Cotton Seedlings Research Articles

Identification, Genome Characterization, and Growth Optimization of Paenibacillus Peoriae MHJL1 for Biocontrol and Growth Promotion of Cotton Seedlings

Fusarium and verticillium wilt are the primary diseases affecting cotton plants, significantly reducing both the yield and quality of cotton. Paenibacillus spp. are crucial biocontrol strains for controlling plant diseases. In this study, Paenibacillus peoriae MHJL1, which could prevent the pathogenic fungi of fusarium and verticillium wilt and promote cotton growth, was isolated from the rhizosphere soil of cotton plants. Whole-genome analysis of strain MHJL1 identified 16 gene clusters for secondary metabolite synthesis, including fusaricidins with potent antifungal properties. By optimizing the fermentation process, the cell and spore numbers of MHJL1 were increased to 2.14 × 108 CFU/mL and 8.66 × 108 CFU/mL, respectively. Moreover, the antifungal ability of MHJL1 was also increased by 31.48%. In pot experiments conducted with healthy soil, the control rates for MHJL1 against fusarium and verticillium wilt were found to be 44.83% and 58.27%, respectively; in experiments using continuously cropped soil, the control rates were 55.22% against fusarium wilt and 48.46% against verticillium wilt. Our findings provide valuable insights for the biocontrol application and fermentation of P. peoriae MHJL1, while also contributing a new resource for the development of microbial agents.

Qualitative and Quantitative Analyses of 1-Aminocyclopropane-1-carboxylic Acid Concentrations in Plants Organs Using Phenyl Isothiocyanate Derivatization.

1-Aminocyclopropane-1-carboxylic acid (ACC) is a direct precursor of phytohormone ethylene. We used a phenyl isothiocyanate (PITC) derivatization modification method combined with spectrographic analysis to isolate and identify three products of the derivatization reactions of ACC and PITC. The MRM+ mode of UPLC-MS/MS was used to establish the analysis of 6-phenyl-5-thioxo-4,6-diazaspiro[2.4]heptan-7-one (PTH-ACC). Three fragment ions detected at the precursor ion (m/z 219.10) were selected for qualitative analysis (m/z 98.10, 77.15, and 72.10), and the most abundant product ion (m/z 98.10) was selected for quantitative analysis. The conditions for the derivatization reaction for the main product PTH-ACC were analyzed and optimized using response surface methodology, resulting in the optimal derivatization conditions being a reaction temperature of 90 °C, a reaction time of 1.5 h, and a formic acid (FA) concentration of 40%. ACC concentrations in 25-200 mg rice samples was successfully determined. Moreover, the ACC concentrations in the shoots, seeds, and roots of rice, maize, and cotton seedlings were all analyzed. The ACC concentrations were found to exhibit tissue specificity. Interestingly, during the ripening process in tomato and mango fruits, the concentrations of ACC in the fruits showed an initial increase, followed by a decrease. In black nightshade fruits, ACC content was the highest in the immature stage, decreased with fruit ripening, and remained stable from the semimature to mature stages. These results provide a reliable analysis technology foundation for the study of ethylene.

Development, Shelf Stability, and In-Vitro Evaluation of Liquid Bacterial Inoculant Acinetobacter lwoffii Strain PAU_31LN.

Acinetobacter has been recognized as a versatile plant growth promoting (PGP) rhizobacteria (PGPR) that produce multiple PGP traits. The present study was conducted to formulate an efficient and stable liquid bacterial inoculant (LBI) of Acinetobacter lwoffii strain PAU_31LN. In the current investigation, total 16 endophytic bacteria were isolated from cotton leaves and evaluated for plant growth-promoting features such as production of phytohormones, mineral solubilization, siderophore production, hydrogen cyanide (HCN) production, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. The leaf endophytic bacteria designated as 31LN was found promising for all the PGP traits and it was identified as A. lwoffii strain PAU_31LN by 16S rRNA gene sequencing. For the development of LBI of A. lwoffii strain PAU_31LN, 4.5 g/L yeast extract, 5 g/L NaCl, 5 g/L peptone, and 12.5 mM food-grade trehalose was optimized as appropriate medium composition using response surface methodology (RSM) and Box-Behnken design. Further, the viability of A. lwoffii strain PAU_31LN in the optimized formulation was observed as 1.1 folds higher over the control after 180 days of storage at room temperature. Moreover, nonsignificant variation was recorded in the functional traits of 180 days old LBI of A. lwoffii strain PAU_31LN and freshly prepared LBI. The in-vitro plant growth parameters such as length and seed vigor index of 7-day-old cotton seedlings were enhanced by the seed bio-priming with LBI of A. lwoffii strain PAU_31LN over the control. The results of the present study signify the importance of endophytes and statistical methods to formulate prominent LBI.

The influence of crop and leaf position on thrips (Thysanoptera: Thripidae) oviposition in cotton, soybean, and peanut seedlings.

Thrips (Thysanoptera: Thripidae) can injure seedling cotton (Gossypium hirsutum L.), soybean (Glycine max (L.) Merr.), and peanut (Arachis hypogaea L.) crops in the southern United States. The planting window and timing of thrips infestations into these crops overlap in the region, but thrips preference for oviposition has not been investigated. We evaluated thrips preference for cotton, soybean, and peanut by counting eggs, immatures, and adults at the cotyledon to 4 true leaf stages. Peanut was significantly more attractive for oviposition than cotton and soybean. Oviposition in cotton was significantly higher in the cotyledons than the other leaves. The highest oviposition in soybeans also occurred in the cotyledons but differed only significantly from the fourth true leaf. In all crops, there was no significant difference among oviposition in the true leaves. The highest number of immatures were found on cotton, followed by peanut and then soybean, while adults were evenly distributed among crops. Our results suggest that while peanut is preferred for oviposition, this crop may not facilitate immature development and survival as effectively when compared with cotton. This study presents an initial examination of crop selection by thrips under field conditions and suggests peanut may be the preferred oviposition host.

Comprehensive analysis of amino acid/auxin permease family genes reveal the positive role of GhAAAP128 in cotton tolerance to cold stress.

Amino acid/auxin permeases (AAAPs) play crucial roles in plant development and response to environmental stimuli. They have been characterized at genome-wide levels in several plant species. However, little is known about the AAAP genes in Gossypium. Here, we identified 149, 141, 73, and 70 AAAPs from four Gossypium species G. hirsutum, G. barbadense, G. arboreum, and G. raimondii, respectively. All the AAAPs were categorized into eight subfamilies (Groups I-VIII). Moreover, we found that 182 and 179 AAAP paralogous gene pairs existed within G. hirsutum and G. barbadense genomes, respectively, and whole genome duplication (WGD) or segmental duplication contributed to the expansion of these AAAPs during evolution. Additionally, many cis-elements related to abiotic stress responses were detected in the promoter regions of GhAAAPs and GbAAAPs. Consistently, the expression of multiple AAAPs was significantly induced by NaCl, polyethylene glycol 6000, and especially cold stress. Among these GhAAAPs, GhAAAP128 had clearly positive roles in cotton and Arabidopsis seedling tolerance to cold stress. GhAAAP128 may also improve cold tolerance by up-regulating the expression of some anthocyanin synthesis genes rather than CBF (C-repeat binding factor) signaling genes. Our findings provide important information for further functional analysis of GhAAAPs in response to stressful cues, particularly cold stress in cotton plants.

The Application of Melatonin and Organic Waste Derived from Vitamin C Industry Effectively Promotes Seed Germination and Seedling Growth of Cotton in Saline–Alkali Soil

Saline–alkali stress severely affects plant growth and productivity. Although melatonin can promote seed germination as a growth regulator, it cannot address the weak seedling growth caused by insufficient organic nutrients in saline–alkali soil. The RAE (residue after evaporation, an industrial waste from the industrial production of vitamin C) can enhance plant salt tolerance by stimulating vitamin C (ASA) synthesis and contains abundant small molecular organic acids. We hypothesized that the combined application of melatonin and RAE might synergistically enhance cotton germination and seedling growth. The cotton seeds used in this study were “Xin Lu Zhong No. 87”; a Petri dish simulation experiment and a pot experiment were conducted in 2023. Four treatments were set: control (CK), melatonin (MT), RAE (RAE), and the combined application of MT and RAE (MR). Compared to CK, MT significantly increased the germination rate of cotton seed (194.4%), while RAE significantly enhanced the underground biomass of cotton seedlings (40.3%) and ASA content (203.8%). Compared to MT and R, the combined application of melatonin and RAE significantly increased the ASA content (54.5%, 29.6%) in roots, superoxide dismutase (SOD) activity (220.3%, 89.6%) in roots, catalase (CAT) activity (15.8%, 97.5%) in leaves on the 15th day, soil cation exchange capacity (CEC) (57.2%, 9.7%), and total fresh weight (20.8%, 33.8%). Collectively, these findings indicate that the synergistic effect under the combined use of melatonin and RAE promotes cotton seed germination and seedling growth, offering a novel technical solution for salt–alkali soil cotton cultivation along with an innovative approach for the resource utilization of RAE.

Decision-Making Using the Correlation Coefficient Measures of Intuitionistic Fuzzy Rough Graph

The hybrid approach produced by combining mathematical representations of intuitionistic fuzzy sets and rough sets is called an intuitionistic fuzzy rough framework. This novel approach addresses vagueness and soft computation by using the lower and upper approximation spaces. The degree of connection between intuitionistic fuzzy rough preference relations is assessed in this study using the correlation coefficient method. An improved comprehension of the link between fuzzy elements is made possible by the superior features of the suggested correlation coefficient measure over the current one. An intuitionistic fuzzy rough environment in which attribute decision-making is based on integrated with the correlation coefficient measure. Additionally, a novel method for determining expert weights based on intuitionistic fuzzy rough preference relations uncertainty and the degree of each IFRPR's correlation coefficient is proposed in the paper. The correlation coefficient measurements between each option and the optimal choice are used in the study to calculate the ranking order of the alternatives. Finally, we introduce a cooperative decision-making method in a cotton seed; this concept may be developed in several advantageous cotton seedlings.

GhCOMT33D modulates melatonin synthesis, impacting plant response to Cd2+ in cotton via ROS.

Caffeic acid-3-O-methyltransferase (COMT) serves as the final pivotal enzyme in melatonin biosynthesis and plays a crucial role in governing the synthesis of melatonin in plants. This research used bioinformatics to analyze the phylogenetic relationships, gene structure, and promoter cis-acting elements of the upland cotton COMT gene family members， which it identified as the key gene GhCOMT33D to promote melatonin synthesis and responding to Cd2+ stress. After silencing GhCOMT33D through virus-induced gene silencing (VIGS), cotton seedlings showed less resistance to Cd2+ stress. Under Cd2+ stress, the melatonin content in the silenced plants significantly decreased, while ROS, MDA, and proline accumulated in the plant cells. The stomatal aperture of the leaves was reduced, hindering normal photosynthesis, leading to cotton leaves withering and yellowing, and epidermal cells becoming twisted and deformed, with a large number of gaps appearing. The non-silenced plants had a significantly higher melatonin content and were in better condition, providing important evidence for further research on how plant melatonin enhances the Cd2+ resistance of cotton and its regulatory mechanisms.

Growth Parameters of Cotton in Relay Strip Intercropping: Before and After Wheat Harvest

To investigate cotton's adaptation to various microclimates provided by wheat height, a field experiment was conducted to observe the morphological and physiological traits of cotton seedlings before and after wheat harvest. The cotton was grown in relay strip intercropping with wheat of varying heights. The study observed canopy temperature depression (CTD), average leaf area (ALA), specific leaf area (SLA), SPAD values, net assimilation rates (NAR), total dry weight (TDW). During the shading period, intercropped cotton exhibited stress, indicated by CTD, compared to monocropped cotton (MC). This negative effect was more pronounced in short wheat-cotton intercropping (SC). Microclimates influenced leaf traits and biomass accumulation, with smaller ALA, higher SLA, higher SPAD values, and lower NAR observed in intercropped cotton, especially in SC, resulting in decreased TDW. Following wheat harvest, cotton plants, particularly in SC, exhibited significant NAR recovery by adjusting leaf structure. However, while this adjustment mitigated differences in TDW and yield compared to tall wheat-cotton intercropping (TC), disparities with MC remained. SC had a more pronounced negative impact on cotton before wheat harvest compared to TC. However, rapid recovery of cotton mitigated this negative effect in SC after wheat harvest.

Functions of exogenous strigolactone application and strigolactone biosynthesis genes GhMAX3/GhMAX4b in response to drought tolerance in cotton (Gossypium hirsutum L.)

BackgroundDrought stress markedly constrains plant growth and diminishes crop productivity. Strigolactones (SLs) exert a beneficial influence on plant resilience to drought conditions. Nevertheless, the specific function of SLs in modulating cotton’s response to drought stress remains to be elucidated.ResultsIn this study, we assess the impact of exogenous SL (rac-GR24) administration at various concentrations (0, 1, 5, 10, 20 µM) on cotton growth during drought stress. The findings reveal that cotton seedlings treated with 5 µM exogenous SL exhibit optimal mitigation of growth suppression induced by drought stress. Treatment with 5 µM exogenous SL under drought stress conditions enhances drought tolerance in cotton seedlings by augmenting photosynthetic efficiency, facilitating stomatal closure, diminishing reactive oxygen species (ROS) generation, alleviating membrane lipid peroxidation, enhancing the activity of antioxidant enzymes, elevating the levels of osmoregulatory compounds, and upregulating the expression of drought-responsive genes. The suppression of cotton SL biosynthesis genes, MORE AXILLARY GROWTH 3 (GhMAX3) and GhMAX4b, impairs the drought tolerance of cotton. Conversely, overexpression of GhMAX3 and GhMAX4b in respective Arabidopsis mutants ameliorates the drought-sensitive phenotype in these mutants.ConclusionThese observations underscore that SLs significantly bolster cotton’s resistance to drought stress.

Assessing the Pathogenicity of Berkeleyomyces rouxiae and Fusarium oxysporum f. sp. vasinfectum on Cotton (Gossypium hirsutum) Using a Rapid and Robust Seedling Screening Method.

Cotton (Gossypium spp.) is the most important fibre crop worldwide. Black root rot and Fusarium wilt are two major diseases of cotton caused by soil-borne Berkeleyomyces rouxiae and Fusarium oxysporum f. sp. vasinfectum (Fov), respectively. Phenotyping plant symptoms caused by soil-borne pathogens has always been a challenge. To increase the uniformity of infection, we adapted a seedling screening method that directly uses liquid cultures to inoculate the plant roots and the soil. Four isolates, each of B. rouxiae and Fov, were collected from cotton fields in Australia and were characterised for virulence on cotton under controlled plant growth conditions. While the identities of all four B. rouxiae isolates were confirmed by multilocus sequencing, only two of them were found to be pathogenic on cotton, suggesting variability in the ability of isolates of this species to cause disease. The four Fov isolates were phylogenetically clustered together with the other Australian Fov isolates and displayed both external and internal symptoms characteristic of Fusarium wilt on cotton plants. Furthermore, the isolates appeared to induce varied levels of plant disease severity indicating differences in their virulence on cotton. To contrast the virulence of the Fov isolates, four putatively non-pathogenic Fusarium oxysporum (Fo) isolates collected from cotton seedlings exhibiting atypical wilt symptoms were assessed for their ability to colonise cotton host. Despite the absence of Secreted in Xylem genes (SIX6, SIX11, SIX13 and SIX14) characteristic of Fov, all four Fo isolates retained the ability to colonise cotton and induce wilt symptoms. This suggests that slightly virulent strains of Fo may contribute to the overall occurrence of Fusarium wilt in cotton fields. Findings from this study will allow better distinction to be made between plant pathogens and endophytes and allow fungal effectors underpinning pathogenicity to be explored.

Controlling Damping - Off Disease on Cotton Seedlings Caused by Rhizoctonia solani and Fusarium oxysporum Via Plant Growth-Promoting Rhizobacteria (PGPR)

Controlling Damping - Off Disease on Cotton Seedlings Caused by Rhizoctonia solani and Fusarium oxysporum Via Plant Growth-Promoting Rhizobacteria (PGPR)

Exogenous application of silica nanoparticles mitigates combined salt and low-temperature stress in cotton seedlings by improving the K+/Na+ ratio and antioxidant defense

Silica nanoparticles (SiO2-NPs) have been demonstrated to alleviate the adverse impacts of salt or low temperature on crop growth, especially for individual stress. The aim of this study was to elucidate the regulatory effect of SiO2-NPs on plant performance under combined salt and low-temperature stress. Therefore, a phytotron experiment was performed to explore the effects of SiO2-NPs application (0, 50, 100, 200 mg L−1) on the plant growth, ionic content, antioxidant activities, photosynthetic parameters, and osmoregulator concentrations of cotton seedlings subjected to the combined stress of salinity (50, 100, and 150 mmol L−1 NaCl) and low temperature (day and night temperatures of 15 and 10 °C). The results indicated that the combinatorial stress strongly decreased the plant height and leaf area of cotton seedlings, and obviously suppressed the aboveground biomass by 10.26 %, 11.42 %, and 15.70 % with the increase in salinity. While SiO2-NPs application significantly increased the plant growth, photosynthetic rate, transpiration rate, stomatal conductance, superoxide dismutase, catalase and glutathione reductase activities, leaf water potential, K+, and proline contents, and reduced the Na+ content and Na+/K+ ratio of cotton seedlings under the combinatorial stress. However, the effects of SiO2-NPs on reduced glutathione, total soluble sugar and protein content, and peroxidase activity did not exhibit a clear pattern. The aboveground biomass of cotton seedlings subjected to the combinatorial stress was closely correlated with the Na+/K+ ratio, Na+ content, K+ content, proline content, SOD activity, and CAT activity, indicating that SiO2-NPs could alleviate the suppression of combinatorial stress on cotton seedling growth by decreasing the Na+/K+ ratio and increasing the antioxidant capacity.

Evaluation of memory drought stress effects on storage compounds seedlings of cotton (Gossypium hirsutum) and in-silico analysis of glutathione reductase

In breeding programs, stress memory in plants can develop drought stress tolerance. Memory stress, as an approach, can keep stress data by activating tolerance mechanisms. This research was conducted to evaluate some physiologically effective mechanisms in inducing memory drought stress in the seeds that were exposed to water stress three times in four treatments including rainfed, 33%, 66%, and 100% of field capacity (FC). After the production of the seeds, the third-generation seeds were placed under different irrigation treatments, seed and seedling traits, starch to carbohydrate ratio in seed, protein concentration and glutathione reductase were investigatied in a factorial format based on a randomized complete block design with three replications. Results showed that percentage of changes from the lowest to the highest value for traits including seed vigor, seed endosperm weight, seed coat weight, accelerated aging, cold test, seedling biomass and seedling length were 25, 37, 65, 65, 55, 77, 55, 65 and 79, respectively and germination uniformity was 3.9 times higher than the lowest amount. According to the deterioration percentage, seed vigor and the percentage of seed germination in cold test data, it can be reported that seed production by 100% FC was not appropriate for rainfed plots. However, considering the the appropriate results in the percentage of germination for a cold test, germination uniformity percentage, and the lowest accelerated aging seeds, seed production under the rainfed conditions with 33% FC watering can be recommended. In-silico analysis was coducted on Glutathione reductase (GR) enzymes in Gossypium hirsutum. It is clear that GR has a Redox-active site and NADPH binding, and it interacts with Glutathione S transferase (GST). So, memory drought stress through inducing physiological drought tolerance mechanisms such as starch-to-carbohydrate ratio and GR can determine the suitable pattern for seed production for rainfed and low rainfall regions in a breeding program. Our study thus illustrated that seed reprduction under 33% FC equipped cotton with the tolerance against under draught stress from the seedling stage. This process is done through activating glutathione reductase and balancing the ratio of starch to carbohydrates concentration.

Enhancing cotton seedling recognition: a method for high-resolution UAV remote sensing images

ABSTRACT Timely and accurate acquisition of cotton seedling information is crucial for seedling replenishment, yield increase, and effective cotton field management. This study proposes a cotton seedling recognition model and weed removal method for high-resolution UAV (Unmanned Aerial Vehicle) remote sensing images. First, the image information of cotton seedlings is enhanced by calculating the remote sensing index and using threshold segmentation. Second, the recognition model is constructed based on the spatial morphological characteristics of cotton seedlings, with weed interference removed using the straight-line method. Finally, the growth condition of cotton seedlings in farmland is comprehensively evaluated by calculating the seedling emergence rate and coverage rate. The experimental results show that: (1) the combination of the GLI (Green Leaf Index) and Otsu threshold segmentation algorithm effectively distinguishes cotton seedlings from the soil background and accurately portrays cotton seedling contours, further enhancing image information; (2) the proposed recognition model achieves an average overall accuracy of 95.75%, making it a practical method for cotton seedling recognition; and (3) the overall growth condition of cotton seedlings in the study area is good, enabling farmers to apply appropriate seedling replenishment and fertilizer based on the comprehensive cotton evaluation map to further improve the final cotton yield. This study aims to provide new research ideas for crop seedling identification and serve as a reference for the practical application of UAVs in crop monitoring.

A new host record of Alternaria argyroxiphii on Upland cotton (Gossypium hirsutum)

For the first time, we isolated and identified Alternaria argyroxiphii on Upland cotton (Gossypium hirsutum) in Australia and elsewhere. A single-spored A. argyroxiphii isolate was obtained from diseased cotton leaves that exhibited small circular to enlarged and coalesced irregular necroses in the 2021–2022 cropping season in northwest New South Wales, Australia. We identified A. argyroxiphii based on its large conidia with filiform beaks and sequences of the internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and calmodulin (CAL). These multigene sequences of the cotton-A. argyroxiphii were 100% identical to those of the type A. argyroxiphii isolate CBS 117222; thus, confirming the identity. On two-true-leaf cotton seedlings, A. argyroxiphii was able to incite necrotic symptoms resembling those observed in the field, and was reisolated and re-identified, thus, fulfilling Koch's postulates. This is the first record of A. argyroxiphii on Upland cotton.

Cell wall-associated receptor kinase GhWAKL26 positively regulates salt tolerance by maintaining Na+ and K+ homeostasis in cotton

Cell wall-associated receptor kinases (WAKs/WAKLs), are a specialized class of plant receptor kinases essential for signaling during stress conditions. However, there has been no report on the involvement of WAKs/WAKLs in salt tolerance in cotton. In this study, we report the functional characterization of GhWAKL26, whose expression is induced by salt, with its levels increasing over time and with higher salt concentrations. In addition, the fusion protein of GhWAKL26 and GFP was localized to the plasma membrane. In transgenic Arabidopsis, the dry weight, fresh weight, and root length were significantly higher than those of wild-type plants, indicating enhanced salt tolerance. While in GhWAKL26-silenced cotton seedlings, H2O2, O2−, and MDA content were increased, and chlorophyll content was reduced under salt stress, displaying compromised salt tolerance. RNA-seq analysis revealed that the silencing of GhWAKL26 resulted in the down-regulation of expression levels of certain ion transport-related genes under salt stress, concurrently leading to an increased Na+/K+ ratio in cotton seedlings. Overall, our findings indicate that GhWAKL26 enhanced plant resistance to salt stress in cotton by regulating the balance of Na+ and K+ ions.

A novel role of the cotton calcium sensor CBL3 was involved in Verticillium wilt resistance in cotton.

Verticillium wilt, causes mainly by the soilborne pathogen Verticillium dahliae, is a devastated vascular disease resulting in huge financial losses in cotton, so research on improving V. dahliae stress tolerance in cotton is the utmost importance. Calcium as the second messenger acts as a crucial role in plant innate immunity. Cytosolic Ca2+during the pathogen infection is a significant increase in plant immune responses. Calcineurin B-like (CBL) proteins are widely known calcium sensors that regulate abiotic stress responses. However, the role of cotton CBLs in response to V. dahliae stress remains unclear. To discover and utilize the gene to Verticillium wilt resistance and defense response mechanism of cotton. Through screening the gene to Verticillium wilt resistance in cotton, four GhCBL3 copies were obtained from the current common cotton genome sequences. The protein domain and phylogenetic analyses of GhCBL3 were performed using NCBI Blast, DNAMAN, and MotifScan programs. Real-time RT-PCR was used to detect the expression of GhCBL3 gene in cotton seedlings under various stress treatments. The expression construct including GhCBL3 cDNA was transduced into Agrobacterium tumefaciens (GV3101) by heat shock method and transformed into cotton plants by Virus-Induced Gene Silencing (VIGS) method. The results of silencing of GhCBl3 on ROS accumulation and plant disease resistance in cotton plants were assessed. A member of calcineurin B-like proteins (defined as GhCBL3) in cotton was obtained. The expression of GhCBL3 was significantly induced and raised by various stressors, including dahliae, jasmonic acid (JA) and H2O2 stresses. Knockdown GhCBL3 in cotton by Virus-Induced Gene Silencing analysis enhanced Verticillium wilt tolerance and changed the occurrence of reactive oxygen species. Some disease-resistant genes were increased in GhCBL3-silencing cotton lines. GhCBL3 may function on regulating the Verticillium dahliae stress response of plants.

Exogenous Melatonin Enhances Cold Tolerance by Regulating the Expression of Photosynthetic Performance, Antioxidant System, and Related Genes in Cotton.

In China, cotton is a significant cash crop, and cold stress negatively impacts the crop's development, production, and quality formation. Recent studies have shown that melatonin (MT) can alleviate the damage to plants under cold stress and promote good growth and development. In this study, the morphological and physiological changes induced by exogenous melatonin pretreatment on 'Xinluzao 33' cotton seedlings under cold stress were examined to investigate its defensive effects. The results showed that 100 μM MT pretreatment improved the cold resistance of cotton most significantly. It also improved the wilting state of cotton under cold stress, greatly increased the photosynthetic rate (Pn), stomatal conductance (Gs), maximum photochemical efficiency (Fv/Fm), and photosynthetic performance index (PIabs) by 116.92%, 47.16%, 32.30%, and 50.22%, respectively, and mitigated the adverse effects of low-temperature. In addition, MT supplementation substantially reduced the accumulation of superoxide anion (O2•-) and hydrogen peroxide (H2O2) by 14.5% and 45.49%, respectively, in cold-stressed cotton leaves by modulating the antioxidant system, thereby mitigating oxidative damage. Furthermore, MT pretreatment increased the endogenous melatonin content (23.80%) and flavonoid content (21.44%) and considerably induced the expression of biosynthesis enzyme-related genes. The above results indicate that exogenous melatonin improves the low-temperature resistance of cotton seedlings by regulating photosynthetic performance, antioxidant enzyme activity, antioxidant content, endogenous melatonin and flavonoid content, and the expression levels of genes related to their synthesis.

Isolation and Characterization of Potassium-Solubilizing Rhizobacteria (KSR) Promoting Cotton Growth in Saline-Sodic Regions.

Cotton is highly sensitive to potassium, and Xinjiang, China's leading cotton-producing region, faces a severe challenge due to reduced soil potassium availability. Biofertilizers, particularly potassium-solubilizing rhizobacteria (KSR), convert insoluble potassium into plant-usable forms, offering a sustainable solution for evergreen agriculture. This study isolated and characterized KSR from cotton, elucidated their potassium solubilization mechanisms, and evaluated the effects of inoculating KSR strains on cotton seedlings. Twenty-three KSR strains were isolated from cotton rhizosphere soil using modified Aleksandrov medium. Their solubilizing capacities were assessed in a liquid medium. Strain A10 exhibited the highest potassium solubilization capacity (21.8 ppm) by secreting organic acids such as lactic, citric, acetic, and succinic acid, lowering the pH and facilitating potassium release. A growth curve analysis and potassium solubilization tests of A10 under alkali stress showed its vigorous growth and maintained solubilization ability at pH 8-9, with significant inhibition at pH 10. Furthermore, 16S rRNA sequencing identified strain A10 as Pseudomonas aeruginosa. Greenhouse pot experiments showed that inoculating cotton plants with strain A10 significantly increased plant height and promoted root growth. This inoculation also enhanced dry biomass accumulation in both the aerial parts and root systems of the plants, while reducing the root-shoot ratio. These results suggest that Pseudomonas aeruginosa A10 has potential as a biofertilizer, offering a new strategy for sustainable agriculture.