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Abstract Background The rising demand for food production along with the concerns regarding the injudicious use of chemicals in pest management has paved way for the alternatives that could promise sustainable pest management. Bacillus thuringiensis Berliner (Bt), a soil bacterium, is a potential biopesticide with its ability to produce crystal toxins that are insecticidal in nature. Main body This article provides an insight into the diverse Bt toxins and their applications as biopesticides in pest management. The selective action of Bt towards target organism is based on its specific interactions with the insect gut receptors. The significance of Bt in the management of lepidopteran, coleopteran, hemipteran, dipteran and nematode pests of crops and livestock through its mode of action is extensively reviewed. Conclusion Besides being a promising pest control option, the challenges faced through resistance development, variation in susceptibility across species and non-target effects of Bt are also discussed. Proactive approaches and multiple modes of action can mitigate this issue.

Pyramiding transgenes of interest is one of the strategies to engineer multiple stress resistance in crop plants. Transgenic plants which stably express different genes can be hybridized to bring these genes together in one plant. Transgenic rice (Oryza sativa L. cv. ASD 16) plants harbouring genes Xa21 (conferring bacterial blight resistance), tlp (conferring resistance to sheath blight), or gna (conferring resistance to brown planthopper) were used in hybridization experiments. Sexual hybridization was carried out in two different gene combinations: Xa21 × gna and tlp × gna. Molecular analyses were carried out to confirm the presence of transgenes. In F1 generation, lines harbouring either gene in each of the cross-combination were selected and forwarded to F2 generation. The presence of genes in F2 generation was confirmed by PCR, Southern blot hybridization, and Western blotting. The F2 progeneis harbouring Xa21 and gna exhibited resistance against bacterial blight and moderate resistance against brown planthopper. Similarly, the F2 lines of tlp and gna combination provided resistance against sheath blight and moderate resistance against brown planthopper. The level of resistance observed in pyramided lines for insect or pathogens was comparable to the resistance observed in their parental lines. Our study shows that pyramiding genes by hybridization between transgenic plants could be one of the strategies to develop cultivars with multiple biotic stress resistances.

The number of genes controlling the traits and the nature of gene action are the important criteria for the selection of individual traits in a segregating population. The current study is focused to analyze the skewness and kurtosis in the backcross population of UMI1200β+ × HKI163 and UMI1230β+ × HKI163. The BC2F2 population showed positive skewness and platykurtic distribution for plant height. In the present study the dominant × dominant based complementary gene action played a role and more number of genes controlled the plant height. Hence, rigorous selection is needed to achieve the genetic gain in the later generation. The negative skewness and platykurtic distribution was recorded for single plant yield in UMI1200β+ × HKI163 which indicated the duplicate gene action and required mild selection to fix the individual traits for rapid genetic gain.

Genetic variability, heritability and genetic advance are the important factors which provides the knowledge about the nature of traits in breeding programme. The aim of this study is to estimate the genetic variability, heritability, and genetic advance in the backcross population of UMI1200β+ × HKI163 and UMI1230β+ × HKI163 to identify the individuals in the population with superior agronomic traits. Fourteen biometrical traits were analysed and thus revealed that all the backcross (BC1F1, BC2F1) and selfed (BC2F2) generations, phenotypic coeffiecient of variation is higher than the genotypic coefficient of variation. Highest heritability combined with genetic advance as percent of mean was observed in BC2F2 generation for 100 kernel weight (UMI1200β+ × HKI163) and single plant yield (UMI1230β+ × HKI163). Hence, the genetic gain of the individuals in the population are controlled by additive gene action.

Development of transgenic plants by introducing defense genes is one of the strategies to engineer disease resistance. Transgenic ASD16 rice plants harbouring rice chitinase chi11 gene, belonging to a PR-3 group of defense gene conferring sheath blight (Rhizoctonia solani Kuhn) resistance, were used in this study. Three T2 homozygous lines (ASD16-4-1-1, 5-1-1, and 6-1-1) were identified from seven putative (T0) transgenic lines expressing chi11 using Western blotting analysis. The inheritance of sheath blight resistance in those lines was studied over generations. The stability of chi11 expression up to T4 generation in all the three homozygous lines was proved by Western blot and the stability of sheath blight resistance in the homozygous lines was proved up to T4 generation using detached leaf and intact leaf sheath assays. Among the three homozygous lines tested, ASD16-4-1-1 showed consistent results in all the generations and gave a better protection against the sheath blight pathogen than the other two lines.

Evaluation of turmeric genotypes is useful to study genetic variation among them and to identify high yielding genotypes. Analysis of genetic divergence in turmeric genotypes is much essential for grouping them based on the observed biometrical and yield traits and to choose the traits responsible for contribution to diversity. Turmeric genotypes were evaluated during 2020 -2021 and 2021 – 2022 and they exhibited wide variation among the observed quantitative traits. Among the turmeric genotypes, CL 95 recorded the highest fresh rhizome yield per plant of 381.8 g followed by CL 258 (341.2 g). CL 95, CL 258, Salem local and CL 197 exhibited better performance for yield and yield contributing traits. Totally six clusters were formed by using Mahalanobis D2 statistics method and genotypes listed in cluster VI were more diverse. Fresh rhizome yield per plant contributed more (41. 99 %) for genetic diversity. The genotypes selected in the present study could used to improve the rhizome yield of turmeric.

CO 51 is a recently developed semi dwarf, short duration variety of rice popularly grown in Tamil Nadu. Optimization of tissue culture protocol for the variety was one of the most important steps required; in order to make the variety suitable for genetic transformation and gene editing techniques. Immature embryos of CO 51 have been used as explant for callus induction. The immature embryos were cultured on callus induction media (NB media) containing Naphthalene Acetic Acid (NAA) 1 mg l-1, 6-Benzylaminopurine (6-BA) 1 mg l-1 and various concentrations of 2,4 Dichlorophenoxy acetic acid (2,4-D). NB media supplemented with 2.5 mg l-1of 2,4-D have been found to show the highest callus induction frequency that is 94.4%. The calli showing desired features were transferred from NB media to pre-regeneration media (NB-PR) having 2,4-D (2 mg l-1), 6-BA (1 mg l-1 ), NAA (1 mg l-1) where the calli tuned golden- yellow. These calli were then transferred to regeneration media (RNM media) supplemented with 6-BA (3 mg l-1) along with various concentrations of NAA. RNM media with1 mg l-1 NAA showed the highest frequency of shoot induction that is 72.2% with an average of 12 shoots per callus.

Pigeon pea’s productivity has been stagnant over the years because of the devastating pest Helicoverpa armigera which causes major yield losses. The present study explored different responses of various defense strategies in leaves and pods of four pigeon pea cultivars (ICP-12142, ICP-11543, LRG-41 and CO-8) after infestation. Two pigeon pea cultivars viz; ICP-11543 and CO-8 were ascertained to be susceptible to infestation with excessive leaf and pod damage compared to the other two cultivars. Decreased activities of defensive enzymes/compounds like peroxidase (POD), superoxide dismutase (SOD), polyphenol oxidase (PPO) and total phenols were reported following infestation in cultivars of ICP-11543 and CO-8 which resulted in intensification of infestation. The cultivars; LRG-41 and ICP-12142 were found to be moderately resistant to pest infestation because of the up-regulation of PPO, POD and SOD along with accumulation of total phenols which might be held accountable for shifting the oxidative status of the respective cultivars.

In the present study, molecular characterization was carried out at the Department of Plant Biotechnology, Tamil Nadu Agricultural University, Coimbatore to identify the strains of fall armyworm collected from pearl millet crop at four different locations in Tamil Nadu, India. PCR-RFLP profile of mitochondrial COI fragment exhibited the presence of both ‘C’ and ‘R’ strains of FAW. MtCOI region analysis revealed that, thirteen samples showed ‘R’ strain identity, and others assumed ‘C’ strain identity. Sequence analyses of mtCOI region of FAW feeding on pearl millet showed nucleotide variations in 22 positions. The Strain, ON142640 (Pearl millet Vridhachalam India) totally diverged from all populations subjected to phylogenetic analysis in this study and was suspected to be an inter-strain (R/C) hybrid. The per cent identity analysis of S. frugiperda ranged from 99% to 100% with previously deposited sequences in the NCBI-GenBank database. [ABSTRACT FROM AUTHOR]

Paper and pulp mills use a huge quantity of water in the manufacturing process and release a substantial quantity of salts in the effluent. The use of industrial effluents for irrigating crops due to the nutrient content in arid zones is under practice. The long-term use of paper and pulp mill effluent as a source of irrigation accumulates salts in the soil surface and rhizospheric zone. In this study, halophytes, namely Sesuvium portulacastrum, Salicornia brachiata, and Suaeda maritima were evaluated for their phytodesalination potential in paper and pulp mill effluent irrigated soil. Among these Sesuvium portulacastrum recorded the highest dry matter production (8.21 g pot-1), and the sodium accumulation was 6.7% greater than S. brachiata on 120th day. Furthermore, the soil EC was also 7.7 % lower in pots cultivated with S. portulacastrum than pots cultivated with S. brachiata. Hence, Sesuvium portulacastrum could effectively be used to phytodesalinate saline soils and ensure the sustainable cultivation of crops using paper and pulp mill effluent. [ABSTRACT FROM AUTHOR]

Thermosensitive genic male sterile (TGMS) rice genotypes, which are malesterile at the restrictive temperature (>26°C) but becomes male-fertile at the permissive temperature (< 22°C) are widely used in hybrid rice breeding. Mutation in tms5 gene located on chromosome 2 is responsible for the malesterility trait in rice. Through gene editing, it is possible to create a specific mutation in the tms5 locus of male fertile rice lines and convert them into male sterile lines. The CRISPR/Cas9 editing system was employed to induce specific mutation in tms5 gene of rice variety ASD16. CRISPR/Cas9 vector with guide RNA targeting the second exon of tms5 gene was constructed and used for rice transformation. Four putative transgenic ASD16 events were generated through rice immature embryo transformation and analysed for the presence of hpt and mutation in tms5 locus in T0 generation. [ABSTRACT FROM AUTHOR]

Abstract  Elite indica rice cultivars were cotransformed with genes expressing a rice chitinase (chi11) and a thaumatin-like protein (tlp) conferring resistance to fungal pathogens and a serine-threonine kinase (Xa21) conferring bacterial blight resistance, through particle bombardment, with a view to pyramiding sheath blight and bacterial blight resistance. Molecular analyses of putative transgenic lines by polymerase chain reaction, Southern Blot hybridization, and Western Blotting revealed stable integration and expression of the transgenes in a few independent transgenic lines. Progeny analyses showed the stable inheritance of transgenes to their progeny. Coexpression of chitinase and thaumatin-like protein in the progenies of a transgenic Pusa Basmati1 line revealed an enhanced resistance to the sheath blight pathogen, Rhizoctonia solani, as compared to that in the lines expressing the individual genes. A transgenic Pusa Basmati1 line pyramided with chi11, tlp, and Xa21 showed an enhanced resistance to both sheath blight and bacterial blight. [ABSTRACT FROM AUTHOR]

IRT2 is involved in regulating uptake of iron (Fe) and is considered as one of the potential targets for genetic manipulation for Fe accumulation in crops. Genetic transformation of tobacco with an IRT2 gene of Echinochloa frumentacea was carried out in tobacco model system to study the expression of the gene. Twenty four putative transgenic tobacco plants were generated through Agrobacterium mediated transformation. Thirteen tobacco events were screened for presence of EfIRT2 and hptII genes and all thirteen were found positive for gene of interest as well as for the selectable marker gene, hptII. In addition, qRT-PCR analysis confirmed the EfIRT2 gene expression in three tested transgenic tobacco plants.

Hygienic behavior (HB) emerges as a pivotal trait, impacting colony resistance to diseases. This study aimed to understand the behavioral traits of Apis cerana indica colonies, with a focus on HB and other key characteristics crucial for colony health, and to screen and identify colonies with superior hygienic behavior and better performance to combat prevailing diseases and pests. This research spans a comprehensive field analysis with different seasons and locations, encompassing the distinct environmental and management factors that influence honey bee behavior. The inclusion of A. cerana indica colonies from various locations provides a novel perspective, offering valuable insights regarding the hygienic behavior of A. cerana indica . Several statistical analyses, including descriptive statistics, principal component analysis (PCA), and Aligned Rank Transformation-Analysis of Variance (ART-ANOVA) for repeated measures, shed light on the distribution of hive metrics, emphasizing the significance of considering seasonality and location-specific factors. PCA highlights unique characteristics in Tirupur and Coimbatore colonies, while correlation analyses uncover relationships among HB, honey, pollen, brood area, and adult population. Moreover, the study's nuanced findings gave the status of hygienic behavior of A. cerana indica colonies and identified colonies with better colony performance, which will be useful for future breeding programs with A. cerana indica .

Halophytic plants can tolerate a high level of salinity through several morphological and physiological adaptations along with the presence of salt tolerant rhizo-microbiome. These microbes release phytohormones which aid in alleviating salinity stress and improve nutrient availability. The isolation and identification of such halophilic PGPRs can be useful in developing bio-inoculants for improving the salt tolerance and productivity of non-halophytic plants under saline conditions. In this study, salt-tolerant bacteria with multiple plant growth promoting characteristics were isolated from the rhizosphere of a predominant halophyte, Sesuvium portulacastrum grown in the coastal and paper mill effluent irrigated soils. Among the isolates, nine halotolerant rhizobacterial strains that were able to grow profusely at a salinity level of 5% NaCl were screened. These isolates were found to have multiple plant growth promoting (PGP) traits, especially 1-aminocyclopropane-1-carboxylic acid deaminase activity (0.32-1.18  μM of α-ketobutyrate released mg -1 of protein h -1 ) and indole acetic acid (9.4-22.8  μg mL -1 ). The halotolerant PGPR inoculation had the potential to improve salt tolerance in Vigna mungo L. which was reflected in significantly ( p  < 0.05) higher germination percentage (89%) compared to un-inoculated seeds (65%) under 2% NaCl. Similarly, shoot length (8.9-14.6 cm) and vigor index (792-1785) were also higher in inoculated seeds. The strains compatible with each other were used for the preparation of two bioformulations and these microbial consortia were tested for their efficacy in salt stress alleviation of Vigna mungo L. under pot study. The inoculation improved the photosynthetic rate (12%), chlorophyll content (22%), shoot length (5.7%) and grain yield (33%) in Vigna mungo L. The enzymatic activity of catalase and superoxide dismutase were found to be lower (7.0 and 1.5%, respectively) in inoculated plants. These results revealed that halotolerant PGPR isolated from S. portulacastrum can be a cost-effective and ecologically sustainable method to improve crop productivity under high saline conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 John, Maheswari, Kalaiselvi, Prasanthrajan, Poornachandhra, Rakesh, Gopalakrishnan, Davamani, Kokiladevi and Ranjith.)

In this study, we present the molecular and insecticidal characteristics of an indigenous Bt isolate T405 toxic against the maize fall armyworm (FAW), Spodoptera frugiperda. The presence of cry1, cry2 (cry2Aa & cry2Ab) and vip3A1 genes in T405 was confirmed. The SDS-PAGE gel analysis confirmed the occurrence of Cry and Vip proteins with molecular masses of 130, ∼88 and 65 kDa in T405. LC 50 estimates of T405 and HD1 were 161.37 and 910.73 μg ml -1 for neonates whereas, 412.29 and 1014.95 μg ml -1 correspondingly for 2 nd instar FAW larvae. Scanning Electron Microscopy depicted the existence of bipyramidal, spherical and cubic crystals in T405 spore suspension. The whole genome sequencing and assembly of T405 produced a total of 563 scaffolds with a genome size of 6,673,691 bp. The BLAST similarity search showed that 12 plasmids were distributed in this genome. Genome annotation revealed the presence of 6174 protein coding genes, 13 rRNA and 98 tRNA, in which 6126 genes were completely annotated for their functions through sequence similarity search, domains/motifs identification and gene ontology studies. Further analysis of these genes identified the presence of many insecticidal toxin protein coding genes viz., cry1Ac32, cry1Ab9, cry1Aa6, cry1Ac5, cry1Aa18, cry1Ab8, cry1Ab11, cry2Aa9, cry1Ia40, cry2Aa9, cry1Ia40, cry2Ab35, cyt, vip3Aa7 and tpp80Aa and several additional virulence assisted factors viz., immune inhibitor A, phospholipase C, sphingomyelinase, cell wall hydrolases, chitinase, hemolysin XhlA and seven urease subunit coding genes (ureA, ureB, ureC, ureD, ureE, ureF, ureG) in the annotated genome., Competing Interests: Declaration of competing interest All the authors have declared that they have no potential competing interests both in personally and financially., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

RNA interference (RNAi) is an evolutionarily conserved gene silencing mechanism in eukaryotes including fungi, plants, and animals. In plants, gene silencing regulates gene expression, provides genome stability, and protect against invading viruses. During plant virus interaction, viral genome derived siRNAs (vsiRNA) are produced to mediate gene silencing of viral genes to prevent virus multiplication. After the discovery of RNAi phenomenon in eukaryotes, it is used as a powerful tool to engineer plant viral disease resistance against both RNA and DNA viruses. Despite several successful reports on employing RNA silencing methods to engineer plant for viral disease resistance, only a few of them have reached the commercial stage owing to lack of complete protection against the intended virus. Based on the knowledge accumulated over the years on genetic engineering for viral disease resistance, there is scope for effective viral disease control through careful design of RNAi gene construct. The selection of target viral gene(s) for developing the hairpin RNAi (hp-RNAi) construct is very critical for effective protection against the viral disease. Different approaches and bioinformatics tools which can be employed for effective target selection are discussed. The selection of suitable target regions for RNAi vector construction can help to achieve a high level of transgenic virus resistance., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature.)

A full-length cDNA of phyA gene of Aspergillus niger , encoding phytase enzyme, was cloned and expressed in E. coli BL21 cells and assayed for its activity. The phyA cDNA consisted of 1404 bp, which encoded 467 amino acid residues. The phytase activity of purified phytase was 826.33 U/mL. The phyA gene under the control of endosperm-specific promoters was transformed into an Indian maize inbred line, UMI29, using particle bombardment-mediated transformation method to generate transgenic maize plants over-expressing phytase in seeds. PCR and GUS analyses demonstrated the presence of transgenes in T 0 transgenic plants and their stable inheritance in the T 1 progenies. Three transgenic events expressing detectable level of A. niger phytase were characterized by western blot analysis. Phytase activity of 463.158 U/kg of seed was observed in one of the events, JB-UMI29-Z17/2. The phytase activity of transgenic maize seeds was 5.5- to 7-fold higher than the wild-type UMI29 seeds and, consequently, the seeds had 0.6- to 5-fold higher inorganic phosphorus content., Competing Interests: Compliance with ethical standardsThe authors declare that they have no conflict of interest.

An alpha-zein promoter isolated from maize containing P-box, E motif sequence TGTAAAGT, opaque-2 box and TATA box was studied for its tissue-specific expression in rice. A 1,098 bp promoter region of alpha-zein gene, fused to the upstream of gusA reporter gene was used for transforming rice immature embryos (ASD 16 or IR 64) via the particle bombardment-mediated method. PCR analysis of putative transformants demonstrated the presence of transgenes (the zein promoter, gusA and hpt). Nineteen out of 37 and two out of five events generated from ASD 16 and IR 64 were found to be GUS-positive. A histological staining analysis performed on sections of mature T1 seeds revealed that the GUS expression was limited to the endosperm and not to the pericarp or the endothelial region. GUS expression was observed only in the following seed development stages : milky (14-15 DAF), soft dough (17-18 DAF), hard dough (20-23 DAF), and mature stages (28-30 DAF) of zein-gusA transformed (T0) plants. On the contrary a constitutive expression of GUS was evident in CaMV35S-gusA plants. PCR and Southern blotting analyses on T1 plants demonstrated a stable integration and inheritance of transgene in the subsequent T1 generation. GUS assay on T2 seeds revealed that the expression of gusA gene driven by alpha-zein promoter was stable and tissue-specific over two generations. Results suggest that this alpha-zein promoter could serve as an alternative promoter to drive endosperm-specific expression of transgenes in rice and other cereal transformation experiments.

Elite indica rice cultivars were cotransformed with genes expressing a rice chitinase (chi11) and a thaumatin-like protein (tlp) conferring resistance to fungal pathogens and a serine-threonine kinase (Xa21) conferring bacterial blight resistance, through particle bombardment, with a view to pyramiding sheath blight and bacterial blight resistance. Molecular analyses of putative transgenic lines by polymerase chain reaction, Southern Blot hybridization, and Western Blotting revealed stable integration and expression of the transgenes in a few independent transgenic lines. Progeny analyses showed the stable inheritance of transgenes to their progeny. Coexpression of chitinase and thaumatin-like protein in the progenies of a transgenic Pusa Basmati1 line revealed an enhanced resistance to the sheath blight pathogen, Rhizoctonia solani, as compared to that in the lines expressing the individual genes. A transgenic Pusa Basmati1 line pyramided with chi11, tlp, and Xa21 showed an enhanced resistance to both sheath blight and bacterial blight.