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The cotton bollworm causes severe mechanical damage to plants during feeding and leaves oral secretions (OSs) at the mechanical wounds. The role these OSs play in the invasion of plants is still largely unknown. Here, a novel H. armigera effector peptidyl prolyl trans‐isomerase 5 (PPI5) was isolated and characterized. PPI5 induces the programmed cell death (PCD) due to the unfolded protein response (UPR) in tobacco leaf. We reveal that PPI5 is important for the growth and development of cotton bollworm on plants, as it renders plants more susceptible to feeding. The GhFKBP17‐2, was identified as a host target for PPI5 with peptidyl‐prolyl isomerase (PPIase) activity. CRISPR/Cas9 knock‐out cotton mutant (CR‐GhFKBP17‐1/3), VIGS (TRV: GhFKBP17‐2) and overexpression lines (OE‐GhFKBP17‐1/3) were created and the data indicate that GhFKBP17‐2 positively regulates endoplasmic reticulum (ER) stress‐mediated plant immunity in response to cotton bollworm infestation. We further confirm that PPI5 represses JA and SA levels by downregulating the expression of JA‐ and SA‐associated genes, including JAZ3/9, MYC2/3, JAR4, PR4, LSD1, PAD4, ICS1 and PR1/5. Taken together, our results reveal that PPI5 reduces plant defense responses and makes plants more susceptible to cotton bollworm infection by targeting and suppressing GhFKBP17‐2 ‐mediated plant immunity. [ABSTRACT FROM AUTHOR]

N6‐methyladenosine (m6A) is the most prevalent internal modification of mRNA and plays an important role in regulating plant growth. However, there is still a lack of effective tools to precisely modify m6A sites of individual transcripts in plants. Here, programmable m6A editing tools are developed by combining CRISPR/dCas13(Rx) with the methyltransferase GhMTA (Targeted RNA Methylation Editor, TME) or the demethyltransferase GhALKBH10 (Targeted RNA Demethylation Editor, TDE). These editors enable efficient deposition or removal of m6A modifications at targeted sites of endo‐transcripts GhECA1 and GhDi19 within a broad editing window ranging from 0 to 46 nt. TDE editor significantly decreases m6A levels by 24%–76%, while the TME editor increases m6A enrichment, ranging from 1.37‐ to 2.51‐fold. Furthermore, installation and removal of m6A modifications play opposing roles in regulating GhECA1 and GhDi19 mRNA transcripts, which may be attributed to the fact that their m6A sites are located in different regions of the genes. Most importantly, targeting the GhDi19 transcript with TME editor plants results in a significant increase in root length and enhanced drought resistance. Collectively, these m6A editors can be applied to study the function of specific m6A modifications and have the potential for future applications in crop improvement. [ABSTRACT FROM AUTHOR]

SUMMARY: UV‐B radiation can induce the accumulation of many secondary metabolites, including flavonoids, in plants to protect them from oxidative damage. BRI1‐EMS‐SUPPRESSOR1 (BES1) has been shown to mediate the biosynthesis of flavonoids in response to UV‐B. However, the detailed mechanism by which it acts still needs to be further elucidated. Here, we revealed that UV‐B significantly inhibited the transcription of multiple transcription factor genes in tobacco, including NtMYB27, which was subsequently shown to be a repressor of flavonoids synthesis in tobacco. We further demonstrated that NtBES1 directly binds to the E‐box motifs present in the promoter of NtMYB27 to mediate its transcriptional repression upon UV‐B exposure. The UV‐B‐repressed NtMYB27 could bind to the ACCT‐containing element (ACE) in the promoters of Nt4CL and NtCHS and served as a modulator that promoted the biosynthesis of lignin and chlorogenic acid (CGA) but inhibited the accumulation of flavonoids in tobacco. The expression of NtMYB27 was also significantly repressed by heat stress, suggesting its putative roles in regulating heat‐induced flavonoids accumulation. Taken together, our results revealed the role of NtBES1 and NtMYB27 in regulating the synthesis of flavonoids during the plant response to UV‐B radiation in tobacco. Significance Statement: UV‐B radiation can induce the accumulation of flavonoids in plants to protect them from oxidative damage. BES1 (BRI1‐EMS‐SUPPRESSOR1) has been shown to mediate the biosynthesis of flavonoids in response to UV‐B. However, the detailed mechanism by which BES1 acts still needs to be further elucidated. We provided evidence to reveal the role of NtBES1 and NtMYB27 in modulating plant response to UV‐B radiation by regulating the synthesis of flavonoids in tobacco. [ABSTRACT FROM AUTHOR]

A study published in the journal iMeta highlights the effectiveness of the CRISPR/Mb2Cas12a genome editing system in cotton plants. The system achieved a high efficiency rate of over 90% at target sites and demonstrated tolerance to different temperatures. It also expanded the editing range in the cotton genome. The study also developed a multiplex genome editing system using Mb2Cas12a, allowing for simultaneous editing of eight target sites. These findings suggest that CRISPR/Mb2Cas12a is a precise and efficient tool for genome editing in cotton plants, which has important implications for cotton breeding and genetic studies. [Extracted from the article]

This article, published in the Plant Biotechnology Journal, discusses the use of mitoTALENs to edit the mitochondrial genome of cytoplasmic male sterile (CMS) rice. The researchers focused on a specific CMS-associated gene called WA352 and used mitoTALENs to edit it in CMS-WA rice. They found that the edited offspring showed restored pollen viability and seed setting, confirming that WA352 is the cause of CMS. The study also demonstrated the genetic stability of the edited offspring in the next generation. The results contribute to the understanding of plant mitochondrial genes and have implications for crop breeding research. [Extracted from the article]

SUMMARY: Lignins and their antimicrobial‐related polymers cooperatively enhance plant resistance to pathogens. Several isoforms of 4‐coumarate‐coenzyme A ligases (4CLs) have been identified as indispensable enzymes involved in lignin and flavonoid biosynthetic pathways. However, their roles in plant–pathogen interaction are still poorly understood. This study uncovers the role of Gh4CL3 in cotton resistance to the vascular pathogen Verticillium dahliae. The cotton 4CL3‐CRISPR/Cas9 mutant (CR4cl) exhibited high susceptibility to V. dahliae. This susceptibility was most probably due to the reduction in the total lignin content and the biosynthesis of several phenolic metabolites, e.g., rutin, catechin, scopoletin glucoside, and chlorogenic acid, along with jasmonic acid (JA) attenuation. These changes were coupled with a significant reduction in 4CL activity toward p‐coumaric acid substrate, and it is likely that recombinant Gh4CL3 could specifically catalyze p‐coumaric acid to form p‐coumaroyl‐coenzyme A. Thus, overexpression of Gh4CL3 (OE4CL) showed increasing 4CL activity that augmented phenolic precursors, cinnamic, p‐coumaric, and sinapic acids, channeling into lignin and flavonoid biosyntheses and enhanced resistance to V. dahliae. Besides, Gh4CL3 overexpression activated JA signaling that instantly stimulated lignin deposition and metabolic flux in response to pathogen, which all established an efficient plant defense response system, and inhibited V. dahliae mycelium growth. Our results propose that Gh4CL3 acts as a positive regulator for cotton resistance against V. dahliae by promoting JA signaling‐mediated enhanced cell wall rigidity and metabolic flux. Significance Statement: This study uncovers the biological function of Gh4CL3 in cotton that helped to improve plant resistance against Verticillium dahliae. We believe that this study provides an important addition toward understanding the complex host–pathogen interaction. [ABSTRACT FROM AUTHOR]

Summary: Global food security is one of the utmost essential challenges in the 21st century in providing enough food for the growing population while coping with the already stressed environment. High temperature (HT) is one of the main factors affecting plant growth, development and reproduction and causes male sterility in plants. In male reproductive tissues, metabolic changes induced by HT involve carbohydrates, lipids, hormones, epigenetics and reactive oxygen species, leading to male sterility and ultimately reducing yield. Understanding the mechanism and genes involved in these pathways during the HT stress response will provide a new path to improve crops by using molecular breeding and biotechnological approaches. Moreover, this review provides insight into male sterility and integrates this with suggested strategies to enhance crop tolerance under HT stress conditions at the reproductive stage. [ABSTRACT FROM AUTHOR]

Crossbreeding, mutation breeding, and traditional transgenic breeding take much time to improve desirable characters/traits. CRISPR/Cas-mediated genome editing (GE) is a game-changing tool that can create variation in desired traits, such as biotic and abiotic resistance, increase quality and yield in less time with easy applications, high efficiency, and low cost in producing the targeted edits for rapid improvement of crop plants. Plant pathogens and the severe environment cause considerable crop losses worldwide. GE approaches have emerged and opened new doors for breeding multiple-resistance crop varieties. Here, we have summarized recent advances in CRISPR/Cas-mediated GE for resistance against biotic and abiotic stresses in a crop molecular breeding program that includes the modification and improvement of genes response to biotic stresses induced by fungus, virus, and bacterial pathogens. We also discussed in depth the application of CRISPR/Cas for abiotic stresses (herbicide, drought, heat, and cold) in plants. In addition, we discussed the limitations and future challenges faced by breeders using GE tools for crop improvement and suggested directions for future improvements in GE for agricultural applications, providing novel ideas to create super cultivars with broad resistance to biotic and abiotic stress. [ABSTRACT FROM AUTHOR]

Genome editing technology has become one of the hottest research areas in recent years. Among diverse genome editing tools, the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated proteins system (CRISPR/Cas system) has exhibited the obvious advantages of specificity, simplicity, and flexibility over any previous genome editing system. In addition, the emergence of Cas9 mutants, such as dCas9 (dead Cas9), which lost its endonuclease activity but maintains DNA recognition activity with the guide RNA, provides powerful genetic manipulation tools. In particular, combining the dCas9 protein and transcriptional activator to achieve specific regulation of gene expression has made important contributions to biotechnology in medical research as well as agriculture. CRISPR/dCas9 activation (CRISPRa) can increase the transcription of endogenous genes. Overexpression of foreign genes by traditional transgenic technology in plant cells is the routine method to verify gene function by elevating genes transcription. One of the main limitations of the overexpression is the vector capacity constraint that makes it difficult to express multiple genes using the typical Ti plasmid vectors from Agrobacterium. The CRISPRa system can overcome these limitations of the traditional gene overexpression method and achieve multiple gene activation by simply designating several guide RNAs in one vector. This review summarizes the latest progress based on the development of CRISPRa systems, including SunTag, dCas9-VPR, dCas9-TV, scRNA, SAM, and CRISPR-Act and their applications in plants. Furthermore, limitations, challenges of current CRISPRa systems and future prospective applications are also discussed. [ABSTRACT FROM AUTHOR]