Sorghum is an annual diploid C 4 plant largely grown for food, fodder and feed purposes. Several insect pests pose major challenges to sorghum production from the seedling stage to maturity, among which the sorghum shoot fly Atherigona soccata (Rondani) is a major pest across Asia, Africa and Mediterranean Europe. Infestation by the pest is prevalent both during rainy and postrainy seasons. The exploitation of host-plant resistance can play a vital role in breeding for resistance to shoot flies. The shoot fly causes significant grain and fodder yield losses in sorghum in semi-arid regions. An integrated approach for host-plant resistance that combines morphological, genetic/molecular and agronomic approaches is key for the management of shoot fly infestations and the subsequent increase in sorghum productivity. To complement traditional breeding approaches, intervention in genomic approaches is required to enhance breeding efficiency. This review focuses on genetic approaches in sorghum for integrating shoot fly resistance and exploring genetic inheritance, variability and trait associations, including shoot fly resistance quantitative trait loci (QTLs).

The occurrence of a global pandemic has been known to mankind for decades. With the advent of Corona virus disease 2019 (COVID-19), a tremendous blow has been felt globally in all sectors of society, including agriculture. Hereby, this chapter gives the most comprehensive details on the overall impact of COVID-19 on the global agriculture and food sector. Firstly, the immediate measures taken to prevent the worldwide spread of the deadly virus included travel restrictions, border closure, and social distancing. The primary response to the pandemic across continents to mitigate the alarming increase in COVID-19 cases also had notable adverse effects on the global economy. It affected the functioning of the food production system as well. Hence, this chapter further covers the overall immediate impacts of the pandemic on food production, food processing, connectivity (transport and distribution), labor availability, and the collapse of the farm systems. Eventually, the grave consequence of the pandemic was reflected in the complete breakdown of the market, retailer, and consumer system. These factors collectively impacted the global economy as agriculture is one of the primary sectors contributing to it. Lastly, the future reforms and innovations required to restore agriculture, food, and the economy are also presented that may help to mitigate the global crisis.

Restoration factors (Rfs) belonging to the pentatricopeptide repeat proteins (PPRs) family play an essential role in plant growth and development including their binding to CMS-associated mitochondrial RNAs leading to fertility restoration. The present study identified 22 mitochondrial-specific PPRs in pigeonpea and explored the underlying mechanisms of restoration of fertility in the A4 CMS system through yeast-three hybrid studies. The identified gene was functionally validated through transgenic expression in Arabidopsis model system and obtained conclusive evidence that the identified Rf-PPR was responsible for fertility restoration. The sub-cellular localization studies implied that the identified Rf-PPR is mitochondrial targeting. The study demonstrated that due to the interaction between mitochondrial CMS mRNA and nuclear Rf-PPR protein, post-transcriptional modification occurred, leading to the inability to translate and accumulate cytotoxic CMS protein resulting in fertility restoration. The study specifically looks into the RNA-protein interaction occurring at the nucleo-cytoplasmic level in the A4 cytoplasm of Cajanus cajanifolius .Highlights The study identifies the restoration of fertility genes corresponding to the CMS-causing orf147 gene.### Competing Interest StatementThe authors have declared no competing interest.* CMS : Cytoplasmic male sterility Col-0 : Columbia-0 DDO/X/A : Double dropout media / X-α-gal/ Aureobasidin A GFP : Green fluorescent protein qRT-PCR : quantitative real-time PCR PPR : Pentatricopeptide repeat protein Rf : Restoration factors WT : Wild type Y3H : Yeast three hybrid system

A comprehensive understanding of the nucleocytoplasmic interactions that occur between genes related to the restoration of fertility and cytoplasmic male sterility (CMS) provides insight into the development of hybrids of important crop species. Modern biotechnological techniques allow this to be achieved in an efficient and quick manner. Heterosis is paramount for increasing the yield and quality of a crop. The development of hybrids for achieving heterosis has been well-studied and proven to be robust and efficient. Cytoplasmic male sterility (CMS) has been explored extensively in the production of hybrids. The underlying mechanisms of CMS include the role of cytotoxic proteins, PCD of tapetal cells, and improper RNA editing of restoration factors. On the other hand, the restoration of fertility is caused by the presence of restorer-of-fertility (Rf) genes or restorer genes, which inhibit the effects of sterility-causing genes. The interaction between mitochondria and the nuclear genome is crucial for several regulatory pathways, as observed in the CMS–Rf system and occurs at the genomic, transcriptional, post-transcriptional, translational, and post-translational levels. These CMS–Rf mechanisms have been validated in several crop systems. This review aims to summarize the nucleo-mitochondrial interaction mechanism of the CMS–Rf system. It also sheds light on biotechnological interventions, such as genetic engineering and genome editing, to achieve CMS-based hybrids.

Advances in biocontrol potentials and fungicide resistance are highly desirable for Trichoderma. Thus, it is profitable to use mutagenic agents to develop superior strains with enhanced biocontrol properties and fungicide tolerance in Trichoderma. This study investigates the N-methyl-n-nitro-N-nitrosoguanidine (NTG) (100 mg/L) induced mutants of Trichoderma asperellum. Six NTG (3 each from 1st & 2nd round) induced mutants were developed and evaluated their biocontrol activities and carbendazim tolerance. Among the mutant N2-3, N2-1, N1 and N2-2 gave the best antagonistic and volatile metabolite activities on inhibition of chickpea F. oxysporum f. sp. ciceri, B. cinerea and R. bataticola mycelium under in vitro condition. Mutant N2-2 (5626.40 μg/ml) showed the highest EC50 value against carbendazim followed by N2-3 (206.36 μg/ml) and N2-1 (16.41 μg/ml); and succeeded to sporulate even at 2000 μg/ml of carbendazim. The biocontrol activity of N2-2 and N2 with half-dose of carbendazim was evaluated on chickpea dry root rot under controlled environment. Disease reduction and progress of the dry root rot was extremely low in T7 (N2-2 + with half-dose of carbendazim) treatment. Further, carbendazim resistant mutants demonstrated mutation in tub2 gene of β-tubulin family which was suggested through the 37 and 183 residue changes in the superimposed protein structures encoded by tub2 gene in N2 and N2-2 with WT respectively. This study conclusively implies that the enhanced carbendazim tolerance in N2-2 mutant did not affect the mycoparasitism and plant growth activity of Trichoderma. These mutants were as good as the wild-type with respect to all inherent attributes.

Orf147, a cytotoxic peptide, has been found to cause cytoplasmic male sterility (CMS) in Cajanus cajanifolius (pigeonpea). In our study, Orf147 was introduced into self-pollinating Cicer arietinum (chickpea) using Agrobacterium-mediated transformation for induction of CMS. The stable integration and expression of the transgene has been assessed through PCR and qRT-PCR analysis. In addition, phenotypic sterility analysis has been performed, considering developmental parameters like flower development, pod formation and flower drop. Transgene inheritance analysis demonstrates that out of the five PCR positive events in the T0 generation, two events have segregated according to the Mendelian segregation ratio (3:1) in the T2 generation. Further, pollen viability test using microscopic analysis confirms the induction of partial CMS in transgenic chickpea. The study holds significant value regarding the heterosis of self-pollinating legumes like chickpea. As a part of the prospect, exploring inducible promoters of species-specific or related legumes would be the next step to developing a two-line hybrid system.

Highly diverse and specific microorganisms have been discovered and studied for wastewater treatment (WWT) and bioremoval of metal contaminants. However, it is noteworthy that due to the evolving environmental conditions, the biochemistry of certain contaminants does not allow biodegradation by microbes. Additionally, active biodegradation by microorganisms can be a relatively gradual process diminishing its efficiency. The population of microorganisms, which possess the potential for bioremediation, often are not large enough to completely curb this menace. This calls for modern technologies to enhance the efficacy and effectiveness of microbes for bioremoval of contaminants. For this purpose, novel strains of microorganisms have been developed with desired characteristics such as regulation of inhibitory enzymes, increase in yield, and efficiency for better bioremediation. Genetically engineered microorganisms (GEMs), however, have limited applications due to the regulatory concerns associated with them. These include stability and toxicity of the introduced genetic material in the environment as well the horizontal transfer of genetic material into indigenous species. However, because of the novelty and efficiency of GEMs it is essential to further explore their potency in enhancing bioremediation by increasing field studies. Along with this, nanobiotechnology (NBT) using microbial-based bioreactors and fuel cells has also shown promise in the development of a sustainable method for WWT. Metagenomics, coupled with bioinformatics, has also emerged as a powerful tool for the detection and analysis of microbes in wastewater. Considering the constantly evolving environmental conditions, it is necessary to continuously put the effort into determining molecular tools for efficient WWT.

Photosynthetic microbes like brown algae, red algae, green-algae and blue-green algae (cyanobacteria) are utilized extensively for various commercial and industrial purposes. However, in recent time, their application has shifted to nanotechnology. The synthesis of metal nanoparticles using algal resources is known as Phyconanotechnology. Due to various advantages of the photosynthetic microbes such as presence of bioactive molecules, scalability, high metal uptake and cultivability, these microbes form ideal sources for nanoparticle synthesis. The green synthesis of nanoparticles is a non-toxic and environment-friendly alternative compared to other hazardous chemical and physical routes of synthesis. Several species of algae are explored for the fabrication of metal and metal oxide nanoparticles. Various physical characterization techniques collectively contribute in defining the surface morphology of nanoparticles and the existing functional groups for bioreduction and stability. A wide range of nanostructured metals like gold, silver, copper, zinc, iron, platinum and palladium are fabricated using algae and cyanobacteria. Due to the unique properties of the phycogenic nanoparticles, biocompatibility and safety aspects, all of these metal nanoparticles have their applications in facets like infection control, diagnosis, drug delivery, biosensing and bioremediation. Herein, the uniqueness of the phycogenic nanoparticles along with their distinctive antibacterial, antifungal, antibiofilm, algaecidal, antiviral, anticancer, antioxidant, antidiabetic, dye degradation, metal removal and catalytic properties are featured. Lastly, this work highlights the various challenges and future perspectives for further exploration of the biogenic metal nanoparticles for development of nanomedicine and environmental remediation in the coming years.

Microbial biosorbents are widely used for the removal of various toxic metals which pose a significant threat to agriculture. Metals like cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, palladium, platinum, and zinc are the predominant metal contaminants in our soils and water which call for instantaneous action to design microbiological techniques for effective bioremediation. The associated anthropogenic activities lead to a significant release of toxic metals into the environment purposely. Various industries related to mining, surface finishing, energy and fuel producing, fertilizer, pesticide, metallurgy, iron and steel, electroplating, electrolysis, paints and ceramic discharge metal laden effluents result in severe environmental pollution and health hazards. An indefinite persistence of heavy metals in the environment is a potential health hazard as it leads to bioaccumulation of toxic metals in the crops that eventually leads to biomagnification upon entering the food chain. This chapter highlights the promises of Bacillus as a potential biosorbent for the effective removal of toxic heavy metals from the environment. Numerous members of the genus Bacillus, like B. subtilis, B. thuringiensis, B. sterothermophilus, B. megaterium, B. cereus, B. pumilus, B. licheniformis, and B. jeotgali have been reported to remove heavy metals most effectively. Diverse functional groups like carboxyl, amino, amide, phosphate, and hydroxyl groups associated to bacterial cell walls which attribute to biosorption capacity have been described herein. Numerous contributing factors like time, temperature, pH, cell density, and agitation are also discussed. Bacillus-mediated biosorption and bioaccumulation is a powerful strategy for the removal of toxic heavy metal stress in order to ensure sustainable agriculture.

Climate change has brought in various stress conditions, and salt stress is one of the major concerns for the current agricultural scenario. Salt stress limits crop productivity as it has various deleterious effects on the plants system such as osmotic, nutritional, and hormonal imbalance. All of this eventually leads to reduced plant growth, low yield, and diminished photosynthetic activity which hampers the overall plant development. Additionally, the growing need to fulfill food security emphasizes the need for innovative technologies which can efficiently decrease the effects of abiotic stress conditions. Nanotechnology has emerged as growing field and has its applications in the agriculture, pharmaceutical, and biomedical industries. In this chapter, the significant role of nanoparticles in alleviating the damaging effects of salt stress is discussed in detail. They induce the adaptive mechanism of the plant and allow for response mechanism which helps the plant to overcome harsh conditions. Nanoparticles of various kinds have been employed for this purpose. This chapter gives a comprehensive view of the different metallic and nonmetallic nanoparticles which are successfully used for inducing tolerance in plants against salt stress.

Nanotechnology plays a critical role in agriculture and its associated management strategies. The emergence of plant pathogens (phytopathogens) across various crops has posed a threat to global food production, food security, and food safety. The existing control techniques, such as chemical application of pesticides and insecticides, have become outdated due to their drawbacks. Such methods for plant disease control come with the added disadvantage of threat to natural microflora and fauna along with imparting toxicity to the environment. This in turn causes risk to human health. Therefore researchers have been looking for safer alternatives that are equally or more efficient and effective in dealing with phytopathogens along with possessing least amount of toxicity. The generation of nanoparticles (NPs) and its application in plant disease management has intrigued researchers and therefore has revealed an altogether new dimension for the purpose. NP-mediated disease management strategies have proven to be highly proficient and have been explored for a wide range of plant diseases. However, the NPs derived through chemical and physical methods such as electroreduction, use of reagents for reduction/oxidation of metals, may impart toxicity and also cause environmental hazard. Therefore the synthesis of NPs from microbes, known as green synthesis, is far safer in terms of toxicity. The following chapter elucidates the various bacterial and fungal-derived NPs, their characteristic features, and the associated mechanism for protection against plant pathogens.

Defensins are broad-spectrum antimicrobial peptides that play an important role in providing innate immunity to various biotic stresses in plants. We identified and characterized 22 defensin (DEF) and defensin-like (DEFL) genes in chickpea ( Cicer arientinum ) based on their structures, expression, chromosomal localization, conserved motifs, and cis -regulatory elements. The localization of DEF and DEFL genes in chickpea genome revealed the presence of at least two clusters that are likely evolved through local gene duplications. Genotype-specific responses of several CaDEF and CaDEFL genes in fungal bioassays suggested their involvement in defense against fungal pathogens such as hemi-biotrophic F. oxysporum f. sp. ciceris and dry root rot causing necrotrophic R. bataticola . Molecular docking studies revealed interactions of CaDEFs with fungal plasma membrane components such as phosphatidylserine (PS) and glucosylceramide (GluCer) and their binding sites were identified. Our data will be useful to identify potential candidate genes and their role in host-plant resistance in chickpea, besides presenting opportunities for their potential for possible deployment in other crops.

Toxic metals, often present in various xenobiotics, pose a serious threat to the environment and health. Industrial effluents loaded with hazardous levels of heavy metals may lead to various pathophysiological conditions like dermatitis, nephritis, cancer, and neuronal diseases. Several physical and chemical techniques like settling, sedimentation, evaporative recovery, coagulation, precipitation, floatation, ion exchange, flocculation, chemical oxidation, reduction, reverse osmosis, ultrafiltration, and electrodialysis are generally employed to remove heavy metals from the effluents. However, these methods are not fully efficient and generate a large amount of sludge which is difficult to dispose off. Hereby, microbial processes have gained importance for water treatment and metal removal. In this chapter, an elaborate account on the promises of marine bacteria for the efficient bioremoval of toxic metals is presented. Several marine bacteria like Marinomonas communis, Marinobacter santoriniensis, Pseudomonas pseudoalcaligenes, Exiguobacterium indicum, Rhodobium marinum, Rhodobacter sphaeroides, Alteromonas haloplanktis, Marinobacter hydrocarbonoclasticus, etc., have been reported to remove toxic metals like arsenic, cadmium, chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, selenium vanadium, and zinc. The underlying mechanisms of metal removal using marine bacteria include biosorption, bioaccumulation, and bioconversion, which have also been discussed in detail. Further, the role of genetic elements like mer operon encoding mercury reductase enzyme, bmtA gene for metallothionein, and zntA gene for ATPase efflux systems is explained. Hence, marine bacteria can be applied for developing effective strategies for wastewater treatment of toxic heavy metals.

RNA interference (RNAi) is a method of gene silencing where dsRNA is digested into small interfering RNA (siRNA) in the presence of enzymes. These siRNAs then target homologous mRNA sequences aided by the RNA-induced silencing complex (RISC). The mechanism of dsRNA uptake has been well studied and established across many living organisms including insects. In insects, RNAi is a novel and potential tool to develop future pest management means targeting various classes of insects including dipterans, coleopterans, hemipterans, lepidopterans, hymenopterans and isopterans. However, the extent of RNAi in individual class varies due to underlying mechanisms. The present review focuses on three major insect classes viz hemipterans, lepidopterans and coleopterans and the rationale behind this lies in the fact that studies pertaining to RNAi has been extensively performed in these groups. Additionally, these classes harbour major agriculturally important pest species which require due attention. Interestingly, all the three classes exhibit varying levels of RNAi efficiencies with the coleopterans exhibiting maximum response, while hemipterans are relatively inefficient. Lepidopterans on the other hand, show minimum response to RNAi. This has been attributed to many facts and few important being endosomal escape, high activity dsRNA-specific nucleases, and highly alkaline gut environment which renders the dsRNA unstable. Various methods have been established to ensure safe delivery of dsRNA into the biological system of the insect. The most common method for dsRNA administration is supplementing the diet of insects via spraying onto leaves and other commonly eaten parts of the plant. This method is environment-friendly and superior to the hazardous effects of pesticides. Another method involves submergence of root systems in dsRNA solutions and subsequent uptake by the phloem. Additionally, more recent techniques are nanoparticle- and Agrobacterium-mediated delivery systems. However, due to the novelty of these biotechnological methods and recalcitrant nature of certain crops, further optimization is required. This review emphasizes on RNAi developments in agriculturally important insect species and the major hurdles for efficient RNAi in these groups. The review also discusses in detail the development of new techniques to enhance RNAi efficiency using liposomes and nanoparticles, transplastomics, microbial-mediated delivery and chemical methods.

Sorghum shoot fly, Atherigona soccata,causes substantial economic losses in sorghum globally. Cultural practices and host plant resistance are effective measures for mitigating the losses caused by sorghum shoot fly. Therefore, we evaluated 32 sorghum genotypes consisting of a set of 10 restorer lines, 10 CMS (cytoplasmic male-sterile) lines and their respective maintainers exhibiting resistance/susceptibility to shoot fly along with resistant and susceptible checks under field conditions. The traits such as leaf glossiness, leaf sheath pigmentation, percentage plants with shoot fly deadhearts and number of shoot fly eggs per plant were used as morphological markers for selecting genotypes with resistance to shoot fly during the rainy and post rainy seasons of 2016 and 2017. The test material was also subjected to biochemical analysis (total soluble sugars, protein and tannin contents), while the leaf surface chemicals were analysed by GC-MS to identify the compounds associated with resistance/susceptibility to shoot fly. The genotypes differed significantly for all the traits, except percentage plants with shoot fly deadhearts during the 2016 rainy season. The genotypes ICSB 458, ICSA/B 467, ICSA/B 487, ICSA/B 14037, IS 18551 and ICSV 93046 exhibited moderate to high levels of resistance to shoot fly based on number of plants with shoot fly deadhearts, plants with shoot fly eggs and total number of shoot fly eggs. The shoot fly resistant genotypes ICSB 84, ICSA/B 467, ICSB 487, ICSB 14024, and IS 18551 had low shoot fly deadheart incidence, higher amounts of condensed tannins, soluble sugars, phenols and lower protein content as compared to the susceptible genotypes. Thirteen unique compounds were identified from leaf surface extracts by GC-MS which were associated with shoot fly resistance/susceptibility. While HPLC analysis revealed that Protocatechuic and coumaric acids were present in most of the sorghum genotypes, but their amounts were significantly greater in resistant as compared to the susceptible ones. The findings of the study highlight the importance of various morphological and biochemical traits conferring resistance to sorghum shoot fly, and these traits can be used as markers to identify shoot fly resistant genotypes for use in breeding programs.

Plasma membrane proteolipid 3 (Pmp3) is a gene family involved in abiotic stress response and cellular protection. Here we report cloning of two genes PgPmp3-1 and PgPmp3-2 from Pennisetum glaucum, and characterization with respect to their functions and responsiveness to various abiotic stresses. Both PgPmp3-1 and PgPmp3-2 genes are 171bp long and encode for 56 amino acid long peptides. PgPmp3 sequences share 70–99% sequence identity with their homologs. Protein secondary structure prediction revealed membrane-spanning regions containing a membrane potential modulator domain in both PgPmp3 proteins. In silico network analyses revealed Pmp3 co-expression and association with proteins conferring abiotic stress tolerance in plants. Expression profiles of PgPmp3-1 and PgPmp3-2 revealed their up-regulation in P. glaucum under cold and salt stresses, but showed reduced expression in response to heat stress. These findings provide insight into the role of P. glaucum Pmp3 in abiotic stress amelioration.

High temperature response (HTR) or heat stress response (HSR) is a highly conserved phenomenon, which involves complex networks among different crop species. Heat stress usually results in protein dysfunction by improper folding of its linear amino acid chains to non-native proteins. This leads to unfavourable interactions and subsequent protein aggregation. To tackle this, plants have developed molecular chaperone machinery to maintain high quality proteins in the cell. This is governed by increasing the level of pre-existing molecular chaperones and by expressing additional chaperones through signalling mechanism. Dissecting the molecular mechanism by which plants counter heat stress and identification of important molecules involved are of high priority. This could help in the development of plants with improved heat stress tolerance through advanced genomics and genetic engineering approaches. Owing to this reason molecular chaperones/Heat shock proteins (Hsps) are considered as potential candidates to address the issue of heat stress. In this chapter, recent progress on systematic analyses of heat shock proteins, their classification and role in plant response to heat stress along with an overview of genomic and transgenic approaches to overcome the issue, are summarized.