Drought stress poses a substantial challenge to plant growth and agricultural productivity worldwide. Upon water depletion, plants activate an abscisic acid (ABA) signaling pathway, leading to stomatal closure to reduce water loss. The MYB family of transcription factors plays diverse roles in growth, development, stress responses and biosynthesis, yet their involvement in stomatal regulation remains unclear. Here, we demonstrate that ABA significantly upregulates the expression of MYB41, MYB74, and MYB102, with MYB41 serving as a key regulator that induces the expression of both MYB74 and MYB102. Through luciferase assays, chromatin immunoprecipitation (ChIP) assays and electrophoretic mobility shift assays (EMSA), we reveal that MYB41 engages in positive feedback regulation by binding to its own promoter, thus amplifying its transcription in Arabidopsis (Arabidopsis thaliana). Furthermore, our investigation showed that MYB41 recruits BRAHMA (BRM), the core ATPase subunit of the SWI/SNF complex, to the MYB41 promoter, facilitating the binding of HISTONE DEACETYLASE 6 (HDA6). This recruitment triggers epigenetic modifications, resulting in reduced MYB41 expression characterized by elevated H3K27me3 levels and concurrent decreases in H3ac, H3K27ac, and H3K14ac levels in wild-type plants compared to brm knockout mutant plants. Our genetic and molecular analyses show that ABA mediates autoregulation of the MYB41-BRM module, which intricately modulates stomatal movement in A. thaliana. This discovery sheds light on a drought response mechanism with the potential to greatly enhance agricultural productivity.

Nitric oxide (NO) is a key player in numerous physiological processes. Excessive NO induces DNA damage, but how plants respond to this damage remains unclear. We screened and identified an Arabidopsis NO hypersensitive mutant and found it to be allelic to TEBICHI/POLQ, encoding DNA polymerase θ. The teb mutant plants were preferentially sensitive to NO- and its derivative peroxynitrite-induced DNA damage and subsequent double-strand breaks (DSBs). Inactivation of TEB caused the accumulation of spontaneous DSBs largely attributed to endogenous NO and was synergistic to DSB repair pathway mutations with respect to growth. These effects were manifested in the presence of NO-inducing agents and relieved by NO scavengers. NO induced G2/M cell cycle arrest in the teb mutant, indicative of stalled replication forks. Genetic analyses indicate that Polθ is required for translesion DNA synthesis across NO-induced lesions, but not oxidation-induced lesions. Whole-genome sequencing revealed that Polθ bypasses NO-induced base adducts in an error-free manner and generates mutations characteristic of Polθ-mediated end joining. Our experimental data collectively suggests that Polθ plays dual roles in protecting plants from NO-induced DNA damage. Since Polθ is conserved in higher eukaryotes, mammalian Polθ may also be required for balancing NO physiological signaling and genotoxicity.

The black soil layer has undergone substantial degradation in Northeast China, and it is crucial to adopt reasonable tillage measures to prevent black soil degradation. Organic amendment strategies provide an effective solution for mitigating nutrient loss in black soil; meanwhile, there is still a lack of systematic investigation into their impact on soil microbial communities. Thus, we carried out a five-year field experiment from 2020 to 2025 in Jilin Province. Four organic amendment strategies were set up: conventional tillage (CT); straw returning (SR); straw returning + inorganic fertilizer (SRI); and straw returning + inorganic fertilizer + organic fertilizer (SRIO). Furthermore, we investigated the effects of organic materials on soil properties and microbial communities during the maize seedling stage. The results showed that SR significantly increased the relative abundance of Bradyrhizobium, Tausonia and Coprinopsis, while SRI led to a 140.3% increase in Nocardioides. In SRIO treatment, Gaiella and Fusarium were significantly enriched by 103.9% and 142.5%, respectively. Moreover, SR treatment significantly decreased the fungal Shannon and Simpson index by 18.8% and 4.2%, respectively. Organic matter, alkali nitrogen, and available potassium were the primary environmental factors shaping both bacterial and fungal community structures. Additionally, the co-occurrence network suggested that straw returning promoted more diverse interactions among soil bacterial and fungal communities. Our study highlights the potential of organic amendment strategies in enhancing black soil nutrients, as well as their important role in maintaining soil microbial function and stability.

Soybean is the most crucial oilseed and plant-protein crop worldwide, yet its yield is frequently threatened by salinity and drought stress. In this study, the chitinase gene AcCHI was cloned from the highly stress-tolerant plant Atriplex canescens and heterologously overexpressed in soybean to generate stable T₃ homozygous transgenic lines. Wild-type and transgenic plants were subjected to water-withholding drought treatment, 20% PEG6000-induced osmotic stress, and 150 mM NaCl salt stress. After drought treatment, the survival rate of transgenic lines reached 2.66–2.69 times relative to wild-type plants. Under osmotic and salt stress conditions, AcCHI-overexpressing lines exhibited better-maintained photosynthetic performance, higher proline accumulation, and lower malondialdehyde (MDA) levels compared with wild-type controls. Enhanced antioxidant enzyme activities and weakened histochemical ROS staining were also observed in transgenic leaves. Stress-responsive genes associated with DREB, RD22, and SOS pathways showed stronger stress-inducible expression in transgenic plants. Our results show that heterologous AcCHI expression is associated with improved osmotic- and salt-stress tolerance in soybean seedlings under laboratory conditions. This study provides new observational insights into chitinase-linked abiotic-stress responses and offers candidate genetic resources for breeding stress-tolerant soybean varieties.