Resistant Cotton Research Articles

History of USDA-ARS Cotton Host Plant Resistance and Breeding Research at Mississippi State, MS

Cotton host plant resistance research was initiated with the establishment of the Boll Weevil Research Laboratory in 1960. Laboratory objectives were to conduct research and develop technology that ultimately could be used to eradicate the boll weevil. Early research concentrated on developing techniques and screening germplasm for resistance. A full-scale boll weevil eradication trial began in southern Virginia and eastern North Carolina in 1978 and after initial success the USDA Animal and Plant Health Inspection Service established an eradication program. This led the host plant resistance program to broaden its research into other pests of cotton. During the 1980s, research continued to focus on tarnished plant bug, tobacco budworm, expanding the genetic diversity of cotton, basic genetic and cotton breeding studies. With the development of field infestation techniques for the tobacco budworm, in the 1990s the research team conducted the first field test of Bacillus thuringiensis (Bt) transgenic cotton for resistance. During this time, root-knot nematode research expanded. Cotton fruiting efficiency and distribution of harvestable bolls and the concept of plant mapping were developed. During the 2000s, research expanded with the use of chromosome substitution lines for the introgression of new alleles into Upland cotton. Nematode research remained active during this time. To date, the research program has developed and released more than 800 germplasm lines and four random-mating populations. Scientists in the program have trained more than 60 graduate students and countless others have been mentored. The full impact of the research team will only be revealed with time.

Villin Family Members Associated with Multiple Stress Responses in Cotton

Villin (VLN) is considered to be one of the most important actin-binding proteins, participates in modulating the actin cytoskeleton dynamics, plays essential role in plant development and resisting adverse environments. However, systematic studies of the VLN gene family have not been reported in cotton (Gossypium). In this study, 14 GhVLNs were identified in G. hirsutum. These GhVLN genes were distributed in 6 A-subgenome chromosomes and 6 D-subgenome chromosomes of the allotetraploid upland cotton and classified into three phylogenetical groups based on the classification model of AtVLNs. In addition, the 14 GhVLN genes have highly conserved gene structure and motif architecture. The number of introns was ranged from 18 to 22 and the length of protein sequences was varied from 901 to 1077. Six gelsolin homology domains, G1–G6, and villin headpiece domain, VHP, were existed in all GhVLNs with the exception of two VLNs (GhVLN6 and GhVLN13) which lacked VHP. Cis-elements analysis revealed that the promoter regions of GhVLNs contained various light related components and also elements responsible for phytohormones and stresses response, indicating that, when subjected to those adverse environments, cotton plants may activate the response system by targeting VLN genes to survive the crisis. Heatmaps showed that the GhVLN genes exhibited various expression patterns, some were accumulated in certain tissues, root, petal, stamen or elongating fibers, and some were obviously induced by environmental changes. Especially GhVLN3 and GhVLN10 were highly and preferentially expressed in elongating fibers and distinctly upregulated by abiotic (salt, PEG, cold and heat) and biotic (Verticillium dahliae V991) stresses. This study may provide useful information for biological function identification of GhVLN genes and gene resources for creating high-quality and various resistant cotton germplasms.

Relationships Among the Feeding Behaviors of a Mirid Bug on Cotton Leaves of Different Ages and Plant Biochemical Substances.

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) tends to feed on young plant tissues. To explore the relationship between stylet probing behaviors of adult A. lucorum and conditions of cotton leaves, we conducted an experiment using electropenetrography (EPG). Behaviors were recorded on four cotton varieties, in relation to thickness and biochemical traits of differently-aged leaves. Cotton leaf age had a significant effect on the probing behavior of A. lucorum but cotton variety did not. One-day-old leaves of A. lucorum received the highest mean number of stylet probes (penetrations) per insect, and longest mean durations per insect of combined stylet probing or its components, cell rupture and ingestion behaviors. All of the leaf traits (thickness and biochemical substances) were similar among these four cotton varieties. Leaf thickness had a significantly negative effect on the same four variables above. Gossypol and tannin also had a negative impact on combined probing duration. Redundancy analysis showed that the four EPG variables were closely related to nutrient substances (amino acids, sugar, and water) while they had the opposite relationship with plant defense substances (gossypol and tannin). On cotton in the seedling stages, A. lucorum fed more readily on the youngest, thinnest leaves in our no-choice EPG experiments. Nutrients and chemical resistance substances determined the probing duration of A. lucorum. Our findings can contribute to better understanding of patterns of feeding and host consumption by A. lucorum, ultimately improving cotton resistance to A. lucorum.

EarlySeason Morphological and Physiological Responses of Resistant and Susceptible Cotton Genotypes to Reniform Nematode and Soil Nitrogen

Soil fertility and reniform nematode (RN) directly affect earlyseason growth and physiology of cotton. The growth responses to soil fertility and RN may, however, vary across germplasm. A greenhouse study was conducted to gain information on the role that host plant resistance plays in influencing RN populations, and cotton growth and physiological response to a range of soil nitrogen (N) levels in the presence and absence of RN. RN-resistant cotton lines (08SS110-NE06.OP and 08SS100) along with susceptible cultivars (Deltapine 16 and PHY 490 W3FE) were subjected to four levels of N from planting until biomass harvesting, 60 days after planting(DAP), under the presence orabsence of RN. The linear and quadratic functions (r2 = 0.72 to 0.99) bestdescribed measured responses of cotton genotypes to soil N. However, the responses were not different among genotypes, except for plant height at 30 DAP. This study revealed significant increases in several morphological parameters with increasing rates of N. RN population in the pots grown with resistant lines was lower whencompared to susceptible cultivars at biomassharvest. Physiological responses indicated that 08SS110-NE06.OP was more resilient to RN stress than other genotypes. The information from this study could be useful in managing the early season growth of cotton.

Ergosterol-targeting fusion antifungal peptide significantly increases the Verticillium wilt resistance of cotton.

SummaryIncreasing the targeting ability of antifungal proteins towards specific components of fungal cells has the potential to improve their antifungal activity and reduce harmful effects to nontarget cells. To obtain effective disease resistance genes against cotton Verticillium wilt, we constructed several fusion genes, in which binding domains targeting chitin, sphingolipid or ergosterol in the fungal cell wall or cell membrane were individually fused to the antifungal peptide BbAFP1 from entomopathogenic fungus Beauveria bassiana. Transient expression of fusion genes in cotton cotyledons indicated that the BbAFP1::ErBD fusion peptide with an ergosterol binding domain exhibited better disease resistance against V. dahliae than wild‐type BbAFP1 and other fusion genes. BbAFP1::ErBD and BbAFP1 transgenic cotton were obtained and verified by Southern and Western blotting. Compared with BbAFP1‐expressing cotton, BbAFP1::ErBD‐expressing cotton showed higher disease resistance against V. dahliae, with smaller lesion areas (0.07 cm2 vs. 0.16 cm2) on the leaves and a lower disease index (23.9 vs. 34.5). Overexpression of BbAFP1::ErBD by transgenic tobacco also showed enhanced disease resistance against V. dahliae compared with that of the wild‐type gene. These results indicated that construction of fusion antifungal peptides that target fungal cells is a powerful strategy to obtain new anti‐disease genes, and the obtained fusion gene BbAFP1::ErBD has the potential to defend against plant fungal diseases.

Development of hydrophilic anti-crease finishing method for Cotton fabric using alpha-Lipoic acid without causing strength loss and formaldehyde release problem

Extensive research and practice on anti-crease of cotton fabric has been made in the past few decades because of its easy creasing properties. However, it has not achieved a good balance between anti-crease performance, strength loss, hydrophilicity and formaldehyde release until now. In this study, for the first time, α-lipoic acid (ALA) which contains bifunctional groups, carboxyl group and disulfide bond, has been successfully used as an innovative cross-linking agent in the anti-crease functionalization to prepare high crease resistant and hydrophilic cotton fabric without strength loss and formaldehyde release. The mechanism between ALA and cellulose through esterification, disulfide breaking and reconstruction, and anti-crease mechanism based on topological disulfide bridges among cellulosic molecules were illustrated in terms of the characterization analyses of cross-linked ALA and poly(α-lipoic acid). This study provides a completely different idea for the preparation of anti-crease cotton fabric with high strength and hydrophilic without negative environmental impact.

Comparative transcriptome analysis reveals evolutionary divergence and shared network of cold and salt stress response in diploid D-genome cotton

BackgroundWild species of cotton are excellent resistance to abiotic stress. Diploid D-genome cotton showed abundant phenotypic diversity and was the putative donor species of allotetraploid cotton which produce the largest textile natural fiber.ResultsA total of 41,053 genes were expressed in all samples by mapping RNA-seq Illumina reads of G. thurberi (D1), G. klotzschianum (D3-k), G. raimondii (D5) and G. trilobum (D8) to reference genome. The numbers of differently expressed genes (DEGs) were significantly higher under cold stress than salt stress. However, 34.1% DEGs under salt stress were overlapped with cold stress in four species. Notably, a potential shared network (cold and salt response, including 16 genes) was mined out by gene co-expression analysis. A total of 47,180–55,548 unique genes were identified in four diploid species by De novo assembly. Furthermore, 163, 344, 330, and 161 positively selected genes (PSGs) were detected in thurberi, G. klotzschianum, G. raimondii and G. trilobum by evolutionary analysis, respectively, and 9.5–17% PSGs of four species were DEGs in corresponding species under cold or salt stress. What’s more, most of PSGs were enriched GO term related to response to stimulation. G. klotzschianum showed the best tolerance under both cold and salt stress. Interestingly, we found that a RALF-like protein coding gene not only is PSGs of G. klotzschianum, but also belongs to the potential shared network.ConclusionOur study provided new evidence that gene expression variations of evolution by natural selection were essential drivers of the morphological variations related to environmental adaptation during evolution. Additionally, there exist shared regulated networks under cold and salt stress, such as Ca2+ signal transduction and oxidation-reduction mechanisms. Our work establishes a transcriptomic selection mechanism for altering gene expression of the four diploid D-genome cotton and provides available gene resource underlying multi-abiotic resistant cotton breeding strategy.

Nbnrp1 mediates Verticillium dahliae effector PevD1-triggered defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway in Nicotiana benthamiana.

PevD1, a fungal effector secreted by Verticillium dahliae, could induce hypersensitive responses-like necrosis and systemic acquired resistance (SAR) in cotton and tobacco plants. PevD1 could drastically induce the expression of Nbnrp1, which is an asparagine-rich protein (NRP) of Nicotiana benthamiana. Our previous research indicated that Nbnrp1 positively regulated PevD1-induced cell necrosis and disease resistance. In this study, we further investigated PevD1-induced immune responses in both wild-type (WT) and Nbnrp1-RNAi lines through RNA-seq, in order to reveal the underlying mechanism of Nbnrp1-modulated PevD1-induced disease resistance in N. benthamiana. Results showed that Nbnrp1-RNAi lines exhibited reduced PevD1-induced immune responses, like inhibiting H2O2 accumulation and MAPK phosphorylation. To silence Nbnrp1 inhibited the expression of PevD1-induced differential expression genes (DEGs) involved in pathways associated with sesquiterpenoid and triterpenoid biosynthesis, flavone and flavonol biosynthesis, plant-pathogen interaction and phenylpropanoid biosynthesis, etc. It is worth noting that sesquiterpene phytoalexin capsidiol accumulation were obviously decreased in Nbnrp1-RNAi plants after PevD1 treatment, accompanied with the down-expression of EAS and EAH, which were two key genes related to capsidiol biosynthesis. These results suggested that Nbnrp1 mediates PevD1-induced defense responses by regulating sesquiterpenoid phytoalexins biosynthesis pathway.

Effects of production practices on temporal disease progress of Verticillium wilt of cotton (Gossypium hirsutum L.) in the Texas High Plains, USA

Verticillium wilt of cotton (Gossypium hirsutum L.), caused by the soilborne fungus Verticillium dahliae Kleb., is an economically damaging disease. To date, limited information is available regarding the effects of common production practices on the epidemiology of Verticillium wilt of cotton. Therefore, this study evaluated the effectiveness of different seeding rates and cotton cultivars on suppressing Verticillium wilt and simulate the temporal dynamics of Verticillium wilt in cotton. Field experiments were conducted in 2015 and 2016 at two locations naturally infested with V. dahliae in the Texas High Plains. Results indicated wilt incidence decreased significantly up to 49% when planting partially resistant cotton cultivars at higher seeding rates (9.8–19.5 seeds m−2) at both locations across years (P < 0.05). The area under disease progress curves (AUDPC) increased significantly as seeding rate decreased, and the partially resistant cultivar FiberMax 2484B2F showed a significantly lower AUDPC compared to the susceptible cultivar Deltapine 1212B2RF. Reductions in lint yields by Verticillium wilt, particularly under high disease pressure, could reach 1.03 tons ha−1 (P < 0.05). FiberMax 2484B2F remained significantly lower wilt incidence (23%) than the susceptible cultivar. When characterizing temporal disease progress, nonlinear Gompertz, logistic, and exponential models had better statistical fit (R2) than the linear model (P < 0.05). Under high disease pressure in 2016, the R2 values (0.94 and 0.97 at Quaker and Cone) of the Gompertz model were significantly greater than others. The Gompertz was determined to be the optimal fitting model for simulating the Verticillium wilt epidemics.

Genome-Wide Identification of the Gossypium hirsutum NHX Genes Reveals that the Endosomal-Type GhNHX4A is Critical for the Salt Tolerance of Cotton.

Soil salinization, which is primarily due to excessive Na+ levels, is a major abiotic stress adversely affecting plant growth and development. The Na+/H+ antiporter (NHX) is a transmembrane protein mediating the transport of Na+ or K+ and H+ across the membrane to modulate the ionic balance of plants in response to salt stress. Research regarding NHXs has mainly focused on the vacuolar-type NHX family members. However, the biological functions of the endosomal-type NHXs remain relatively uncharacterized. In this study, 22 NHX family members were identified in Gossypium hirsutum. A phylogenetic analysis divided the GhNHX genes into two categories, with 18 and 4 in the vacuolar and endosomal groups, respectively. The chromosomal distribution of the NHX genes revealed the significant impact of genome-wide duplication during the polyploidization process on the number of GhNHX genes. Analyses of gene structures and conserved motifs indicated that GhNHX genes in the same phylogenetic cluster are conserved. Additionally, the salt-induced expression patterns confirmed that the expression levels of most of the GhNHX genes are affected by salinity. Specifically, in the endosomal group, GhNHX4A expression was substantially up-regulated by salt stress. A yeast functional complementation test proved that GhNHX4A can partially restore the salt tolerance of the salt-sensitive yeast mutant AXT3. Silencing GhNHX4A expression decreased the resistance of cotton to salt stress because of an increase in the accumulation of Na+ in stems and a decrease in the accumulation of K+ in roots. The results of this study may provide the basis for an in-depth characterization of the regulatory functions of NHX genes related to cotton salt tolerance, especially the endosomal-type GhNHX4A. Furthermore, the presented data may be useful for selecting appropriate candidate genes for the breeding of new salt-tolerant cotton varieties.

Phosphate deficiency enhances cotton resistance to Verticillium dahliae through activating jasmonic acid biosynthesis and phenylpropanoid pathway

Living in natural environment, plants often suffer from various biotic and abiotic stresses. Phosphate deficiency is a common factor affecting crop production in field, while pathogen invasion is another serious problem. Here we report that Pi-deficient cotton plants exhibit enhanced resistance to Verticillium dahliae. Transcriptomic and histochemical analysis revealed that cotton phenylpropanoid pathway was activated under phosphate deficiency, including lignin and flavonoid biosynthesis. Metabolomic data showed that Pi-deficient cotton accumulates many flavonoids metabolites and displays obvious anti-fungi activity in terms of methanolic extract. Additionally, JA biosynthesis was activated under phosphate deficiency and the Pi-deficiency induced disease resistance was significantly attenuated in GhAOS knock down plants. Taken together, our study demonstrated that phosphate deficiency enhanced cotton resistance to V. dahliae through activating phenylpropanoid pathway and JA biosynthesis, providing new insights into how phosphate deficiency affects plant disease resistance.

Cotton seedling drought tolerance is improved via salt preconditioning.

In this study, 12 upland cotton seedlings were used as the material, and four treatments were designed (15% PEG for 6 h, 250 mM NaCl for 3 h, 15% PEG for 6 h after 250 mM NaCl pretreatment, and blank control). Various physiological indicators, including the malondialdehyde (MDA) and proline (Pro) contents and superoxide dismutase (SOD) and peroxidase (POD) activities, and the relative electrolyte leakage (REL), were measured during exposure to the aforementioned stresses, and three stress-related transcription factors (GhHsfA, GhbZIP, and GhNAC) were used to assess the differences in the drought resistance of cotton during exposure to PEG stress and NaCl/PEG combined stress. The analyses of the physiological and biochemical indicators revealed that the cotton seedlings exposed to NaCl/PEG combined stress exhibited the highest relative changes in the SOD and POD enzyme activities, while the relative changes in the MDA content and REL were relatively small. The cluster analysis showed that the treatments could be ranked as follows based on degree of damage exhibited by the exposed cotton seedlings: PEG > NaCl > NaCl/PEG. The exposure of cotton to NaCl/PEG combined stress resulted in a lower degree of damage than that obtained after exposure to PEG alone, which indicated that an appropriate amount of NaCl could partially relieve the adverse effects of drought on cotton seedlings. In addition, the relative expression levels of GhHsfA, GhbZIP, and GhNAC were significantly correlated with multiple physiological and biochemical indicators under different stresses, and the principal component analysis identified these transcription factors as important indicators. Based on these findings, these three transcription factors can be used as molecular indicators for the identification of drought resistance. A comprehensive D value cluster analysis ranked the 12 cotton varieties based on their drought resistance, and the most drought-resistant variety was ND359-5. This study provides new methods and materials for research on drought resistance in cotton.

The synergetic modification of surface micro-dissolution and cationization for fabricating cotton fabrics with high UV resistance and conductivity by enriched GO coating

Multifunctional textiles based on cotton have attracted wide attentions recently. In this study, the cotton fabrics were synergistically modified by surface micro-dissolution and cationization to enrich the adsorption of negatively charged graphene oxide (GO) on it. Subsequently, the bound GO was chemically reduced to rGO by using L-Ascorbic acid to endow cotton with high UV resistance and conductivity. By XRD, FTIR and zeta potential analysis, it was concluded that the synergistic modification could alter the structure of cotton and at the same time facilitate the reactions between cotton molecules and cationic agent EPTAC. This would shield more negative charges in cotton to decrease its absolute zeta potential, enhancing the uptake of negatively charged GO on the surface of cotton significantly. In addition, SEM, FTIR and Raman spectroscopy were utilized to confirm the presence of rGO on the surface of cotton fabrics. The result from resistance measurement disclosed that the synergistic modification could significantly reduce the electrical surface resistance of cotton to 3.89 × 103 Ω/sq. Moreover, the synergistic modification could greatly improve the UV protection factor (UPF) of cotton from 24.18 to 487.91, far beyond the excellent UPF rating (50+). The high UV resistance and conductivity of this rGO coated cotton fabrics suggests that they can be used as functional textiles for various applications.

Flame Resistant Cotton Fabric Containing Casein and Inorganic Materials Using an Environmentally-Friendly Microwave Assisted Technique

New methods for formulating flame retardant cotton fabrics have been achieved by applying a microwave-assisted technique with low amounts of solvent. Trials using cotton fabrics treated with casein from bovine milk and eco-friendly inorganic materials, urea and diammonium phosphate, were completed successfully. Thermogravimetric analysis (TGA), 45 ° angle (clothing textiles test), and limiting oxygen index (LOI) tests were carried out for the treated cotton fabrics. When the treated fabrics were tested using the 45 ° angle flame, the ignited fabrics self-extinguished and left behind a streak of char. Treated higher add-on fabrics were neither consumed by flame, nor produced glowing embers upon self-extinguishing. All untreated cotton fabrics showed limiting oxygen index (LOI) values of about 18 % oxygen in nitrogen. For formulations with casein, urea and diammonium phosphate, LOI values of treated fabrics were 32.0–44.0 % oxygen in nitrogen when add-on values for the formulation were 9.71–23.5 wt%. Furthermore, scanning electron microscope (SEM) was employed to characterize the chemical structure on the treated fabrics, as well as, the surface morphology of char areas of treated and untreated fabrics.

Pectin lyase enhances cotton resistance to Verticillium wilt by inducing cell apoptosis of Verticillium dahliae

Verticillium wilt caused by Verticillium dahliae Kleb. is a major disease in cotton. We found that pectin lyase can enhance cotton resistance to Verticillium wilt and induce cell apoptosis of V. dahliae strain Vd080. The biocontrol effect of pectin lyase on Vd080 reached 61.9%. Pectin lyase increased ERG4 (Delta (24 (24 (1)))-sterol reductase) expression, the ergosterol content of the cell membrane, the collapse of mitochondrial membrane potential, hydrogen peroxide content, metacaspase activity, and Ca2+ content in the cytoplasm in the Vd080 strain and induced endoplasmic reticulum (ER) stress. Pectin lyase also increased the expression levels of the ER molecular chaperone glucose regulating protein Grp78 (BiP), protein disulfide isomerase (PDI) and calnexin (CNX), reduced the expression levels of the protein Hsp40. When the PDI and BiP genes of Vd080 were knocked out, the mutants △BiP and △PDI had reduced sensitivity to pectin lyase. In the absence of external stress, ER stress appeared in mutant △BiP cells. Pectin lyase affects the ergosterol content of the Vd080 cell membrane, which causes ER stress and increases the level of BiP to induce Vd080 cell apoptosis. These results demonstrate that pectin lyase can be used to control Verticillium wilt in cotton.

The Cotton BEL1-Like Transcription Factor GhBLH7-D06 Negatively Regulates the Defense Response against Verticillium dahliae.

Verticillium wilt will seriously affect cotton yield and fiber quality. BEL1-Like transcription factors are involved in the regulation of secondary cell wall (SCW) formation, especially the biosynthesis of lignin that also plays a key role in cotton disease resistance. However, there is no report on the role of BEL1-Like transcription factor in the regulation of plant biological stress. In this study, tissue expression pattern analysis showed that a BEL1-Like transcription factor GhBLH7-D06 was predominantly expressed in vascular tissues and the SCW thickening stage of fiber development, while its expression could also respond to Verticillium dahliae infection and the phytohormone MeJA treatment, which indicated that GhBLH7-D06 might be involved in the defense response of Verticillium wilt. Using virus-induced gene silencing (VIGS) technology, we found silencing the expression of GhBLH7-D06 could enhance the resistance of cotton plants to Verticillium wilt, and the acquisition of resistance might be mainly due to the significant overexpression of genes related to lignin biosynthesis and JA signaling pathway, which also proves that GhBLH7-D06 negatively regulates the resistance of cotton to Verticillium wilt. Based on the results of yeast two-hybrid (Y2H) library screening and confirmation by bimolecular fluorescence complementary (BiFC) experiment, we found an Ovate Family Protein (OFP) transcription factor GhOFP3-D13 which was also a negative regulator of cotton Verticillium wilt resistance could that interacts with GhBLH7-D06. Furthermore, the dual-luciferase reporter assay and yeast one-hybrid (Y1H) experiment indicated that GhBLH7-D06 could target binding to the promoter region of GhPAL-A06 to suppress its expression and eventually lead to the inhibition of lignin biosynthesis. In general, the GhBLH7-D06/GhOFP3-D13 complex can negatively regulate resistance to Verticillium wilt of cotton by inhibiting lignin biosynthesis and JA signaling pathway.

Genome-Wide Analysis of OPR Family Genes in Cotton Identified a Role for GhOPR9 in Verticillium dahliae Resistance.

The 12-oxo-phytodienoic acid reductases (OPRs) have been proven to play a major role in plant development and growth. Although the classification and functions of OPRs have been well understood in Arabidopsis, tomato, rice, maize, and wheat, the information of OPR genes in cotton genome and their responses to biotic and abiotic stresses have not been reported. In this study, we found 10 and 9 OPR genes in Gossypium hirsutum and Gossypium barbadense, respectively. They were classified into three groups, based on the similar gene structure and conserved protein motifs. These OPR genes just located on chromosome 01, chromosome 05, and chromosome 06. In addition, the whole genome duplication (WGD) or segmental duplication events contributed to the evolution of the OPR gene family. The analyses of cis-acting regulatory elements of GhOPRs showed that the functions of OPR genes in cotton might be related to growth, development, hormone, and stresses. Expression patterns showed that GhOPRs were upregulated under salt treatment and repressed by polyethylene glycol 6000 (PEG6000). The expression patterns of GhOPRs were different in leaf, root, and stem under V. dahliae infection. GhOPR9 showed a higher expression level than other OPR genes in cotton root. The virus-induced gene silencing (VIGS) analysis suggested that knockdown of GhOPR9 could increase the susceptibility of cotton to V. dahliae infection. Furthermore, GhOPR9 also modulated the expressions of jasmonic acid (JA) pathway-regulated genes under the V. dahliae infection. Overall, our results provided the evolution and potential functions of the OPR genes in cotton. These findings suggested that GhOPR9 might play an important role in cotton resistance to V. dahliae.

Micronutrient Fertilization of Greenhouse Cucumbers Mitigates Pirimicarb Resistance in Aphis gossypii (Hemiptera: Aphididae).

The nutritional status of host plants can have direct impacts on herbivore physiology and insect-plant interactions. We investigated the effect of micronutrients, including manganese, iron, zinc, and copper, on cucumber plant physiology, and on the biology and physiology of a strain of Aphis gossypii Glover selected over 12 generations to be resistant to pirimicarb. The micronutrient treatment increased the activity of superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase in cucumber plants, and also increased levels of total phenolics, hydrogen peroxide, salicylic acid, and total chlorophyl, whereas malondialdehyde levels were unaffected. Pirimicarb-resistant cotton aphids that fed on micronutritient-amended cucumber plants expressed significantly decreased levels of acetylcholinesterase and detoxifying enzymes, specifically glutathione S-transferase, and carboxylesterase. Analysis of energy reserves in resistant A. gossypii fed on micronutritient-amended plants revealed decreases in the lipid and protein contents of aphids, whereas glycogen and carbohydrate contents showed no response. Resistant cotton aphids fed on micronutritient-amended plants showed significantly reduced fecundity, longevity, and reproductive periods, and a 1.7-fold reduction in pirimicarb LC50 compared with those fed on control plants. We conclude that micronutrient amendment negatively impacts the biological performance of insecticide-resistant cotton aphids, and diminishes their resistance to pirimicarb. Both direct effects on plant health, such as enhanced inducible defenses, and indirect effects on aphid fitness, such as reduced biological performance and detoxification abilities, were implicated. Therefore, optimization of micronutrient amendments could be a useful complement to other tactics for managing insecticide-resistant A. gossypii on cucumbers, and warrants exploration in other contexts.

MXene-Coated Air-Permeable Pressure-Sensing Fabric for Smart Wear.

Considering the fast development of wearable electronics and soft robotics, pressure sensors with high sensitivity, durability, and washability are of great importance. However, the surface modification of fabrics with high-sensitivity active materials requires that issues associated with poor interface adhesion and stability are resolved. In this study, we explored the key factors for firmly bonding MXene to fabric substrates to fabricate wearable and washable pressure sensing fabric. The interactions between MXene and various fabrics were elucidated by investigating the adsorption and binding capacities. The natural rough surface of cotton fibers also promoted the firm adsorption of MXene. As a result, MXene was difficult to detach, even with mechanical washing and ultrasonic treatment. Further, the abundant functional groups on the MXene surface were conducive to interfacial interactions with cotton fibers. An increase in the amount of fluorine-containing functional groups also improved the hydrophobicity of the fabric surface. The good force-sensitive resistance of MXene-coated cotton allowed this pressure-sensing fabric to function as a flexible pressure sensor, which showed a high gauge factor (7.67 kPa-1), a rapid response and relaxation speed (<35 ms), excellent stability (>2000 cycles), and good washing durability. Further, the as-fabricated flexible pressure sensor was demonstrated as a wearable human-machine interface that supported multitouch interactions and exhibited a rapid response. Thus, this work provides a new approach for developing next-generation high-sensitivity wearable pressure sensors.

Analysis of differentially expressed proteins affecting insecticidal protein content in Bt cotton under high‐temperature and water deficit stress using label‐free quantitation

AbstractDifferently expression proteins under high‐temperature and drought stress were screened to investigate how stress affected the insecticidal protein content. These stresses decrease insecticidal protein, so the goal of this study was to provide a theoretical reference for maintaining the insect resistance of Bt cotton. The effect of high‐temperature and drought stress on differently expression protein in Bt cotton cultivar Sikang 3 was investigated using a label‐free quantitation method. Two treatments [40% field capacity and 38°C (HD) and 70% field capacity and 32°C (CK)] were imposed in a controlled environment. The results showed that high‐temperature and drought significantly degraded insecticidal protein content in bolls, with a decrease of 65.2 ng/g fresh weight (FW) compared to CK. The analysis of differently expression proteins with a label‐free quantitative proteomic approach showed that 83 proteins were significantly up‐regulated, but 104 proteins were significantly down‐regulated (Ratio &gt; ±2, p value &lt; 0.05) compared with CK. In addition, 122 new proteins were detected and 167 proteins were not detected. The analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways showed that 14 KEGG pathways, in which the difference expression proteins were enriched, were significantly affected and three KEGG pathways (carbohydrate digestion and absorption, protein export and protein processing in endoplasmic reticulum) were related to protein synthesis. In the carbohydrate digestion and absorption pathway, the capacity of starch hydrolysis for HD increased, while the capacity to phosphorylate the hexoses, fructose and glucose decreased. In protein export pathway, the synthesis of peptide for HD was not significant affected, while the process of peptide transferred into the endoplasmic reticulum was confined. In the protein processing in endoplasmic reticulum pathway, the capacity of ubiquitin‐mediated proteolysis increased.