Cotton (Gossypium hirsutum L.), the most important textile crop worldwide, often encounters abiotic stress during its growing season and its productivity is significantly limited by adverse factors. Trihelix transcription factors (also known as GT factors) are important proteins involved in the morphological development and responses to abiotic stress in plants. However, their functions and molecular mechanisms in the cotton toward abiotic stress response remain unclear. In this study, a member (GhGT26) of the cotton Trihelix family was functionally characterized in the model plant Arabidopsis. This protein containing a SANT domain belongs to the GT-1 subgroup of trihelix proteins. GhGT26 was widely expressed in tissues (with the highest level in flower) and responded to high salt and ABA treatments at the transcriptional level. Using the Arabidopsis protoplast assay system, we found that the GhGT26 protein was located in the cell nuclei. The EMSA assay revealed that the GhGT26 protein could bind to the Site1-type GT cis elements (GT-3a) and MYB elements MRE3 and MRE4. The overexpression of GhGT26 improved plant tolerance to salt stress in transgenic Arabidopsis plants. Although ABA inhibits root elongation, the statistical analysis revealed that the root lengths of GhGT26-overexpressing Arabidopsis were the same as the wild plants after ABA treatment. Our results demonstrate that GhGT26 positively regulates salt stress via ABA-independent pathways. This evidence suggests that the GhGT26 may participate in the regulation of stress tolerance in cotton.

Verticillium wilt (VW), caused primarily by Verticillium dahliae , is a significant threat to cotton production. Lignification of the plant cell wall, a defence response triggered by pathogen invasion, is critical for plant resistance to numerous diseases. Laccases are known to participate in the lignification of secondary cell walls, but their role in cotton resistance to V. dahliae is not fully understood. In this study, we identified a cotton laccase gene, GhLAC14‐3 , that was significantly upregulated during early V. dahliae infection and was closely related to a gene previously reported to respond to V. dahliae infection in Arabidopsis . Silencing of GhLAC14‐3 in cotton increased disease susceptibility and reduced lignin deposition and the expression of lignin‐related genes. By contrast, overexpression of GhLAC14‐3 in transgenic Arabidopsis increased lignin content and the expression of lignin‐related genes, thereby enhancing VW resistance. We identified an interaction between GhLAC14‐3 and the mitogen‐activated protein kinase GhMAPKKK2 at the cell membrane. GhMAPKKK2 expression was also significantly induced by V. dahliae infection in cotton, and its overexpression in Arabidopsis activated multiple key resistance genes, thus improving V. dahliae resistance . Transient co‐expression of GhMAPKKK2 and GhLAC14‐3 in Nicotiana benthamiana leaves significantly increased lignin content. Conversely, silencing of AtMAPKKK2 , the homologue of GhMAPKKK2 , in GhLAC14‐3 ‐overexpressing Arabidopsis reduced both lignin levels and disease resistance. Our findings suggest that Gh LAC14‐3 is a promising target for enhancing VW resistance, as its interaction with Gh MAPKKK2 at the cell membrane modulates defence‐induced lignification.

Background: Stripe rust, caused by the fungus Puccinia striiformis f.sp. tritici (Pst), poses a significant threat to global wheat production.Objectives: This study aims to analyze the distribution of stripe rust resistance genes, characterize resistance phenotypes at the seedling stage of 137 spring and 149 winter wheat varieties in Xinjiang, China, and discern differences in resistance between spring and winter wheat varieties.Design: We used various Pst races (CYR23, CYR29, CYR31, CYR32, CYR33, CYR34) to characterize seedling resistance of spring and winter wheat varieties and to correlate resistance to the presence of wheat resistance genes (Yr5, Yr9, Yr10, Yr15, Yr17, Yr18, Yr26, Yr41, Yr80, Yr81) using molecular markers.Results: Among spring wheat varieties, 62, 60, 42, 26, 51, and 24 varieties exhibited resistance to CYR23, CYR29, CYR31, CYR32, CYR33, and CYR34, respectively, with four varieties resistant to all varieties. Among winter wheat varieties, 66, 32, 69, 26, 83, 40 varieties demonstrated resistance to CYR23, CYR29, CYR31, CYR32, CYR33, and CYR34, respectively, with four varieties resistant to all varieties. Molecular testing revealed that, in spring wheat, 2, 17, 21, 61, 10, 0, 10, 79, and 32 varieties carried Yr9, Yr10, Yr15, Yr17, Yr18, Yr26, Yr41, Yr80, and Yr81 genes, respectively. In winter wheat, 40, 20, 7, 143, 15, 1, 6, 38, and 54 varieties carried Yr9, Yr10, Yr15, Yr17, Yr18, Yr26, Yr41, Yr80, and Yr81 genes, respectively. Notably, winter wheat exhibited a significantly higher resistance frequency than spring wheat, particularly in the incidence of Yr9, Yr10, Yr17, Yr18, and multi-gene combinations.Conclusion: In summary, this study provides information on seedling stage resistance to stripe rust 286 Xinjiang wheat varieties, elucidates the distribution of resistance genes in this population, and offers a mechanistic basis for breeding durable resistance in wheat. varieties from Xinjiang.

As a plant-specific Rho-like small G protein, the ROP (Rho-related GTPase of plants) protein regulates the growth and development of plants and various stress responses in the form of molecular switches. Drought is a major abiotic stress that limits cotton yield and fiber quality. In this study, virus-induced gene silencing (VIGS) technology was used to analyze the biological function of GhROP3 in cotton drought stress tolerance. Meanwhile, we used yeast two-hybrid and bimolecular fluorescence complementation assays to examine the interaction between GhROP3 and GhGGB. GhROP3 has a high expression level in cotton true leaves and roots, and responds to drought, high salt, cold, heat stress, and exogenous abscisic acid (ABA) and auxin (IAA) treatments. Silencing GhROP3 improved the drought tolerance of cotton. The water loss rates (WLR) of detached leaves significantly reduced in silenced plants. Also, the relative water content (RWC) and total contents of chlorophyll (Chl) and proline (Pro) of leaves after drought stress and the activities of three antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) significantly increased, whereas the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) significantly reduced. In the leaves of silenced plants, the expression of genes related to ABA synthesis and its related pathway was significantly upregulated, and the expression of decomposition-related GhCYP707A gene and genes related to IAA synthesis and its related pathways was significantly downregulated. It indicated that GhROP3 was a negative regulator of cotton response to drought by participating in the negative regulation of the ABA signaling pathway and the positive regulation of the IAA signaling pathway. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that the GhROP3 protein interacted with the GhGGB protein in vivo and in vitro. This study provided a theoretical basis for the in-depth investigation of the drought resistance–related molecular mechanism of the GhROP3 gene and the biological function of the GhGGB gene.

Cotton is one of the most economically important crops in the world, and drought is a key abiotic factor that can significantly reduce cotton yield. MADS-box transcription factors play essential roles in various aspects of plant growth and development as well as responses to biotic and abiotic stress. However, the use of MADS-box transcription factors to regulate water stress responses has not been fully explored in cotton. Here, we showed that GhAGL16 acts as a negative regulator of water deficit in cotton, at least in part by regulating ABA signaling. GhAGL16-overexpressing (GhAGL16-OE) transgenic Arabidopsis had lower survival rates and relative water contents (RWCs) under water stress. Isolated leaves of GhAGL16-OE Arabidopsis had increased water loss rates, likely attributable to their increased stomatal density. GhAGL16-OE Arabidopsis also showed reduced primary root lengths in response to mannitol treatment and decreased sensitivity of seed germination to ABA treatment. By contrast, silencing GhAGL16 in cotton enhanced tolerance to water deficit by increasing proline (Pro) content, increasing superoxide dismutase (SOD) and peroxidase (POD) activities, and reducing malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) contents under water stress. Subcellular localization and transcriptional activation assays confirmed that GhAGL16 is a nuclear protein that lacks transcriptional self-activation activity. The expression of ABA biosynthesis-related genes (GhNCED3/7/14), a catabolism-related gene (GhCYP707A), and a gene related to the ABA signaling pathway (GhABF4) was altered in GhAGL16-silenced plants. Taken together, our data demonstrate that GhAGL16 plays an important role in cotton resistance to water stress.

Chenopodium album is a troublesome weed in soybean fields in China. Many C. album populations have evolved resistance to herbicides and pose a growing challenge to weed management. This study characterizes the molecular and physiological resistance mechanisms in C. album populations against ALS- and PSII-inhibiting herbicides, focusing on thifensulfuron-methyl and bentazone. Dose-response assays confirmed significant resistance in two populations (R1 and R2), with resistance index values of 5.28 and 6.51 for thifensulfuron-methyl, and 4.83 and 5.10 for bentazone. Herbicide target gene amplification and sequence analysis showed an Ala-122-Thr substitution in the ALS but no psbA mutation in R1, while no ALS or psbA mutation was identified in R2. ALS enzyme assays further supported the resistance in R1. Cross-resistance tests indicated that R1 and R2 populations exhibited low-level resistance to oxyfluorfen and acifluorfen, but no detectable resistance to cloransulam-methyl, flumetsulam, or fomesafen. These findings highlight the need for integrated weed management strategies, including herbicide diversification and metabolic resistance monitoring, to mitigate the further evolution of resistance.