DNA, is assaulted by endogenous and exogenous agents that lead to the formation of damage. In order to maintain genome integrity DNA repair pathways must be efficiently activated to prevent mutations and deleterious chromosomal rearrangements. Conversely, genome rearrangement is also necessary to allow genetic diversity and evolution. The antagonist interaction between maintenance of genome integrity and rearrangements determines genome shape and organization. Therefore, it is of great interest to understand how the whole linear genome structure behaves upon formation and repair of DNA damage. For this, we used long reads sequencing technology to identify and to characterize genomic structural variations (SV) of wild-type Arabidopsis thaliana somatic cells exposed either to UV-B, to UV-C or to protons irradiations. We found that genomic regions located in heterochromatin are more prone to form SVs than those located in euchromatin, highlighting that genome stability differs along the chromosome. This holds true in Arabidopsis plants deficient for the expression of master regulators of the DNA damage response (DDR), ATM (Ataxia-telangiectasia-mutated) and ATR (Ataxia-telangiectasia-mutated and Rad3-related), suggesting that independent and alternative surveillance processes exist to maintain integrity in genic regions. Finally, the analysis of the radiations-induced deleted regions allowed determining that exposure to UV-B, UV-C and protons induced the microhomology-mediated end joining mechanism (MMEJ) and that both ATM and ATR repress this repair pathway.

Tea plants are perennial evergreen woody crops that originated in low latitudes but have spread to high latitudes. Bud dormancy is an important adaptation mechanism to low temperatures, and its timing is economically significant for tea production. However, the core molecular networks regulating dormancy and bud break in tea plants remain unclear. In the present study, a MADS-box transcription factor CsMADS27 was identified in tea plants. Gene and phenotype characterizations following ectopic overexpression and endogenous silencing experiments are consistent with a role for CsMADS27 in dormancy and sprouting in different tea cultivars. Furthermore, CsDJC23 was found to be a downstream target of CsMADS27 and implicated in bud sprouting. Based on yeast one-hybrid screening and comprehensive verification, CsCBF1 and CsZHD9 were identified as upstream transcriptional inhibitors and activators of CsMADS27, respectively, with the two proteins showing direct interactions and competitive binding effects. Histone acetylation (H3K27Ac) in the first exon and intron regions of CsMADS27 was associated with a positive role in CsMADS27 expression. These results revealed that CsMADS27 is a key transcription factor involved in the regulation of dormancy and bud break. Furthermore, the CsCBF1/CsZHD9-CsMADS27 module plays a critical role in sensing environmental factors and accurately regulating the growth and development of overwintering buds in tea plants.

Calcium signaling plays an essential role in integrating plant responses to diverse stimuli and regulating growth and development. While some signaling components and their roles are well-established, such as the ubiquitous calmodulin (CaM) sensor, plants possess a broader repertoire of calcium sensors. Notably, CaM-like proteins (CMLs) represent a poorly characterized class for which interacting partners and biological functions remain largely elusive. Our work investigates the role of Arabidopsis thaliana CML8 that exhibits a unique expression profile in seedlings. A reverse genetic approach revealed a function of CML8 in regulating root growth and hypocotyl elongation. RNA-seq analyses highlighted CML8 association with the regulation of numerous genes involved in growth and brassinosteroid (BR) signaling. Using co-immunoprecipitation experiments, we demonstrated that CML8 interacts with the BR receptor, BRI1, in planta in a ligand-dependent manner. This finding suggests the existence of a novel regulatory step in the BR pathway, involving calcium signaling.

Vascular plant one-zinc finger (VOZ) transcription factors (TFs) play crucial roles in plant immunity. Nevertheless, how VOZs modulate defense signaling in response to elicitor-induced resistance is not fully understood. Here, the defense elicitor β-aminobutyric acid (BABA) resulted in the visible suppression of Rhizopus rot disease of peach fruit caused by Rhizopus stolonifer. Defense priming by BABA was notably associated with increased levels of salicylic acid (SA) and SA-dependent gene expression. Data-independent acquisition proteomic analysis revealed that two VOZ proteins (PpVOZ1 and PpVOZ2) were substantially upregulated in BABA-induced resistance (BABA-IR). Furthermore, the interaction of PpVOZ1 and PpVOZ2 and their potential target of the TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP)-family protein PpTCP2 screened from protein-protein interaction networks was confirmed by yeast two-hybrid (Y2H), luciferase complementation imaging and glutathione S-transferase pull-down assays. Furthermore, subcellular localization, yeast one-hybrid, electrophoretic mobility shift assay and dual-luciferase reporter assays demonstrated that nuclear localization of both PpVOZ1 and PpVOZ2 was critical for their contribution to BABA-IR, as these proteins potentiated the PpTCP2-mediated transcriptional activation of isochorismate synthase genes (ICS1/2). The overexpression of both PpVOZ1 and PpVOZ2 could activate the transcription of SA-dependent genes and provide disease resistance in transgenic Arabidopsis. In contrast, the ppvoz1 and ppvoz2 loss-of-function mutations and the voz1 voz2 double mutation attenuated BABA-IR against R. stolonifer. Therefore, the three identified positive TFs, PpVOZ1, PpVOZ2, and PpTCP2, synergistically contribute to the BABA-activated priming of systemic acquired resistance in postharvest peach fruit by a VOZ-TCP-ICS regulatory module.

Plants have an amazing capacity to outcompete neighboring organisms for space and resources. Toxic metabolites are major players in these interactions, which can have a broad range of effectiveness by targeting conserved molecular mechanisms, such as protein biosynthesis. However, lack of knowledge about defensive metabolite pathways, their mechanisms of action, and resistance mechanisms limits our ability to manipulate these pathways for enhanced crop resilience. Nonproteogenic amino acids (NPAAs) are a structurally diverse class of metabolites with a variety of functions but are typically not incorporated during protein biosynthesis. Here, we investigate the mechanism of action of the NPAA azetidine-2-carboxylic acid (Aze), an analog of the amino acid proline (Pro). Using a combination of plate-based assays, metabolite feeding, metabolomics, and proteomics, we show that Aze inhibits the root growth of Arabidopsis and other plants. Aze-induced growth reduction was restored by supplementing L-, but not D-Pro, and nontargeted proteomics confirm that Aze is misincorporated for Pro during protein biosynthesis, specifically on cytosolically translated proteins. Gene expression analysis, free amino acid profiling, and proteomics show that the unfolded protein response is upregulated during Aze treatment implicating that Aze misincorporation results in accumulation of misfolded proteins triggering a global stress response. This study demonstrates the mechanism of action of Aze in plants and provides a foundation for understanding the biological functions of proteotoxic metabolites.

Toxicodendron species are economically and medicinally important trees because of their rich sources of natural products. We present three chromosome-level genome assemblies of Toxicodendron vernicifluum 'Dali', Toxicodendron succedaneum 'Vietnam', and T. succedaneum 'Japan', which display diverse production capacities of specialized metabolites. Genome synteny and structural variation analyses revealed large genomic differences between the two species (T. vernicifluum and T. succedaneum) but fewer differences between the two cultivars within the species. Despite no occurrence of recent whole-genome duplications, Toxicodendron showed evidence of local duplications. The genomic modules with high expression of genes encoding metabolic flux regulators and chalcone synthase-like enzymes were identified via multiomics analyses, which may be responsible for the greater urushiol accumulation in T. vernicifluum 'Dali' than in other Toxicodendron species. In addition, our analyses revealed the regulatory patterns of lipid metabolism in T. succedaneum 'Japan', which differ from those of other Toxicodendron species and may contribute to its high lipid accumulation. Furthermore, we identified the key regulatory elements of lipid metabolism at each developmental stage, which could aid in molecular breeding to improve the production of urushiol and lipids in Toxicodendron species. In summary, this study provides new insights into the genomic underpinnings of the evolution and diversity of specialized metabolic pathways in three Toxicodendron cultivars through multiomics studies.

The glutamate receptor (GLR) serves as a ligand-gated ion channel that plays a vital role in plant growth, development, and stress response. Nevertheless, research on GLRs in cotton is still very limited. The present study conducted a comprehensive analysis of GLRs gene family in cotton. In total, 41 members of the GLR family were identified in cotton unveiling distinct subgroups in comparison to Arabidopsis. Among these members, the third subgroup highlights its pivotal role in cotton's defense against insect infestation. Furthermore, the CRISPR/Cas9 system was utilized to create a mutant library of GLR members, which consisted of a total of 135 independent mutant lines, resulting in the production of novel cotton materials with valuable breeding potential for pest control. Further, this study elucidates the influence of GhGLR3.4 on jasmonic acid (JA) pathway signal transduction and demonstrated its participation in the influx of intracellular Ca, which regulates "calcium transients" following stimulation, thereby influencing multiple intracellular reactions. The study also found that GhGLR3.4 influences the synthesis of the JA pathway and actively partakes in long-distance signal transmission among plants, facilitating the transfer of defense signals to neighbor leaves and thereby triggering systemic defense. Consequently, this research advances our knowledge of plants' comprehensive defense mechanism against insect pest infestation.

Cold stress affects the growth, development, and yield of asparagus bean (Vigna unguiculata subsp. sesquipedalis). Mediator (MED) complex subunits regulate the cold tolerance of asparagus bean, but the underlying regulatory mechanisms remain unclear. Here, VunMED2 positively responds to cold stress of asparagus beans. Under cold acclimation and freezing treatment, the survival rate, ROS scavenging activity, and expression levels of VunMED2 were increased in VunMED2 transgenic plants. Natural variation in the promoter of VunMED2 in two different cold-tolerant asparagus beans was observed. Under cold stress, the expression of the GUS reporter gene was higher in cold-tolerant plants than in cold-sensitive plants, and the expression of the GUS reporter gene was tissue-specific. VunHY5 positively influenced the expression of VunMED2 by binding to the E-box motif, and the transcriptional activation of the promoter was stronger in the cold-tolerant variety than in cold-sensitive plants. VunHY5 overexpression improved plant freezing resistance by increasing the antioxidant capacity and expression of dehydrin genes. VunHY5 and VunMED2 play a synergistic role in binding to the G-box/ABRE motif and transcriptionally activating the expression of VunERD14. VunERD14 complemented the med2 mutant, which could positively respond to plant freezing resistance by reducing membrane lipid peroxidation and improving the antioxidant capacity. Therefore, the VunHY5-VunERD14 module and the VunHY5-VunMED2-VunERD14 positive cascade effect are involved in the cold signal transduction in asparagus bean. Our findings have implications for the breeding of asparagus bean varieties with improved cold tolerance.

Fruit morphogenesis is determined by the coordination of cell division and expansion, which are fundamental processes required for the development of all plant organs. Here, we show that the regulation of TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) LANCEOLATE (TCP2/LA) by miR319 is crucial for tomato fruit morphology. The loss of miR319 regulation in the semi-dominant La mutant led to a premature SlTCP2/LA expression during gynoecium patterning, which results in modified cell division during carpel development. As a consequence, La mutants exhibited elongated ovary and fruit shape, and a reduced number of ovules and seeds. Elongated fruit shape in La may be partially due to the SlTCP2/LA-mediated repression of OVATE activity in young floral buds. Further analysis showed that the de-repression of SlTCP2/LA decreases auxin responses in young floral buds by directly repressing SlYUCCA4 expression, but SlTCP2/LA also acts in parallel with ENTIRE (E) to orchestrate fruit morphology and seed production. Our study defines a novel miRNA-based molecular link between the domestication-associated OVATE gene and auxin responses. Given the striking variation in fruit morphology among members of the Solanaceae family, fine-tuning regulation of gene expression by miRNA coupled with modulation of auxin dynamics may be a common driver in the evolution of fruit shape diversity.

Plants recognize molecules related to a variety of biotic stresses through pattern recognition receptors to activate plant immunity. In the interactions between plants and chewing herbivores, such as lepidopteran larvae, oral secretions (OS) are deposited on wounded sites, which results in the elicitation of plant immune responses. The widely conserved receptor-like kinase CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) has been broadly associated with the recognition of microbial components, such as fungal chitin, but its relevance to herbivory remained unclear. In this study, we used receptor-knockout rice (Oryza sativa) and larvae of the lepidopteran pest Mythimna loreyi to demonstrate that the induction of immune responses triggered by larval OS in rice cells largely depends on CERK1 (OsCERK1). CHITIN ELICITOR-BINDING PROTEIN (CEBiP), an OsCERK1-interacting receptor-like protein that was proposed as the main chitin receptor, also contributed to the responses of rice cells to OS collected from three different lepidopteran species. Furthermore, CEBiP knockout rice seedlings showed lower OS-triggered accumulation of jasmonic acid. These results strongly suggest that the OsCERK1 and CEBiP recognize a particular OS component in chewing lepidopteran herbivores, and point toward the presence of chitooligosaccharides in the OS. Targeted perturbation to chitin recognition, through the use of fungal effector proteins, confirmed the presence of chitooligosaccharides in the OS. Treatments of wounds on rice plants with chitooligosaccharides enhanced a set of immune responses, leading to resistance against an herbivorous insect. Our data show that rice recognizes chitooligosaccharides during larval herbivory to activate resistance, and identifies chitin as a novel herbivore-associated molecular pattern.

TBL family proteins containing the domain of unknown function mainly act as xylan O-acetyltransferases, but the specific molecular mechanism of their functions remains unclear in plants (especially in cotton) so far. In this study, we characterized the TBL family proteins containing the conserved GDS and DxxH motifs in cotton (Gossypium hirsutum). Among them, GhTBL3 is highly expressed in fibers at the stage of secondary cell wall (SCW) formation and mainly functions as O-acetyltransferase to maintain acetylation of xylan in fiber SCW development. Overexpression of GhTBL3 in cotton promoted fiber SCW formation, resulting in increased fiber cell wall thickness. In contrast, suppression of GhTBL3 expression in cotton impaired fiber SCW synthesis, leading to the decreased fiber cell wall thickness, compared with wild type (WT). Furthermore, two fiber SCW-related transcription factors GhMYBL1 and GhKNL1 were found to directly bind to the promoter of GhTBL3 in cotton. GhMYBL1 enhanced the transcription activity of GhTBL3, whereas GhKNL1 inhibited the expression of GhTBL3 in fibers. The acetylation level of xylan was remarkably decreased in fibers of GhMYBL1 RNAi transgenic cotton, but the acetylation level of xylan was significantly increased in fibers of GhKNL1 RNAi cotton, relative to WT. Given together, the above results suggested that GhTBL3 may be under the dual control of GhMYBL1 and GhKNL1 to maintain the suitable acetylation level of xylan required for fiber SCW formation in cotton. Thus, our data provide an effective clue for potentially improving fiber quality by genetic manipulation of GhTBL3 in cotton breeding.

Because plants are immobile, they have developed intricate mechanisms to sense and absorb nutrients, adjusting their growth and development accordingly. Sulfur is an essential macroelement, but our understanding of its metabolism and homeostasis is limited. LSU (RESPONSE TO LOW SULFUR) proteins are plant-specific proteins with unknown molecular functions and were first identified during transcriptomic studies on sulfur deficiency in Arabidopsis. These proteins are crucial hubs that integrate environmental signals and are involved in the response to various stressors. Herein, we report the direct involvement of LSU proteins in primary sulfur metabolism. Our findings revealed that the quadruple lsu mutant, q-lsu-KO, which was grown under nonlimiting sulfate conditions, exhibited a molecular response resembling that of sulfur-deficient wild-type plants. This led us to explore the interactions of LSU proteins with sulfate reduction pathway enzymes. We found that all LSU proteins interact with ATPS1 and ATPS3 isoforms of ATP sulfurylase, all three isoforms of adenosine 5´ phosphosulfate reductase (APR), and sulfite reductase (SiR). Additionally, in vitro assays revealed that LSU1 enhances the enzymatic activity of SiR. These results highlight the supportive role of LSU proteins in the sulfate reduction pathway.

Lamiales is one of the largest orders of angiosperms with a complex evolutionary history and plays a significant role in human life. However, the polyploidization and chromosome evolution histories within this group remain in mystery. Among Lamiales, Isodon serra (Maxim.) Kudô shines for its abundance of diterpenes, notably tanshinones, long used in East Asia to combat toxicity and inflammation. Yet, the genes driving its biosynthesis and the factors governing its regulation linger in obscurity. Here, we present the telomere-to-telomere genome assembly of I. serra and, through gene-to-metabolite network analyses, pinpoint the pivotal tanshinone biosynthesis genes and their co-expressed transcription factors. Particularly, through luciferase (LUC) assays, we speculate that IsMYB-13 and IsbHLH-8 may upregulate IsCYP76AH101, which is the key step in the biosynthesis of the tanshinone precursor. Among Lamiales, Oleaceae, Gesneriaceae and Plantaginaceae successively sister to a clade of seven Lamiales families, all sharing a recent whole-genome duplication (designated as α event). By reconstructing the ancestral Lamiales karyotypes (ALK) and post-α event (ALKα), we trace chromosomal evolution trajectories across Lamiales species. Notably, one chromosomal fusion is detected from ALK to ALKα, and three shared chromosomal fusion events are detected sequentially from ALKα to I. serra, which fully supports the phylogeny constructed using single-copy genes. This comprehensive study illuminates the genome evolution and chromosomal dynamics of Lamiales, further enhancing our understanding of the biosynthetic mechanisms underlying the medicinal properties of I. serra.

Drought is a major abiotic stress that severely affects cereal production worldwide. Although several genes have been identified that enhance the ability of rice to withstand drought stress, further research is needed to fully understand the molecular mechanisms underlying the response to drought stress. Our study showed that overexpression of rice DNA binding with one finger 12 (OsDof12) enhances tolerance to drought stress. Rice plants overexpressing OsDof12 (OsDof12-OE) displayed significantly higher tolerance to drought stress than the parental japonica rice "Dongjin". Transcriptome analysis revealed that many genes involved in phenylpropanoid biosynthesis were upregulated in OsDof12-OE plants, including phenylalanine ammonia-lyase 4 (OsPAL4), OsPAL6, cinnamyl alcohol dehydrogenase 6 (CAD6), and 4-coumarate-coA ligase like 6 (4CLL6). Accordingly, this transcriptional alteration led to the substantial accumulation of phenolic compounds, such as sinapic acids, in the leaves of OsDof12-OE plants, effectively lowering the levels of reactive oxygen species. Notably, OsDof12 bound to the AAAG-rich core sequence of the OsPAL4 promoter and promoted transcription. In addition, GIGANTEA (OsGI) interacts with OsDof12 in the nucleus and attenuates the transactivation activity of OsDof12 on OsPAL4. Our findings reveal a novel role for OsDof12 in promoting phenylpropanoid-mediated tolerance to drought stress.

Plant roots are essential for water and nutrient uptake, as well as resistance to abiotic stresses. While measuring root systems under field conditions is labor-intensive, most quantitative trait loci (QTLs) related to root traits have been detected under artificial conditions. However, QTLs identified under artificial conditions may not always manifest the expected effects that are observed under field conditions. To address this issue, we developed RSApaddy3D, a rapid phenotyping method for rice root systems, using X-ray computed tomography (CT) volumes of soil blocks collected from paddies. RSApaddy3D employs 2-dimensional kernel filters tailored to extract disk-shaped fragments from the CT volumes. Tubular root fragments are expected to exhibit disk-shaped cross-sections along the x-, y-, or z-axes. By applying these filters along all three axes and integrating the results, 3-dimensional root fragments can be accurately extracted. Furthermore, vectorizing the root system enables geometrical removal of the roots of neighboring individuals. We conducted a genome-wide association study (GWAS) of root diameter, number, and growth angle in 133 Japanese rice varieties and detected three QTLs (qNCR1, qNCR2, and qRGA1) that were associated with each trait. This process was completed within 10 person-days from soil monolith collection in the paddy to the GWAS. Without RSApaddy3D, roots would need to be washed from the soil monolith and measured, which is estimated to require >500 person-days. Therefore, RSApaddy3D was approximately 50× more labor-saving. In summary, we have demonstrated that RSApaddy3D is an efficient method for phenotyping rice root systems under field conditions.

Salinity poses a significant challenge to plant growth and crop productivity by adversely affecting crucial processes, including photosynthesis. Efforts to enhance abiotic stress tolerance in crops have been hindered by the trade-off effect, where increased stress resistance is accompanied by growth reduction. In this study, we identified and characterized a plastocyanin gene (PaPC) from the Antarctic moss Polytrichastrum alpinum, which enhanced photosynthesis and salt stress tolerance in Arabidopsis thaliana without compromising growth. While there were no differences in growth and salt tolerance between the wild type and Arabidopsis plastocyanin genes (AtPC1 and AtPC2)-overexpressing plants, PaPC-overexpressing plants demonstrated superior photosynthetic efficiency, increased biomass, and enhanced salt tolerance. Similarly, PaPC-overexpressing rice plants exhibited improved yield potential and photosynthetic efficiency under both normal and salt stress conditions. Key amino acid residues in PaPC responsible for this enhanced functionality were identified, and their substitution into AtPC2 conferred improved photosynthetic performance and stress tolerance in Arabidopsis, tobacco, and tomato. These findings not only highlight the potential of extremophiles as valuable genetic resources but also suggest a photosynthesis-based strategy for developing stress-resilient crops without a growth penalty.

Cannabis sativa L., known for its medicinal and psychoactive properties, has recently experienced rapid market expansion but remains understudied in terms of its fundamental biology due to historical prohibitions. This pioneering study implements GS and ML to optimize cannabinoid profiles in cannabis breeding. We analyzed a representative population of drug-type cannabis accessions, quantifying major cannabinoids and utilizing high-density genotyping with 250K SNPs for GS. Our evaluations of various models-including ML algorithms, statistical methods, and Bayesian approaches-highlighted Random Forest's superior predictive accuracy for single and multi-trait genomic predictions, particularly for THC, CBD, and their precursors. Multi-trait analyses elucidated complex genetic interdependencies and identified key loci crucial to cannabinoid biosynthesis. These results demonstrate the efficacy of integrating GS and ML in developing cannabis varieties with tailored cannabinoid profiles.

Mexican wild diploid potato species are reproductively isolated from A-genome species, including cultivated potatoes; thus, their genomic relationships remain unknown. Solanum stoloniferum Schlechtd. et Bché. (2n = 4x = 48, AABB) is a Mexican allotetraploid species frequently used in potato breeding. We constructed a chromosome-scale assembly of the S. stoloniferum genome using PacBio long-read sequencing and Hi-C scaffolding technologies. The final assembly consisted of 1742 Mb, among which 745 Mb and 713 Mb were anchored to the 12 A-genome and 12 B-genome chromosomes, respectively. Using the RNA-seq datasets, we detected 20 994 and 19 450 genes in the A and B genomes, respectively. Among these genes, 5138 and 3594 were specific to the A and B genomes, respectively, and 15 856 were homoeologous, of which 18.6-25.4% were biasedly expressed. Structural variations such as large pericentromeric inversions were frequently found between the A- and B-genome chromosomes. A comparison of the gene sequences from 38 diverse genomes of the related Solanum species revealed that the S. stoloniferum B genome and Mexican diploid species, with the exception of S. verrucosum, were monophyletically distinct from the S. stoloniferum A genome and the other A-genome species, indicating that the Mexican diploid species share the B genome. The content and divergence of transposable elements (TEs) revealed recent bursts and transpositions of TEs after polyploidization. Thus, the S. stoloniferum genome has undergone dynamic structural differentiation and TE mobilization and reorganization to stabilize the genomic imbalance. This study provides new insights into polyploid evolution and the efficient use of allotetraploid species in potato breeding.

Ascorbic acid (AsA) serves as a key antioxidant involved in the various physiological processes and against diverse stresses in plants. Due to the insufficiency of AsA de novo biosynthesis, the AsA regeneration is essential to supplement low AsA synthesis rates. Redox reactions play a crucial role in response to biotic stress in plants; however, how AsA regeneration participates in hydrogen peroxide (HO) homeostasis and plant defense remains largely unknown. Here, we identified a Golgi vesicle-membrane-localized cytochrome B561 (CytB561) encoding gene, GhB561-11, involved in AsA regeneration and plant resistance to Verticillium dahliae in cotton. GhB561-11 was significantly downregulated upon V. dahliae attack. Knocking down GhB561-11 greatly enhanced cotton resistance to V. dahliae. We found that suppressing GhB561-11 inhibited the AsA regeneration, elevated the basal level of HO, and enhanced the plant defense against V. dahliae. Further investigation revealed that GhB561-11 interacted with the lipid droplet-associated protein GhLDAP3 to collectively regulate the AsA regeneration. Simultaneously silencing GhB561-11 and GhLDAP3 significantly elevated the HO contents and dramatically improved the Verticillium wilt resistance in cotton. The study broadens our insights into the functional roles of CytB561 in regulating AsA regeneration and HO homeostasis. It also provides a strategy by downregulating GhB561-11 to enhance Verticillium wilt resistance in cotton breeding programs.

Plants are attacked by various insect herbivores. Upon attack-triggered biosynthesis of the phytohormone jasmonates (JAs), the JA receptor CORONATINE INSENSITIVE 1 recruits the JA-ZIM domain (JAZ) repressors for ubiquitination, releases the MYC-MYB transcription factor (TF) complexes, and enhances glucosinolates (GSs) biosynthesis to promote defense against insects in Arabidopsis. However, the negative regulation of JA-regulated defense remains largely unclear. Here, we found that Arabidopsis IVa bHLH TFs bHLH19 and bHLH20 interacted with JAZs. The bhlh19/20 mutations enhanced defense against the insects Spodoptera frugiperda and S. exigua, while their overexpression inhibited defense. bHLH19/20 repressed defense via at least two layers of regulation: first, bHLH19/20 interacted with the members MYC2/3/4/5 and MYB34/51/122 of MYC-MYB complexes, and inhibited the interaction/transcription activity of MYC2-MYB34; second, bHLH19/20 activated the RNA level of nitrile-specifier protein 1, which converts GSs into the less toxic nitriles. bhlh19/20 exhibited no penalty in JA-regulated growth inhibition. Collectively, our findings reveal the molecular mechanism for negatively regulating JA-mediated defense against insects in Arabidopsis without growth penalty by the pair of bHLH19/20 TFs.

Non-coding RNAs play crucial roles in plant responses to viral stresses. However, their molecular mechanisms in tea leaf spot responses remain unclear. In this study, using Camellia sinensis, we identified lncRNA81246 as a long non-coding RNA that localizes to both the nucleus and cytoplasm. It functions as a competitive endogenous RNA, thereby disrupting CsNAC1 (encoding NAC domain-containing protein 1) degradation mediated by miR164d. Silencing lncRNA81246 increased the resistance of tea plants to presistanceathogens, whereas transient lncRNA81246-overexpression plants showed decreased resistance to pathogens. Co-expression assays in Nicotiana benthamiana revealed that lncRNA81246 affects the miR164d-CsNAC1 regulatory module. Transient miR164d-overexpression and silencing assays demonstrated its positive regulation of tea plant resistance. Specifically, silencing its target, CsNAC1,enhanced disease resistance, whereas transient overexpression reduced plant resistance. Yeast one-hybrid, dual-luciferase, and RT-qPCR assay results suggested that CsNAC1 alters the expression of CsEXLB1, whereas AsODN and tobacco transient overexpression assays showed that CsEXLB1 negatively regulated tea plant resistance. Thus, our research demonstrated that lncRNA81246 acts as a mediator to interfere with the miR164d-CsNAC1 regulatory module involved in the disease resistance of tea plants.