International Crops Research Institute for the Semi-Arid Tropics
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Metabolic pathway responsive gene encoding enzyme anchored EST–SSR markers based genetic and population assessment among Capsicum accessions
No full textGene encoding enzyme based EST–SSR markers are more potent or functional marker system to evaluate astounding genetic and structural differentiation in plants. It is very useful in shaping divergences in metabolic fingerprinting, ecological interactions, conservation and adaptation among plants. Therefore, gene encoding enzyme mediated EST–SSR markers system were used presently to evaluate genetic and population structure among 48 Capsicum accessions. Total of 35 gene encoding enzyme based EST–SSR markers was used and generated 184 alleles at 35 loci with an average of 5.25 alleles per locus. The average value of polymorphic information content, marker index and discriminating power was 0.40, 0.232, and 0.216 respectively which revealed noteworthy degree of marker efficacy and their competency was further supported by primer polymorphism (93.57%) and cross transferability (44.52%). A significant genetic variability (Na = 1.249, Ne = 1.269, I = 0.247, He = 0.163, and uHe = 0.183) was identified among the Capsicum accession using EST–SSR markers. The mean value for Nei gene diversity, total species diversity (Ht), and diversity within population (Hs) were 0.277, 0.240 and 0.170 respectively. The coefficient of gene differentiation (Gst) was 0.296 indicating significant genetic differentiation within the population and Gene flow (Nm) was 1.189, which reflect a constant gene flow among populations. AMOVA revealed more genetic differentiation within the population which is similarly supported by principal coordinate analysis among the different Capsicum population. Thus, gene encoding enzyme based EST–SSR markers represent a potent system for estimation of genetic and structural relationship and is helpful for estimation of relationships or variations studies in plants
Multiplexed Host-Induced Gene Silencing of Aspergillus flavus Genes Confers Aflatoxin Resistance in Groundnut
Get PDFAflatoxins are immunosuppressive and carcinogenic secondary metabolites, produced by the filamentous ascomycete Aspergillus flavus, that are hazardous to animal and human health. In this study, we show that multiplexed host-induced gene silencing (HIGS) of Aspergillus flavus genes essential for fungal sporulation and aflatoxin production (nsdC, veA, aflR, and aflM) confers enhanced resistance to Aspergillus infection and aflatoxin contamination in groundnut (<20 ppb). Comparative proteomic analysis of contrasting groundnut genotypes (WT and near-isogenic HIGS lines) supported a better understanding of the molecular processes underlying the induced resistance and identified several groundnut metabolites that might play a significant role in resistance to Aspergillus infection and aflatoxin contamination. Fungal differentiation and pathogenicity proteins, including calmodulin, transcriptional activator-HacA, kynurenine 3-monooxygenase 2, VeA, VelC, and several aflatoxin pathway biosynthetic enzymes, were downregulated in Aspergillus infecting the HIGS lines. Additionally, in the resistant HIGS lines, a number of host resistance proteins associated with fatty acid metabolism were strongly induced, including phosphatidylinositol phosphate kinase, lysophosphatidic acyltransferase-5, palmitoyl-monogalactosyldiacylglycerol Δ-7 desaturase, ceramide kinase-related protein, sphingolipid Δ-8 desaturase, and phospholipase-D. Combined, this knowledge can be used for groundnut pre-breeding and breeding programs to provide a safe and secure food supply
RNA Pol III promoters—key players in precisely targeted plant genome editing
Get PDFThe clustered regularly interspaced short palindrome repeat (CRISPR)/CRISPR-associated protein Cas) system is a powerful and highly precise gene-editing tool in basic and applied research for crop improvement programs. CRISPR/Cas tool is being extensively used in plants to improve crop yield, quality, and nutritional value and make them tolerant to environmental stresses. CRISPR/Cas system consists of a Cas protein with DNA endonuclease activity and one
CRISPR RNA transcript that is processed to form one or several short guide RNAs that direct Cas9 to the target DNA sequence. The expression levels of Cas proteins and gRNAs significantly influence the editing efficiency of CRISPR/Cas-mediated genome editing. This review focuses on insights into RNA Pol III promoters and their types that govern the expression levels of sgRNA in the CRISPR/Cas system. We discussed Pol III promoters structural and functional characteristics and their comparison with Pol II promoters. Further, the use of synthetic promoters to increase the targeting efficiency and overcome the structural, functional, and expressional limitations of RNA Pol III promoters has been discussed. Our review reports various studies that illustrate the use of endogenous U6/U3 promoters for improving editing efficiency in plants and the
applicative approach of species-specific RNA pol III promoters for genome editing in model crops like Arabidopsis and tobacco, cereals, legumes, oilseed, and horticultural crops. We further highlight the significance of optimizing these species-specific promoters’ systematic identification and validation for crop improvement and biotic and abiotic stress tolerance through CRISPR/Cas mediated genome editing
Bacteria-Premised Nanobiopesticides for the Management of Phytopathogens and Pests
Get PDFRising awareness of the risks regarding chemical formulations and the surging need for eco-friendly inputs in
sustainable agriculture have driven the use of bacterial biocontrol agents to the frontline of plant protection. Bacterial biocontrol agents (BBCAs) have been preferred as feasible alternatives to synthetic formulations due to their increased specificity and safety. Nanotechnology has facilitated the better addressing of product development and performance concerns related to BBCAs. Leveraging nanotechnology in the synthesis of novel nanomaterials with amended properties at the nanoscale has offered efficient
and ecologically sound nanoformulations such as nanobiopesticides. The nanobiopesticides of bacterial origin, known as bacteria premised nanobiopesticides (B-NBPs), are efficient alternatives to agrochemicals. The B-NBPs include living or nonliving bacterial nanoformulations or nanoparticles synthesized using bacteria (BNPs) as the nanofactories. The B-NBPs were synthesized using high-pressure homogenization (HPH), jet milling, and hammer milling, giving rise to competent bacterial nanoformulations of size ranging from 250 to 500 nm. Following an overview of bacteria-based nanobiopesticides (B-NBPs) employed to prevent/treat plant diseases, the article highlights the role of BBCA’s role in plant protection as well as its antagonistic mechanisms. Further, the concept of B-NBPs, concentrating on Bacillus thuringensis-driven forms, is reviewed. The review then briefly explains the significance of BNPs in plant infection management. Finally, the concerns related to the efficacy of B-NBPs along with the prospects are also described
Modelling the impact of climate change on agriculture in West Africa
No full textThe overall objective of this chapter is to highlight the manner in which climate change continues to be a major challenge to agricultural development and productivity in West Africa. In particular, the current state of knowledge and understanding of the West African climate, and the changes in patterns and trends that have occurred over the years, is discussed. The chapter also presents the tools (especially models) that are available as well as those still required to assess the impact of climate change on agriculture in the region.
This chapter begins with an overview of West Africa as a region, followed by an overview of West African climatic conditions. The chapter then provides a meta-analysis of studies investigating the effects of climate change on the
productivity of cereals and legumes in West Africa. It also highlights challenges in modelling the varied and distinctive characteristics of West African farming
systems as well as potential adaptation options. The next section reviews the impact of climate change on livestock production, followed by a brief section on integrated climate change impact assessment. The chapter ends with future developments and links to further reading
Functional groups and mineralization kinetics of soil organic matter under contrasting hydro-thermal regimes under conservation agriculture-based rice–wheat system in eastern Indo-Gangetic Plains
No full textSoil organic carbon (SOC) sequestration is important to counteract anthropogenic climate change at the global level. Studying the effect of conservation agriculture (CA) on SOC dynamics in the presence of two distinctively different
hydro-thermal regimes across the year in rice–wheat (RW) systems in eastern Indo-Gangetic Plains (E-IGP) is of topical interest. The stabilization mechanism of soil organic matter (SOM), and its effect on C mineralization kinetics in these conditions is not well understood. We collected soil samples from six combinations of CA and conventional farming in an ongoing experiment at CIMMYT-Borlaug Institute for South Asia, Bihar, India. CA enhanced SOC, specifically labile C, while decreasing mineral N, as a result of encapsulation/assimilation in aggregates/microbial biomass. Humic acids registered characteristic Fourier
transform infrared (FTIR) peaks at 3200–3600 cm−1, 2920–2930
cm−1, 1645–1655 cm−1 and 1220–1240 cm−1, and displayed lesser degree of humification, aromaticity and redox status under CA. SOC and N mineralization were studied in two different hydro-thermal regimes pertaining to rice (submergence, 35°C; SM35) and wheat (field capacity, 25°C; FC25) growing periods of E-IGP. SM35 displayed temperature-mediated higher decay of SOC. Decay constants of C
mineralization were lesser under CA compared with CT. CA promoted higher SOM stability, evidenced by lower decay rates of SOC and N, attributed to (1) better protection of SOM in well-aggregated soil structure and (2) an excess supply of fresh crop residues ensuring higher rate of SOM formation than its decay. Practising CA in E-IGP is imperative towards C-neutral agriculture, especially in
the impending global warming scenario
Spatially differentiated nitrogen supply is key in a global food–fertilizer price crisis
Get PDFA regional geopolitical conflict and sudden massive supply disruptions have revealed vulnerabilities in our global fuel–fertilizer–food nexus. As nitrogen (N) fertilizer price spikes threaten food security, differentiated responses are required to maintain staple cereal yields across over- and underfertilized agricultural systems. Through integrated management of organic and inorganic N sources in high- to low-input cereal production systems, we estimate potential total N-fertilizer savings of 11% in India, 49% in Ethiopia and 44% in Malawi. Shifting to more cost-effective, high-N fertilizer (such as urea), combined with compost and integration of legumes, can optimize N in N-deficient systems. Better targeted and more efficient N-fertilizer use will benefit systems with surplus N. Geospatially differentiated fertilization strategies should prioritize high-N fertilizer supply to low-yield, N-deficient locations and balanced fertilization of N, P, K and micronutrients in high-yield systems. Nationally, governments can invest in extension and realign subsidies to enable and incentivize improved N management at the farm level
ICRISAT AND WFP: India Working Paper Effects of Climate Change on Food Security and Nutrition in India A Systematic Review
Get PDFClimate change is probably the most complex and
intractable environmental challenge faced by the
world today and is increasingly being recognized as a
potent threat to agriculture in general and specific to food
security (Pattanayak & Kumar, 2014; Mahapatra et al.,
2021). Without a doubt, climate change is occurring and
already has significant impacts through increased climatic
variability, global temperatures, and sea level (Masters
et al., 2010; Sharma et al., 2018). Climate change will
continue to significantly impact agriculture, reflecting the
close link between climate (temperature and precipitation
in particular) and agriculture productivity. These effects
are likely to have the greatest impacts in the low-income
countries of the tropical zones where agricultural
productivity would decrease. Climate variability and
change influence ecosystems, food security, health,
and other domains fundamental to human existence
and well-being (Ghosh-Jerath et al., 2021). An increased
frequency of extreme events, heat stress, droughts, and
floods negatively impact crop yields (Masters et al., 2010).
These negative impacts of climate change on agricultural
and food production has got the attention of the global
research community to undertake rigorous research in
this area (Joshi et al., 2016)
Temporal Changes in Minimum and Maximum Temperatures at Selected Locations of Southern Africa
Get PDFAgriculture is threatened by ever increasing temperatures and this trend is predicted to continue for the near and distant future. The negative impact of rising temperatures on agri-food systems is also compounded by the erratic and highly variable rainfall in most parts of southern Africa. Minimum and maximum temperatures’ variability and trend analysis were undertaken using daily time series data derived from 23 meteorological stations spread across Malawi, Mozambique, South Africa and Zimbabwe. The modified Mann–Kendall and Theil–Sen slope models were used to assess temperature trends and their magnitudes. Temperature varied with location and minimum temperature was more variable than maximum temperature. Semi-arid regions had higher variation in minimum temperature compared to humid and coastal environments. The results showed an upward trend in minimum (0.01–0.83 °C over a 33–38 year period) and maximum (0.01–0.09 °C over a 38–57 year period) temperatures at 9 and15 locations, respectively. A downward trend in minimum temperature (0.03–0.20 °C over 38–41 years) occurred in South Africa at two locations and Dedza (Malawi), while a non-significant decline in maximum temperature (0.01 °C over 54 years) occurred at one location in coastal dry sub-humid Mozambique. The results confirm the increase in temperature over 33–79 years, and highlight the importance of including temperature when designing climate change adaption and mitigation strategies in southern Africa and similar environments
EVALUATION OF FERMENTATION PROGRESS DURING STORAGE OF MILLET STOVERS SILAGE BASED ON pH-INDICATORS
Get PDFThis study aimed at evaluating the fermentation levels of pearl millet [Pennisetum Glaucum (L.) R. Br] stovers silage during storage based on pH evolution. A completely randomized experimental design in a 6×2×2 factorial scheme with three replications for each treatment was used to evaluate three factors (6 cultivars, 2 different cutting stages, and with or without salt addition to the cultivars). The silages were prepared in plastic bags and stored for 60 days at room temperature. The results revealed that the pH values of the treatments were significantly (P<0.05) higher on the first day than in the other periods and a rapid drop in pH, with significant differences (P<0.05), to levels below 4 was obtained on the third day of storage for the majority of local Sadoré and Siaka Millet silages (Niger). Four types of pH evolution were recorded and the variation was statistical significant among cultivars. Also, analysis of the relationships between pH, chemical composition parameters and In Vitro Digestibiliy of Organic Matter (IVDOM) showed that increasing pH values were associated with increasing Dry Matter content of stovers before silage (DM_BE), Dry Matter content of silages (DM_S), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Acid Detergent Lignin (ADL) values and decreasing Crude Protein (CP), Metabolizable Energy (ME), IVOMD, and Ash values. However, the pH values obtained for all silages showed that all the millet stovers used were suitable for silage. At the maturity stage, it is thus possible to use the grain for human consumption and to ensile the stovers for animal feed. This study also shows that monitoring the pH in the silo makes it possible to evaluate the quality of the fermentations to avoid losses on the farms