Smut Resistance Research Articles

Genetic identification of SNP markers and candidate genes associated with sugarcane smut resistance using BSR-Seq.

Sugarcane smut caused by Sporisorium scitamineum is one of the most severe fungal diseases worldwide. In this study, a cross was made between a smut-resistant variety YT93-159 and a smut-susceptible variety ROC22, and 312 progenies were obtained. Two bulks of progenies were then constructed, one consisted of 27 highly smut resistant progenies and the other 24 smut susceptible progenies. Total RNAs of the progenies of each bulk, were pooled and subject to bulked segregant RNA-sequence analysis (BSR-Seq). A total of 164.44 Gb clean data containing 2,341,449 SNPs and 64,999 genes were obtained, 7,295 of which were differentially expressed genes (DEGs). These DEGs were mainly enriched in stress-related metabolic pathways, including carbon metabolism, phenylalanine metabolism, plant hormone signal transduction, glutathione metabolism, and plant-pathogen interactions. Besides, 45,946 high-quality, credible SNPs, a 1.27 Mb region at Saccharum spontaneum chromosome Chr5B (68,904,827 to 70,172,982), and 129 candidate genes were identified to be associated with smut resistance. Among them, twenty-four genes, either encoding key enzymes involved in signaling pathways or being transcription factors, were found to be very closely associated with stress resistance. RT-qPCR analysis demonstrated that they played a positive role in smut resistance. Finally, a potential molecular mechanism of sugarcane and S. scitamineum interaction is depicted that activations of MAPK cascade signaling, ROS signaling, Ca2+ signaling, and PAL metabolic pathway and initiation of the glyoxalase system jointly promote the resistance to S. scitamineum in sugarcane. This study provides potential SNP markers and candidate gene resources for smut resistance breeding in sugarcane.

Development of a SCAR marker based on SCoT polymorphisms for sugarcane smut resistance

Development of a SCAR marker based on SCoT polymorphisms for sugarcane smut resistance

WGCNA Identifies a Comprehensive and Dynamic Gene Co-Expression Network That Associates with Smut Resistance in Sugarcane.

Sugarcane smut is a major fungal disease caused by Sporisorium scitamineum, which seriously reduces the yield and quality of sugarcane. In this study, 36 transcriptome data were collected from two sugarcane genotypes, YT93-159 (resistant) and ROC22 (susceptible) upon S. scitamineum infection. Data analysis revealed 20,273 (12,659 up-regulated and 7614 down-regulated) and 11,897 (7806 up-regulated and 4091 down-regulated) differentially expressed genes (DEGs) in YT93-159 and ROC22, respectively. A co-expression network was then constructed by weighted gene co-expression network analysis (WGCNA), which identified 5010 DEGs in 15 co-expressed gene modules. Four of the 15 modules, namely, Skyblue, Salmon, Darkorange, and Grey60, were significantly associated with smut resistance. The GO and KEGG enrichment analyses indicated that the DEGs involving in these four modules could be enriched in stress-related metabolic pathways, such as MAPK and hormone signal transduction, plant-pathogen interaction, amino acid metabolism, glutathione metabolism, and flavonoid, and phenylpropanoid biosynthesis. In total, 38 hub genes, including six from the Skyblue module, four from the Salmon module, 12 from the Darkorange module, and 16 from the Grey60 module, were screened as candidate hub genes by calculating gene connectivity in the corresponding network. Only 30 hub genes were amplifiable with RT-qPCR, of which 27 were up-regulated upon S. scitamineum infection. The results were consistent with the trend of gene expression in RNA-Seq, suggesting their positive roles in smut resistance. Interestingly, the expression levels of AOX, Cyb5, and LAC were higher in ROC22 than in YT93-159, indicating these three genes may act as negative regulators in response to S. scitamineum infection. This study revealed the transcriptome dynamics in sugarcane challenged by S. scitamineum infection and provided gene targets for smut resistance breeding in sugarcane.

Полная иммунологическая характеристика коллекции голозерного ячменя в условиях южной зоны

Abstract. Barley production in Russia and, in particular, in the Rostov region, is of great economic importance. There are positive and negative cultivation feature of the crop in this region. Spring barley has occupied its niche in production here, and in recent years the interest of breeders has been turned to its hulles forms. In order to develop a new promising breeding material, it is necessary to study comprehensively a various source material, including its responsiveness to diseases. The purpose of the current study was an immunological estimation of the world collection of hulles barley, provided by the N. I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR), according to resistance to the main pathogens widely spread in the Rostov region. The applied methods have included observations under conditions of an artificial infectious background, which revealed the immunological response of the varieties to the studied diseases. The created provocative conditions reduced the time of manifestation of susceptibility, and made it possible to cull the studied material at the early stages of the breeding process. The estimation was carried out for resistance to both leaf diseases (powdery mildew and net blotch) and smuts (head and loose). The study was carried out in the period from 2016 to 2018. There were evaluated 95 samples of various ecological and geographical origin. The result of the conducted study was as follows: according to powdery mildew there have been recommended such varieties as 84469/70 (Czech Republic), 1057-1923 (Czech Republic), Orgeniepetite (France) and Yudinsky 1 (Russian Federation). According to barley net blotch resistance, there have been recommended such varieties as 84469/70 (Czech Republic), Mestny (Dagestan), CDC Dawn (Canada) and NB-owa (Nepal). According to head smut resistance, there have been recommended such varieties as CDC Dawn (Canada), CDC Buck (Canada), H 235/66 and 84469/70 (Czech Republic). According to loose smut resistance, there have been recommended such varieties as CDC Dawn (Canada), CDC Buck (Canada), H 235/66, 84469/70 (Czech Republic) and Dublet (Belarus).

Development of smut resistance genetic resources in millet with other economically valuable features

Aim. Creation and transfer to the National Center of Plant Genetic Resources of Ukraine genetic sources of millet with race-specific resistance against smut in combination with other economically valuable traits. Methods. In 2019 was laid a breeding nursery of raw material with signs of improved technological qualities of grain (high mass of 1000 grains, optimum film density, high grain alignment and spherical grain shape). In order to isolate forms of millet that are immune to different races of smut and to create sources of simultaneous resistance against damage to the most aggressive races of smut an analysis of the virulence of races was carried out and the most virulent of them were selected, which can characterize resistance against all 13 pathotypes in total. Results. A reconsideration for the resistance of millet against smut was carried out on a p infectious background of the most effective races of the pathogen for a well-established method of assessing the race-specific resistance of millet to smut, developed in the National Research Center of Institute of agriculture. Conclusion. In 2020 5 lines – sources of group resistance against smut – were selected in the nurseries of trials of breeding material of millet ( (l. 1110-05, l. 1727-14, l. 2142-14, l. 3199-16, l. 3267-16), which combined resistance in different ratios against the most virulent and aggressive pathotypes of smut – Rs2, Rs3 and Rs12 with economically valuable traits. 3 samples are also selected (l. 1427-08, l. 2098-14, l. 2155-14), which overwhelm the standards for a complex of economic and valuable signs: resistance to lodging (8.5 points), resistance to melanosis damage (lesion – 0%), high weight of 1000 grains > 9g, low film density (13.5–15.0%), spherical grain shape, race-specific resistance to the soot race group with the most virulent and aggressive races of the pathogen – Rs2 and Rs12. These lines of own breeding were transferred to the National Center of Plant Genetic Resources of Ukraine under catalog numbers IUDS019538, IUDS019539, IUDS019540, IUDS019541, IUDS019542, IUDS019543, IUDS019544, IUDS019545) as genetic sources of resistance of millet to the most common race of smut in combination with other economically valuable traits for use in breeding and scientific programs of scientific-research institutions of Ukraine.

Identification of Putative SNP Markers Associated with Resistance to Egyptian Loose Smut Race(s) in Spring Barley.

Loose smut (LS) disease is a serious problem that affects barley yield. Breeding of resistant cultivars and identifying new genes controlling LS has received very little attention. Therefore, it is important to understand the genetic basis of LS control in order to genetically improve LS resistance. To address this challenge, a set of 57 highly diverse barley genotypes were inoculated with Egyptian loose smut race(s) and the infected seeds/plants were evaluated in two growing seasons. Loose smut resistance (%) was scored on each genotype. High genetic variation was found among all tested genotypes indicating considerable differences in LS resistance that can be used for breeding. The broad-sense heritability (H2) of LS (0.95) was found. Moreover, genotyping-by-sequencing (GBS) was performed on all genotypes and generated in 16,966 SNP markers which were used for genetic association analysis using single-marker analysis. The analysis identified 27 significant SNPs distributed across all seven chromosomes that were associated with LS resistance. One SNP (S6_17854595) was located within the HORVU6Hr1G010050 gene model that encodes a protein kinase domain-containing protein (similar to the Un8 LS resistance gene, which contains two kinase domains). A TaqMan marker (0751D06 F6/R6) for the Un8 gene was tested in the diverse collection. The results indicated that none of the Egyptian genotypes had the Un8 gene. The result of this study provided new information on the genetic control of LS resistance. Moreover, good resistance genotypes were identified and can be used for breeding cultivars with improved resistance to Egyptian LS.

Identification of Germplasm Resistant to Peanut Smut

Peanut smut, caused by Thecaphora frezzii, is an emerging threat to global peanut production. Found in 100% of Argentinian peanut growing regions, smut infestation can result in substantial yield reductions. Although peanut smut has not been reported outside of South America, immediate proactive measures must be taken so that global peanut production will not be threatened. The first step in preventative breeding for resistance to peanut smut is to identify sources of resistance. Therefore, the objective of this study was to identify germplasm resistant to T. frezzii that can be used to incorporate smut resistance into cultivars optimized for U.S. peanut production areas. In this study, peanut genotypes, including accessions from the USDA germplasm collection that were purified by single-seed descent, peanut breeding lines, and U.S. cultivars, were screened for resistance. Trials were planted in test plots highly infested with T. frezzii in Córdoba Province, Argentina. For screening purposes, entries were retained for future testing if they scored 10% or less disease incidence. Among the entries tested in the 2017-2020 growing seasons, potential new sources of peanut smut resistance were noted. Eight USDA peanut mini-core accessions were identified as immune, demonstrating 0% incidence for three years. These accessions are being used to incorporate smut resistance into cultivars suitable for production in all growing regions of the U.S.

Genetic dissection of false smut resistance in rice through Genome Wide Association Mapping

AbstractThe present investigation was performed to identify resistance sources and to unravel the genomic regions controlling false smut resistance by genome‐wide association mapping (GWAS) in 150 diverse rice accessions. This study revealed 13 highly resistant, 9 resistant, 119 moderately resistant and 9 moderately susceptible genotypes. Correlation analysis revealed that the percentage of infected florets, percentage of infected tillers, percentage of infected plants and spikelet sterility percentage showed significant association with disease severity. GWAS was performed using GLM, GLM+Q and MLM+Q+K with 214 SSR markers and resulted in 16 significant marker–trait associations with the traits, viz., percentage of infected plants, percentage of infected tillers, percentage of infected florets and disease severity. This study resulted in two major QTLs for the percentage of infected florets in the marker RM16131 (126.9 cM) and RM44 (60.9 cM) on chromosomes 3 and 8 and these can be further used in marker‐assisted selection. Several genes were portrayed around major QTL regions and further validation is needed to identify candidate genes for false smut resistance.

AAC Justice oat

AAC Justice is a white-hulled spring oat ( Avena sativa L.) cultivar. It was postulated to carry the crown rust resistance gene Pc91, which was effective against the prevalent crown rust races on the Canadian Prairies at the time of its release. It had very good resistance to loose and covered smut and moderate resistance to most of the prairie stem rust races, and was intermediate in reaction to the barley yellow dwarf virus. AAC Justice has a high test weight, average kernel weight, and average groat percentage and kernel plumpness. AAC Justice exhibited high yield potential in the eastern oat-growing areas of Western Canada. AAC Justice was registered (reg. no. 7439) in Canada on 15 October 2013.

A Plant-Derived Alkanol Induces Teliospore Germination in Sporisorium scitamineum.

Sugarcane smut caused by the basidiomycetes fungus Sporisorium scitamineum is a devastating disease for the sugarcane industry worldwide. As the initial step, the smut teliospores germinate on sugarcane buds, and subsequently, the mycelium infects the bud tissues. However, chemical signals that induce spore germination are still unknown. By comparison of the behavior of the teliospores on the buds of both resistant and susceptible varieties, we found that spore germination rates were significantly lower on the buds of resistant cultivars ZZ1, ZZ6, and ZZ9 than on the susceptible varieties GT42 and ROC22. It was found that the levels of hexacosanol and octacosanol were higher on the buds of smut-susceptible varieties than on the smut-resistant varieties. These observations were extended to the smut-resistant and smut-susceptible sub-genetic populations derived from the cross of ROC25 and YZ89-7. In artificial surface assays, we found that hexacosanol and octacosanol promoted smut teliospore germination. Transcriptome analysis of smut teliospores under the induction by octacosanol revealed that genes in the MAPK signaling pathway and fatty acid metabolism were significantly differentially expressed. Overall, our results provide evidence that alkanol plays important roles in smut teliospore germination and thus could be used as a potential marker for smut resistance in sugarcane breeding programs.

Identification of potential donors for false smut resistance in elite breeding lines of rice (Oryza sativaL.) under field conditions

AbstractFalse smut of rice is an emerging disease and caused severe damage to hybrids and inbred rice cultivars grown in Asian countries. The objective of the study was to quantify of false smut resistance and identification of donors in some of the advanced breeding lines and rice varieties developed at Punjab Agricultural University, Ludhiana, India. A total of 31 genotypes were evaluated for three years in two planting date per year under field conditions. The lines were categorized into short, medium and long durations based on days to flowering. False smut was quantified using different disease variables such as per cent infected panicle, number of false smut ball per plant and disease score. Disease variables were significantly and positively correlated to each other. The infected panicle ranged 0.0–75.4% was observed among the genotypes. Three advanced lines namely RGS-2 (short), RGM-3 (medium) and RGL-3 (long) showed the lowest ranged 0.0–4.9% of infected panicle as compared to susceptible checks (47.7–75.4%). The genotypes were divided into five groups according to a component of resistance. The third group had the lowest average values (3.3%) of infected panicle as compared to the fifth group with the highest values (36.2%) of the infected panicle. The overall trend of disease variables was higher in short duration genotypes as compared to medium and long durations. Weather factors such as rain fall, rainy days and high relative humidity during the flowering period were favourable for disease development. The genotypes with lower disease variables could be utilized in diseases resistance breeding programme.

Effects of varying levels of cleistogamy on natural smut infection in oats

AbstractSmut of oats, caused byUstilago avenae, is an important disease in organic seed production and resistance breeding via seed inoculation is an elaborate routine in organic oat breeding. The life cycle of smuts is known to depend on open flowers, for example, spores ofUstilagossp. need to settle inside the flower to start a next life cycle. Increasing the level of cleistogamy as a way to avoid initial infections instead of selecting for genetic resistance to the pathogens has previously been proposed to speed up and/or improve the breeding for resistance toUstilago nudain barley. In the present study, this concept of avoidance of infection by cleistogamy was evaluated for oat, using three experiments with 25, 64 and 49 oat lines, tested in the first year with artificial inoculation at one or two sites for smut resistance, and in the second year with saved seeds for smut incidence (SI). Generalized linear models were fitted to analyze the effects of environment, susceptibility (SUSC), cleistogamy index (CI), and infection pressure during flowering represented by the portion of smutted panicles in the first year. The results confirmed that cleistogamy reduces the smut infection of the derived seeds for up to 68%, influenced by the susceptibility level and environmental factors. We conclude that cleistogamy can, in addition to genetic resistance, be used to manage smut in organic production systems. For the usage of cleistogamy instead of physiological resistance, the types of cleistogamy and the required level of cleistogamy to reduce smut infection should be studied in more detail.

Quantitative Trait Loci Mapping and Development of KASP Marker Smut Screening Assay Using High-Density Genetic Map and Bulked Segregant RNA Sequencing in Sugarcane (Saccharum spp.).

Sugarcane is one of the most important industrial crops globally. It is the second largest source of bioethanol, and a major crop for biomass-derived electricity and sugar worldwide. Smut, caused by Sporisorium scitamineum, is a major sugarcane disease in many countries, and is managed by smut-resistant varieties. In China, smut remains the single largest constraint for sugarcane production, and consequently it impacts the value of sugarcane as an energy feedstock. Quantitative trait loci (QTLs) associated with smut resistance and linked diagnostic markers are valuable tools for smut resistance breeding. Here, we developed an F1 population (192 progeny) by crossing two sugarcane varieties with contrasting smut resistance and used for genome-wide single nucleotide polymorphism (SNP) discovery and mapping, using a high-throughput genotyping method called “specific locus amplified fragment sequencing (SLAF-seq) and bulked-segregant RNA sequencing (BSR-seq). SLAF-seq generated 148,500 polymorphic SNP markers. Using SNP and previously identified SSR markers, an integrated genetic map with an average 1.96 cM marker interval was produced. With this genetic map and smut resistance scores of the F1 individuals from four crop years, 21 major QTLs were mapped, with a phenotypic variance explanation (PVE) > 8.0%. Among them, 10 QTLs were stable (repeatable) with PVEs ranging from 8.0 to 81.7%. Further, four QTLs were detected based on BSR-seq analysis. aligning major QTLs with the genome of a sugarcane progenitor Saccharum spontaneum, six markers were found co-localized. Markers located in QTLs and functional annotation of BSR-seq-derived unigenes helped identify four disease resistance candidate genes located in major QTLs. 77 SNPs from major QTLs were then converted to Kompetitive Allele-Specific PCR (KASP) markers, of which five were highly significantly linked to smut resistance. The co-localized QTLs, candidate resistance genes, and KASP markers identified in this study provide practically useful tools for marker-assisted sugarcane smut resistance breeding.

Genetic Diversity and Population Structure of the Rice False Smut Pathogen Ustilaginoidea virens in the Sichuan-Chongqing Region.

Rice false smut caused by Ustilaginoidea virens is one of the most devastating fungal diseases of rice panicles worldwide. In this study, two novel molecular markers derived from single nucleotide polymorphism-rich genomic DNA fragments and a previously reported molecular marker were used for analyzing the genetic diversity and population structure of 167 U. virens isolates collected from nine areas in the Sichuan-Chongqing region, China. A total of 62 haplotypes were identified, and a few haplotypes with high frequency were found and distributed in two to three areas, suggesting gene flow among different geographical populations. All isolates were divided into six genetic groups. Groups I and VI were the largest, with 61 and 48 isolates, respectively. The pairwise FST values showed significant genetic differentiation among all compared geographical populations. Analysis of molecular variance showed that intergroup genetic variation accounted for 40.17% of the total genetic variation, while 59.83% of genetic variation came from intragroup genetic variation. The unweighted pair-group method with arithmetic means dendrogram and population structure revealed that the genetic composition of isolates collected from Santai, Nanchong, Yongchuan, and Wansheng dominated by the same genetic subgroup was different from those collected from other areas. In addition, genetic recombination was found in a few isolates. These findings will help to improve the strategies for rice false smut management and resistance breeding, such as evaluating breeding lines with different isolates or haplotypes at different elevations and landforms.

Location and seasonal effects on sugarcane smut and implications for resistance breeding in South Africa

Smut, Sporisorium scitamineum (Syd.) (formerly Ustilago scitamineum), is a major disease of sugarcane causing cane yield losses of 0.25 to 0.75% for every 1% of infected stools. Breeding resistant cultivars is part of integrated smut management. The objective of this study was to determine the effects of locations and seasons on smut infection genotype in irrigated sugarcane breeding trials. Data for smut-infected stools and smut whips collected from early and late season trials at Pongola (NPG) and Mpumalanga research stations (MP) were analysed using linear mixed models. There were significant (p < 0.001) location, season, location by season, genotype, genotype by location, genotype by season and genotype by location by season interaction effects for infected stools and whips. Broad sense heritability in late season trials averaged 0.89 compared to 0.61 in early season, while that for MP (0.79) was higher than for NPG (0.69) indicating higher selection efficiency for smut resistance in late season MP trials. Genotypes had significantly (p < 0.001) higher infected stools and whips at MP than at NPG and in late than early season trials. Smut-screening using MP late season trials will increase efficiency of breeding for smut resistance in South Africa.

Application amylos-free starch millet (Panicum miliaceum L.) varieties

Materials and methods. Four amylopectin varieties Chabanivske, Zhyvynka (NSC Institute of Agriculture) and Osoblyve and Alternatyvne (Institute of Plant Industry named after V.Ya. Yuriev) were taken as experimental material. The main economically valuable characteristics of the varieties and their biochemical properties of grain were made in 2018–-2020. The main technological indicators of the dough and the assessment of the quality of bread from a mixture of spring wheat flour of the Myronivska variety and grain flour of the Chabanivske variety were carried out in accordance with the current methods. Millet flour was added to wheat flour in proportions of 2.5, 5.0, 7.5 and 10.0%.&#x0D; The purpose of our research was to study the main economically valuable traits, biochemical properties and resistance to 13 smut races of Ukrainian amylopectin varieties of millet and to determine the optimal percentage of adding millet flour to spring wheat flour to improve the quality of bread.&#x0D; The discussion of the results. According to the results of scientific work, it has been established that millet waxy varieties differ in their economically valuable characteristics. So, varieties Chabanivske and Zhyvynka have a short growing season, on average, 75 and 77 days, respectively, and varieties Osoblyve and Alternatyvne – 93 and 100 days, respectively. Due to the increased height of the plants of the Osoblyve and Alternatyvne varieties, they can also be grown for animal feed. In terms of biochemical parameters, modern amylopectin varieties did not differ significantly, but showed a high content of protein (13.50–14.0%) and carotenoids (4.8–5.6 mg/kg). Amylos-free starch genotypes varied significantly in terms of head smut resistance. Variety Chabanivske was affected by 13 smut races, varieties Alternatyvne and Osoblyve received 8 and 7 points in 1 and 10 races. Variety Zhyvynka showed high resistance to 8 smut races: Rs 1, Rs 4–Rs 7, Rs 9–Rs 11 – 9 points. The addition of flour from amylos-free starch millet improved the elasticity and extensibility of the dough, increased the balance of these physical properties of the dough with each other, improved the strength of the flour, but did not affect the sedimentation rate. Bread baked with the addition of 2.5% or 5.0% Chabanivske grain flour to the Myronivska spring wheat flour had a larger volume, better taste and appearance compared to the standard.&#x0D; Conclusions. Waxi varieties (Chabanivske, Zhyvynka, Osoblyve, Alternatyvne), were developed in Ukraine, are characterized by high economically valuable traits and high indicators of grain quality. The main use of these varieties is grain and fodder. The Zhyvynka variety is characterized by high resistance (9 points) to 8 races of smut (Rs 1, Rs 4–Rs 7, Rs 9–Rs 11). The addition of Chabanivske grade waxy-millet flour to wheat flour improves its baking qualities and the taste of bread, while the films are additional fiber that promotes digestion

Genome Characteristics Reveal the Biocontrol Potential of Actinobacteria Isolated From Sugarcane Rhizosphere.

To understand the beneficial interaction of sugarcane rhizosphere actinobacteria in promoting plant growth and managing plant diseases, this study investigated the potential role of sugarcane rhizospheric actinobacteria in promoting plant growth and antagonizing plant pathogens. We isolated 58 actinobacteria from the sugarcane rhizosphere, conducted plant growth-promoting (PGP) characteristics research, and tested the pathogenic fungi in vitro. Results showed that BTU6 (Streptomyces griseorubiginosus), the most representative strain, regulates plant defense enzyme activity and significantly enhances sugarcane smut resistance by regulating stress resistance-related enzyme (substances (POD, PAL, PPO, TP) in sugarcane) activity in sugarcane. The genomic evaluation indicated that BTU6 has the ability to biosynthesize chitinase, β-1,3-glucanase, and various secondary metabolites and plays an essential role in the growth of sugarcane plants under biotic stress. Potential mechanisms of the strain in improving the disease resistance of sugarcane plants and its potential in biodegrading exogenous chemicals were also revealed. This study showed the importance of sugarcane rhizosphere actinobacteria in microbial ecology and plant growth promotion.

Sugarcane Smut: Current Knowledge and the Way Forward for Management.

Whip smut of sugarcane is the most serious and widely spread disease of sugarcane and causes a significant reduction in cane quantity and quality. The severity of this disease often depends on the pathogen races, environmental conditions, cultivar genotype and the interaction among these three factors. Under optimum climatic conditions, this disease has the potential to cause total crop failure. Resistance screening is an ongoing process due to the variability among smut pathogen isolates. Multiple races and mutation ability of smut pathogen makes the breeding task more complex. A number of studies on various aspects of the disease epidemiology and management have been published. Due to many overlapping characteristics within the species complex, there is a dearth of information on early detection and strategies to control the smut pathogen. Furthermore, there is a need to coordinate these findings to expedite its research and control. In this paper, we summarize the disease etiology, especially disease impact on the qualitative and quantitative parameters of sugarcane. We also gathered research progress on molecular-based detection and available information on genetic variability in S. scitamineum. The research on the set of management options needed to effectively cope with the disease are reviewed herein. The present review is expected to be helpful for the further investigation on smut resistance in sugarcane.

Evaluation of natural resistance to smut in elite sugarcane varieties (lines)

<p indent=0mm>Sugarcane smut is a systemic fungal disease that seriously affects the development of sugarcane industry in China. Different sugarcane varieties have various resistance to smut. Screening and planting resistant varieties are the most economical and effective measure to control smut disease. In order to determine the smut resistance of elite varieties (lines) bred in China in recent year and screen resistant varieties for application in production, the resistance of 100 Chinese elite sugarcane varieties (lines) were evaluated by artificial inoculation with the impregnation method in smut epidemic area Yuanjiang, Yunnan Province. The results revealed that 56 of the 100 elite varieties (lines) were highly resistant to moderately resistant, accounting for 56%, and 44 were moderately susceptible to highly susceptible 2, accounting for 44%. The results showed that current large-scale planted and promoted varieties (lines) Mintang 69-421, ROC 22, Liucheng 03-182, Liucheng 03-1137, Guitang 42, Yuegan 26, Guitang 02-351, and Yunzhe 09-1601 were highly susceptible. And the sugarcane varieties (lines) bred in recent years, Funong 15, Funong 36, Funong 1110, Funong 07-3206, Funong 11-2907, Mintang 11-610, Yuegan 39, Yuegan 43, Yuegan 48, Yuegan 49, Yuegan 50, Yuetang 00-236, Ganzhe 02-70, Yunzhe 99-596, Yunzhe 03-258, Yunzhe 04-241, Yunzhe 06-80, Yunzhe 07-2800, Yunzhe 08-2060, Yunzhe 10-2698, Yunzhe 13-1139, Yunrui 10-701, Dezhe 09-84, Dezhe 12-88, Guitang 08-1589, and Zhongzhe 1 were highly resistant to smut disease. It was suggested that in the high incidence area of sugarcane smut in low altitude valley, efforts should be carried out to eliminate the elite varieties susceptible to the disease and popularize and apply the superior varieties resistant to the disease in order to achieve the rational distribution of varieties, control the outbreak and epidemic of sugarcane smut, and provide guarantee for the high-quality development of sugarcane industry.

Engineering false smut resistance rice via host-induced gene silencing of two chitin synthase genes of Ustilaginoidea virens.

Rice false smut (RFS), caused by the pathogenic ascomycete fungus Ustilaginoidea virens (U. virens), is one of the severely devastating diseases worldwide (Sun et al., 2020; Zhang et al., 2014). U. virens infects rice flowers causing over 25% yield loss, also producing poisonous mycotoxins that threaten the health of humans and animals (Fan et al., 2016; Zhang et al., 2014). So far, rice varieties showing resistance to RFS are rarely mined and none resistant genes are genetically confirmed (Zhang et al., 2019). Host-induced gene silencing (HIGS) is a powerful strategy to control diseases, where small interference RNAs (siRNAs) are produced by plants to silence essential genes of pathogens. Application of HIGS to control fungal diseases is successfully reported in several crops (Hou and Ma, 2020). Here, we evaluated the potential of HIGS for engineering rice against RFS by silencing chitin synthase genes of U. virens.