A thaumatin-like effector protein suppresses the rust resistance of wheat and promotes the pathogenicity of Puccinia triticina by targeting TaRCA

Thaumatin-like proteins (TLPs) in plants play a crucial role in combating stress, and they have been proven to possess antifungal properties. However, the role of TLPs in pathogens has not been reported. We identified a effector protein, Pt9029, which contained a Thaumatin domain in Puccinia triticina (Pt), possessing a chloroplast transit peptide and localized in the chloroplasts. Silencing Pt9029 in the Pt physiological race THTT resulted in a notable reduction in virulence and stunted growth and development of Pt hypha in near-isogenic wheat line TcLr2b. Overexpression of Pt9029 in wheat exerted a suppressive effect on H2O2 production, consequently impeding the wheat's disease resistance mechanisms. The TLP domain of Pt9029 targets the Rubisco activase (TaRCA) in chloroplasts. This interaction effectively inhibited the function of TaRCA, subsequently leading to a decrease in Rubisco enzyme activity. Therefore, this indicates that TLPs in Pt can inhibit host defense mechanisms during the pathogenic process of Pt. Moreover, TaRCA silencing resulted in reduced resistance of TcLr2b against Pt race THTT. This clearly demonstrated that TaRCA positively regulates wheat resistance to leaf rust. These findings reveal a novel strategy exploited by Pt to manipulate wheat rust resistance and promote pathogenicity.

Early detection of gray blight in tea leaves and rapid screening of resistance varieties by hyperspectral imaging technology

BACKGROUND

Gray blight (GB) is a significant disease of tea leaves, posing a severe threat to both the yield and quality. In this study, the process of leaf infection by a pathogenic isolate of the GB disease (DDZ-6) was simulated. Hyperspectral images of normal leaves, infected leaves without symptoms, and infected leaves with mild and moderate symptoms were collected. Combining convolution neural network (CNN), long short-term memory (LSTM), and support vector machine (SVM) algorithms, the early detection model of GB disease, and the rapid screening model of resistant varieties were established. The generality of this method was verified by collecting datasets under field conditions.

RESULTS

The visible red-light band demonstrated a pronounced responsiveness to GB disease, with three sensitive bands identified through rigorous screening processes utilizing uninformative variable elimination (UVE), competitive adaptive reweighted sampling (CARS), and the successive projections algorithm (SPA). The 693, 727, and 766 nm bands emerged as highly sensitive indicators of GB. Under ideal conditions, the CARS-LSTM model excelled in early detection of GB, achieving an accuracy of 92.6%. However, under field conditions, the combination of 693 and 727 nm bands integrated with a CNN provided the most effective early detection model, attaining an accuracy of 87.8%. For screening tea varieties resistant to GB, the SPA-LSTM model excelled, achieving an accuracy of 82.9%.

CONCLUSION

This study provides a core algorithm for a GB disease instrument with detection capabilities, which is of great importance for the early prevention of GB disease in tea plantations. © 2024 Society of Chemical Industry.

TaWRKY24 integrates the tryptophan metabolism pathways to participate in defense against Fusarium crown rot in wheat

Wheat growth process has been experiencing severe challenges arising from the adverse environment. Notably, the incidence of Fusarium crown rot (FCR), a severe soil-borne disease caused by Fusarium pseudograminearum (Fp), has significantly intensified in various wheat-growing regions, resulting in a decline in grain yield. However, the identification of wheat varieties and the exploration of effective gene resources resistant to FCR have not yet been accomplished. Here, we screened and identified the tryptophan metabolism pathway to participate in wheat resistance to FCR by correlation analysis between transcriptome and metabolome, and found that indole-3-acetaldehyde (IAAld) and melatonin, two key metabolites in the tryptophan metabolic pathway, were significantly accumulated in Fp-induced wheat stem bases. Interestingly, exogenous application of these two metabolites could significantly enhance wheat resistance against Fp. Additionally, we observed that the activity of TaALDHase, a crucial enzyme responsible for catalyzing IAAld to produce indole-3-acetic acid (IAA), was inhibited. Conversely, the activity of TaMTase, a rate-limiting involved in melatonin biosynthesis, was enhanced in the Fp-induced wheat transcriptome. Further analysis showed that TaWRKY24 could regulate IAA and melatonin biosynthesis by inhibiting the expression of TaALDHase and enhancing the transcription of TaMTase, respectively. Silencing of TaALDHase could significantly increase wheat resistance to FCR. However, interference with TaWRKY24 or TaMTase could decrease wheat resistance to FCR. Collectively, our findings demonstrate the crucial role of the tryptophan metabolism pathway in conferring resistance against FCR in wheat, thereby expanding its repertoire of biological functions within the plant system.

A novel protein elicitor (Cs08297) from Ciboria shiraiana enhances plant disease resistance

Ciboria shiraiana is a necrotrophic fungus that causes mulberry sclerotinia disease resulting in huge economic losses in agriculture. During infection, the fungus uses immunity elicitors to induce plant tissue necrosis that could facilitate its colonization on plants. However, the key elicitors and immune mechanisms remain unclear in C. shiraiana. Herein, a novel elicitor Cs08297 secreted by C. shiraiana was identified, and it was found to target the apoplast in plants to induce cell death. Cs08297 is a cysteine-rich protein unique to C. shiraiana, and cysteine residues in Cs08297 were crucial for its ability to induce cell death. Cs08297 induced a series of defence responses in Nicotiana benthamiana, including the burst of reactive oxygen species (ROS), callose deposition, and activation of defence-related genes. Cs08297 induced-cell death was mediated by leucine-rich repeat (LRR) receptor-like kinases BAK1 and SOBIR1. Purified His-tagged Cs08297-thioredoxin fusion protein triggered cell death in different plants and enhanced plant resistance to diseases. Cs08297 was necessary for sclerotial development, oxidative-stress adaptation, and cell wall integrity but negatively regulated virulence of C. shiraiana. In conclusion, our results revealed that Cs08297 is a novel fungal elicitor in fungi inducing plant immunity. Furthermore, its potential to enhance plant resistance provides a new target to control agricultural diseases biologically.

Evolutionary arms race: the role of xylan modifications in plant-pathogen interactions

This article is a Commentary on Yu et al. (2024), 244: 1024–1040.

Heterografting enhances chrysanthemum resistance to Alternaria alternata via jasmonate-mediated increases in trichomes and terpenoids

Trichomes are specialized hair-like structures in the epidermal cells of the above-ground parts of plants and help to protect them from pests and pathogens, and produce valuable metabolites. Chrysanthemum morifolium, which is used in tea products, has both ornamental and medicinal value; however, it is susceptible to infection by the fungus Alternaria alternata, which can result in substantial economic losses. Increasing the density of glandular trichomes enhances disease resistance and improves the production of medicinal metabolites in chrysanthemums, and jasmonate (JA) is known to promote the formation of trichomes in various plants. However, it remains unclear whether glandular trichomes in chrysanthemums are regulated by JA. In addition, grafting, a technique that can improve plant resistance to biotic stresses, has been poorly examined for its impact on glandular trichomes, terpenoids, and disease resistance. In this study, we demonstrate that grafting with Artemisia vulgaris rootstocks improves the resistance of chrysanthemum scions to A. alternata. Heterografted chrysanthemums exhibited higher trichome density and terpenoid content compared to self-grafted counterparts. Transcriptome analysis highlighted the significant role of CmJAZ1-like in disease resistance in heterografted chrysanthemums. Lines overexpressing CmJAZ1-like exhibited sensitivity to A. alternata, and this was characterized by reduced glandular trichome density and limited terpenoid content. Conversely, CmJAZ1-like silenced lines exhibited resistance to A. alternata and showed increased glandular trichome density and terpenoid content. Higher JA content was found in the heterografted chrysanthemum scions compared to self-grafted ones. Furthermore, we established that JA promoted the development of glandular trichomes and the synthesis of terpenoids while also inducing the degradation of CmJAZ1-like proteins in chrysanthemums. Our findings suggest that higher JA increases trichome density and terpenoid content, thereby enhancing resistance to A. alternata by regulating CmJAZ1-like in heterografted chrysanthemums.

Peroxisomal Localization of Benzyl Alcohol O-Benzoyltransferase HSR201 Is Mediated by a Non-canonical Peroxisomal Targeting Signal and Required for Salicylic Acid Biosynthesis

The phytohormone salicylic acid (SA) regulates plant responses to various types of environmental stress, particularly pathogen infections. We previously revealed that the benzyl alcohol O-benzoyltransferase HSR201 was required for pathogen signal-induced SA synthesis, and its overexpression together with NtCNL, encoding a cinnamate-coenzyme A ligase, was sufficient for the production of significant amounts of SA in tobacco. We herein examined the subcellular localization of HSR201 and found that it fused to a yellow fluorescent protein localized in peroxisomes. Most peroxisomal matrix proteins possess peroxisomal targeting signal type-1 (PTS1) located at the extreme C terminus or PTS2 located at the N terminus; however, a bioinformatics analysis failed to identify similar signals for HSR201. Deletion and mutation analyses of HSR201 identified one essential (extreme C-terminal Leu46°) and three important (Ile455, Ile456 and Ala459) amino acid residues for its peroxisomal localization. The virus-induced gene silencing (VIGS) of PEX5, a PTS1 receptor, but not PEX7, a PTS2 receptor, compromised the peroxisomal targeting of HSR201 in Nicotiana benthamiana. When overexpressed with NtCNL, HSR201 mutants with reduced or non-peroxisomal targeting induced lower SA levels than the wild type; however, these mutations did not affect the protein stability or activity of HSR201. VIGS of the HSR201 homolog compromised pathogen signal-induced SA accumulation in N. benthamiana, which was complemented by the HSR201 wild type, but not the mutant with non-peroxisomal targeting. These results suggest that the peroxisomal localization of HSR201 is mediated by a non-canonical PTS1 and required for SA biosynthesis.

Experimental evolution for improved postinfection survival selects for increased disease resistance in Drosophila melanogaster

Disease resistance (defined as the host capacity to limit systemic infection intensity) and disease tolerance (defined as the host capacity to limit infection-induced damage) are 2 complementary defense strategies that help the hosts maximize their survival and fitness when infected with pathogens and parasites. In addition to the underlying physiological mechanisms, the existing theory postulates that these 2 strategies differ in terms of the conditions under which each strategy evolves in the host populations, their evolutionary dynamics, and the ecological and epidemiological consequences of their evolution. Here, we explored if one or both of these strategies evolve when host populations are subjected to selection for increased postinfection survival. We experimentally evolved Drosophila melanogaster populations, selecting for the flies that survived an infection with the entomopathogen Enterococcus faecalis. We found that the host populations evolved increased disease resistance in response to selection for increased survival. This was despite the physiological costs associated with increased resistance, the expression of which varied with the phase of infection. We did not find evidence of any change in disease tolerance in the evolved host populations.

[Progress in the resistance mechanism and breeding of Camellia oleifera with resistance to anthracnose]

Camellia oleifera is an important woody oil crop in China, and its seed oil has a high economic value. Anthracnose, one of the main diseases in C. oleifera, occurs in a wide range in the production areas, limiting the growth and development of plants and causing serious losses of oil production. With the rapid development of the C. oleifera industry in recent years, great progress has been achieved in the research on anthracnose in C. oleifera. This paper summarized the resistance mechanisms, the mining of resistance genes, and the evaluation of resistant germplasm resources, aiming to provide a theoretical basis for the prevention and control of anthracnose and the breeding of C. oleifera germplasm with resistance to anthracnose.

Effects of acetic acid fermentation product and its components on defense signaling in rice

Acetic acid fermentation product made from isomalto-oligosaccharide as the main raw material is composed of isomalto-oligosaccharide and acetic acid. In this paper, we have shown that the fermentation product enhanced the expression of disease resistance genes in rice, and that its main functional component was acetic acid. It has been reported so far that acetic acid enhances the jasmonic acid signaling pathway, while the role of isomalto-oligosaccharide in plant defense signaling remains unclear. In this study, we demonstrated the possibility that isomalto-oligosaccharide shifted part of the jasmonic acid signaling pathway, which is enhanced by acetic acid, to the salicylic acid signaling pathway, which is the other major defense pathway. Furthermore, glucose, a constituent monosaccharide of isomalto-oligosaccharide, and a disaccharide maltose had little effect on the signaling pathway, but a trisaccharide maltotriose tended to have a similar effect to isomalto-oligosaccharide on the defense signaling pathway.

Evaluating Native Bacillus Strains as Potential Biocontrol Agents against Tea Anthracnose Caused by Colletotrichum fructicola

Anthracnose of the tea plant (Camellia sinensis), caused by Colletotrichum spp., poses a significant threat to both the yield and quality of tea production. To address this challenge, researchers have looked to the application of endophytic bacteria as a natural alternative to the use chemical pesticides, offering potential for enhancing disease resistance and abiotic stress tolerance in tea plants. This study focused on identifying effective microbial agents to combat tea anthracnose caused by Colletotrichum fructicola. A total of 38 Bacillus-like strains were isolated from the tea rhizosphere, with 8 isolates showing substantial inhibitory effects against the mycelial growth of C. fructicola, achieving an average inhibition rate of 60.68%. Among these, strain T3 was particularly effective, with a 69.86% inhibition rate. Through morphological, physiological, and biochemical characterization, along with 16S rRNA gene phylogenetics analysis, these strains were identified as B. inaquosorum (T1 and T2), B. tequilensis (T3, T5, T7, T8, and T19), and B. spizizenii (T6). Biological and molecular assays confirmed that these strains could induce the expression of genes associated with antimicrobial compounds like iturin, fengycin, subtilosin, and alkaline protease, which effectively reduced the disease index of tea anthracnose and enhanced tea plant growth. In conclusion, this study demonstrates that B. inaquosorum, B. tequilensis, and B. spizizenii strains are promising biocontrol agents for managing tea anthracnose.

Genome of Russian Snow-White Chicken Reveals Genetic Features Associated with Adaptations to Cold and Diseases

Russian Snow White (RSW) chickens are characterized by high egg production, extreme resistance to low temperatures, disease resistance, and by the snow-white color of the day-old chicks. Studying the genome of this unique chicken breed will reveal its evolutionary history and help to understand the molecular genetic mechanisms underlying the unique characteristics of this breed, which will open new breeding opportunities and support future studies. We have sequenced and made a de novo assembly of the whole RSW genome using deep sequencing (250×) by the short reads. The genome consists of 40 chromosomes with a total length of 1.1 billion nucleotide pairs. Phylogenetic analysis placed the RSW near the White Leghorn, Fayoumi, and Houdan breeds. Comparison with other chicken breeds revealed a wide pool of mutations unique to the RSW. The functional annotation of these mutations showed the adaptation of genes associated with the development of the nervous system, thermoreceptors, purine receptors, and the TGF-beta pathway, probably caused by selection for low temperatures. We also found adaptation of the immune system genes, likely driven by selection for resistance to viral diseases. Integration with previous genome-wide association studies (GWAS) suggested several causal single nucleotide polymorphisms (SNPs). Specifically, we identified an RSW-specific missense mutation in the RALYL gene, presumably causing the snow-white color of the day-old chicks, and an RSW-specific missense mutation in the TLL1 gene, presumably affecting the egg weight.

QTL Mapping-Based Identification of Visceral White-Nodules Disease Resistance Genes in Larimichthys polyactis

Disease outbreaks in aquaculture have recently intensified. In particular, visceral white-nodules disease, caused by Pseudomonas plecoglossicida, has severely hindered the small yellow croaker (Larimichthys polyactis) aquaculture industry. However, research on this disease is limited. To address this gap, the present study employed a 100K SNP chip to genotype individuals from an F1 full-sib family, identify single nucleotide polymorphisms (SNPs), and construct a genetic linkage map for this species. A high-density genetic linkage map spanning a total length of 1395.72 cM with an average interval of 0.08 cM distributed across 24 linkage groups was obtained. Employing post-infection survival time as an indicator of disease resistance, 13 disease resistance-related quantitative trait loci (QTLs) were detected, and these regions included 169 genes. Functional enrichment analyses pinpointed 11 candidate disease resistance-related genes. RT-qPCR analysis revealed that the genes of chmp1a and arg1 are significantly differentially expressed in response to P. plecoglossicida infection in spleen and liver tissues, indicating their pivotal functions in disease resistance. In summary, in addition to successfully constructing a high-density genetic linkage map, this study reports the first QTL mapping for visceral white-nodules disease resistance. These results provide insight into the intricate molecular mechanisms underlying disease resistance in the small yellow croaker.

An Overview of the Biological Functions and Mechanisms of Action of Medicinal Plants and Seaweeds in the Shrimp Culture

Diseases are major constraints to developing large-scale aquaculture practices in many countries. For decades, synthetic chemotherapeutic agents have been widely applied both as prophylactics and therapeutics to inhibit and control aquatic disease outbreaks. However, their use has become more restricted due to the negative impacts they have on the environment, the host and humans, as well as their limitations in preventing the emergence of antimicrobial-resistant bacteria. Therefore, there is a growing interest in the use of medicinal plants and seaweeds as potential alternatives to antibiotics and other synthetic chemotherapeutics. Medicinal plants and seaweeds can enhance the immune systems of animals, thereby providing protection against numerous diseases while minimizing the adverse effects associated with synthetic chemotherapeutics. Furthermore, the advantages of medicinal plants and seaweeds, such as their effectiveness, easy availability and ability to be applied on a large scale, make them appealing for use in the aquaculture industry. The main goal of this study was to review the existing knowledge of the effects of medicinal plants and seaweeds, as well as their extracts, on shrimp growth, immune response and disease resistance against bacterial and viral agents. Moreover, this paper discusses the application of seaweeds in shrimp culture. We also conducted a literature review to identify gaps in the research and provide recommendations for further advancement in this field of study. Further studies should focus on evaluating other physiological aspects, such as feed and mineral utilization, enzyme activities and histological examination.

Genotypic variation in winter wheat for fusarium foot rot and its biocontrol using Clonostachys rosea

Biological control to manage plant diseases is an environmentally friendly alternative to using chemical pesticides. However, little is known about the role of genetic variation in plants affecting the efficacy of biological control agents (BCAs). The aim of this study was to explore the genetic variation in winter wheat for disease susceptibility to fusarium foot rot caused by Fusarium graminearum and variation in biocontrol efficacy of the fungal BCA Clonostachys rosea to control the disease. In total, 190 winter wheat genotypes were evaluated under controlled conditions in two treatments, i.e. (i) F. graminearum (Fg) and (ii) F. graminearum infection on C. rosea treated seeds (FgCr). Alongside disease severity, plant growth-related traits such as shoot length and root length were also measured. Comparison of genotypes between the two treatments enabled the dissection of genotypic variation for disease resistance and C. rosea efficacy. The study revealed significant variation among plant genotypes for fusarium foot rot susceptibility and other growth traits in treatment Fg. Moreover, significant variation in C. rosea efficacy was also observed in genotype contrasts between the two treatments for all traits. Using a 20K marker array, a genome-wide association study was also performed. We identified a total of 18 significant marker-trait associations for disease resistance and C. rosea efficacy for all the traits. Moreover, the markers associated with disease resistance and C. rosea efficacy were not co-localized, highlighting the independent inheritance of these traits, which can facilitate simultaneous selection for cultivar improvement.

Callose and Salicylic Acid Are Key Determinants of Strigolactone-Mediated Disease Resistance in Arabidopsis

Research has demonstrated that strigolactones (SLs) mediate plant disease resistance; however, the basal mechanism is unclear. Here, we provide key genetic evidence supporting how SLs mediate plant disease resistance. Exogenous application of the SL analog, rac-GR24, increased Arabidopsis thaliana resistance to virulent Pseudomonas syringae. SL-biosynthetic mutants and overexpression lines of more axillary growth 1 (MAX1, an SL-biosynthetic gene) enhanced and reduced bacterial susceptibility, respectively. In addition, rac-GR24 promoted bacterial pattern flg22-induced callose deposition and hydrogen peroxide production. SL-biosynthetic mutants displayed reduced callose deposition but not hydrogen peroxide production under flg22 treatment. Moreover, rac-GR24 did not affect avirulent effector-induced cell death between Col-0 and SL-biosynthetic mutants. Furthermore, rac-GR24 increased the free salicylic acid (SA) content and significantly promoted the expression of pathogenesis-related gene 1 related to SA signaling. Importantly, rac-GR24- and MAX1-induced bacterial resistance disappeared completely in Arabidopsis plants lacking both callose synthase and SA. Taken together, our data revealed that callose and SA are two important determinants in SL-mediated plant disease resistance, at least in Arabidopsis.

Molecular insights into OPR gene family in Saccharum identified a ScOPR2 gene could enhance plant disease resistance

12-Oxo-phytodienoic acid reductases (OPRs) perform vital functions in plants. However, few studies have been reported in sugarcane (Saccharum spp.), and it is of great significance to systematically investigates it in sugarcane. Here, 61 ShOPRs, 32 SsOPRs, and 36 SoOPRs were identified from R570 (Saccharum spp. hybrid cultivar R570), AP85-441 (Saccharum spontaneum), and LA-purple (Saccharum officinarum), respectively. These OPRs were phylogenetically classified into four groups, with close genes similar structures. During evolution, OPR gene family was mainly expanded via whole-genome duplications/segmental events and predominantly underwent purifying selection, while sugarcane OPR genes may function differently in response to various stresses. Further, ScOPR2, a tissue-specific OPR, which was localized in cytoplasm and cell membrane and actively response to salicylic acid (SA), methyl jasmonate, and smut pathogen (Sporisorium scitamineum) stresses, was cloned from sugarcane. In addition, both its transient overexpression and stable overexpression enhanced the resistance of transgenic plants to pathogen infection, most probably through activating pathogen-associated molecular pattern/pattern-recognition receptor-triggered immunity, producing reactive oxygen species, and initiating mitogen-activated protein kinase cascade. Subsequently, the transmission of SA and hypersensitive reaction were triggered, which stimulated the transcription of defense-related genes. These findings provide insights into the function of ScOPR2 gene for disease resistance.

Impacts of Increasing Soil Salinity on Genetic Resistance (I-3 Gene)-Based Management of Fusarium Wilt (Fusarium oxysporum f. sp. lycopercisi Race 3) in California Processing Tomatoes

California is the primary processing tomato (Solanum lycopersicum) producer in the United States. Fusarium oxysporum f. sp. lycopercisi race 3 (Fol3), the cause of Fusarium wilt, is a major driver of yield losses. Fol3 has recently been observed causing disease in resistant cultivars (I-3 R-gene), often reported in association with high soil salinity. This study was undertaken to better understand the role of salinity in compromising resistance-based management of Fol3. Surveys established opportunity for salinity-Fol3-tomato interactions in 44% of commercial fields examined, with harmful soil salt levels up to 3.6 dS/m (P < 0.001), high sodium (P < 0.001), and high sodicity (sodium adsorption ratio > 13; P < 0.001). In controlled field studies of Fol3 in NaCl/CaCl2-treated soil, Fol3-resistant cultivars either only developed wilt under salt or only developed wilt above the industry non-hybrid threshold (2%) under salt across two trial years. The absence of yield differences indicates low to no economic impact of disease enhancement (P > 0.05). NaCl, CaCl2, and Na2SO4 had no effect on Fol3 propagule production in liquid agar versus water agar controls (P > 0.05), although CaCl2 increased propagule loads sevenfold versus ionic controls (polyethylene glycol) (P = 0.036). NaCl/CaCl2 (2:1) reduced propagule loads up to 65% versus no salt (P = 0.029) in soil with pathogen-infested tomato tissue. These results together establish the opportunity for salinity-Fol3-tomato interactions and potential for salt to influence the efficacy of resistant cultivar-based management-this does not appear to be primarily due to salt enhancement of pathogen populations, pointing to a yet-unexplored direct influence of salt on host resistance.

A virulent milRNA inhibits host immunity by silencing a host receptor-like kinase MaLYK3 and facilitates infection by Fusarium oxysporum f. sp. cubense

MicroRNA-like RNAs (milRNAs) play a significant role in the infection process by plant-pathogenic fungi. However, the specific functions and regulatory mechanisms of fungal milRNAs remain insufficiently elucidated. This study investigated the function of Foc-milR138, an infection-induced milRNA secreted by Fusarium oxysporum f. sp. cubense (Foc), which is the causal agent of Fusarium wilt of banana. Initially, through precursor gene knockout and phenotypic assessments, we confirmed that Foc-milR138 acts as a virulent milRNA prominently upregulated during the early stages of Foc infection. Subsequent bioinformatic analyses and transient expression assays in Nicotiana benthamiana leaves identified a host receptor-like kinase gene, MaLYK3, as the direct target of Foc-milR138. Functional investigations of MaLYK3 revealed its pivotal role in triggering immune responses of N. benthamiana by upregulating a suite of resistance genes, bolstering reactive oxygen species (ROS) accumulation and callose deposition, thereby fortifying disease resistance. This response was markedly subdued upon co-expression with Foc-milR138. Expression pattern analysis further verified the specific suppression of MaLYK3 by Foc-milR138 during the early root infection by Foc. In conclusion, Foc secretes a virulent milRNA (Foc-milR138) to enter the host banana cells and inhibit the expression of the plant surface receptor-like kinase MaLYK3, subverting the disease resistance activated by MaLYK3, and ultimately facilitating pathogen invasion. These findings shed light on the roles of fungal milRNAs and their targets in resistance and pathogenicity, offering promising avenues for the development of disease-resistant banana cultivars.

Evaluation of Reduced Fungicide Applications for Disease Management in Cold-Climate Wine Grapes in Wisconsin

Cold-climate wine grapes are produced on 8,000 ha in the North Central region of the United States. Wisconsin has experienced considerable growth, with a 26% increase in acreage since 2017. Chemical management of fungal diseases in cold-climate, interspecific hybrid grapes mirrors that of traditional Vitis vinifera cultivars despite significant differences in disease susceptibility. Most cold-climate cultivars display disease tolerance or resistance to key pathogens such as Plasmopara viticola (downy mildew), Erysiphe necator (powdery mildew), and Phyllosticta ampelicida (black rot). Current fungicide programs in Wisconsin's cold-climate grape industry underutilize genetic resistance, resulting in overreliance on at-risk fungicides and an increased threat of fungicide resistance development. In vineyard trials, the impacts of a reduced fungicide application number compared to current grower "Standard" programs was assessed for disease incidence and severity for five diseases: anthracnose, black rot, downy mildew, Phomopsis cane and leaf spot and powdery mildew. In 2022, with moderate disease pressure at both vineyard sites, there were no significant differences observed when fewer fungicides (six or five applications vs. four applications) were applied. In 2023, higher disease incidence was observed in the "Standard" spray program at one study location which received a greater number of fungicide applications. In both years, grape cultivar was a significant factor with the 'LaCrosse' displaying greater average disease severity than the 'St. Pepin' in both the "Standard" and "Reduced" Programs. These findings present a promising opportunity for cold-climate grape growers to reduce the number of fungicide applications while maintaining disease control and marketable yield.

Estimation of genetic parameters and genome-wide association study for enzootic bovine leukosis resistance in Canadian Holstein cattle

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (leukosis) frequently observed in North American dairy herds. Infection with BLV can lead to persistent lymphocytosis and tumors, and is associated with decreased production, immunity and fertility. With no available treatment or vaccine, reducing the prevalence of leukosis through management and culling has not yet been successful. Genetic selection could contribute to permanent improvement in dairy cattle resistance to leukosis. This study aimed to examine the prevalence and impact of leukosis in Canada, and to assess the potential for including leukosis resistance in Canadian national genetic evaluations by characterizing the genetic architecture of leukosis resistance using pedigree and genomic information. A total of 117,349 milk enzyme-linked immunosorbent assay test records on 96,779 Holstein cows from 950 Canadian herds taken between 2007 and 2021 were provided by Lactanet Canada (Guelph, ON, Canada). Each cow was classified as test-positive for leukosis or test-negative for leukosis. Leukosis was present in approximately 77% of herds tested; within those herds, an average of 39% of cows tested were test positive for leukosis. Heritabilities of 0.10 (SE = 0.001) and 0.07 (SE <0.001) were estimated for leukosis resistance using a linear animal model and BLUP or single-step GBLUP methodology, respectively. Breeding value correlations were estimated between leukosis resistance and economically important and phenotypically relevant traits. Most correlations between leukosis resistance and traits already included in Canadian genetic evaluations were favorable, with the exception of somatic cell score. The candidate genes for leukosis resistance identified using a genome-wide association study, were on chromosome 23, with some being part of the major histocompatibility complex. This study showed that genetic evaluation for leukosis resistance is possible, and could be considered for inclusion in Canadian national selection indices.

Capitalizing on genebank core collections for rare and novel disease resistance loci to enhance barley resilience

In the realm of agricultural sustainability, the utilization of plant genetic resources for enhanced disease resistance is paramount. Preservation efforts in genebanks are justified by their potential contributions to future crop improvement. To capitalize on the potential of plant genetic resources, we focused on a barley core collection from the German ex situ genebank and contrasted it with a European elite collection. The phenotypic assessment included 812 plant genetic resources and 298 elites, with a particular emphasis on four disease traits (Puccinia hordei, Blumeria graminis hordei, Ramularia collo-cygni, and Rhynchosporium commune). An integrated genome-wide association study, employing both Bayesian-information and linkage-disequilibrium iteratively nested keyway (BLINK) and a linear mixed model, was performed to unravel the genetic underpinnings of disease resistance. A total of 932 marker-trait associations were identified and assigned to 49 quantitative trait loci. The accumulation of novel and rare resistance alleles significantly bolstered the overall resistance level in plant genetic resources. Three plant genetic resources donors with high counts of novel/rare alleles and exhibiting exceptional resistance to leaf rust and powdery mildew were identified, offering promise for targeted pre-breeding goals and enhanced resilience in future varieties. Our findings underscore the critical contribution of plant genetic resources to strengthening crop resilience and advancing sustainable agricultural practices.

Feruloyl-CoA 6'-hydroxylase-mediated scopoletin accumulation enhances cotton resistance to Verticillium dahliae

Verticillium dahliae is a widespread and destructive soilborne fungus that can cause vascular wilt disease and substantially reduce cotton (Gossypium hirsutum) yield and quality. Scopoletin, a natural coumarin, exhibits antifungal activity against V. dahliae; however, the mechanisms of action remain unclear. In this study, we reveal the regulatory activities of feruloyl-CoA 6'-hydroxylase 1 (GhF6'H1) in enhancing V. dahliae resistance by modulating scopoletin accumulation. Silencing GhF6'H1, encoding the pivotal enzyme in scopoletin biosynthesis, through virus-induced silencing resulted in increased susceptibility to V. dahliae and decreased scopoletin accumulation. In transgenic cotton plants expressing GhF6'H1 under the CaMV 35S promoter, GhF6'H1 modulated scopoletin accumulation, affecting cotton resistance to V. dahliae, with increased resistance associated with increased scopoletin accumulation. GhF6'H1 has been identified as a direct target of the transcription factor GhWRKY33-like, indicating that GhWRKY33-like can bind to and activate the GhF6'H1 promoter. Moreover, GhWRKY33-like overexpression in cotton enhanced resistance to V. dahliae through scopoletin accumulation, phenylpropanoid pathway activation, and upregulation of defense response genes. Ectopic expression of GhF6'H1 resulted in effective catalysis of scopoletin synthesis in enzyme assays using substrates like feruloyl coenzyme A, while molecular docking analysis revealed specific amino acid residues playing crucial roles in establishing salt-bridge interactions with the substrate. These findings suggest that GhF6`H1, regulated by GhWRKY33-like, plays a crucial role in enhancing cotton resistance to V. dahliae by modulating scopoletin accumulation.

INDETERMINATE DOMAIN Transcription Factors in Crops: Plant Architecture, Disease Resistance, Stress Response, Flowering, and More

INDETERMINATE DOMAIN (IDD) genes encode plant-specific transcription factors containing a conserved IDD domain with four zinc finger motifs. Previous studies on Arabidopsis IDDs (AtIDDs) have demonstrated that these genes play roles in diverse physiological and developmental processes, including plant architecture, seed and root development, flowering, stress responses, and hormone signaling. Recent studies have revealed important functions of IDDs from rice and maize, especially in regulating leaf differentiation, which is related to the evolution of C4 leaves from C3 leaves. Moreover, IDDs in crops are involved in the regulation of agriculturally important traits, including disease and stress resistance, seed development, and flowering. Thus, IDDs are valuable targets for breeding manipulation. This review explores the role of IDDs in plant development, environmental responses, and evolution, which provides idea for agricultural application.