Unraveling the mechanisms of plant disease resistance and immunity is crucial for breeding disease-resistant crops and safeguarding national food security. Photoreceptors, which are central for perceiving environmental signals, not only fine-tune plant growth and development, but also serve as key signaling hubs in plant-pathogen interactions. Studies have demonstrated that photoreceptor interact directly or indirectly with the COP1/SPA complex, HY5, PIFs, and other light-signaling components. By regulating the spatiotemporal expression of resistance-related defense genes and controlling the synthesis and response networks of defense-related hormones, photoreceptors precisely integrate light signals with pattern-triggered immunity (PTI) and effector-triggered immunity (ETI), thereby balancing plant growth and immunity. In recent years, research into the interaction between light signaling and plant immune systems has become a hot topic in the field of plant biology. Elucidating these underlying mechanisms offers new directions for breeding disease-resistant crops. This paper focuses on the molecular mechanisms of plant disease resistance regulated by photoreceptors, particularly the immune activation mechanisms mediated by photoreceptors and their spatiotemporal integration with immune-related hormone signals. Additionally, it delves into the potential application of optogenetic technology in studying this interaction. The aim is to provide new theoretical and technical avenues for future molecular breeding of disease-resistant crops, which will be based on photoreceptor modification and signal transduction pathways.

INTRODUCTION: The genetic diversity of common wheat (Triticum aestivum) has decreased sharply due to the domestication and modern breeding operations, making it more vulnerable to the threats from pests and pathogens. Leaf rust, caused by the fungal pathogen Puccinia triticina (Pt), is a devastating disease in wheat. Over 80 leaf rust resistance (Lr) genes have been identified, with nearly half originating from wheat wild relatives. However, the rapid evolution of Pt has rendered many Lr genes ineffective against prevalent Pt races. Consequently, identifying novel sources of resistance in wild relatives of common wheat remains an urgent priority for sustainable wheat breeding.

RATIONALE: As one of the most widely used relatives in the genetic improvement of wheat, decaploid Thinopyrum ponticum shows excellent resistance to multiple diseases including leaf rust. By distant hybridization and chromosome engineering, we created a wheat-Th. ponticum line WTS135. We evaluated its disease resistance with Pt race THTT, developed Th. ponticum specific markers by specific-locus amplified fragment sequencing technology and assessed its agronomic traits by phenotypic investigation. Genomic in situ hybridization (GISH)-fluorescence in situ hybridization analysis (FISH) and liquid chip analysis have been used to identify its chromosome composition.

RESULTS: WTS135 is immune to the Pt race THTT. Pedigree analysis showed that this resistance originated from the exogenous chromosome of Th. ponticum. GISH-FISH analysis revealed that the wheat chromosomes 7D were replaced by the Th. ponticum-derived chromosomes. Liquid chip analysis showed that the alien chromosomes belonged to the homoeologous group 7, and the density and abundance of the signals in the peri-centromeric region were significantly lower, which was consistent with the GISH results. Therefore, it is indicated that WTS135 is a 7St (7D) disomic substitution line. After detected by the molecular markers related to known Lr genes on wheat 7D chromosome, it is speculated that WTS135 probably carries a novel resistance gene that is different from genes Lr19 and Lr29. Ten primers specific to Th. ponticum were developed to rapidly trace the exogenous chromatin in WTS135. Phenotypic investigation showed that the yield of WTS135 was not significantly different from that of the recurrent parent Jimai 22, suggesting that this line can be useful for improving disease resistance in wheat.

CONCLUSION: Introducing resistance genes from wild relatives into wheat through distant hybridization can broaden the genetic base of wheat and provide new sources for breeding disease-resistant varieties. We developed a common wheat-Th. ponticum 7St (7D) substitution line, which possibly has a novel alien resistance gene and could be used in the breeding for enhancing wheat disease resistance.

Chromosome composition and leaf rust resistance evaluation of WTS135. (A) GISH analysis using Thinopyrum ponticum gDNA as a probe and Chinese Spring gDNA as a block; (B) Mc-FISH analysis using combined oligo probes; (C) The liquid chip analysis of WTS135; (D) Evaluation for leaf rust resistance in WTS135 and its parents (1: WTS135; 2: Xiaoyan 81; 3: Jimai 22, 4: Zhongnong 28, 5: Th. ponticum). The white arrows indicate exogenous chromosomes, purple frames indicate chromosome additions or deletions.

INTRODUCTION: Verticillium wilt (VW), caused by Verticillium dahliae, severely reduces cotton yield and fiber quality. Previous transcriptomic analysis in V. dahliae-inoculated Arabidopsis thaliana identified the pathogen-induced DIR1-like gene AT3G53980.2. In cotton, we discovered a homologous gene, GhDIR1 (Gh_A09G180700.1), encoding a lipid transfer protein. This study investigates its role in cotton resistance to V. dahliae.

RATIONALE: We characterized GhDIR1’s molecular features, expression patterns under pathogen stress, and functional impact using bioinformatics, subcellular localization, qRT-PCR, and virus-induced gene silencing (VIGS) analyses. Transcriptomic analysis of wild-type and GhDIR1-silenced plants were conducted to unravel downstream regulatory networks, focusing on metabolic pathways linked to plant immunity.

RESULTS: The results showed that GhDIR1 contains a 351 bp ORF encoding 116 amino acids. Subcellular localization confirmed its presence on the cell membrane. qRT-PCR showed rapid induction of GhDIR1 by V. dahliae. Silencing GhDIR1 increased cotton susceptibility to the pathogen. Transcriptomic data revealed that differentially expressed genes in silenced plants were enriched in flavonoid biosynthesis, sesquiterpene/triterpene biosynthesis, and α-linolenic acid metabolism. Key genes (GhCHS, GhDFR, GhCAD, GhSEQ, GhLOX, and GhAOC) in these pathways were downregulated, suggesting impaired synthesis of protective metabolites.

CONCLUSION: It is speculated that GhDIR1 positively regulates cotton resistance to VW by modulating flavonoid and terpenoid biosynthesis and jasmonic acid-related signaling. Its silencing disrupts critical defense pathways, highlighting its role in coordinating immune responses. These findings propose GhDIR1 as a potential target for enhancing disease resistance in cotton.

The induced expression pattern of GhDIR1 and related genes after inoculation with Verticillium dahliae.

INTRODUCTION: Bacterial blight is one of the three major diseases that threaten global rice production, seriously damaging the yield and quality of rice. The utilization of resistance genes is one of the most effective ways to control bacterial blight.

RATIONALE: To cultivate rice varieties with both resistance to bacterial blight and high-yield characteristics, stable and efficient resistance genes need to be identified and used. To identify quantitative trait locus (QTL) related to bacterial blight resistance in rice, this study used the indica rice HZ, the japonica rice Nekken2 and their 120 recombinant inbred lines (RILs) as experimental materials. Four different races of bacterial blight pathogens were inoculated at the tillering stage of rice and the resistance phenotypes were evaluated.

RESULTS: Based on the high-density genetic map constructed previously, we identified 19 QTLs for resistance to rice bacterial blight, with the maximum limit of detection (LOD) value being 5.49. Candidate genes within the detected QTL intervals were screened based on their expression levels analyzed by qRT-PCR. LOC_Os04g01310 and LOC_ Os04g01320, which are related to the regulatory pathway of STK receptor protein, showed significant upregulated expression after inoculation treatment. Meanwhile, the expression levels of the MYB transcription factor family gene LOC_Os05g10690 and the gene LOC_Os01g12320 related to GDSL-like lipase/acylhydrolase showed an extremely significant increase after inoculation treatment. The expression levels of the candidate genes LOC_Os02g13270 (Mpv17/PMP22 family domain containing protein), LOC_Os02g13410 (leucine rich repeat family protein), LOC_ Os02g13420 (leucine rich repeat receptor protein kinase EXS precursor), LOC_Os02g13430 (receptor-like protein kinase 5 precursor) and LOC_Os01g12130 (enodulin MtN3 family protein) were significantly different between the two parents and were induced after inoculation with the bacterial blight pathogen.

CONCLUSION: By QTL mapping and gene expression analysis, we identified several candidate genes related to rice bacterial blight resistance. These results provide clues for further fine mapping and cloning of new bacterial blight resistance genes for future breeding of rice varieties with strong resistance to bacterial blight.

QTL mapping of resistance to bacterial blight in recombinant inbred lines of rice. QTLs can be used to reveal the structure of complex quantitative traits and identify candidate genes. Based on a high-density genetic map, a total of 19 QTLs were co-located and multiple candidate genes were screened out. To further locate and clone the related genes and lay a theoretical foundation for breeding new high-yield and disease-resistant rice varieties.

INTRODUCTION: The phytohormone salicylic acid (SA) plays multiple important roles in plants, such as disease resistance, seed germination, and leaf senescence. Among these, the role of SA in plant disease resistance is the most studied. Since SA promotes disease resistance at the cost of plant growth, plants need to dynamically regulate the content of SA to balance disease resistance and growth. Therefore, fast and accurate measurement of SA content is a critical basis for plant immunity research.

RATIONALE: High-performance liquid chromatography (HPLC)-fluorescence detector is the most popular method for the quantitative measurement of SA. In order to improve the efficiency and sensitivity of current methods, this study optimized the composition, ion concentration, and pH of the mobile phase, as well as the detection wavelength and detection procedure.

RESULTS: The baseline of the chromatogram was more stable when using acetonitrile instead of methanol in the mobile phase. When the pH of the mobile phase was 5.2, the retention time of SA was the shortest, without interference peak near the SA peak, which was preferred for minimizing the detection time. The higher concentration of sodium acetate (100 mmol∙L^-1) in the mobile phase was better than that of lower concentration (20-50 mmol∙L^-1). Wavelength scanning revealed that the optimal excitation wavelength was 300 nm and the optimal emission wavelength was 405 nm, under which the highest sensitivity for SA detection was obtained. At a flow rate of 2 mL∙min^-1, it took 3.5 min for elution, 3.5 min for column wash, and 3 min for column balance, shortening the measurement time per sample from 50 min to 10 min.

CONCLUSION: These optimizations greatly improved the sensitivity, stability, and efficiency of the SA measurement using HPLC, which will contribute to the plant immunity research.

Optimization of salicylic acid (SA) measurement. (A) SA detection procedure; (B) Chromatogram using the optimized condition. The samples are total SA in Arabidopsis without Psm ES4326 infection. EU: Emission units. The peak labeled in red indicates SA.

In recent years, significant progresses have been made in plant stress biology, particularly in elucidating the mechanisms underlying responses to extreme temperatures and salinity-alkalinity stresses. These advancements have not only broadened our understanding of plant resilience but also provided a wealth of potential targets for molecular breeding, paving new avenues for developing climate-resilient crop varieties that maintain high yield potential under both optimal and adverse conditions. This review concisely summarizes current knowledge on signal perception and transduction mechanisms during plant adaptation to extreme temperature and saline-alkali stresses, discusses the balance regulation between growth/development and stress tolerance, particularly highlights recent breakthroughs by Chinese scientists in discovering key genes and deciphering mechanisms that synergistically improve crop stress resistance and yield. We also provide future prospects for breeding strategies.

Iron-sulfur [Fe-S] clusters, which act as cofactors for iron-sulfur proteins, are ubiquitously implicated in a diverse array of biological processes, such as photosynthesis, respiration, electron transport, and the biosynthesis of essential vitamins and cofactors. Their intracellular biogenesis is modulated by a suite of proteins that catalyze and regulate the process, with compartmentalization occurring within discrete subcellular compartments. Mitochondria, as the central organelles for cellular energy metabolism, harbor numerous key metabolic enzymes that are iron-sulfur proteins, necessitating the provision of iron-sulfur clusters by the mitochondrial assembly machinery, the iron-sulfur cluster (ISC). Advancements in research, particularly from bacteria and yeast systems, have facilitated significant strides in the identification and functional characterization of pivotal catalytic and regulatory proteins within the plant mitochondrial ISC system. Additionally, considerable progress has been made in the research of the role in iron-sulfur clusters in the plant growth and development. The elucidation of plant-specific components within the iron-sulfur cluster synthesis machinery and the mechanisms by which this system responds to environmental stress are areas of growing interest. This manuscript provides a comprehensive review of the current state of research on the mechanism of iron-sulfur cluster synthesis in plants, with a particular focus on the mitochondrial ISC assembly system. It also provides a succinct synopsis of the role of key genes within the ISC system in plant growth and development, as well as their involvement in the response to abiotic stressors.

INTRODUCTION Cucumber (Cucumis sativus) is one of the foremost vegetable crops globally. Photosynthesis intricately influences the fruit yield of cucumber, and leaf color determines the photosynthetic efficiency to a large extent. Therefore, Leaf color mutants serve as ideal materials for scrutinizing diverse physiological processes, including photomorphogenesis, chloroplast development, chlorophyll metabolism, and photosynthetic mechanisms. Currently, the molecular mechanisms underlying the yellowing lethal phenotype remain unclear.

RATIONALE In this study, a stable cucumber yellowing lethal mutant, ycl(yellow cotyledon lethal), was isolated from the near-isogenic line XYYH-2-1-1. The phenotype, leaf microstructure and chloroplast ultrastructure, as well as physiological and biochemical analyses, were conducted on the mutant ycl and the wild-type XYYH-3-1 to explore the physiological mechanisms underlying the yellowing lethal phenotype. Preliminary localisation of yellowing lethal mutation genes was performed by whole genome resequencing using BSA. The integration of transcriptome sequencing allowed us to analyze the expression of genes related to yellowing death and the main pathways. This approach laid a solid foundation for further investigation into the molecular mechanisms responsible for the lethal phenotype associated with yclyellowing.

RESULTS The ycl mutant exhibited yellow cotyledons, which ultimately withered and perished within approximately two weeks. Notably, its growth-inhibiting phenotype appeared to be light-independent. Compared to the wild type, ycl accumulated extremely low Chl a and Chl b contents, which was consistent with the blockade in the magnesium ion chelation process within the chlorophyll biosynthesis pathway. Microscopic and ultrastructural analyses revealed disordered ycl leaf structure and inhibited chloroplast development. Additionally, the ycl mutant displayed significantly increased antioxidant enzyme activities and malondialdehyde contents, suggesting elevated oxidative stress levels and robust antioxidant capacities. The substantial decrease in net photosynthetic rate and rise in intercellular CO₂ concentration in ycl were hypothesized to stem from reduced stomatal conductance, diminished chlorophyll content, and impaired chloroplast development in the mutant. Transcriptomic analyses suggested that key pathways including photosynthesis, flavonoid biosynthesis, chlorophyll metabolism, and reactive oxygen species metabolism were affected in ycl. The ycl mutant gene was preliminarily mapped to a region between 1.48 to 1.9 Mb on chromosome 3 through BSA-seq analysis, encompassing 41 candidate genes.

CONCLUSION The study investigated the physiological mechanisms underlying the yellowing lethal phenotype of the yclmutant, preliminarily mapped the mutant gene to chromosome 3, and identified differentially expressed genes (DEGs) and key pathways associated with the lethal phenotype. These findings provide valuable insights into the molecular mechanisms of chloroplast development in cucumber.

Phenotypic changes of WT and the ycl mutant at the cotyledon stage under natural light conditions, and preliminary mapping of the mutant gene.

INTRODUCTION Due to differences in breeding objectives, northeast japonica rice (Oryza sativa subsp. geng or japonica) is more advantageous than Japanese japonica rice in terms of yield level, whereas Japanese japonica rice is significantly better than Chinese japonica rice in terms of eating quality. Clarifying the genetic basis of the differences in eating quality between Chinese and Japanese japonica rice is highly valuable for the cultivation of high-yield and high-quality japonica rice.

RATIONALEA total of 274 Chinese and Japanese japonica rice varieties were used as research materials to quantify the eating quality of the rice and to analyze the genetic basis of the taste differences between Chinese and Japanese japonica rice by combining genome-wide association analysis with the downscaling of many parameters.

RESULTSThe results revealed that the significant differences in the taste values of Chinese and Japanese japonica rice were reflected in three textural parameters: the adhesion force (ADF), first recoverable deformation cycle (FRDC), and elasticity index (EI). Moreover, the correlation analysis between the taste values and 30 textural characters showed that 24 characters were significantly correlated with the taste value of rice. The 30 metrics of textural characterization were downscaled to four principal components that explained 80% of the phenotypic variation in the population, and the genome-wide associations of their eigenvalues were mined to two primary effector loci affecting the textural characterization of Chinese-Japanese japonica rice, qFPC4.3 and qFPC9.2.

CONCLUSION In this study, we quantified the parameters of eating quality from a qualitative perspective, and thus analyzed the genetic basis of the differences in eating quality between Chinese and Japanese rice, which provided valuable genetic information and a theoretical basis for the genetic improvement of the eating quality of japonica rice in China.

PCA analysis and genome-wide association studies based on principal component eigenvalues of texture characteristics indicators. PCA analysis was performed using 2021 data.

INTRODUCTION: Plant roots respond to various abiotic stresses, including drought stress, heavy metal stress, salt stress, and deficiencies in essential nutrients, during their growth and development. Among these factors, soil structure, especially soil compaction, significantly affects root growth and morphology, ultimately influencing crop yield.

RATIONALE: The Golgi apparatus plays a role in root growth and responds to abiotic stress through vesicle secretion. However, the mechanisms by which the Golgi apparatus contributes to the response of the root system to soil compaction remain unclear. Previous studies have demonstrated that AtFTCD-L in Arabidopsis is located on the trans-Golgi network (TGN) opposite the Golgi apparatus, and plays a role in vesicle sorting and/or secretion regulation of mucin components in the peripheral cells of the root cap.

RESULTS: Compared with those of the wild type, the root tips and root tip cells of the ftcd mutant are shorter in the longitudinal direction, but wider in the transverse direction, indicating abnormal cell morphology. Analysis of fluorescent signals from PIN-GFP plants revealed that PIN7 was either not expressed or expressed at very low levels in mutants. This study provides theoretical insights into the adaptive mechanisms of plant roots in response to abiotic stress induced by soil compaction.

CONCLUSION: In summary, AtFTCD-L responds to soil compaction in the roots of Arabidopsis by regulating the distribution or expression of PIN7.

Phenotypic differences in the effects of soil compaction on AtFTCD-L (WT)-, and mutant (ftcd)-mediated PIN7 regulation of root cell growth. The growth phenotypes of the root tips of the Arabidopsis lines on the 7^th day.