Search Results (71)

The insect resistance expression of Bacillus thuringiensis (Bt) cotton (Gossypium hirsutum L.) is unstable due to temporal and spatial variations in the Bt protein content in different organs and growth stages. The aim of this study was to improve the Bt protein content in cotton flowers and investigate the underlying physiological mechanism using biochemical analytical methods. In this study, a split-plot design with three replications was used. The main plots included two Bt cotton cultivars (a conventional cultivar, Sikang1 (S1), and a hybrid cultivar, Sikang3 (S3)), while five soil nitrogen application levels (CK (control check): normal level; N1: 125% of the CK; N2: 150% of the CK; N3: 175% of the CK; N4: 200% of the CK) constituted the subplots. The Bt protein content and related nitrogen metabolism parameters were measured. We found that the Bt protein content increased and then decreased with increasing nitrogen rates. It reached its maximum at N3, with significant increases of 71.86% in 2021 and 39.36% in 2022 compared to the CK. Correlation analysis indicated that the Bt protein content was significantly positively related to the soluble protein and free amino acid contents, as well as the GPT (glutamic pyruvic transaminase), GOT (glutamic oxaloacetic transaminase), GS (glutamine synthetase) and GOGAT (glutamate synthetase) activities. On the other hand, negative correlations were found between the Bt protein content and protease and peptidase activities. In addition, stepwise regression and path analysis indicated that the increased Bt protein content was mainly due to the enhanced GS and GOGAT activities. In summary, appropriately increasing nitrogen fertilizer application is a practical way to increase flower Bt protein content and insecticidal efficacy of Bt cotton. These findings provide an actionable agronomic strategy for sustaining Bt expression during the critical flowering period. Full article

Food grain production has multiplied over the last two decades in India, but natural resources are overexploited in modern farming. Farmers, especially those with small and marginal holdings, are suffering losses more often than not, the cost of production is increasing year after year, and profits are not up to the necessary levels. To address such challenges, there has been a broad recognition of the importance of employing farming system approaches in research. The cultivation of cropping systems with orchard crops and livestock components can play a significant role in the optimal utilization of resources, enhancing energy use efficiency as well as the eco-efficiency index, and reducing carbon footprints. This study was carried out to create a suitable IFS model with high economic and energy efficiency for small-holder farmers in India’s southern plateau and hills with a negligible impact on the environment. The following were the seven models: M₁: Rice − Groundnut; M₂: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Bt cotton + Greengram (1:2) − Maize; M₃: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Pigeonpea + Maize (1:3) − Sunhemp; Napier grass, Sheep (5 + 1); M₄: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Bt cotton + Greengram (1:2) − Maize, Pigeonpea + Maize (1:3) − Sunhemp, Poultry unit; M₅: Guava, Hedge Lucerne, Napier grass, Bt cotton + Greengram (1:2) − Maize, Sheep (5 + 1); M₆: Guava, Bt cotton + Greengram (1:2) − Maize, Rice − Groundnut, Poultry; M₇: Rice − Groundnut, Pigeonpea + Sweetcorn (1:3) − Bajra, Pigeonpea + Maize (1:3) − Sunhemp; Napier grass, Hedge lucerne, Poultry (100), Sheep (5 + 1). Model M₁ was used to represent the local region, and the other models were compared in terms of economics, energetics, greenhouse gas emissions, and employment creation. The M₇ and M₃ models, according to the results, have higher economic efficiency (₹342.3 day⁻¹, ₹263.7 day⁻¹), increase output energy (228,529 and 183,231 MJ) net energy (258,184 and 198,920 MJ), produce net negative emissions (−2842 and −2399 kg CO₂ eq.), and create jobs year-round (112.5 and 110.5 man days year⁻¹), respectively. This is primarily because they have multiple highly efficient components that make them viable for Telangana’s small and marginal farmers. Full article

The beet armyworm, Spodoptera exigua (Hübner), is a major pest of maize, cotton, soybean, and many other crops globally. Despite the widespread deployment of Bt transgenic maize for pest control worldwide, the efficacy of Bt lepidopteran-resistant transgenic maize in managing S. exigua remains rarely studied. In this study, we quantified the expression level of pyramided Cry1Ab and Vip3Aa toxins in Bt maize (event DBN3601T) and evaluated their control efficiency against S. exigua under both laboratory and field conditions. The enzyme-linked immunosorbent assay (ELISA) results showed that the expression levels of Cry1Ab and Vip3Aa proteins in DBN3601T maize tissues followed a decreasing order as follows: V5-leaf > V8-leaf > VT-tassel > R2-kernel > R1-silk. Diet-overlay assay results showed that the LC₅₀ values of Cry1Ab and Vip3Aa proteins against S. exigua larvae were 11.66 ng/cm² and 27.74 ng/cm², respectively, with corresponding GIC₅₀ values at 1.59 ng/cm² and 7.93 ng/cm². Bioassay using various tissues of the DBN3601T maize indicated that after 7 days of infestation, mortality rates of neonates and third-instar larvae ranged from 86% to 100% and 58% to 100%, respectively. Mortality was highest on V5 and V8 leaves, followed by R2-kernel, VT-tassel, and R1-silk. Field trials demonstrated that DBN3601T maize exhibited significantly lower larval density, damage rate, and leaf damage score compared to non-Bt maize. Field cage trial showed that the control efficacy of DBN3601T maize at the vegetative stage could reach 98%. These findings provide a theoretical basis for utilizing Bt transgenic maize to enhance the sustainable management of S. exigua in Asia. Full article

Intercropping presents an opportunity to optimise land use and resource efficiency in cotton cultivation, particularly for small and marginal farmers facing climate-related challenges and rising input costs. This study explores the potential of intercropping short-duration vegetables with cotton to transform this production system into a more economically viable and sustainable one. The study was conducted in the Cotton Department of Tamil Nadu Agricultural University in Coimbatore during the winter irrigated season, from August to January, in both 2020 and 2021. The growth, yield parameters, equivalent yield (3645 and 4234 kg ha⁻¹), and net return (Rs. 123,434 ha⁻¹ and Rs. 154,034 ha⁻¹) were higher in the intercropping system with the paired row planting of Bt cotton with two rows of cluster bean. Upon comparing sole cropping and the paired row method of planting, it was found that adopting the paired row system of planting Bt cotton with two rows of cluster bean was highly profitable in all aspects of crop production. Therefore, the adoption of paired row cropping systems with compatible intercrops that promote synergistic effects on the main crop should be considered for enhancing overall productivity, as well as sustainability. Full article

The expression of Bacillus thuringiensis (Bt) toxins in transgenic cotton confers resistance to insect pests. However, it has been demonstrated that its effectiveness varies among cotton cultivars and different tissues. In this study, we evaluated the expression of Bt protein in 28 cotton cultivars and selected 7 cultivars that differed in Bt protein expression for transcriptome analysis. Based on their Bt protein expression levels, the selected cultivars were categorized into three groups: H (high Bt protein expression), M (moderate expression), and L (low expression). In total, 342, 318, and 965 differentially expressed genes were detected in the H vs. L, M vs. L, and H vs. M comparison groups, respectively. And three modules significantly associated with Bt protein expression were identified by weighted gene co-expression network analysis. Three hub genes were selected to verify their relationships with Bt protein expression using virus-induced gene silencing (VIGS). Silencing GhM_D11G1176, encoding an MYC transcription factor, was confirmed to significantly decrease the expression of Bt protein. The present findings contribute to an improved understanding of the mechanisms that influence Bt protein expression in transgenic cotton. Full article

The recent dominance of Adelphocoris suturalis Jakovlev as the primary cotton field pest in Bt-cotton-cultivated areas has generated significant interest in cotton pest control research. This study addresses the limited understanding of cotton defense mechanisms triggered by A. suturalis feeding. Utilizing LC-QTOF-MS, we analyzed cotton metabolomic changes induced by A. suturalis, and identified 496 differential positive ions (374 upregulated, 122 downregulated) across 11 categories, such as terpenoids, alkaloids, phenylpropanoids, flavonoids, isoflavones, etc. Subsequent iTRAQ-LC-MS/MS analysis of the cotton proteome revealed 1569 differential proteins enriched in 35 metabolic pathways. Integrated metabolome and proteome analysis highlighted significant upregulation of 17 (89%) proteases in the α-linolenic acid (ALA) metabolism pathway, concomitant with a significant increase in 14 (88%) associated metabolites. Conversely, 19 (73%) proteases in the fructose and mannose biosynthesis pathway were downregulated, with 7 (27%) upregulated proteases corresponding to the downregulation of 8 pathway-associated metabolites. Expression analysis of key regulators in the ALA pathway, including allene oxidase synthase (AOS), phospholipase A (PLA), allene oxidative cyclase (AOC), and 12-oxophytodienoate reductase3 (OPR3), demonstrated significant responses to A. suturalis feeding. Finally, this study pioneers the exploration of molecular mechanisms in the plant–insect relationship, thereby offering insights into potential novel control strategies against this cotton pest. Full article

Fall armyworm (FAW, Spodoptera frugiperda) is a polyphagous and migratory lepidopteran pest insect in field crops and is notoriously invasive worldwide. In large portions of the Americas, its populations are managed using transgenic maize or cotton varieties producing insecticidal proteins from Bacillus thuringiensis (Bt), primarily Vip3Aa pyramided with Cry Bt proteins. We determined the susceptibility of FAW field populations from locations pressured with such maize hybrids for over five years. We used time–mortality bioassays with F₁ third-instar larvae of six geographically distinct populations collected in maize fields of a tropical agricultural region encompassing four Brazilian states. We maintained the neonate progeny from the field populations on an artificial diet until the third instar, and then determined their survival curves on the foliage of three Vip3Aa/Cry-producing Bt maize hybrids. Death of the mid-size, third-instar FAWs occurred relatively rapidly, with larval mortality rates reaching 98–100% in less than five days regardless of Bt maize hybrid. However, median survival time (ST₅₀) for the larvae differed among the populations, with the lowest and highest ST₅₀ values occurring for PI-Cr (42 h, 1.75 d) and PI-Ur populations (66–90 h, 2.75–3.75 h), respectively. Therefore, the F₁ third-instar larvae of FAW populations were largely susceptible to Vip3Aa/Cry-producing maize foliage, and the most contrasting susceptibility occurred in the insects from Piauí state, Brazil. These results indicate that progeny of FAWs from areas highly pressured with Vip3Aa/Cry Bt maize hybrids are killed on maize foliage producing Vip3Aa and Cry Bt proteins despite field reports of increased leaf damage by the larvae in some locations. This research informs decision making for Bt-crop resistance management by producers, technicians, and researchers in local, regional, and world agriculture. Full article

The comment titled “Factors related to Bacillus thuringiensis and gut physiology” disputes some of the inferences in the paper “An Alkaline Foregut Protects Herbivores from Latex in Forage, but Increases Their Susceptibility to Bt Endotoxin” published in this journal. The key points in the dissent are the following: 1. Bt is generally safe to non-target species. 2. Transgenic Bt crops provide additional ecological benefits due to reductions in conventional pesticide use. 3. Susceptibility to Bt does not indicate alkalinity, nor vice versa. My response is summarized as follows: 1. Bt can form non-specific pores at concentrations of 100 ng/mL in culture, and so is potentially unsafe for animals with gut environments in which Bt persists at or above this level. 2. Initial reductions in insecticide applications have not been sustained and are even increasing in areas planted with transgenic Bt cotton. 3. Acidic guts degrade Bt more efficiently, but I concede that gut alkalinity does not imply susceptibility to Bt due to many factors including resistance in target species, toxin heterogeneity and variable modes of action. However, the susceptibility of foregut-fermenting herbivores with alkaline guts to Bt intoxication cannot be invalidated without further study. Full article

Pink bollworms severely affect the production of cotton. The method currently used for pink bollworm control is the planting of Bt (Bacillus thuringiensis) protein-expressing transgenic cotton. However, pink bollworms can develop strong resistance to Bt proteins in transgenic cotton because of the large planting area and long planting time of this crop, which severely affects the control of pink bollworms. Intestinal microorganisms play very important roles in insect growth, development and Bt resistance. However, the effect of intestinal microorganisms on pink bollworm Bt resistance is still unclear. The current study aimed to analyze the effect of intestinal microorganisms on the Bt resistance of pink bollworms. Intestinal microorganisms associated with Bt resistance were initially screened through Illumina MiSeq sequencing and analysis. The results showed that feeding with a mixture of gentamicin, Cry1Ac and an artificial diet could significantly increase the mortality of pink bollworm larvae compared with feeding with of a mixture of Cry1Ac and an artificial diet or an artificial diet alone. The microbial diversity, community structure and composition of the pink bollworm larval intestine were significantly influenced by feeding with a mixture of gentamicin, Cry1Ac and an artificial diet. Several intestinal bacteria with significantly altered abundances after treatment with gentamicin were preliminarily screened as potential resources for addressing Bt toxicity. This study provides useful strategies for addressing the Bt resistance of pink bollworms. Full article

Background and Objectives: The aim of this study were to compare the cervical ROM data obtained from accelerometer exams between patients suffering from TMDs (study group) and healthy patients (control group). Material and Methods: A sample of 43 young adult subjects (23 control subjects and 20 TMD patients) were included in this study and analyzed with the accelerometer (Baiobit™, BTS, Garbagnate Milanese, Milan, Italy) to assess cervical ROM using a standardized protocol, including the following occlusal conditions: mandibular rest position, clenching, clenching with cotton rolls, maximal intercuspation, and mandibular position with cotton rolls. The cervical ROM was measured in degrees and expressed as the mean and standard deviation. Results: TMD patients showed a reduced cervical extension compared to control subjects in all the conditions, with statistically significant relevance. Regarding the other movements, the differences were not statistically or clinically significant. Conclusions: Based on the results of the present study, it can be observed that temporomandibular disorders are associated with a decreased cervical extension range, while the remaining components of ROM do not seem to be significantly associated. The use of accelerometers in ROM analysis could be helpful in improving interdisciplinary communication between dentists and physiotherapists. Full article

The fall armyworm (JE Smith) (Spodoptera frugiperda) is a polyphagous pest targeted by selected Cry and Vip3A insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) that are produced in transgenic Bt corn and cotton. Available evidence suggests that sublethal larval exposure to Cry1Ac increases flight activity in adult Spodoptera spp. However, it is not known whether this effect is also observed in survivors from generally lethal exposure to Cry1Ac. Moreover, while multiple cases of field-evolved resistance to Bt proteins have been described in the native range of S. frugiperda, the effect of resistance on flight behavior has not been examined. Long-distance migratory flight capacity of S. frugiperda is of concern given its ongoing global spread and the possibility that migrants may be carrying resistance alleles against pesticides and Bt crops. In this study, we used rotational flight mills to test the effects of generally lethal exposure to Cry1Ac in susceptible and sublethal exposure in Cry1F-resistant S. frugiperda strains. The results detected altered pupal weight after larval feeding on diet containing Cry proteins, which only translated in significantly increased tendency for longer flights in female moths from the susceptible strain. This information has relevant implications when considering current models and assumptions for resistance management of Bt crops. Full article

Bacillus thuringiensis is a Gram-positive bacterium known for its insecticidal proteins effective against various insect pests. However, limited strains and proteins target coleopteran pests like Anthonomous grandis Boheman, causing substantial economic losses in the cotton industry. This study focuses on characterizing a Bacillus sp. strain, isolated from Oncativo (Argentina), which exhibits ovoid to amorphous parasporal crystals and was designated Bt_UNVM-84. Its genome encodes genes for the production of two pairs of binary Vpb1/Vpa2 proteins and three Cry-like proteins showing similarity with different Cry8 proteins. Interestingly, this gene content was found to be conserved in a previously characterized Argentine isolate of B. thuringiensis designated INTA Fr7-4. SDS-PAGE analysis revealed a major band of 130 kDa that is proteolytically processed to an approximately 66-kDa protein fragment by trypsin. Bioassays performed with spore-crystal mixtures demonstrated an interesting insecticidal activity against the cotton boll weevil A. grandis neonate larvae, resulting in 91% mortality. Strain Bt_UNVM-84 is, therefore, an interesting candidate for the efficient biological control of this species, causing significant economic losses in the cotton industry in the Americas. Full article

Cotton (Gossypium spp. L.) is a major origin of natural fiber, and is projected at 117 million bales worldwide for 2021/22. A variety of biotic and abiotic stresses have considerable negative impacts on cotton. The significantly decreased applications of chemical insecticidal sprays in the agro-ecosystem have greatly affected the biodiversity and dynamics of primary and secondary insects. Various control measures were taken around the globe to increase production costs. Temperature, drought, and salinity, and biotic stresses such as bacteria, viruses, fungi, nematodes, insects, and mites cause substantial losses to cotton crops. Here, we summarize a number of biotic and abiotic stresses upsetting Bt cotton crop with present and future biotechnology solution strategies that include a refuge strategy, multi-gene pyramiding, the release of sterile insects, seed mixing, RNAi, CRISPR/Cas9, biotic signaling, and the use of bioagents. Surveillance of insect resistance, monitoring of grower compliance, and implementation of remedial actions can lead to the sustainable use of cotton across the globe. Full article

Pectinophora gossypiella (Saunders) is a potential threat for the successful cultivation of cotton all over the world. Despite the use of modern management strategies, the damage caused by this pest is increasing. The repeated exposure of this pest to Bacillus thuringenisis (Bt) crops resulted in resistance development, which has threatened the continued success of Bt cotton cultivation. Salicylic acid has been reported to enhance the efficiency of crops. The present study was carried out to determine the effect of salicylic acid on the oviposition (pre-oviposition and post-oviposition time) and feeding behavior (pre-feeding time and post-feeding time) of pink bollworm larvae in two cotton varieties, i.e., CIM-70 and NIAB-78. In the first experiment, leaves and bolls treated with different concentrations of salicylic acid were kept in an oviposition chamber and adults were released in a chamber with a ratio of 5:5 males to females, respectively. The experiment was performed following a Completely Randomized Design (CRD) with three replications and six concentrations of salicylic acid (0, 10, 20, 40, 80, and 160 ppm). In a second complementary experiment, salicylic acid was evaluated against feeding behavior, i.e., larval duration, pre-feeding time, feeding time, post-feeding time, and percentage mortality of pink bollworm. In both experiments, the results revealed that the application of salicylic acid at a maximum concentration was effective against the oviposition and feeding of pink bollworm only in the NIAB-78 cultivar. It is concluded that salicylic acid has the potential to reduce pink bollworm risks, and the present investigation will help researchers as well as farmers plan for the timely sustainable management of pink bollworm. Full article

Cotton (Gossypium hirsutum L.) is an economically important crop in China, and responses of cotton yield in different regions to separate and joint changes in natural and anthropogenic factors are the foundation for sustainable development under climate change; however, these remain uncertain. Here, we analyzed the spatiotemporal evolution and heterogeneity of cotton cultivation in China from 1949 to 2020 and quantified the response of cotton yield variations in air temperature, precipitation, solar radiation, disaster, and crop management factors between 1980 and 2020 by the Pettitt mutation test and GeoDetector. Multi-site meteorological data were obtained from different cotton-growing regions and corresponding cotton yield and phenology data were obtained from provinces. Our findings showed that all 17 Chinese provinces experienced advancements in cotton yield. Relative to 1949–1967, China’s cotton production in 2007–2020 increased by 400% while cotton yield increased by 420%. Increases in factors such as minimum temperature (TES), average temperature (ADT), effective accumulated temperature (EAT), precipitation (PP), daily solar radiation (SSD), non-farm employment opportunities (O), disaster area (D), geographic region (GEO) and agricultural technologies like fertilizer usage (F), genetically modified varieties (Bt), and mechanized farming (M) have contributed to the enhanced cotton yield. The importance of single factors influencing cotton yield of China in descending order was as follows: F > Bt > M > GEO > EAT > O > PP > TES > ADT > SSD > D. However, the effects of different climatic and agriculture technological elements on cotton yield are spatially heterogeneous by region, and the combined effects of those elements are higher than those of single elements. The effects of driving factors vary across regional scales. The most significant interaction effects were observed between chemical fertilizer use and other driving factors. Specifically, the interaction between F and TES has the greatest explanatory influence in Northwest China. Our findings provide a reference for the development of more accurate adaptation strategies and management measures in different regions. We recommend that policymakers prioritize measures such as improving climate-resilient cotton varieties, encouraging technological advancements, and implementing policies that support equitable distribution of cultivation. Full article