evaluation of spinetoram 12 SC against Lampides boeticus on pigeonpea

The young larvae of L. boeticus damage flowers and pods. A new biological insecticide molecule, spinetoram 12 SC was evaluated for acute toxicity on greenhouse environment reared L. boeticus and persistence on pigeonpea pods at laboratory; and effect on L. boeticus on pigeonpea at field conditions during 2012-2013 and 2013-2014. Acute toxicity studies revealed that LC50‘s of spinetoram on third instar larvae after 24, 48 and 72 hours after treatment were 6.71, 2.23 and 1.28 ppm respectively. In persistence studies, spinetoram 12 SC 27 g a.i./ha was upto 11 DAT and 14 DAT for spinetoram 12 SC 36 and 45 g a.i./ha. More than 50 per cent mortality was observed in spinetoram 12 SC at 45 g a.i./ha upto 9 DAT, spinetoram 12 SC at 27 and 36 g a.i./ha, spinosad 45 SC 78 g a.i./ha and emamectin benzoate 5 SG at 11 g a.i./ha upto 7 DAT, monocrotophos 36 SL at 500 g a.i./ha upto 5 DAT, respectively. Results indicated that spinetoram 12 SC was significantly effective at 36 and 45 g a.i./ha when sprayed thrice at 15 days interval and minimized the incidence of L. boeticus on pigeonpea plants and increases the grain yield. All the spinetoram doses did not show any phytotoxic symptoms on pigeonpea plants.

Molecular characterization of a novel cryptic virus infecting pigeonpea plants.

A new member of the genus Deltapartitivirus was identified containing three dsRNAs with an estimated size of 1.71, 1.49 and 1.43 kb. The dsRNAs were extracted from symptomless pigeonpea [Cajanus cajan (L.) Millspaugh] plants cv. Erra Kandulu. This new virus with 4.64 kb genome was tentatively named Arhar cryptic virus-1 (ArCV-1). The genomic RNAs were amplified and characterized by sequence independent single primer amplification. The dsRNAs shared a highly conserved 16 nt 5’ non-coding region (5’-GATAATGATCCAAGGA-3’). The largest dsRNA (dsRNA-1) was identified as the viral RNA dependent RNA polymerase (replicase), predicted to encode a putative 55.34 kDa protein (P1). The two other smaller dsRNAs (dsRNA-2 and dsRNA-3) predicted to encode for putative capsid proteins of 38.50kDa (P2) and 38.51kDa (P3), respectively. Phylogenetic analysis indicated that ArCV-1 formed a clade together with Fragaria chiloensis cryptic virus, Rosa multiflora cryptic virus and Rose cryptic virus-1, indicating that ArCV-1 could be a new member of the genus Deltapartitivirus. ArCV-1 3Dpol structure revealed several interesting features. The 3Dpol in its full-length shares structural similarities with members of the family Caliciviridaeand family Picornaviridae. In addition, fourth dsRNA molecule (dsRNA-2A), not related to ArCV-1 genome, was found in the same plant tissue. The dsRNA-2A (1.6 kb) encodes a protein (P4), with a predicted size of 44.5 kDa. P4 shares similarity with coat protein genes of several cryptic viruses, in particular the bipartite cryptic viruses including Raphanus sativus cryptic virus-3. This is the first report of occurrence of a cryptic virus in pigeonpea plants.

Field evaluation of spinetoram 12 SC against Maruca vitrata on pigeonpea

The acute and persistent toxicity experiments was conducted in the Insectary of Agricultural College and Research Institute (ACandRI), Maduari, Tamil Nadu Agricultural University. Two field experiments were conducted at farmer’s field at Jadhi Goundanpatti, Attur Block, Dindigul district, Tamil Nadu. The incidence of M. vitrata (Geyer) has been increasing for the last few years and the larvae bore inside the flower buds, flowers and the green pods and cause upto 40-70 per cent damage. A new biological insecticide molecule, spinetoram 12 SC was evaluated for acute toxicity on laboratory reared M. vitrata population, and persistence on pigeonpea leaves at laboratory conditions; and effect on M. vitrata on pigeonpea at field conditions during 2012-13 and 2013-2014 seasons. Acute toxicity studies revealed that LC50‘s of spinetoram on third instar larvae after 24, 48 and 72 hours after treatment were 4.30, 1.95 and 1.46 ppm respectively. In persistence studies, Persistence was upto 11 DAT for spinetoram 12 SC 27 g a.i./ha, spinosad 45 SC 78 g, emamectin benzoate 5 SG at 11 g a.i./ha, and monocrotophos 36 SL at 500 g; and 14 DAT for spinetoram 12 SC 36 and 45 g a.i./ha. There was a reduction in the mortality of M. vitrata larvae as the time increased and there was no mortality at 21 DAT. Results indicated that spinetoram 12 SC was significantly effective at 36 and 45 g a.i./ha when sprayed thrice at 15 days interval and minimized the incidence of leaf feeder, M. vitrata on pigeonpea plants.

High effectiveness of Rhizophagus irregularis is linked to superior modulation of antioxidant defence mechanisms in Cajanus cajan (L.) Millsp. genotypes grown under salinity stress.

Salinity stress leads to the production of reactive oxygen species (ROS) which can cause oxidative damage in plants. A correlation between antioxidant capacity and salt tolerance has been demonstrated in several plant species, which may be enhanced by inoculation with arbuscular mycorrhizal fungi (AMF). However, plant responses to mycorrhization may differ depending on the host plant as well as AMF isolate. It has been proposed that AMF sourced from stressed environments may be better suited as stress ameliorators than non-native/exotic ones. The present study compared the effectiveness of a native inoculum from saline soil and two exotic single isolates, Funneliformis mossseae and Rhizophagus irregularis (single or dual mix), and associated their effectiveness with modulation of antioxidant defence, in two Cajanus cajan (pigeonpea) genotypes (salt sensitive-Paras, salt tolerant-Pusa 2002) under NaCl stress. Plants subjected to NaCl (0-100mM) recorded a substantial build-up of ROS, more in Paras than Pusa 2002. Although mycorrhization with all AMF improved plant biomass and reduced oxidative burst by strengthening antioxidant enzymatic activities, inoculation with R. irregularis (alone or in combination with F. mosseae) resulted in higher biomass accumulation which correlated with its higher root colonization and improved redox stability through rapid recycling of reduced ascorbate and glutathione. The study thus suggested that mitigation of salt-induced oxidative burden by increased activation of scavenging antioxidants is an important mechanism that determined the higher effectiveness of R. irregularis over the native saline mix in pigeonpea plants.

The root endophytic fungus Curvularia geniculata from Parthenium hysterophorus roots improves plant growth through phosphate solubilization and phytohormone production

The plant growth promoting ability of Curvularia geniculata (Tracy & Earle) Boedijn, a dark septate endophyte (DSE) fungus isolated from Parthenium hysterophorus L., was examined under in-vitro conditions for the first time. The abilities of the fungus to solubilize different sources of phosphorus (P) [AlPO4, FePO4 and Ca3(PO4)2] and to produce indole acetic acid (IAA) were also determined. C. geniculata-inoculated pigeon pea (Cajanus cajan) plants exhibited superior growth over uninoculated control plants and the fungus solubilized different sources of P in the order of FePO4>AlPO4>Ca3(PO4)2. The pH of the culture medium, fungal biomass production and acid phosphatase activity was significantly influenced by phosphate source and incubation period. IAA production, confirmed by chromatographic analysis, increased with increasing concentrations of tryptophan in a non-linear manner. It can be concluded from the results that C. geniculata mediates plant growth through phosphate solubilization and phytohormone production. This would enable the use of this fungus as bioinoculant in plant production systems.

A Cyclin Dependent Kinase Regulatory Subunit (CKS) Gene of Pigeonpea Imparts Abiotic Stress Tolerance and Regulates Plant Growth and Development in Arabidopsis.

Frequent climatic changes in conjunction with other extreme environmental factors are known to affect growth, development and productivity of diverse crop plants. Pigeonpea, a major grain legume of the semiarid tropics, endowed with an excellent deep-root system, is known as one of the important drought tolerant crop plants. Cyclin dependent kinases (CDKs) are core cell cycle regulators and play important role in different aspects of plant growth and development. The cyclin-dependent kinase regulatory subunit gene (CKS) was isolated from the cDNA library of pigeonpea plants subjected to drought stress. Pigeonpea CKS (CcCKS) gene expression was detected in both the root and leaf tissues of pigeonpea and was upregulated by polyethylene glycol (PEG), mannitol, NaCl and abscisic acid (ABA) treatments. The overexpression of CcCKS gene in Arabidopsis significantly enhanced tolerance of transgenics to drought and salt stresses as evidenced by different physiological parameters. Under stress conditions, transgenics showed higher biomass, decreased rate of water loss, decreased MDA levels, higher free proline contents, and glutathione levels. Moreover, under stress conditions transgenics exhibited lower stomatal conductance, lower transpiration, and higher photosynthetic rates. However, under normal conditions, CcCKS-transgenics displayed decreased plant growth rate, increased cell size and decreased stomatal number compared to those of wild-type plants. Real-time polymerase chain reaction revealed that CcCKS could regulate the expression of both ABA-dependent and ABA-independent genes associated with abiotic stress tolerance as well as plant growth and development. As such, the CcCKS seems promising and might serve as a potential candidate gene for enhancing the abiotic stress tolerance of crop plants.

Effect of waterlogging and salinity on antioxidative system in pigeonpea plant leaves at different stages of development

Effect of waterlogging, salinity and combined stress on pigeonpea genotypes was studied in the present investigation. Four pigeonpea genotypes (ICPH-2431, PARAS, UPAS-120, HO 933) were raised in polythene bags filled with half kg soil+FYM manure mixture. Waterlogging, salinity and waterlogging+salinity treatments were given for 12 days and observations were recorded 1 and 8 days after removal from treatment in 20 and 40-day old plant leaves. A significant increase in superoxide radical and H2O2 content was observed with all the three treatments both 1 and 8 days after removal from treatment. However, increase was comparatively less 8-day after removal from salinity treatment. Among both the treatments, salinity alone was found least deleterious. Increase in antioxidative enzyme activity and antioxidative metabolite content was also observed with both the treatments. Maximum increase was observed in ICPH 2431 followed by PARAS, HO 933 and minimum was observed in UPAS 120.

Determination of Cry1Ac copy number in transgenic pigeonpeaplants using quantitative real time PCR.

Copy number of Cry1Ac in transgenic pigeonpea plants was determined by quantitative real time PCR using Syber Green as fluorescence indicator. Gene specific primers designed to amplify relatively long amplicons (400 – 600 bp), for Cry1Ac was used to increase specificity and sensitivity of Real time PCR. Estimated copy number in transgenic lines using real-time quantitative PCR and southern hybridization was correlated and found to be same i.e. single copy number. This study shows effectivness of real-time PCR method for estimating the transgene copy number in transgenic pigeonpea plants by a simple, accurate and cost effective manner.Keywords: Copy number, Cry1Ac, Pigeonpea transformation, Real-time PCR, Syber green.

Pod borer resistant transgenic pigeon pea (Cajanus cajan L.) expressing cry1Ac transgene generated through simplified Agrobacterium transformation of pricked embryo axes

Pod borer resistant transgenic pigeon pea (Cajanus cajan L.) plants expressing cry1Ac transgene were generated through Agrobacterium transformation of differentiated and meristematic cells in pricked embryo axes. The uptake of transgene by such cells was expected to produce chimeric T0 plants that were grown to maturity without characterization. The putative transformants were identified from thousands of T1 and T2 seedlings following high throughput paromomycin screening. The presence of transgene in putative T1 and T2 plants was established by polymerase chain reaction and its expression was confirmed in six T2 plants by reverse transcription-PCR and quantitative real time-PCR. The T2 plant PAU 881-21 showed upto 10-fold higher cry1Ac transgene expression as compared to non-transgenic plant. The in vitro bioassay of pods and leaves from PAU 881-21 using third instar Helicoverpa armigera larvae demonstrated 97.78 % larval mortality just after 48 h, pointing towards direct correlation between transgene expression and larval mortality. The pod borer resistant T2 plant PAU 881-21 was phenotypically normal, self fertile and the transgene segregated in 3:1 Mendelian pattern in its T3 progeny.

Genetic Analysis Reveals the Essential Role of Nitrogen Phosphotransferase System Components in Sinorhizobium fredii CCBAU 45436 Symbioses with Soybean and Pigeonpea Plants.

The nitrogen phosphotransferase system (PTS(Ntr)) consists of EI(Ntr), NPr, and EIIA(Ntr). The active phosphate moiety derived from phosphoenolpyruvate is transferred through EI(Ntr) and NPr to EIIA(Ntr). Sinorhizobium fredii can establish a nitrogen-fixing symbiosis with the legume crops soybean (as determinate nodules) and pigeonpea (as indeterminate nodules). In this study, S. fredii strains with mutations in ptsP and ptsO (encoding EI(Ntr) and NPr, respectively) formed ineffective nodules on soybeans, while a strain with a ptsN mutation (encoding EIIA(Ntr)) was not defective in symbiosis with soybeans. Notable reductions in the numbers of bacteroids within each symbiosome and of poly-β-hydroxybutyrate granules in bacteroids were observed in nodules infected by the ptsP or ptsO mutant strains but not in those infected with the ptsN mutant strain. However, these defects of the ptsP and ptsO mutant strains were recovered in ptsP ptsN and ptsO ptsN double-mutant strains, implying a negative role of unphosphorylated EIIA(Ntr) in symbiosis. Moreover, the symbiotic defect of the ptsP mutant was also recovered by expressing EI(Ntr) with or without the GAF domain, indicating that the putative glutamine-sensing domain GAF is dispensable in symbiotic interactions. The critical role of PTS(Ntr) in symbiosis was also observed when related PTS(Ntr) mutant strains of S. fredii were inoculated on pigeonpea plants. Furthermore, nodule occupancy and carbon utilization tests suggested that multiple outputs could be derived from components of PTS(Ntr) in addition to the negative role of unphosphorylated EIIA(Ntr).

Deep sequencing of dsRNAs recovered from mosaic-diseased pigeonpea reveals the presence of a novel emaravirus: pigeonpea sterility mosaic virus 2.

Deep-sequencing analysis of double-stranded RNA extracted from a mosaic-diseased pigeonpea plant (Cajanus cajan L., family Fabaceae) revealed the complete sequence of six emaravirus-like negative-sense RNA segments of 7009, 2229, 1335, 1491, 1833 and 1194 nucleotides in size. In the order from RNA1 to RNA6, these genomic RNAs contained ORFs coding for the RNA-dependent RNA polymerase (RdRp, p1 of 266 kDa), the glycoprotein precursor (GP, p2 of 74.5 kDa), the nucleocapsid (NC, p3 of 34.9 kDa), and the putative movement protein (MP, p4 of 40.7 kDa), while p5 (55 kDa) and p6 (27 kDa) had unknown functions. All RNA segments showed distant relationships to viruses of the genus Emaravirus, and in particular to pigeonpea sterility mosaic virus (PPSMV), with which they shared nucleotide sequence identity ranging from 48.5 % (RNA3) to 62.5 % (RNA1). In phylogenetic trees constructed from the sequences of the proteins encoded by RNA1, RNA2 and RNA3 (p1, p2 and p3), this new viral entity showed a consistent grouping with fig mosaic virus (FMV) and rose rosette virus (RRV), which formed a cluster of their own, clearly distinct from PPSMV-1. In experimental greenhouse trials, this novel virus was successfully transmitted to pigeonpea and French bean seedlings by the eriophyid mite Aceria cajani. Preliminary surveys conducted in the Hyderabad region (India) showed that the virus in question is widespread in pigeonpea plants affected by sterility mosaic disease (86.4 %) but is absent in symptomless plants. Based on molecular, biological and epidemiological features, this novel virus is the second emaravirus infecting pigeonpea, for which the provisional name pigeonpea sterility mosaic virus 2 (PPSMV-2) is proposed.

Study the effect of insecticide dimethoate on photosynthetic pigments and photosynthetic activity of pigeon pea: Laser-induced chlorophyll fluorescence spectroscopy

Pigeon pea is one of the most important legume crops in India and dimethoate is a widely used insecticide in various crop plants. We studied the effect of dimethoate on growth and photosynthetic activity of pigeon pea plants over a short and long term exposure. Plant growth parameters, photosynthetic pigment content and chlorophyll fluorescence response of pigeon pea (Cajanus cajan L.) plants treated with various concentrations of the insecticide dimethoate (10, 20, 40 and 80ppm) have been compared for 30days at regular intervals of 10days each. Laser induced chlorophyll fluorescence spectra and fluorescence-induction kinetics (FIK) curve of dimethoate treated pigeon pea plants were recorded after 10, 20 and 30days of treatment. Fluorescence intensity ratio at the two fluorescence maxima (F685/F730) was calculated by evaluating curve-fitted parameters. The variable chlorophyll fluorescence decrease ratio (Rfd) was determined from the FIK curves. Our study revealed that after 10days of treatment, 10ppm of dimethoate showed stimulatory response whereas 20, 40 and 80ppm of dimethoate showed inhibitory response for growth and photosynthetic activity of pigeon pea plants, but after 20 and 30days of treatment all the tested concentrations of dimethoate became inhibitory. This study clearly shows that dimethoate is highly toxic to the pigeon pea plant, even at very low concentration (10ppm), if used for a prolonged duration. Our study may thus be helpful in determining the optimal dose of dimethoate in agricultural practices.

Siderophore as a potential plant growth-promoting agent produced by Pseudomonas aeruginosa JAS-25.

Siderophores scavenges Fe(+3) from the vicinity of the roots of plants, and thus limit the amount of iron required for the growth of pathogens such as Fusarium oxysporum, Pythium ultimum, and Fusarium udum, which cause wilt and root rot disease in crops. The ability of Pseudomonas to grow and to produce siderophore depends upon the iron content, pH, and temperature. Maximum yield of siderophore of 130 μM was observed at pH 7.0 ± 0.2 and temperature of 30 °C at 30 h. The threshold level of iron was 50 μM, which increases up to 150 μM, favoring growth but drastically affecting the production of siderophore by Pseudomonas aeruginosa JAS-25. The seeds of agricultural crops like Cicer arietinum (chick pea), Cajanus cajan (pigeon pea), and Arachis hypogaea (ground nut) were treated with P. aeruginosa JAS-25, which enhanced the seed germination, root length, shoot length, and dry weight of chick pea, pigeon pea, and ground nut plants under pot studies. The efficient growth of the plants was not only due to the biocontrol activity of the siderophore produced by P. aeruginosa JAS-25 but also may be by the production of indole acetic acid (IAA), which influences the growth of the plants as phytohormones.

Overexpression of pigeonpea stress-induced cold and drought regulatory gene (CcCDR) confers drought, salt, and cold tolerance in Arabidopsis.

A potent cold and drought regulatory protein-encoding gene (CcCDR) was isolated from the subtractive cDNA library of pigeonpea plants subjected to drought stress. CcCDR was induced by different abiotic stress conditions in pigeonpea. Overexpression of CcCDR in Arabidopsis thaliana imparted enhanced tolerance against major abiotic stresses, namely drought, salinity, and low temperature, as evidenced by increased biomass, root length, and chlorophyll content. Transgenic plants also showed increased levels of antioxidant enzymes, proline, and reducing sugars under stress conditions. Furthermore, CcCDR-transgenic plants showed enhanced relative water content, osmotic potential, and cell membrane stability, as well as hypersensitivity to abscisic acid (ABA) as compared with control plants. Localization studies confirmed that CcCDR could enter the nucleus, as revealed by intense fluorescence, indicating its possible interaction with various nuclear proteins. Microarray analysis revealed that 1780 genes were up-regulated in CcCDR-transgenics compared with wild-type plants. Real-time PCR analysis on selected stress-responsive genes, involved in ABA-dependent and -independent signalling networks, revealed higher expression levels in transgenic plants, suggesting that CcCDR acts upstream of these genes. The overall results demonstrate the explicit role of CcCDR in conferring multiple abiotic stress tolerance at the whole-plant level. The multifunctional CcCDR seems promising as a prime candidate gene for enhancing abiotic stress tolerance in diverse plants.

Efficacy of Botanical Pesticides in Controlling Insect Pests of Three Pigeon Pea Varieties

Pigeon Pea (Cajanus cajan) is a high-value crop with its nutritional and medicinal properties that could augment food security. Pigeon pea is prone to pests attack that could affect its yield, thus, this study is conceived. This study aimed to evaluate the effect of botanical pesticides in controlling insect pests of three pigeon pea varieties. Specifically, it sought to: 1) determine which of the botanical pesticides can effectively control insect pests of pigeon pea; 2) find out which among the pigeon pea varieties has the least damage by insect pests; and 3) identify and recommend the best-botanical pesticides to control insect pests of pigeon peas. The experiment was laid out in Factorial Randomized Complete Block Design. Data gathered were analyzed using the Analysis of Variance. Significant differences among treatment means were analyzed using the Duncan Multiple Range Test. The results implied that the botanical extract applied to the pigeon pea plants exhibited a significant effect in terms of controlling the pests. The results of the study conclude that the application of botanical extracts is comparably effective in controlling pests of pigeon pea. The study recommends that B1 (Neem Leaf Extract), B2 (Yellow Ginger Extract) and B3 (Hot Pepper Extract) can be used to control insect pests of pigeon peas; V2 (ICPL 87119) is recommended for production due to its resistance to pests.

Phenotypic and molecular fingerprinting of fast growing rhizobia of field-grown pigeonpea from the eastern edge of the Brazilian Pantanal

The aim of this study was to evaluate the diversity of rhizobial isolates obtained from root nodules of pigeonpea plants grown at the eastern edge of the Brazilian Pantanal. The bacterial isolates were isolated from root nodules from field-growing pigeonpea grown in two rural settlements of the Aquidauana municipality. The bacterial isolates were characterized phenotypically by means of cultural characterization, intrinsic antibiotic resistance (IAR), salt and high incubation temperature tolerance, and amylolytic and cellulolytic activities. The molecular characterization of the bacterial isolates was carried out using amplified ribosomal DNA restriction analysis (ARDRA) and Box-polymerase chain reaction (PCR) techniques. In addition, the symbiotic performance of selected rhizobial isolates was evaluated in a greenhouse experiment using sterile substrate. The phenotypic characterization revealed that the bacterial strains obtained from pigeonpea root nodules presented characteristics that are uncommon among rhizobial isolates, indicating the presence of new species nodulating the pigeonpea plants in the Brazilian Pantanal. The molecular fingerprinting of these bacterial isolates also showed a highly diverse collection, with both techniques revealing less than 25% similarity among bacterial isolates. The evaluation of symbiotic performance also indicated the presence of microorganisms with high potential to increase the growth and nitrogen content at the shoots of pigeonpea plants. The results obtained in this study indicate the presence of a highly diversified rhizobial community nodulating the pigeonpea at the eastern edge of the Brazilian Pantanal.