Myeloblastosis (MYB) transcription factors, particularly those in the R2R3 MYB subclass, are pivotal in plant growth, development, and environmental stress responses. As one of the largest transcription factor families in plants, the MYB family significantly regulates plant secondary metabolism, including the biosynthetic pathways for phenylpropanoids, which are crucial for stress resistance. This review presents a comprehensive overview of MYB transcription factor classification and their regulatory mechanisms in plant metabolism and stress responses. We discuss the roles of MYB transcription factors in biotic stress resistance, such as defense against pathogens and pests, and in abiotic stress tolerance, including responses to drought and salinity. Special attention is given to the interactions of R2R3 MYB with other transcription factors and co-repressors, focusing on how these synergistic or antagonistic relationships modulate physiological processes. The multifunctional role of R2R3 MYBs in stress responses positions them as promising targets for enhancing crop resilience through genetic breeding. Furthermore, this review highlights potential applications of MYB transcription factors in developing stress-resistant crops and their utility in plant resistant breeding programs.

The rice leaffolder, Cnaphalocrocis medinalis (Guenée), is a major migratory insect pest in paddy fields that damages rice by folding and feeding on leaves, causing chlorophyll loss and resulting in significant yield losses when its population density exceeds an economic threshold. Sustainable pest management requires ‘green plant protection’ solutions. Advances in science and technology have introduced numerous green methods for sustainable management of the rice leaffolder. This paper reviews recent research advancements in rice leaffolder management, such as ecological regulation, healthy cultivation, behavioral regulation, biological control, and rational insecticide application. Based on accurate monitoring and early warning systems, rice leaffolder management can incorporate comprehensive green control products, green control technologies, and control modes. This paper provides prospects for discussing the future of rice leaffolder management, achieving sustainable management of the rice leaffolder, and ensuring rice production safety.

Brown planthopper (BPH) is a highly destructive pest that presents a significant challenge to rice production, particularly in the Asia-Pacific region. Numerous BPH-resistant rice varieties have been successfully bred and released for commercial cultivation across diverse rice-growing ecosystems. However, resistance breakdown in several varieties carrying major resistance genes has been reported, highlighting the urgent need for the development of novel, genetically diverse, and broad-spectrum resistant varieties. To date, more than 45 resistance loci have been identified and mapped from both cultivated and wild rice species. Among these, a subset of genes (including Bph1, Bph3, Bph6, Bph7, Bph9, Bph10, Bph14, Bph15, Bph18, Bph21, Bph26/2, bph29, Bph32, Bph37, and Bph30/Bph40) have been positionally cloned. Most of these genes encode coiled-coil nucleotide-binding leucine-rich repeat proteins, which are central to plant immune responses, along with a few signaling molecules playing pivotal roles. In addition to these core resistance genes, various other genetic components, including miRNAs, protein kinases, and transcription factors, have been functionally characterized for their roles in mediating BPH resistance. The advent of post-genomic tools such as RNA sequencing and single-cell sequencing, along with cutting-edge genomic technologies like CRISPR/Cas gene editing, has significantly accelerated resistance breeding programs. In this context, we provide an overview of genetics, mapping, isolation, and functional characterization of BPH resistance, along with strategies for incorporating resistance using advanced genomics-assisted breeding tools. Furthermore, we present a snapshot of how the integration of genomics and novel breeding technologies holds great promise for dissecting the genetic architecture of pest resistance and accelerating crop improvement.

Rice is a poor source of folate, an essential micronutrient for the body. Biofortification offers an effective way to enhance the folate content of rice and alleviate folate deficiencies in humans. In this study, we confirmed that OsADCS and OsGTPCHI, encoding the initial enzymes necessary for folate synthesis, positively regulate folate accumulation in knockout mutants of both japonica and indica rice backgrounds. The folate content in the low-folate japonica variety was slightly increased by the expression of the indica alleles driven by the endosperm-specific promoter. We further obtained co-expression lines by stacking OsADCS and OsGTPCHI genes; the folate accumulation in brown rice and polished rice reached 5.65 μg/g and 2.95 μg/g, respectively, representing 37.9-fold and 26.5-fold increases compared with the wild type. Transcriptomic analysis of rice grains from six transgenic lines showed that folate changes affected biological pathways involved in the synthesis and metabolism of rice seed storage substances, while the expression of other folate synthesis genes was weakly regulated. In addition, we identified Aus rice as a high-folate germplasm carrying superior haplotypes of OsADCS and OsGTPCHI through natural variation. This study provides an alternative and effective complementary strategy for rice biofortification, promoting the rational combination of metabolic engineering and conventional breeding to breed high-folate varieties.

Ethylene response factors (ERFs) are plant transcription agents that play a pivotal role in disease resistance through the ethylene signaling pathway. However, whether and how ERFs regulate resistance to sheath blight (ShB), caused by Rhizoctonia solani in rice, remains largely unknown. Here, we demonstrated that OsERF7 negatively regulates rice resistance to ShB by inhibiting phytoalexin biosynthesis. Overexpression of OsERF7 (OsERF7OE) significantly decreased ShB resistance, whereas knockout of OsERF7 (oserf7) enhanced it. Mechanistically, antioxidant enzyme activities are significantly reduced in OsERF7OE plants, but increased in oserf7 plants. Furthermore, transcriptome analysis revealed that oserf7 plants exhibited significant upregulation of pathogenesis-related (PR) and phytoalexin biosynthesis genes upon R. solani infection. Consistently, transcript levels of phytoalexin biosynthesis genes, including OsKSL7, OsKSL8, OsKOL5, and OsCPS4, were significantly elevated in oserf7 plants, but reduced in OsERF7OE plants in response to R. solani infection. Electrophoretic mobility shift assays and dual-luciferase (LUC) reporter assays further confirmed that OsERF7 directly binds to the promoters of OsKSL8, OsKOL5, and OsCPS4, thereby repressing their expression. In summary, our study revealed that OsERF7 negatively regulated rice resistance to ShB primarily by inhibiting phytoalexin biosynthesis.

Herbivorous insects and pathogens cause severe damage to rice tissues, affecting yield and grain quality. Damaged cells trigger downstream defense responses through various signals. Extracellular ATP (eATP), a signaling molecule released during mechanical cell damage, is considered a constitutive damage-associated molecular pattern (DAMP), which is crucial for initiating plant defense responses. Thus, understanding how rice plants cope with DAMPs such as eATP is essential. Here, we found that exogenous ATP affected rice growth and development, cell wall composition, chloroplast development, and cell death. Subsequent global transcriptome analysis revealed that several pathways were involved in the eATP response, including genes related to cell surface receptors, cell wall organization, chlorophyll biosynthesis, heat and temperature stimulation, epigenetic regulation, and reactive oxygen species metabolism. Cell surface receptors, including members of the lectin receptor-like kinases (LecRKs), were found to participate in the eATP response. We further investigated ATP-induced genes in T-DNA activation mutants of OsLecRKs, demonstrating their involvement in eATP signaling in rice. This study confirms a DAMP-mediated transcriptional response in plants and provides novel candidates for advancing resistant rice breeding against insect herbivores and pathogens.

Intergenerational inheritance of stress memory plays a crucial role in plant adaptation to environmental changes, particularly in the context of spaceflight, where plants may serve as a food source for humans on long-duration missions. However, the intergenerational genetic effects of spaceflight-induced stress memory in plants remain unclear. In this study, we assessed the cross-generational genetic effects of spaceflight stress memory using the rice mutant B10, identified during the SJ-10 return satellite mission. Our results showed that the oxidative stress effects induced by spaceflight persisted until the M5 generation in rice. We found that the rice genome remained unstable post-spaceflight, leading to alterations in genome methylation levels. Additionally, we observed significant changes in the methylation levels of transposons, suggesting their involvement in the intergenerational inheritance of spaceflight-induced stress memory. Furthermore, we identified thousands of differentially expressed genes (DEGs) and differentially alternatively spliced (DAS) genes induced by spaceflight stress memory across multiple rice generations. Notably, differentially methylated cytosines were more abundant in non-expressed genes than in DEGs or DAS genes. A substantial number of DEGs and DASs related to oxidative stress were identified, primarily involved in the generation and scavenging of reactive oxygen species. This study also presented report on the response of alternative splicing events in rice to spaceflight stress. Moreover, our findings revealed that genome methylation was associated with gene expression but not with DAS. In conclusion, our study provides comprehensive insights into the intergenerational inheritance of spaceflight-induced stress in rice and may contribute to uncovering novel mechanisms of oxidative stress-induced genomic instability and epigenetic regulation in plant stress inheritance.

Strategies for increasing rice yield are needed to keep pace with the expected global population growth and sustainably address the challenges posed by climate change. In Southeast Asian countries, rice farming benefits from the use of Azolla spp. for nitrogen supply. By virtue of their symbiosis with the nitrogen-fixing cyanobacterium Trichormus azollae, Azolla spp. are ferns that release nitrogen into the environment upon biomass decomposition. However, whether and to what extent actively growing Azolla plants influence the development of co-cultivated rice seedlings remains unclear. To address this, rice (Oryza sativa L. var. Kitaake) seedlings were co-cultivated hydroponically with Azolla filiculoides for up to two months. Morphological changes in rice roots and aerial organs were assessed alongside nitric oxide assays in rice roots, root transcriptomics, and targeted hormonomics of rice roots, leaves, and growth media. Here, we showed that co-cultivation with actively growing A. filiculoides alters rice root architecture by inducing a nitric oxide boost and accelerates leaf and tiller differentiation and proliferation. Overall, this study provides an in-depth analysis of the morphogenetic effects of co-cultivated A. filiculoides on rice during early vegetative growth. It also paves the way for studies assessing whether A. filiculoides co-cultivation primes rice plants to better withstand abiotic and biotic stresses.