Aquaporins (AQPs) significantly impact the regulation of water transport and can modulate traits related to tolerance to abiotic stress. Our previous study confirmed that SbTIP2;1 is expressed in response to abiotic stress conditions in sorghum. This study examined the role of the SbTIP2;1 gene in transgenic tobacco plants. The SbTIP2;1 gene has been cloned into the Gateway-compatible plant expression vector pMDC100, driven by the CaMV35S promoter, and subsequently transferred into tobacco plants using the leaf-disc method. Tobacco plants expressing the SbTIP2;1 gene were propagated to the T2 generation and exposed to increasing drought, salinity, heat, and cold stresses. Water use traits, including transpiration, canopy temperature (CT), canopy temperature difference (CTD), and expression profiles, showed significant differences among transgenic tobacco events and wild-type (WT) plants under abiotic stress treatments. Overexpression of the SbTIP2;1 gene in roots and leaves showed that transgenic plants regulate transpiration differently than WT under drought and heat stress, enabling more water conservation and/or better leaf cooling. Transgenics showed cooler canopy temperature (CT) and higher canopy temperature depression (CTD) compared to WT, along with significant upregulation of SbTIP2;1 under stress, underscoring its role in improving adaptation to drought and heat. Therefore, the sorghum AQP gene SbTIP2;1 may serve as a promising candidate for enhancing abiotic stress tolerance in crops.
A major issue in India is the sustainability of agriculture due to population expansion, climate change, and mounting demands on natural resources. This review paper explores how millet crops might help India's agriculture become more sustainable. A family of small-seeded grains known as millets has been cultivated for millennia and has various distinctive qualities that make them appropriate for sustainable farming methods. The paper looks at the advantages of growing millet from an environmental, economic, and social standpoint, as well as the difficulties and potential solutions for their broad adoption. Additionally, millet contributes to improved soil health, water resource conservation, mitigation against climate change, and strengthening rural communities. The review's conclusions underscore the important part millet crops can play in achieving agricultural sustainability and offer suggestions for how politicians, academics, and farmers should encourage the development of millet crops.
Aflatoxins 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.
Technologies and innovations are critical for addressing the future food system needs where genetic resources are an essential component of the change process. Advanced breeding tools like “genome editing” are vital for modernizing crop breeding to provide game-changing solutions to some of the “must needed” traits in agriculture. CRISPR/Cas-based tools have been rapidly repurposed for editing applications based on their improved efficiency, specificity and reduced off-target effects. Additionally, precise gene-editing tools such as base editing, prime editing, and multiplexing provide precision in stacking of multiple traits in an elite variety, and facilitating specific and targeted crop improvement. This has helped in advancing research and delivery of products in a short time span, thereby enhancing the rate of genetic gains. A special focus has been on food security in the drylands through crops including millets, teff, fonio, quinoa, Bambara groundnut, pigeonpea and cassava. While these crops contribute significantly to the agricultural economy and resilience of the dryland, improvement of several traits including increased stress tolerance, nutritional value, and yields are urgently required. Although CRISPR has potential to deliver disruptive innovations, prioritization of traits should consider breeding product profiles and market segments for designing and accelerating delivery of locally adapted and preferred crop varieties for the drylands. In this context, the scope of regulatory environment has been stated, implying the dire impacts of unreasonable scrutiny of genome-edited plants on the evolution and progress of much-needed technological advances.
Pearl millet [Pennisetum glaucum (L) R. Br.] is an important cereal crop of the semiarid tropics, which can withstand prolonged drought and heat stress. Considering an active involvement of the aquaporin (AQP) genes in water transport and desiccation tolerance besides several basic functions, their potential role in abiotic stress tolerance was systematically characterized and functionally validated. A total of 34 AQP genes from P. glaucum were identified and categorized into four subfamilies, viz., plasma membrane intrinsic proteins (PIPs), tonoplast intrinsic proteins (TIPs), nodulin-26-like intrinsic proteins (NIPs), and small basic intrinsic proteins (SIPs). Sequence analysis revealed that PgAQPs have conserved characters of AQP genes with a closer relationship to sorghum. The PgAQPs were expressed differentially under high vapor pressure deficit (VPD) and progressive drought stresses where the PgPIP2;6 gene showed significant expression under high VPD and drought stress. Transgenic tobacco plants were developed by heterologous expression of the PgPIP2;6 gene and functionally characterized under different abiotic stresses to further unravel their role. Transgenic tobacco plants in the T2 generations displayed restricted transpiration and low root exudation rates in low- and high-VPD conditions. Under progressive drought stress, wild-type (WT) plants showed a quick or faster decline of soil moisture than transgenics. While under heat stress, PgPIP2;6 transgenics showed better adaptation to heat (40°C) with high canopy temperature depression (CTD) and low transpiration; under low-temperature stress, they displayed lower transpiration than their non-transgenic counterparts. Cumulatively, lower transpiration rate (Tr), low root exudation rate, declined transpiration, elevated CTD, and lower transpiration indicate that PgPIP2;6 plays a role under abiotic stress tolerance. Since the PgPIP2;6 transgenic plants exhibited better adaptation against major abiotic stresses such as drought, high VPD, heat, and cold stresses by virtue of enhanced transpiration efficiency, it has the potential to engineer abiotic stress tolerance for sustained growth and productivity of crops.
ABSTRACT Commercialization and utilization of pearl millet ( Pennisetum glaucum L.) by consumers and processing industry is constrained due to rapid onset of rancidity in its milled flour. We studied the underlying biochemical and molecular mechanisms to flour rancidity in contrasting inbreds under 21-day accelerated storage. Rapid TAG decrease was accompanied by FFA increase in high rancidity genotype compared to the low rancidity line, that maintained lower FFA and high TAG levels, besides lower headspace aldehydes. DNA sequence polymorphisms observed in two lipase genes revealed loss-of-function mutations that were functionally confirmed in yeast system. We outline a direct mechanism for mutations in these key TAG lipases in pearl millet and the protection of TAG and fatty acids from hydrolytic and oxidative rancidity respectively,. Natural variation in the PgTAGLip1 and PgTAGLip2 genes may be selected through marker assisted breeding or by precision genetics methods to develop hybrids with improved flour shelf life.
Potato is one of the cheapest sources of energy-rich natural nutritive foods containing ample starch, sugar and protein, and carotene, phenol and ascorbic acid in minute quantities.Potato is an important vegetable and staple food crop in India after rice and wheat.A greenhouse experiment on potato, in which ten kilograms of soil was placed in a polyethene-lined earthen pot, was conducted on each of the soils of twenty-three different locations.The NPK recommended dose was applied at the rate of 200, 150 and 150 kg ha -1 in the form of G.R. grade reagent quality of Urea, Single Super Phosphate and Muriate of Potash to avoid any Boron (B) addition through them.The half N and full quantities P and K were applied as basal doses, and the rest of N was applied in two equal split doses -one at 20 and another at 35 days after sowing.The treatment combination of B application in the form of Boric Acid (H 3 BO 3) reagent grade in the pot experiment was like the following: B 0 : 0 kg B ha -1 , B 1.0 : 1 kg B ha -1 , B2 .0: 2kg B ha -1 , B 4.0 : 4 kg B ha -1 .The critical limit of B in soil for the B nutrition of potato plants was determined following both the graphical and statistical methods of Cate and Nelson (1965 and 1971).We used Bray % Yield (BPY) of potato (leaf and tuber) and available B concentration of initial soils (before sowing) of 15 sites for estimating the critical value of available B. The result indicated that in respect of potato cultivation, B concentration below 0.48 mg kg -1 would show a deficiency of B. Below this concentration of B would be considered as a deficiency of B concentration in potato shoot which would influence to reduce yield and quality of potato.
Pearl millet is an important cereal crop of semi-arid regions since it is highly nutritious and climate resilient. However, pearl millet is underutilized commercially due to the rapid onset of hydrolytic rancidity of seed lipids post-milling. We investigated the underlying biochemical and molecular mechanisms of rancidity development in the flour from contrasting inbred lines under accelerated aging conditions. The breakdown of storage lipids (triacylglycerols; TAG) was accompanied by free fatty acid accumulation over the time course for all lines. The high rancidity lines had the highest amount of FFA by day 21, suggesting that TAG lipases may be the cause of rancidity. Additionally, the high rancidity lines manifested substantial amounts of volatile aldehyde compounds, which are characteristic products of lipid oxidation. Lipases with expression in seed post-milling were sequenced from low and high rancidity lines. Polymorphisms were identified in two TAG lipase genes (PgTAGLip1 and PgTAGLip2) from the low rancidity line. Expression in a yeast model system confirmed these mutants were non-functional. We provide a direct mechanism to alleviate rancidity in pearl millet flour by identifying mutations in key TAG lipase genes that are associated with low rancidity. These genetic variations can be exploited through molecular breeding or precision genome technologies to develop elite pearl millet cultivars with improved flour shelf life.
Smallholder farmers across the drylands of Africa and Asia face similar challenges—low agricultural productivity, lack of profitable alternative livelihoods, lack of access to technology, capital, and markets, low resilience to face climate change and other issues. The challenge before African countries is to transform agriculture from the predominantly subsistence orientated smallholder systems to more sustainable, efficient and market-orientated ones which create jobs for the youth on a rapidly growing continent. International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) provides a global platform for regular knowledge exchange between agricultural research and development professionals from Africa and India. We share some of our experiences over four decades of work in Africa and India mainly through: ICRISAT uses crop improvement as a core approach to providing crop varieties that are adapted to the ecologies of sub-Saharan Africa. These include varieties that are resistant to a wide range of biotic and abiotic stresses and acceptable by farmers and markets. These successful crop improvement programmes have been underpinned by the genetic resources available in the ICRISAT gene banks in India and Africa, resulting in the development and release of over 452 varieties and hybrids of cereals and legumes in 34 African countries. Agri-based entrepreneurship promotion is another key approach towards improving the economic prosperity of smallholder farmers in the region and harnessing Africa’s youth bulge. Through its Agribusiness and Innovation Platform (AIP), ICRISAT has developed and implemented novel agribusiness entrepreneurship promotion models in twelve African countries in partnership with a diverse set of stakeholders from the agricultural and rural development ecosystem. Other areas of intervention which are not discussed in this paper include the natural resource management programmes that have created knowledge, technologies and practices that enable resilience in the farming system. In addition, the socio-economic programmes are key to understanding the potential for adoption of technologies including new varieties.
Late embryogenesis abundant (LEA) genes display distinct functions in response to abiotic stresses in plants. In pearl millet (Pennisetum glaucum L.), a total of 21 PgLEA genes were identified and classified into six groups including LEA1, LEA2, LEA3, LEA5, LEA7, and dehydrins (DHN). Open reading frames (ORFs) of PgLEAs range from 291 bp (PgLEA1-1) to 945 bp (PgLEA2-11) and distributed randomly among the seven chromosomes. Phylogenetic analysis revealed that all PgLEA proteins are closely related to sorghum LEA proteins. The PgLEAs were found to be expressed differentially under high progressive vapor pressure deficit (VPD), PgLEA7 was significantly expressed under high VPD and was selected for functional validation. In silico analysis of the PgLEA promoter regions revealed abiotic stress-specific cis-acting elements such as ABRE, CCAAT, MYBS, and LTRE. Based on the type of motifs, PgLEAPC promoter (758 bp), its deletion 1 (PgLpd1, 349 bp) and deletion 2 (PgLpd2, 125 bp) were cloned into the plant expression vector pMDC164 having the promoter-less uidA gene. All the three plant expression vectors were introduced into tobacco through Agrobacterium tumefaciens-mediated transformation to obtain T-1 and T-2 generations of transgenic plants. Based on expression of the uidA gene, tissue-specific expression was observed in mature stems, roots and seedlings of PgLEAPC and PgLpd1 carrying transgenics only. While the transgenic PgLEAPC plants displayed significantly higher uidA expression in the stem and root tissues under salt, drought, heat, and cold stresses, very low or no expression was observed in PgLpd1 and PgLpd2 transgenics under the tested stress conditions. The results of this study indicate that the complete promoter of PgLEAPC plays a role in developing abiotic stress tolerance in plants.
Neurodegenerative disorders are characterized by a collapse in proteostasis, as shown by the accumulation of insoluble protein aggregates in the brain. Proteostasis involves a balance of protein synthesis, folding, trafficking, and degradation, but how aggregates perturb these pathways is unknown. Using Parkinson’s disease (PD) patient midbrain cultures, we find that aggregated α-synuclein induces endoplasmic reticulum (ER) fragmentation and compromises ER protein folding capacity, leading to misfolding and aggregation of immature lysosomal β-glucocerebrosidase. Despite this, PD neurons fail to initiate the unfolded protein response, indicating perturbations in sensing or transducing protein misfolding signals in the ER. Small molecule enhancement of ER proteostasis machinery promotes β-glucocerebrosidase solubility, while simultaneous enhancement of trafficking improves ER morphology, lysosomal function, and reduces α-synuclein. Our studies suggest that aggregated α-synuclein perturbs the ability of neurons to respond to misfolded proteins in the ER, and that synergistic enhancement of multiple proteostasis branches may provide therapeutic benefit in PD.
Aspergillus flavus is an opportunistic fungal pathogen that produces carcinogenic aflatoxin, a serious constraint for food safety and human health. In this study, to better understand the molecular mechanism/s of peanut resistance to A. flavus growth and aflatoxin accumulation, comparative proteomic analysis was performed in two contrasting peanut genotypes, variety JL 24 (susceptible) and its near-isogenic resistant transgenic derivative expressing an alfalfa defensin gene. Several resistance proteins associated with secondary metabolic pathways were strongly induced in the resistant genotypes including phenylalanine ammonia lyase, cinnamic acid-4-hydroxylase, chalcone synthase, resveratrol synthase, flavanone-3-hydroxylase, lipoxygenase, diacylglycerol-glycerol-3-phosphate-3-phosphatidyltransferase, β-ketoacyl-ACP-reductase, monoacylglycerol acyltransferase, and diacylglycerol acyltransferase, indicating their roles in resistance. Besides, several putative susceptibility-associated proteins were revealed providing knowledge on potential candidate target genes for precise breeding interventions for aflatoxin mitigation. This is the first study to demonstrate comparative proteomics analysis in Aspergillus–peanut interaction using contrasting near-isogenic lines to elucidate the underlying molecular mechanisms of resistance.
GBA1 mutations that encode lysosomal β-glucocerebrosidase (GCase) cause the lysosomal storage disorder Gaucher disease (GD) and are strong risk factors for synucleinopathies, including Parkinson's disease and Lewy body dementia. Only a subset of subjects with GBA1 mutations exhibit neurodegeneration, and the factors that influence neurological phenotypes are unknown. We find that α-synuclein (α-syn) neuropathology induced by GCase depletion depends on neuronal maturity, the physiological state of α-syn, and specific accumulation of long-chain glycosphingolipid (GSL) GCase substrates. Reduced GCase activity does not initiate α-syn aggregation in neonatal mice or immature human midbrain cultures; however, adult mice or mature midbrain cultures that express physiological α-syn oligomers are aggregation prone. Accumulation of long-chain GSLs (≥C22), but not short-chain species, induced α-syn pathology and neurological dysfunction. Selective reduction of long-chain GSLs ameliorated α-syn pathology through lysosomal cathepsins. We identify specific requirements that dictate synuclein pathology in GD models, providing possible explanations for the phenotypic variability in subjects with GCase deficiency.
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.
In the present study, the promoter region of the pearl millet heat shock protein 10 (PgHsp10) gene was cloned and characterized. The PgHsp10 promoter (PgHsp10pro) sequence region has all the cis-motifs required for tissue and abiotic stress inducibility. The complete PgHsp10pro (PgHsp10PC) region and a series of 5′ truncations of PgHsp10 (PgHsp10D1 and PgHsp10D2) and an antisense form of PgHsp10pro (PgHsp10AS) were cloned into a plant expression vector (pMDC164) through gateway cloning. All four constructs were separately transformed into tobacco through Agrobacterium-mediated genetic transformation, and PCR-confirmed transgenic plants progressed to T1 and T2 generations. The T2 transgenic tobacco plants comprising all PgHsp10pro fragments were used for GUS histochemical and qRT-PCR assays in different tissues under control and abiotic stresses. The PgHsp10PC pro expression was specific to stem and seedlings under control conditions. Under different abiotic stresses, particularly heat stress, PgHsp10PCpro had relatively higher activity than PgHsp10D1pro, PgHsp10D2pro and PgHsp10ASpro. PgHsp10pro from a stress resilient crop like pearl millet responds positively to a range of abiotic stresses, in particular heat, when expressed in heterologous plant systems such as tobacco. Hence, PgHsp10pro appears to be a potential promoter candidate for developing heat and drought stress-tolerant crop plants.
Pearl millet is a C4 cereal crop that grows in arid and semi-arid climatic conditions with the remarkable abiotic stress tolerance. It contributed to the understanding of stress tolerance not only at the physiological level but also at the genetic level. In the present study, we functionally cloned and characterized three abiotic stress-inducible promoters namely cytoplasmic Apx1 (Ascorbate peroxidase), Dhn (Dehydrin), and Hsc70 (Heat shock cognate) from pearl millet. Sequence analysis revealed that all three promoters have several cis-acting elements specific for temporal and spatial expression. PgApx pro, PgDhn pro and PgHsc70 pro were fused with uidA gene in Gateway-based plant transformation pMDC164 vector and transferred into tobacco through leaf-disc method. While PgApx pro and PgDhn pro were active in seedling stages, PgHsc70 pro was active in stem and root tissues of the T2 transgenic tobacco plants under control conditions. Higher activity was observed under high temperature and drought, and less in salt and cold stress conditions. Further, all three promoters displayed higher GUS gene expression in the stem, moderate expression in roots, and less expression in leaves under similar conditions. While RT-qPCR data showed that PgApx pro and PgDhn pro were expressed highly in high temperature, salt and drought, PgHsc70 pro was fairly expressed during high temperature stress only. Histochemical and RT-qPCR assays showed that all three promoters are inducible under abiotic stress conditions. Thus, these promoters appear to be immediate candidates for developing abiotic stress tolerant crops as these promoter-driven transgenics confer high degree of tolerance in comparison with the wild-type (WT) plants.
Hydrogen sulfide (H2S) is an emerging, multitasking cell signaling molecule in plants often considered as third gasotransmitter after nitric oxide and carbon monoxide. Accumulating evidence has imparted many biological functions to H2S including seed germination, plant growth, and physiology as well as the moderation of defense responses. While its production in plants during sulfur assimilation has been known for quite a while, our knowledge of the complete synthesis and signaling role of H2S only started emerging recently. Several recent reports have pointed the controlled release of H2S in plant cells as a crucial signal for the survival under abiotic stress conditions. Besides, H2S priming also induce systemic resistance against a range of abiotic stress conditions majorly by reestablishment of redox homeostasis, maintaining ion balance, enhancing osmolyte accumulation, regulating gene expression. Additionally, mounting evidence indicates that H2S signaling interacts with plant hormones, hydrogen peroxide, nitric oxide, and other signaling molecules. However, current research on the role of H2S mediated post translational modification, S‐sulfhydration, and its direct effects on the activity of proteins is still in its infancy in plants. The growing importance of H2S and our insufficient knowledge on its functions and targets in plants calls for further detailed analyses at the physiological, biochemical and molecular levels before fully accepting its signaling roles in plant stress tolerance.