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Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas have been recognized as powerful genome-editing tools in diverse eukaryotic species, including plants, and thus hold great promise for engineering virus resistance in plants. Nevertheless, further attention is required regarding various issues associated with applying new powerful technologies in the field. This mini-review focuses on the recent advances in using CRISPR/Cas9 and CRISPR/Cas13 systems to combat DNA and RNA viruses in plants. We explored the utility of CRISPR/Cas for targeting the viral genome and editing host susceptibility genes in plants. We also provide insights into the limitations and challenges of using CRISPR/Cas for plant virus interference and propose individual combinatorial solutions. In conclusion, CRISPR/Cas technology has the potential to offer innovative and highly efficient approaches for controlling viruses in important crops in the near future. [ABSTRACT FROM AUTHOR]

This paper presents a Large Eddy Simulation (LES) study investigating jet flame ignition characteristics to achieve stable ammonia combustion for novel applications in gaseous ammonia/hydrogen-fueled engines with an active prechamber. The study investigated three cases with initial global equivalence ratios of 0.6, 0.8, and 1.0. Two main ignition modes were proposed, and five stages of coupled flame propagation processes were identified. The oscillation of supersonic hydrogen jet flame was investigated. The modes of flame-vortex interaction including vortex ring formation, along with the mechanism of highly reactive zone formation, were proposed. The effects of reactivity and turbulence transition on piloted ammonia flame were investigated to attain stable ammonia combustion and achieve a high heat release rate. The results showed that oscillations in the jet flame were strengthened at low global equivalence ratios with high hydrogen mass ratios. Enhancing propagation of initial and secondary vortex rings broadened highly reactive zones. Vorticity dissipated more rapidly at low equivalence ratios, leading to a stratified structure and enhanced piloted spherical flame. The Unsteady Flamelet Ignition Prediction (UFIP) sub-model of combustion was verified for the piloted ammonia flame, enabling a more comprehensive discussion of flame propagation tendencies. • The transient characteristics of jet flames ignited by H 2 /NH 3 mixtures were analyzed using LES. • The behavior of stratified flames at various equivalence ratios was investigated. • Various modes of turbulent jet flame ignition were proposed according to different stages. • The mechanism of vortex evolution to form the reactive zone and pilot flame was proposed. [ABSTRACT FROM AUTHOR]

Salt and osmotic stress seriously restrict the growth, development, and productivity of horticultural crops in the greenhouse. The papain-like cysteine proteases (PLCPs) participate in multi-stress responses in plants. We previously demonstrated that salt and osmotic stress affect cysteine protease 15 of pepper (Capsicum annuum L.) (CaCP15); however, the role of CaCP15 in salt and osmotic stress responses is unknown. Here, the function of CaCP15 in regulating pepper salt and osmotic stress resistance was explored. Pepper plants were subjected to abiotic (sodium chloride, mannitol, salicylic acid, ethrel, methyl jasmonate, etc.) and biotic stress (Phytophthora capsici inoculation). The CaCP15 was silenced through the virus-induced gene silencing (VIGS) and transiently overexpressed in pepper plants. The full-length CaCP15 fragment is 1568 bp, with an open reading frame of 1032 bp, encoding a 343 amino acid protein. CaCP15 is a senescence-associated gene 12 (SAG12) subfamily member containing two highly conserved domains, Inhibitor 129 and Peptidase_C1. CaCP15 expression was the highest in the stems of pepper plants. The expression was induced by salicylic acid, ethrel, methyl jasmonate, and was infected by Phytophthora capsici inoculation. Furthermore, CaCP15 was upregulated under salt and osmotic stress, and CaCP15 silencing in pepper enhanced salt and mannitol stress resistance. Conversely, transient overexpression of CaCP15 increased the sensitivity to salt and osmotic stress by reducing the antioxidant enzyme activities and negatively regulating the stress-related genes. This study indicates that CaCP15 negatively regulates salt and osmotic stress resistance in pepper via the ROS-scavenging. [ABSTRACT FROM AUTHOR]

Filamentation temperature-sensitive H (FtsH) is a proteolytic enzyme that plays an important role in plant photomorphogenesis and stress resistance. However, information regarding the FtsH family genes in pepper is limited. In our research, through genome-wide identification, 18 members of the pepper FtsH family (including five FtsHi members) were identified and renamed based on phylogenetic analysis. CaFtsH1 and CaFtsH8 were found to be essential for pepper chloroplast development and photosynthesis because FtsH5 and FtsH2 were lost in Solanaceae diploids. We found that the CaFtsH1 and CaFtsH8 proteins were located in the chloroplasts and specifically expressed in pepper green tissues. Meanwhile, CaFtsH1 and CaFtsH8-silenced plants created by virus-induced gene silencing exhibited albino leaf phenotypes. In addition, CaFtsH1-silenced plants were observed to contain very few dysplastic chloroplasts and lost the capacity for photoautotrophic growth. Transcriptome analysis revealed that the expression of chloroplast-related genes such as those coding the photosynthesis-antenna protein and structural proteins was downregulated in CaFtsH1-silenced plants, resulting in the inability to form normal chloroplasts. This study improves our understanding of pepper chloroplast formation and photosynthesis through the identification and functional study of CaFtsH genes. [ABSTRACT FROM AUTHOR]

Bacterial spot (BS), incited by Xanthomonas campestris pv. vesicatoria (Xcv), is one of the most serious diseases of pepper. For a comparative analysis of defense responses to Xcv infection, we performed a transcriptomic analysis of a susceptible cultivar, ECW, and a resistant cultivar, VI037601, using the HiSeqTM 2500 sequencing platform. Approximately 120.23 G clean bases were generated from 18 libraries. From the libraries generated, a total of 38,269 expressed genes containing 11,714 novel genes and 11,232 differentially expressed genes (DEGs) were identified. Functional enrichment analysis revealed that the most noticeable pathways were plant-pathogen interaction, MAPK signaling pathway—plant, plant hormone signal transduction and secondary metabolisms. 1,599 potentially defense-related genes linked to pattern recognition receptors (PRRs), mitogen-activated protein kinase (MAPK), calcium signaling, and transcription factors may regulate pepper resistance to Xcv. Moreover, after Xcv inoculation, 364 DEGs differentially expressed only in VI037601 and 852 genes in both ECW and VI037601. Many of those genes were classified as NBS-LRR genes, oxidoreductase gene, WRKY and NAC transcription factors, and they were mainly involved in metabolic process, response to stimulus and biological regulation pathways. Quantitative RT-PCR of sixteen selected DEGs further validated the RNA-seq differential gene expression analysis. Our results will provide a valuable resource for understanding the molecular mechanisms of pepper resistance to Xcv infection and improving pepper resistance cultivars against Xcv. [ABSTRACT FROM AUTHOR]

Cucumber mosaic virus (CMV) is a prevalent virus affecting the quality and yield of pepper, resulting in yield losses of greater than 80% during severe local epidemics. Cultural practices and the heavy use of agrochemicals are the most common control measures for CMV. Sources of resistance provide a practical reference and a basis for breeding for CMV resistance. Genetic factors underlying CMV resistance have been studied and advanced breeding lines and cultivars with improved resistance have been developed by traditional breeding methods. Additionally, QTLs or genes for CMV resistance have been identified and can be utilized for marker-assisted resistance breeding. This review focuses on status and prospect of CMV against different virus strains, host resistance, and its applied genetics. With the advent of novel technologies, more useful markers and precise approaches can facilitate the progress for improving CMV resistance in Capsicum. [ABSTRACT FROM AUTHOR]

TIFY [TIF(F/Y)XG] proteins are a plant particular transcription factor family that regulates plant stress responses. Therefore, to fill this gap, we investigated CaTIFY genes in pepper. Gene structure and conserved motifs of the pepper TIFY gene family were systematically analyzed using sequence alignment analysis, Cis -acting element analysis, transcriptomic data, and RT-qPCR analysis, and their expression patterns were further analyzed using Virus-Induced Gene Silencing (VIGS) and cold stress reactive oxygen species (ROS) response. We identified 16 CaTIFY genes in pepper, which were dispersed among seven subgroups (JAZI, JAZII, JAZIII, PPD, TIFY, and ZIM/ZML). Several CaTIFY members had stress-related harmonic-responsive elements, and four ( CaTIFY7 , CaTIFY10b , CaTIFY1b , and CaTIFY6b ) had low-temperature-responsive elements. Transcriptomic data and RT-qPCR analysis revealed that the TIFY genes in pepper displayed different expression patterns in the roots, stems, leaves, flower fruits, and seeds. In particular, CaTIFY7 was highly expressed in young leaves, and CaTIFY10b was highly expressed in roots. CaTIFY s participated in the regulation of several different abiotic stresses and CaTIFY7 and CaTIFY10b were significantly induced by cold stress. Additionally, Virus-Induced Gene Silencing (targeting CaTIFY7 and CaTIFY10b ) resulted in plants that were sensitive to cold stress. Conversely, overexpression of CaTIFY7 and CaTIFY10b enhanced plant cold tolerance by promoting the expression of genes related to cold stress and the ROS response. CaTIFY7 and CaTIFY10b interacted with themselves and CaTIFY7 also interacted with CaTIFY10b in the yeast two-hybrid (Y2H) system. Our data provide a basis for further analysis of the role of pepper TIFY genes in cold-stress responses in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Wang, Li, Zan, Xu, Gao, Yin, Yao and Wang.)

The purple color of unripe pepper fruit is attributed to the accumulation of anthocyanins. Only a few genes controlling the biosynthesis and regulation of anthocyanins have been cloned in Capsicum . In this study, we performed a bulked segregant analysis of the purple striped trait using an F 2 population derived from a cross between the immature purple striped fruit line Chen12-4-1-1-1-1 and the normal green fruit line Zhongxian101-M-F 9 . We mapped the CaPs locus to an 841.39 kb region between markers M-CA690-Xba and MCA710-03 on chromosome 10. CA10g11690 encodes an R2R3-MYB transcription factor that is involved in the biosynthesis of anthocyanins as the best candidate gene. Overexpression and silencing in transformed tobacco ( Nicotiana tabacum ) lines indicated that CA10g11690 is involved in the formation of purple stripes in the exocarp. A comparison of parental sequences identified an insertion fragment of 1,926 bp in the second intron region of Chen12-4, and eight SNPs were detected between the two parents. Additionally, there were 49 single nucleotide polymorphic variations, two sequence deletions, and four sequence insertions in the promoter region. We found that CA10g11690 undergoes alternative splicing and generates different transcripts. Thus, the functional transcript of CA10g11690 appeared to be primarily involved in the development of purple phenotype in the exocarp. Our data provide new insight into the mechanism of anthocyanin biosynthesis and a theoretical basis for the future breeding of purple striped pepper varieties., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Liu, Yin, Gao, Wu, Yu, Wang, Kang, Xu, Jiao and Yao.)

Pepper ( Capsicum ) is one of the most important vegetable and spice crops. Aphid-transmitted cucumber mosaic virus (CMV) causes significant damage to pepper crops across the world. The genetic basis of CMV resistance in pepper is complex, and the mechanisms underlying resistance remain largely unknown. Here, we employed a SLAF-seq approach to generate a high-density genetic map of pepper. The map spanned 1,785.46 cM, containing 12,727 markers on 12 chromosomes, with a mean marker distance of 0.16 cM between adjacent markers. We used this map and the interval mapping (IM) and multiple QTL mapping (MQM) procedures to detect genetic regions associated with quantitative trait for CMV resistance. Three QTLs, qcmv11.1 , qcmv11.2 and qcmv12.1 , conferred resistance to CMV and showed trait variation of 10.2%, 19.2% and 7.3% respectively. Our results will help to develop markers linked to CMV-resistant QTLs to improve pepper resistance to CMV.

The F-box protein family is characterized by an F-box motif that has been shown to play an important role in regulating various developmental processes and stress responses. In this study, a novel F-box-containing gene was isolated from leaves of pepper cultivar P70 (Capsicum annuum L.) and designated CaF-box. The full-length cDNA is 2088 bp and contains an open reading frame of 1914 bp encoding a putative polypeptide of 638 amino acids with a mass of 67.8 kDa. CaF-box was expressed predominantly in stems and seeds, and the transcript was markedly upregulated in response to cold stress, abscisic acid (ABA) and salicylic acid (SA) treatment, and downregulated under osmotic and heavy metal stress. CaF-box expression was dramatically affected by salt stress, and was rapidly increased for the first hour, then sharply decreased thereafter. In order to further assess the role of CaF-box in the defense response to abiotic stress, a loss-of-function experiment in pepper plants was performed using a virus-induced gene silencing (VIGS) technique. Measurement of thiobarbituric acid reactive substances (TBARS) and electrolyte leakage revealed stronger lipid peroxidation and cell death in the CaF-box-silenced plants than in control plants, suggesting CaF-box plays an important role in regulating the defense response to abiotic stress resistance in pepper plants.