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Soil salinity and water-deficit conditions often affect crop productivity in groundnut. Therefore, developing transgenic groundnut that can grow under such abiotic stress conditions is crucial to stabilize its yield. Sodium proton antiporter-like protein (NHXLP) is a plasma membrane-bound protein associated with Na+ exclusion and helps to maintain ion homeostasis under saline conditions. In the present study, salt tolerant transgenic groundnut variety JL-24 was developed by expressing SbNHXLP gene isolated from Sorghum bicolor. Molecular analysis of transgenics by PCR and Southern blot confirmed the integration of SbNHXLP gene. SbNHXLP expression at the transcript level was checked by reverse transcriptase (RT)-PCR. Homozygous T2 lines along with wild-type (WT) plants were evaluated for 150 mM NaCl stress tolerance. Biochemical analysis of transgenics under salt stress revealed higher chlorophyll content, superoxide dismutase, and catalase activities, accumulation of proline, and K+ accompanied by lower Na+ accumulation compared to WT plants. Additionally, transgenics displayed higher biomass and pod yield when compared with WT plants under stress. Our findings indicate that overexpression of SbNHXLP gene in groundnut results in enhanced tolerance to salinity stress. This highlights the potential of SbNHXLP as a target candidate gene to impart salt stress tolerance in groundnut. A sodium proton antiporter-like protein isolated from Sorghum (SbNHXLP) was overexpressed in groundnut and stably integrated. Transgenics displayed higher chlorophyll, proline, K+, and better yields than WT plants under salt stress.

Genetically engineered plants have varied applications in agriculture for enhancing the values of food and feed. Genetic engineering aims to introduce selected genetic regions with desirable traits into target plants for both spatial and temporal expressions. Promoters are the key elements responsible for regulating gene expressions by modulating the transcription factors (TFs) through recognition of RNA polymerases. Based on their recognition and expression, RNA polymerases were categorized into RNA pol II and pol III promoters. Promoter activity and specificity are the two prime parameters in regulating the transgene expression. Since the use of constitutive promoters like Cauliflower mosaic virus (CaMV) 35S may lead to adverse effects on non-target organisms or ecosystem, inducible/tissue specific promoters and/or the RNA pol III promoters provide myriad opportunities for gene expressions with controlled regulation and with minimum adverse effects. Besides their role in transgene expression, their influence in synthetic biology and genome editing are also discussed. This review provides an update on the importance, current prospects, and insight into the advantages and disadvantages of promoters reported thus far would help to utilize them in the endeavour to develop nutritionally and agronomically improved transgenic crops for commercialization.

Pearl millet is an important crop for alleviating micronutrient malnutrition through genomics-assisted breeding for grain Fe (GFeC) and Zn (GZnC) content. In this study, we identified candidate genes related to iron (Fe) and zinc (Zn) metabolism through gene expression analysis and correlated it with known QTL regions for GFeC/GZnC. From a total of 114 Fe and Zn metabolism-related genes that were selected from the related crop species, we studied 29 genes. Different developmental stages exhibited tissue and stage-specific expressions for Fe and Zn metabolism genes in parents contrasting for GFeC and GZnC. Results revealed that PglZIP, PglNRAMP and PglFER gene families were candidates for GFeC and GZnC. Ferritin-like gene, PglFER1 may be the potential candidate gene for GFeC. Promoter analysis revealed Fe and Zn deficiency, hormone, metal-responsive, and salt-regulated elements. Genomic regions underlying GFeC and GZnC were validated by annotating major QTL regions for grain Fe and Zn. Interestingly, PglZIP and PglNRAMP gene families were found common with a previously reported linkage group 7 major QTL region for GFeC and GZnC. The study provides insights into the foundation for functional dissection of different Fe and Zn metabolism genes homologs and their subsequent use in pearl millet molecular breeding programs globally.

Key message The HbCAld5H1 gene cloned from Hevea brasiliensis regulates the cambial activity, xylem differentiation, syringyl–guaiacyl ratio, secondary wall structure, lignification pattern and xylan distribution in xylem fibres of transgenic tobacco plants. Abstract Molecular characterization of lignin biosynthesis gene coniferaldehyde-5-hydroxylase (CAld5H) from Hevea brasiliensis and its functional validation was performed. Both sense and antisense constructs of HbCAld5H1 gene were introduced into tobacco through Agrobacterium-mediated genetic transformation for over expression and down-regulation of this key enzyme to understand its role affecting structural and cell wall chemistry. The anatomical studies of transgenic tobacco plants revealed the increase of cambial activity leading to xylogenesis in sense lines and considerable reduction in antisense lines. The ultra-structural studies showed that the thickness of secondary wall (S2 layer) of fibre had been decreased with non-homogenous lignin distribution in antisense lines, while sense lines showed an increase in S2 layer thickness. Maule color reaction revealed that syringyl lignin distribution in the xylem elements was increased in sense and decreased in antisense lines. The immunoelectron microscopy revealed a reduction in LM 10 and LM 11 labelling in the secondary wall of antisense tobacco lines. Biochemical studies showed a radical increase in syringyl lignin in sense lines without any significant change in total lignin content, while S/G ratio decreased considerably in antisense lines. Our results suggest that CAld5H gene plays an important role in xylogenesis stages such as cambial cell division, secondary wall thickness, xylan and syringyl lignin distribution in tobacco. Therefore, CAld5H gene could be considered as a promising target for lignin modification essential for timber quality improvement in rubber.

Peanut (Arachis hypogaea L.) is an important oil-yielding cash crop as well as an exportable agricultural commodity. It is a rich source of proteins, fats, and plays a crucial role in oilseed economy of India and many other countries. Peanut frequently encounters water-deficit and soil salinity conditions that affect its growth and productivity. Traditional breeding methods were not successful in generating lines tolerant to abiotic stress conditions. On the other hand, introduction of genes through genetic engineering methods conferred tolerance against both biotic and abiotic stresses. In all, the transgenics that were developed so far, stable inheritance of transgenes was noticed. Transgenics displayed higher biomass, yield and better resistance to abiotic stresses when compared with wild-type plants inferring that this method has potential for improving the crop with desired traits. Genetically engineered stress tolerant peanut plants could provide an avenue to the restoration of farmlands lost due to severe drought or salinity conditions and highlight the potential of this technology for developing climate resilient crop.

Sorghum is a major staple globally and biofortifying sorghum with increased grain iron and zinc complements ongoing efforts to combat micronutrient malnutrition. Limited information available on the nature and magnitude of gene effects for grain iron and zinc. So generation mean analysis was done using four crosses, ICSB 52 × IS 13211, ICSB 52 × SPV 1359, IS 20843 × IS 2248 and IS 2248 × IS 20843. Six generations, P1, P2, F1, F2, B1 and B2, were generated for each of these crosses which were evaluated during the postrainy season 2012–13. The mean sum of squares due to generations were significant for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Fe and Zn. Generation mean studies revealed the presence of both additive and dominant gene interactions in inheritance of agronomic traits. Duplicative epistasis was observed for days to flowering, plant height, grain yield/plant, 100-grain weight, and grain Zn with a predominance of dominant gene action in inheritance of these traits. Panicle length, panicle width, and grain Fe showed both additive and dominance gene effects, with higher magnitude of dominance. This information can be utilized in developing sorghum lines with high grain Fe and Zn.

Plants overcome the effect of Na+ toxicity either by excluding Na+ at the plasma membrane or by sequestering them into the vacuoles. Influx of Na+ ions into the plant vacuoles is usually driven by H+ generated by vacuolar-type H+-ATPase as well as vacuolar proton pyrophosphatse (VPPase). In the present study, we have developed Bacopa monnieri transgenics via Agrobacterium tumefaciens containing the recombinant vector pCAMBIA2300-SbVPPase gene. Transformants were produced using nodal explants. Transformants were confirmed by PCR and DNA blot analysis. qPCR analysis showed higher transcript levels of SbVPPase compared to untransformed control (UC). Higher VPPase activity was recorded in transgenics compared to UC. Under 150 mM salt stress, transgenic shoots showed enhanced Na+ accumulation with better biomass production, increased glycine betaine content, and total soluble sugar levels than UC. Transgenic shoots showed 2.9–3.8-folds lower levels of malondialdehyde content indicating lesser membrane damage. Increase in antioxidant enzyme activities (1.4–3.2-folds) was observed in transgenics compared to UC. Transgenics also displayed 7.3–9.0-folds enhanced accumulation of the medicinally important compound bacoside A. Increased biomass production, accumulation of Na+, osmolytes (glycine betaine, sugars etc.), and elevated antioxidant enzyme activities indicate better osmotic adjustment in transgenics by compartmentalization of Na+ into the vacuoles under salt stress conditions. Thus, overexpression of SbVPPase in Bacopa alleviated salt stress by sequestering Na+.

Morphogenic cultures of Gloriosa superba were initiated on Murashige and Skoog’s medium fortified with 2 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D), 0.5 mg L−1 naphthaleneacetic acid (NAA), 4% sucrose and 0.1% activated charcoal. To enhance the content of the alkaloid colchicine, morphogenic cultures were treated with different concentrations of abiotic elicitors like signalling compounds, metals, biotic elicitors, precursors and a combination of elicitors. Signalling molecules like acetyl salicylic acid (ASA) and sodium nitroprusside improved the production of colchicine. Abiotic elicitors have markedly (p ≤ 0.05 or ≤ 0.01) enhanced the colchicine content either at lower or higher concentrations. Among the metals, the highest amount of 11.67 mg of colchicine g−1 dry wt was noticed at 60 mM rubidium chloride, followed by 60 mM NaCl (11.18 mg g−1). Contrarily, in the presence of biotic elicitors such as Fusarium oxysporum, Alternaria solani, and Saccharomyces cerevisiae, colchicine content ranged only between 2 and 5.32 mg g−1, but Bacillus subtilis repressed it. Among the aromatic amino acids, phenylalanine at 500 mg L−1 influenced the highest accumulation of 19.48 mg g−1 dry tissue, followed by tryptophan (12.47 mg g−1), and tyrosine (9.87 mg g−1), a direct precursor of colchicine biosynthesis, while intact tubers and leaves contained 4.65 and 4.16 mg of colchicine g−1 dry tissue respectively. A combination of 10 µM AlCl3 and 50 µM salicylic acid (SA) registered 17.34 mg g−1 followed by 16.24 mg g−1 tissue in presence of 1 µM HgCl2 and 50 µM SA. The results suggest that the elicitor-stimulated colchicine accumulation was a stress response and can be exploited further for commercial production.

An efficient protocol for somatic embryogenesis and plant regeneration from rhizome explants of Gloriosa superba L. was developed using various plant growth regulators (PGRs), Ulva lactuca extracts (ULE), and phycomolecule-coated U. lactuca silver nanoparticles (ULAgNPs). Callus was initiated from rhizome explants on the Murashige and Skoog (MS) medium supplemented with various concentrations of 2,4-dichlorophenoxyacetic acid (1.0–5.0 mg L−1), α-naphthaleneacetic acid (NAA) (0.5 mg L−1), ULE (10–50%), and ULAgNPs (0.1–0.5 mg L−1). Callus was cultured on MS medium fortified with various concentrations and combinations of 6-benzylaminopurine (BAP) (0.5–2.5 mg L−1), kinetin (KIN) (0.5–2.5 mg L−1), ULAgNPs (0.1–0.5 mg L−1), and 20% ULE along with 0.5 mg L−1 NAA for the development of somatic embryos (SEs). The maximum percentage of embryo maturation (100%) was observed on the medium containing 0.5 mg L−1 ULAgNPs, 2.0 mg L−1 BAP, 0.5 mg L−1 abscisic acid (ABA), 0.5 mg L−1 silver nitrate (AgNO3), and 20% ULE. The highest percentage of embryo germination (86.1%) was noticed on the MS medium containing 0.3 mg L−1 ULAgNPs, 5.0 mg L−1 gibberellic acid (GA3), 2.0 mg L−1 BAP, 0.5 mg L−1 adenine sulfate (AdS), and 20% ULE. Well-rooted plantlets were successfully acclimatized in the greenhouse with 70% survival rate. Results suggest that U. lactuca extract-derived silver nanoparticles could be used as biostimulants for the enhancement of somatic embryogenesis and plant regeneration rate in G. superba.

Fusarium wilt (FW) is one of the most important biotic stresses causing yield losses in pigeonpea. Genetic improvement of pigeonpea through genomics-assisted breeding (GAB) is an economically feasible option for the development of high yielding FW resistant genotypes. In this context, two recombinant inbred lines (RILs) (ICPB 2049 × ICPL 99050 designated as PRIL_A and ICPL 20096 × ICPL 332 designated as PRIL_B) and one F2 (ICPL 85063 × ICPL 87119) populations were used for the development of high density genetic maps. Genotyping-by-sequencing (GBS) approach was used to identify and genotype SNPs in three mapping populations. As a result, three high density genetic maps with 964, 1101 and 557 SNPs with an average marker distance of 1.16, 0.84 and 2.60 cM were developed in PRIL_A, PRIL_B and F2, respectively. Based on the multi-location and multi-year phenotypic data of FW resistance a total of 14 quantitative trait loci (QTLs) including six major QTLs explaining >10% phenotypic variance explained (PVE) were identified. Comparative analysis across the populations has revealed three important QTLs (qFW11.1, qFW11.2 and qFW11.3) with upto 56.45% PVE for FW resistance. This is the first report of QTL mapping for FW resistance in pigeonpea and identified genomic region could be utilized in GAB.

SbAP37 transcription factor contributes to a combination of abiotic stresses when applied simultaneously in rice. It modulates a plethora of proteins that might regulate the downstream pathways to impart salt stress tolerance. APETALA type of transcription factor was isolated from Sorghum bicolor (SbAP37), overexpressed in rice using a salt inducible abscisic acid 2 (ABA2) promoter through Agrobacterium tumefaciens following in planta method. Transgenics were confirmed by PCR amplification of SbAP37, hygromycin phosphotransferase (hptII) marker and ABA2 promoter and DNA blot analysis. Plants were exposed to 150 mM NaCl coupled with high day/night 36 ± 2/25 ± 2 °C temperatures and also drought stress by withholding water for 1-week separately at the booting stage. SbAP37 expression was 2.8- to 4.7-folds higher in transgenic leaf under salt, but 1.8- to 3.3-folds higher in roots under drought stress. Native gene expression analysis showed that it is expressed more in stem than in roots and leaves under 150 mM NaCl and 6% PEG stress. In the present study, proteomic analysis of transgenics exposed to 150 mM NaCl coupled with elevated temperatures was taken up using quadrupole time-of-flight (Q-TOF) mass spectrometry (MS). The leaf proteome revealed 11 down regulated, 26 upregulated, 101 common (shared), 193 newly synthesized proteins in transgenics besides 368 proteins in untransformed plants. Some of these protein sets appeared different and unique to combined stresses. Our results suggest that the SbAP37 has the potential to improve combined stress tolerance without causing undesirable phenotypic characters when used under the influence of ABA2 promoter.

Osmotin like protein ( OLP ) and chitinase ( Chi11 ) belong to pathogenesis-related (PR) class of proteins and are induced during both biotic and abiotic stresses. Transgenic tomato was developed with OLP and Chi11 via in vitro and in planta transformation methods. Transgenes integration and transcript levels were confirmed by multiplex PCR, DNA blot, and multiplex reverse transcriptase PCR. Homozygous T 2 transgenics when evaluated for salt, drought, and fungal stresses showed enhanced tolerance compared to untransformed controls (UC). Transgenics showed enhanced endochitinase activity and root biomass under normal conditions. Transformants also displayed higher proline content, K + , relative water content, chlorophyll fluorescence, total biomass, vascular conductivity, and fruit yield than the UC under stress conditions. Co-immunoprecipitation revealed that Chi11 co-expresses with phosphofructokinase2 (PFK2), which may play a role in enhanced root biomass. qPCR analysis resulted in higher transcript levels of OLP , Chi11, and PFK2 in transgenics as compared to the untransformed controls. Our findings suggest the use of multiples genes to confer multiple stress tolerance for enhanced crop productivity. This work unveils a new molecular player PFK2, which may play a role in enhanced root biomass.

This study was conducted to dissect the genetic basis and to explore the candidate genes underlying one of the important genomic regions on an SBI-10 long arm (L), governing the complex stay-green trait contributing to post-flowering drought-tolerance in sorghum. A fine-mapping population was developed from an introgression line cross&mdash, RSG04008-6 (stay-green) &times, J2614-11 (moderately senescent). The fine-mapping population with 1894 F2 was genotyped with eight SSRs and a set of 152 recombinants was identified, advanced to the F4 generation, field evaluated with three replications over 2 seasons, and genotyped with the GBS approach. A high-resolution linkage map was developed for SBI-10L using 260 genotyping by sequencing&mdash, Single Nucleotide Polymorphism (GBS&ndash, SNPs). Using the best linear unpredicted means (BLUPs) of the percent green leaf area (%GL) traits and the GBS-based SNPs, we identified seven quantitative trait loci (QTL) clusters and single gene, mostly involved in drought-tolerance, for each QTL cluster, viz., AP2/ERF transcription factor family (Sobic.010G202700), NBS-LRR protein (Sobic.010G205600), ankyrin-repeat protein (Sobic.010G205800), senescence-associated protein (Sobic.010G270300), WD40 (Sobic.010G205900), CPK1 adapter protein (Sobic.010G264400), LEA2 protein (Sobic.010G259200) and an expressed protein (Sobic.010G201100). The target genomic region was thus delimited from 15 Mb to 8 genes co-localized with QTL clusters, and validated using quantitative real-time (qRT)&ndash, PCR.

Members of the plant Heme Activator Protein (HAP) or NUCLEAR FACTOR Y (NF-Y) are trimeric transcription factor complexes composed of the NF-YA, NF-YB and NF-YC subfamilies. They bind to the CCAAT box in the promoter regions of the target genes and regulate gene expressions. Plant NF-Ys were reported to be involved in adaptation to several abiotic stresses as well as in development. In silico analysis of Sorghum bicolor genome resulted in the identification of a total of 42 NF-Y genes, among which 8 code for the SbNF-YA, 19 for SbNF-YB and 15 for the SbNF-YC subunits. Analysis was also performed to characterize gene structures, chromosomal distribution, duplication status, protein subcellular localizations, conserved motifs, ancestral protein sequences, miRNAs and phylogenetic tree construction. Phylogenetic relationships and ortholog predictions displayed that sorghum has additional NF-YB genes with unknown functions in comparison with Arabidopsis. Analysis of promoters revealed that they harbour many stress-related cis-elements like ABRE and HSE, but surprisingly, DRE and MYB elements were not detected in any of the subfamilies. SbNF-YA1, 2, and 6 were found upregulated under 200 mM salt and 200 mM mannitol stresses. While NF-YA7 appeared associated with high temperature (40°C) stress, NF-YA8 was triggered by both cold (4°C) and high temperature stresses. Among NF-YB genes, 7, 12, 15, and 16 were induced under multiple stress conditions such as salt, mannitol, ABA, cold and high temperatures. Likewise, NF-YC 6, 11, 12, 14, and 15 were enhanced significantly in a tissue specific manner under multiple abiotic stress conditions. Majority of the mannitol (drought)-inducible genes were also induced by salt, high temperature stresses and ABA. Few of the high temperature stress-induced genes are also induced by cold stress (NF-YA2, 4, 6, 8, NF-YB2, 7, 10, 11, 12, 14, 16, 17, NF-YC4, 6, 12, and 13) thus suggesting a cross talk among them. This work paves the way for investigating the roles of diverse sorghum NF-Y proteins during abiotic stress responses and provides an insight into the evolution of diverse NF-Y members.

Late embryogenesis abundant (LEA) proteins, the space fillers or molecular shields, are the hydrophilic protective proteins which play an important role during plant development and abiotic stress. The systematic survey and characterization revealed a total of 68 LEA genes, belonging to 8 families in Sorghum bicolor. The LEA-2, a typical hydrophobic family is the most abundant family. All of them are evenly distributed on all 10 chromosomes and chromosomes 1, 2, and 3 appear to be the hot spots. Majority of the S. bicolor LEA (SbLEA) genes are intron less or have fewer introns. A total of 22 paralogous events were observed and majority of them appear to be segmental duplications. Segmental duplication played an important role in SbLEA-2 family expansion. A total of 12 orthologs were observed with Arabidopsis and 13 with Oryza sativa. Majority of them are basic in nature, and targeted by chloroplast subcellular localization. Fifteen miRNAs targeted to 25 SbLEAs appear to participate in development, as well as in abiotic stress tolerance. Promoter analysis revealed the presence of abiotic stress-responsive DRE, MYB, MYC, and GT1, biotic stress-responsive W-Box, hormone-responsive ABA, ERE, and TGA, and development-responsive SKn cis-elements. This reveals that LEA proteins play a vital role during stress tolerance and developmental processes. Using microarray data, 65 SbLEA genes were analyzed in different tissues (roots, pith, rind, internode, shoot, and leaf) which show clear tissue specific expression. qRT-PCR analysis of 23 SbLEA genes revealed their abundant expression in various tissues like roots, stems and leaves. Higher expression was noticed in stems compared to roots and leaves. Majority of the SbLEA family members were up-regulated at least in one tissue under different stress conditions. The SbLEA3-2 is the regulator, which showed abundant expression under diverse stress conditions. Present study provides new insights into the formation of LEAs in S. bicolor and to understand their role in developmental processes under stress conditions, which may be a valuable source for future research.

Na+ transporters play an important role during salt stress and development. The present study is aimed at genome-wide identification, in silico analysis of sodium-proton antiporter (NHX) and sodium-proton exchanger (NHE)-type transporters in Sorghum bicolor and their expression patterns under varied abiotic stress conditions. In Sorghum, seven NHX and nine NHE homologs were identified. Amiloride (a known inhibitor of Na+/H+ exchanger activity) binding motif was noticed in both types of the transporters. Chromosome 2 was found to be a hotspot region with five sodium transporters. Phylogenetic analysis inferred six ortholog and three paralog groups. To gain an insight into functional divergence of SbNHX/NHE transporters, real-time gene expression was performed under salt, drought, heat, and cold stresses in embryo, root, stem, and leaf tissues. Expression patterns revealed that both SbNHXs and SbNHEs are responsive either to single or multiple abiotic stresses. The predicted protein–protein interaction networks revealed that only SbNHX7 is involved in the calcineurin B-like proteins (CBL)- CBL interacting protein kinases (CIPK) pathway. The study provides insights into the functional divergence of SbNHX/NHE transporter genes with tissue specific expressions in Sorghum under different abiotic stress conditions.

Shoot fly is a major insect pest of sorghum damaging early crop growth, establishment and productivity. Host plant resistance is an efficient approach to minimize yield losses due to shoot fly infestation. Seedling leaf blade glossiness and trichome density are morphological traits associated with shoot fly resistance. Our objective was to identify and evaluate QTLs for glossiness and trichome density using- i) 1894 F2s, ii) a sub-set of 369 F2-recombinants, and iii) their derived 369 F2:3 progenies, from a cross involving introgression lines RSG04008-6 (susceptible) × J2614-11 (resistant). The QTLs were mapped to a 37–72 centimorgan (cM) or 5–15 Mb interval on the long arm of sorghum chromosome 10 (SBI-10L) with flanking markers Xgap001 and Xtxp141. One QTL each for glossiness (QGls10) and trichome density (QTd10) were mapped in marker interval Xgap001-Xnhsbm1044 and Xisep0630-Xtxp141, confirming their loose linkage, for which phenotypic variation accounted for ranged from 2.29 to 11.37 % and LOD values ranged from 2.03 to 24.13, respectively. Average physical map positions for glossiness and trichome density QTLs on SBI-10 from earlier studies were 4 and 2 Mb, which in the present study were reduced to 2 Mb and 800 kb, respectively. Candidate genes Glossy15 (Sb10g025053) and ethylene zinc finger protein (Sb10g027550) falling in support intervals for glossiness and trichome density QTLs, respectively, are discussed. Also we identified a sub-set of recombinant population that will facilitate further fine mapping of the leaf blade glossiness and trichome density QTLs on SBI-10.

Abutilon indicum exploited for its immense value has been propagated successfully through multiple shoot induction and somatic embryogenesis. Direct regeneration (8.20 ± 0.83 shoots) was achieved from nodal explants using 0.5 mg/l kinetin (Kn) in MS media. The basal callus from nodal explants turned embryogenic on subsequent introduction of 0.2 mg/l TDZ into the Kn-supplemented media, giving rise to somatic embryos. The embryogenic potential of calli expressed in terms of embryo-forming capacity (EFC) increased from 8.15 EFC to 20.95 EFC after plasmolysis. The phytochemical analysis (HPLC) for the presence of scopoletin and scoparone has revealed a unique accumulation pattern, with higher levels of scopoletin during the earlier stages and scoparone in the later stages of development. The embryogenic calli contained the highest amount of coumarins (99.20 ± 0.97 and 61.03 ± 0.47 μg/gFW, respectively) followed by regenerated plant (9.43 ± 0.20 and 36.36 ± 1.19 μg/gFW, respectively), obtained via somatic embryogenesis. Rapid multiplication of A. indicum equipped with two potent coumarins is important in order to meet the commercial demand for combat against dreadful diseases, thereby providing a new platform for plant-based drugs and their manufacture on a commercial scale.

Contact: fax: +91 40 30713074/30713075. E-mail address: r.k.varshney@cgiar.org; International audience; The transcription factor, DREB2A, is one of the promising candidate genes involved in dehydration tolerance in crop plants. In order to isolate DREB2A homologues across cereals (rice, barley and sorghum) and legumes (common bean and chickpea), specific or degenerate primers were used. Gene/phylogenetic trees were constructed using a non-redundant set of 19 DREB1A and 27 DREB2A amino acid sequences and were combined with taxonomic/species tree to prepare reconciled phylogenetic trees. In total, 86 degenerate primers were designed for different clades and 295 degenerate primer combinations were used to amplify DREB homologues in targeted crop species. Successful amplification of DREB2A was obtained in case of sorghum. In parallel, gene-specific primers were used to amplify DREB2A homologues in rice, barley, common bean and chickpea. Seven to eight diverse genotypes from targeted species were used for sequence analysis at DREB2A locus identified/isolated. A maximum of eight SNPs were found in the common bean DREB2A, indicating two distinct haplotypes, three SNPs with five haplotypes were observed in barley whereas a single SNP was observed in rice, sorghum and chickpea. Parsimony based phylogenetic tree revealed distinct clustering of cereals and legumes. Furthermore, alignment of corresponding amino acid sequences showed conservation of AP2 domain across the targeted species.

Aluminum (Al) stress is one of the serious limiting factors in plant productivity in acidic soils, which constitute about 50 % of the world's potentially arable lands and causes anywhere between 25 and 80 % of yield losses depending upon the species. The mechanism of Al toxicity and tolerance has been examined in plants, which is vital for crop improvement and enhanced food production in the future. Two mechanisms that facilitate Al tolerance in plants are Al exclusion from the roots and the ability to tolerate Al in the symplast or both. Although efforts have been made to unravel Al-resistant factors, many aspects remain unclear. Certain gene families such as MATE, ALMT, ASR, and ABC transporters have been implicated in some plants for resistance to Al which would enhance the opportunities for creating crop plants suitable to grow in acidic soils. Though QTLs have been identified related to Al-tolerance, no crop plant that is tolerant to Al has been evolved so far using breeding or molecular approaches. The remarkable changes that plants experience at the physiological, biochemical and molecular level under Al stress, the vast array of genes involved in Al toxicity-tolerance, the underlying signaling events and the holistic image of the molecular regulation, and the possibility of creating transgenics for Al tolerance are discussed in this review.

This study presents the development and mapping of simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers in chickpea. The mapping population is based on an inter-specific cross between domesticated and non-domesticated genotypes of chickpea (Cicer arietinum ICC 4958 × C. reticulatum PI 489777). This same population has been the focus of previous studies, permitting integration of new and legacy genetic markers into a single genetic map. We report a set of 311 novel SSR markers (designated ICCM—ICRISAT chickpea microsatellite), obtained from an SSR-enriched genomic library of ICC 4958. Screening of these SSR markers on a diverse panel of 48 chickpea accessions provided 147 polymorphic markers with 2–21 alleles and polymorphic information content value 0.04–0.92. Fifty-two of these markers were polymorphic between parental genotypes of the inter-specific population. We also analyzed 233 previously published (H-series) SSR markers that provided another set of 52 polymorphic markers. An additional 71 gene-based SNP markers were developed from transcript sequences that are highly conserved between chickpea and its near relative Medicago truncatula. By using these three approaches, 175 new marker loci along with 407 previously reported marker loci were integrated to yield an improved genetic map of chickpea. The integrated map contains 521 loci organized into eight linkage groups that span 2,602 cM, with an average inter-marker distance of 4.99 cM. Gene-based markers provide anchor points for comparing the genomes of Medicago and chickpea, and reveal extended synteny between these two species. The combined set of genetic markers and their integration into an improved genetic map should facilitate chickpea genetics and breeding, as well as translational studies between chickpea and Medicago. Electronic supplementary material The online version of this article (doi:10.1007/s00122-010-1265-1) contains supplementary material, which is available to authorized users.