This study investigates the functional role of OsHSBP1, a heat shock factor-binding protein, in regulating abiotic stress tolerance in rice, with the aim of enhancing climate resilience in the elite indica cultivar Bacthom 7 (BT7). Using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9) genome editing, we generated transgene-free homozygous knockout lines targeting OsHSBP1 and evaluated their physiological, biochemical, and agronomic responses under heat stress. Mutant lines exhibited markedly improved tolerance to both stresses, with survival rates reaching 43–46% under heat stress, compared to near-zero in wildtype plants. Enhanced tolerance was associated with significantly increased catalase and peroxidase activities and reduced oxidative damage, including lower malondialdehyde content and decreased superoxide accumulation. Despite these stress-related advantages, the knockout lines showed minimal differences in key agronomic traits under normal growing conditions, with comparable plant height, tillering ability, grain yield, and amylose content relative to the wildtype. These results demonstrate that OsHSBP1 functions as a negative regulator of abiotic stress tolerance in rice, and its knockout enhances resilience without compromising yield potential. The study highlights OsHSBP1 as a promising target for precision breeding of climate-resilient rice cultivars.

Outbreaks of the Southern rice black-streaked dwarf virus (SRBSDV) have caused significant losses in many rice-growing areas in Vietnam, especially in both North and Central Vietnam in recent years. To detect the virus, traditional reverse transcription polymerase chain reaction (RT-PCR) methodology and immunoassays are currently employed. RT-PCR is accurate but requires expensive chemicals and instruments, as well as complex procedures that limit its applicability for field tests. To develop a cheaper, simpler, and reliable SRBSDV diagnosis assay based on the dot-enzyme-linked immunosorbent assay (dot-ELISA) method, anti-SRBSDV polyclonal antibodies were produced by using the antigens derived from the P10 coat protein of SRBSDV, which was achieved from a previous study. The IgG antibody purified from the antiserum of recombinant P10-immunized mice by protein A-agarose affinity chromatography could specifically detect both the target protein and SRBSDV at a dilution of 1:100000. In the trial test of SRBSDV diagnosis, the dot-ELISA assay using the obtained anti-SRBSDV antibody showed an accuracy rate of 90.9% in comparison with the standard RT-PCR assay. These results are important premises for the large-scale application of dot-ELISA assay for SRBSDV diagnosis in order to protect rice crops against viral disease damage.

Southern rice black-streaked dwarf virus (SRBSDV) causes severe epidemical disease on rice with the infected area up to millions of hectares in South China and North and Central of Vietnam. So far, there are no effective, cheap, quick, and practicable methods for diagnosing SRBSDV. The conventional RT-PCR technique is the most popular method for detecting SRBSDV with high accuracy. However, it is hard to apply this method for large-scale SDBSDV diagnosis because of the requirements of expensive reagents and instruments, as well as complex procedures. Meanwhile, SRBSDV diagnostic techniques based on antigen detection have outstanding advantages due to their low cost, easy manipulation, and wide application possibility. Today, there are still no commercially available specific antibodies to SRBSDV. In a previous study, to develop the SRBSDV diagnostic technique by the ELISA technique, a SRBSDV specific antibody was generated by a recombinant P10 envelope protein (66kDa), which has a titer of 1:5,000. In this study, we continued to study the production of SRBSDV specific polyclonal antibodies from small antigen–rich peptides from the SRBSDV P10 envelope protein. The resulting purified antibody can specifically bind to the P10 protein and at the diluted concentration of 1:100,000 it can detect SRBSDV in infected rice samples via the dot-blot technique. Our research results open up new opportunities for proactive antibodies to develop a SRBSDV membrane rapid diagnostic kit.

Salt stress severely impacts rice productivity worldwide, with increasing soil salinization threatening food security in many regions. This study examined the physiological function of proline dehydrogenase (OsProDH) in salt stress responses using a Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-edited Bac Thom 7 (BT7) rice line carrying a 39-nucleotide deletion in the OsProDH gene. Seedlings of wild-type and mutant plants were subjected to 100−200 mM NaCl treatments to evaluate biochemical and physiological responses. Free proline quantification revealed distinct accumulation patterns, with the OsProDH mutant maintaining significantly higher proline levels before stress (1.8-fold) and during recovery (1.6-fold). Oxidative stress markers showed that the mutation significantly reduced salt-induced reactive oxygen species (ROS) accumulation, with H2O2 content decreased by 41% and malondialdehyde (MDA) levels reduced by 37% compared to wild-type plants under 100 mM NaCl. Antioxidant enzyme analysis revealed a selective enhancement pattern in the mutant, with peroxidase (POD) and ascorbate peroxidase (APX) activities increased by 42% and 38% respectively, during salt stress. Under severe salt stress (200 mM NaCl), physiological parameters, including survival rate and chlorophyll content, showed only minor improvements in the mutant despite substantial biochemical protection. These results demonstrate that OsProDH influences BT7 rice salt responses through multiple pathways, particularly in the regulation of proline metabolism and specific antioxidant enzyme activities. The findings contribute to our understanding of proline metabolism in cereal crops and provide insights for future development of salt-resilient rice varieties.