Influence of different carbon sources on in vitro induction of anthocyanin pigments in callus cultures of petunia (Petunia hybrida)

Anthocyanins are naturally occurring compounds that impart color to fruits, flowers, vegetables, and plants. They are probably the most important group of visible plant pigments besides chlorophyll pigments. Apart from imparting color to plants, anthocyanins also have an array of health-promoting benefits, as they can protect against a variety of free radicals through a various number of mechanisms. Development of an efficient tissue culture system for commercial production of anthocyanins requires an integrated approach through manipulation of various media constituents. The effect of varied concentrations of different carbon sources on anthocyanin production in callus cultures of Petunia hybrida cv Bravo Blue was studied. Explants from young leaves were cultured on Murashige and Skoog (MS) medium supplemented with MS + IBA (19.6 µM) + Kin. (4.65 µM) + AdS (81.45 mM), 3% sucrose and 0.7% agar. Among the various carbon sources tested, incorporation of Glucose at 5% was found to have earliest pigment induction with maximum response coefficient with highest pigment content (1.36 ± 0.012 CV/g FCW). Highest gain in fresh cell weight was noticed with the addition of sucrose 5% (3.96 ± 0.06 g). When MS medium was supplemented with different concentrations of Galactose, the explants failed to respond

Mapping QTLs Controlling Flowering Time, Plant Height, Panicle length and Grain Mass in Pearl Millet [Pennisetum glaucum (L.) R. Br.]

Pearl millet is an important cereal of arid- and semi-arid regions, and can endure dry conditions but experiences drought stress during post-flowering growth. Exploiting the bold seeded semi-dwarf early flowering genotypes in pearl millet is a key breeding strategy to enhance yield and for adequate food in resource-poor zones. Genetic variation for agronomic traits of pearl millet inbreds can be used to dissect complex traits through QTL mapping. Quantitative trait locus (QTL) mapping for 50% flowering time, plant height, panicle length, and grain mass (self and open pollinated seeds) was performed in recombinant inbred line (RIL) population, ICMB 841-P3 ? 863B-P2. Correlations between traits were also performed and significantly negative association between plant height and TGM was observed. High heritabilities (>0.6) were recorded for all traits. A total of 50 QTLs that affected above traits were detected. Six putative QTLs for 50% flowering time were identified on five chromosomes. One QTL on LG3 were common between flowering time and plant height. Three major QTLs for panicle length, one each on LG1, LG2 and LG6B were detected.The major QTL for TGM_self on LG 6B had a partial R2 of 23.8% and 0.8 additive effects.The total phenotypic variance for 50% FT, TGM_self, and panicle length was 23.2% (LOD- 56.28), 22.3% (LOD- 5.96) and 59.4% (LOD- 52), respectively.A total of 21 digenic interactions were demonstrated for 50%FT (R2=18%-40%) and PL (R2publishersversionPeer reviewe

Identification of key genes and molecular pathways regulating heat stress tolerance in pearl millet to sustain productivity in challenging ecologies

Pearl millet is a nutri-cereal that is mostly grown in harsh environments, making it an ideal crop to study heat tolerance mechanisms at the molecular level. Despite having a better-inbuilt tolerance to high temperatures than other crops, heat stress negatively affects the crop, posing a threat to productivity gain. Hence, to understand the heat-responsive genes, the leaf and root samples of two contrasting pearl millet inbreds, EGTB 1034 (heat tolerant) and EGTB 1091 (heat sensitive), were subjected to heat-treated conditions and generated genome-wide transcriptomes. We discovered 13,464 differentially expressed genes (DEGs), of which 6932 were down-regulated and 6532 up-regulated in leaf and root tissues. The pairwise analysis of the tissue-based transcriptome data of the two genotypes demonstrated distinctive genotype and tissue-specific expression of genes. The root exhibited a higher number of DEGs compared to the leaf, emphasizing different adaptive strategies of pearl millet. A large number of genes encoding ROS scavenging enzymes, WRKY, NAC, enzymes involved in nutrient uptake, protein kinases, photosynthetic enzymes, and heat shock proteins (HSPs) and several transcription factors (TFs) involved in cross-talking of temperature stress responsive mechanisms were activated in the stress conditions. Ribosomal proteins emerged as pivotal hub genes, highly interactive with key genes expressed and involved in heat stress response. The synthesis of secondary metabolites and metabolic pathways of pearl millet were significantly enriched under heat stress. Comparative synteny analysis of HSPs and TFs in the foxtail millet genome demonstrated greater collinearity with pearl millet compared to proso millet, rice, sorghum, and maize. In this study, 1906 unannotated DEGs were identified, providing insight into novel participants in the molecular response to heat stress. The identified genes hold promise for expediting varietal development for heat tolerance in pearl millet and similar crops, fostering resilience and enhancing grain yield in heat-prone environments

Deciphering Genomic Regions for High Grain Iron and Zinc Content Using Association Mapping in Pearl Millet

Micronutrient malnutrition, especially deficiency of two mineral elements, iron [Fe] and zinc [Zn] in the developing world needs urgent attention. Pearl millet is one of the best crops with many nutritional properties and is accessible to the poor. We report findings of the first attempt to mine favorable alleles for grain iron and zinc content through association mapping in pearl millet. An association mapping panel of 130 diverse lines was evaluated at Delhi, Jodhpur and Dharwad, representing all the three pearl millet growing agro-climatic zones of India, during 2014 and 2015. Wide range of variation was observed for grain iron (32.3–111.9 ppm) and zinc (26.6–73.7 ppm) content. Genotyping with 114 representative polymorphic SSRs revealed 0.35 mean gene diversity. STRUCTURE analysis revealed presence of three sub-populations which was further supported by Neighbor-Joining method of clustering and principal coordinate analysis (PCoA). Marker-trait associations (MTAs) were analyzed with 267 markers (250 SSRs and 17 genic markers) in both general linear model (GLM) and mixed linear model (MLM), however, MTAs resulting from MLM were considered for more robustness of the associations. After appropriate Bonferroni correction, Xpsmp 2261 (13.34% R2-value), Xipes 0180 (R2-value of 11.40%) and Xipes 0096 (R2-value of 11.38%) were consistently associated with grain iron and zinc content for all the three locations. Favorable alleles and promising lines were identified for across and specific environments. PPMI 1102 had highest number (7) of favorable alleles, followed by four each for PPMFeZMP 199 and PPMI 708 for across the environment performance for both grain Fe and Zn content, while PPMI 1104 had alleles specific to Dharwad for grain Fe and Zn content. When compared with the reference genome Tift 23D2B1-P1-P5, Xpsmp 2261 amplicon was identified in intergenic region on pseudomolecule 5, while the other marker, Xipes 0810 was observed to be overlapping with aspartic proteinase (Asp) gene on pseudomolecule 3. Thus, this study can help in breeding new lines with enhanced micronutrient content using marker-assisted selection (MAS) in pearl millet leading to improved well-being especially for women and children

Towards defining heterotic gene pools using SSR markers in pearl millet [Pennisetum glaucum (L.) R. Br.]

Pearl millet is a climate resilient crop and the most widely grown millet worldwide. In a maiden attempt to identify potential heterotic groups for grain yield in pearl millet, a total of 88 polymorphic SSR markers were used to genotype 343 hybrid parental lines of pearl millet. The SSR markers generated a total of 532 alleles with a mean value of 6.05 alleles per locus, mean gene diversity of 0.55, and an average PIC of 0.50. Out of 532 alleles, 443 (83.27%) alleles were contributed by B- lines with a mean of 5.03 alleles per locus. R- lines contributed 476 alleles (89.47%) with a mean of 5.41, while 441 (82.89%) alleles were shared commonly between B- and R- lines. The gene diversity and PIC were high among R- lines (0.55 and 0.50) than B- lines (0.49 and 0.44) revealed that R- lines were more diverse than B- lines. The unweighted neighbor-joining tree based on simple matching dissimilarity matrix obtained from SSR data clearly differentiated B- lines into 10 sub-clusters (B1, B2, B3, B4, B5, B6, B7, B8, B9 and B10), and Rlines into 11 sub-clusters (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10 and R11). The parents, three checks and 99 hybrids generated by crossing between representative lines of each of the B- cluster with that of each of the R- cluster were evaluated in line ? tester design over three environments. Based on pooled mean performance, the cross combinations generated between clusters B1 and R3, B2 and R4, B3 and R5, B4 and undetermined cluster, B5 and 11R, B6 and R3, B8 and R4, B9 and R7 and B10 and R5 had shown higher grain yield per plant compared to their counterparts. Based on per se performance, high sca effects and standard heterosis over superior check, F1s generated from crosses between representatives of groups B3 and B10 with representative of group R5 resulted in best heterotic combinations for grain yield. These represent putative heterotic gene pools in pearl millet.publishersversionPeer reviewe

Combining ability and heterosis studies for grain iron and zinc concentrations in pearl millet [Cenchrus americanus (L). Morrone]

Iron (Fe) and zinc (Zn) deficiency has been identified as a major food-related health issue, affecting two billion people globally. Efforts to enhance the Fe and Zn content in food grains through plant breeding are an economic and sustainable solution to combat micronutrient deficiency in resource-poor populace of Asia and Africa. Pearl millet, Cenchrus americanus (L). Morrone, considered as a hardy nutri-cereal, is the major food crop for millions of people of these nations. As an effort to enhance its grain mineral content, an investigation was conducted using line × tester analysis to generate information on the extent of heterosis, gene action, combining ability for grain yield potential, and grain mineral nutrients (Fe and Zn). The partitioning of variance attributable to parents indicated that the lines and testers differed significantly for the traits studied. For most of the attributes, hybrids that were superior to the parents in the desired direction in terms of per se performance were identified. The analysis of combining ability variance indicated the preponderance of both additive and non-additive genetic effects. Thus, reciprocal recurrent selection can be used to develop a population with high–grain Fe and Zn contents. The Fe and Zn content in grain exhibited a highly significant and positive association between them, whereas the Fe and Zn contents individually showed a negative, albeit weak, correlation with grain yield and a moderate positive relation with grain weight. This indicates that mineral nutrient contents in grains can be improved without significant compromise on yield. The consistency of these trends across the environment suggests that these findings could be directly used as guiding principles for the genetic enhancement of Fe and Zn grain content in pearl millet

Genomic resources in plant breeding for sustainable agriculture

Climate change during the last 40 years has had a serious impact on agriculture and threatens global food and nutritional security. From over half a million plant species, cereals and legumes are the most important for food and nutritional security. Although systematic plant breeding has a relatively short history, conventional breeding coupled with advances in technology and crop management strategies has increased crop yields by 56 % globally between 1965-85, referred to as the Green Revolution. Nevertheless, increased demand for food, feed, fiber, and fuel necessitates the need to break existing yield barriers in many crop plants. In the first decade of the 21st century we witnessed rapid discovery, transformative technological development and declining costs of genomics technologies. In the second decade, the field turned towards making sense of the vast amount of genomic information and subsequently moved towards accurately predicting gene-to-phenotype associations and tailoring plants for climate resilience and global food security. In this review we focus on genomic resources, genome and germplasm sequencing, sequencing-based trait mapping, and genomics-assisted breeding approaches aimed at developing biotic stress resistant, abiotic stress tolerant and high nutrition varieties in six major cereals (rice, maize, wheat, barley, sorghum and pearl millet), and six major legumes (soybean, groundnut, cowpea, common bean, chickpea and pigeonpea). We further provide a perspective and way forward to use genomic breeding approaches including marker-assisted selection, marker-assisted backcrossing, haplotype based breeding and genomic prediction approaches coupled with machine learning and artificial intelligence, to speed breeding approaches. The overall goal is to accelerate genetic gains and deliver climate resilient and high nutrition crop varieties for sustainable agriculture

Development of a High Quality, Rapid, Efficient and Economical DNA Extraction Protocol from Climate Resilient Pearl Millet Crop Without Liquid Nitrogen

Extraction of good quality genomic deoxyribonucleic acid (DNA) from plants is a major prerequisite for molecular biology experiments. An efficient genomic DNA protocol must be simple, fast and cost effective with high yield and purity. Presence of polyphenols, polysaccharides and secondary metabolites in some plants hamper with DNA extraction making it a very laborious, difficult and time consuming procedure. Here, we portrayed a modified protocol based on the cetyl trimethyl ammonium bromide (CTAB) method to isolate DNA from climate resilient pearl millet leaf tissues having higher amount of polysaccharides. It also excludes the use of expensive chemicals and equipments like proteinase K, liquid nitrogen and tissue lyser. This method includes extraction of DNA using a buffer (pH 8.0) containing 200 mM Tris-HCl, 20 mM ethylenediamine tetracetic acid (EDTA),1.4 M NaCl, 2% CTAB, 2% sodium dodecyl sulphate (SDS) and 1.0 % β-mercaptoethanol followed by purification of DNA with phenol, chloroform, isoamyl alcohol and finally precipitation of DNA by sodium acetate and isopropanol. Good quality genomic DNA with sharp and clear bands was obtained from 48 pearl millet genotypes using this protocol. The yield of DNA varied from 105.2 to 328.3 ng/μl. The purity of DNA sample ranged from 1.74 to 1.95 based on the absorbance at A260/A280 ratio indicating that it’s free from ribonucleic acid (RNA) and protein contamination. PCR analysis using simple sequence repeat (SSR) primers exhibited consistent and reliable amplification products ranging from 150 to 650 bp.This study reveals a fast, simple, efficient, specific, reproducible, reliable and cost effective method for extraction of DNA from small to large number of plant samples amenable to PCR amplification and could be stored for longer duration

Molecular Characterization of Drought Tolerant Genotypes of Pearl Millet [Pennisetum glaucum (L.) R. Br.] for A1 Zone

Pearl millet is a widely grown, climate resilient rainfed cereal crop cultivated on 29 million ha in the arid and semi-arid tropical regions of Asia and Africa accounting for almost half of global millet production. It is useful for minimizing the adverse effect of climate change, hence facilitating income and food security among farming communities. It has deep root system and exhibit climate-resilient features including adaptation to a wide range of ecological conditions, less irrigational requirements, better growth and productivity in low nutrient input conditions, less dependent on synthetic fertilizers and minimum vulnerability to environmental stresses and thus can survive in harsh climatic conditions, less fertile soil under water scarcity. Breeding of drought tolerant varieties and selecting genotypes for better water use efficiency is important in pearl millet to mitigate the changing climatic scenario. In this study, 24 genotypes of pearl millet which are drought tolerant and specific for A1 zone were characterized using 15 drought specific SSR primers. All the 15 SSRs amplified products of varying sizes ranging between 90-550 bp. A total of 40 alleles were obtained in this study and the number of alleles per locus varied between 2 to 5 with an average of 2.67 alleles. Polymorphic Information Content (PIC) varied from 0.34 to 0.76 with an average of 0.53 PIC value. This study will be useful for developing high yielding, dual purpose cultivars for low rainfall areas i.e. A1 zone and increasing pearl millet productivity.&nbsp