Plant Pathology Journal最新文献

SUMOylation plays a pivotal role in DNA replication and repair, transcriptional stability, and stress response. Although SUMOylation is a conserved posttranslational modification (PTM) in eukaryotes, the number, type, and function of SUMOylation-associated components vary among mammals, plants, and fungi. SUMOylation shares overlapping features with ubiquitination, another well-known PTM. However, comparative studies on the interplay between these two PTMs are largely limited to yeast among fungal species. Recently, the role of SUMOylation in pathogenicity and its potential for crosstalk with ubiquitination have gained attention in fungal pathogens. In this review, we summarize recent findings on the distinct components of SUMOylation across organisms and describe its critical functions in fungal pathogens. Furthermore, we propose new research directions for SUMOylation in fungal pathogens, both independently and in coordination with other PTMs. This review aims to illuminate the potential for advancing PTM crosstalk research in fungal systems.

Cyst nematodes are among the major plant-parasitic nematodes worldwide, and they cause significant damage to Brassicaceae crops, including Kimchi-cabbage, in Korea. To survey the incidence of cyst nematodes in Kimchi-cabbage fields, 469 soil samples were collected from the main producing areas between 2018 and 2021. Only cyst nematodes belonging to the genus Heterodera were investigated, and the overall nematode incidence was found to be 40%. Regionally, the highest incidence was observed in Taebaek, reaching 89%, with mean densities of cysts and eggs per 500 cm³ of soil recorded at 522 and 49,734, respectively. Based on Bayesian analysis of the mitochondrial DNA cytochrome c oxidase subunit I gene sequence, the cyst nematodes were identified as four species: clover cyst nematode (Heterodera trifolii, HT, frequency: 78%), soybean cyst nematode (H. glycines, HG, 11%), sugar beet cyst nematode (H. schachtii, 4%), and white soybean cyst nematode (H. sojae, HSo, 2%). Mixed infestations were found in some fields, with HT + HG (4%) and HG + HSo (1%). These results indicate that HT is the dominant species in the main Kimchi-cabbage producing areas in Korea. In conclusion, implementing effective HT management strategies is critical to minimize economic losses in Kimchi-cabbage production in Korea.

Continuous flooding in rice production presents significant challenges, such as increased labor intensity and soil degradation. However, when properly implemented, alternate wetting and drying can mitigate these issues. Despite its potential advantages, the effects of different water management practices on the soil microbiome are not well understood. This study explored how intermittent flooding and drying influence the soil microbiome by analyzing microbial communities under varying moisture conditions using Illumina sequencing. The results showed notable shifts in the abundance of Bacillota and Actinomycetota in response to fluctuations in water levels, although the overall microbial abundance returned to its original state under stable moisture conditions. In contrast, the abundance of Chloroflexota, which increased during waterlogging, remained elevated even under dry conditions. Additionally, microbial interactions were more pronounced during waterlogging compared to both moist and dry conditions. Overall, this research underscores the significant role of water management in shaping soil bacterial communities.

Cyst nematodes, some of the most important plant-parasitic nematodes globally, cause major damage to Chinese cabbage and soybean plants in Korea. Cysts are commonly used for cyst nematode bioassays because many eggs are included inside cyst. Traditionally, cysts are extracted from the soil using the paper strip method or the centrifugal flotation method (CFM) combined with sieving. The specific gravity of sugar solution (SGSS) is often used in the CFM; however, the efficiency of cyst extraction and egg hatching in the CFM has not been studied. In this study, we assessed the effects of SGSS in a specific gravity range of 1.15 to 1.30 in the CFM on the cyst extraction and egg hatching of clover cyst nematode (Heterodera trifolii) and sugar beet cyst nematode (H. schachtii). High SGSS in the CFM within the range of 1.15 to 1.30 was positively correlated with the extraction of more cysts. Egg-hatching rates were not different between SGSSs, indicating that SGSS did not directly affect egg-hatching rates. These results showed that the cysts of cyst nematodes can be efficiently extracted with high SGSS in the CFM.

Large-scale culture of the microalga Chlorella produces valuable products. Cultivation also generates tons of supernatant waste that require detoxification and disposal. Recent research has focused on recycling waste supernatant as a plant protectant and biofertilizer, although, to date, most studies have considered its use as a biological control of pathogens infecting dicot plants. By contrast, the current study evaluated whether Chlorella supernatant could protect turfgrass (Agrostis stolonifera), a monocot plant widely used as a turfgrass, against dollar spot disease caused by the fungal pathogen Clarireedia jacksonii (formerly Sclerotinia homoeocarpa) under greenhouse and field conditions. Foliar application of supernatants from Chlorella sp. ABC001 and HS2 cultures reduced the incidence of dollar spot disease in turfgrass under both greenhouse and field conditions without directly inhibiting growth. The effects of supernatant application on the rhizosphere microbiome were investigated using 16S rRNA amplicon sequencing. Application of ABC001 and HS2 supernatants modulated the structure of the rhizosphere microbiome and enriched specific microbial taxa that improved turfgrass health in the presence of C. jacksonii. The application of waste Chlorella supernatant therefore offers an alternative method for protecting monocot plants against fungal pathogens, while also enhancing the composition of soil microbes in the rhizosphere.

Estrogen, a key sex hormone in humans and other mammals, regulates the female reproductive system and has important medicinal applications. It enters the environment through sources such as animal feces and medical waste. It is structurally similar to the mycotoxin zearalenone produced by the homothallic fungus Fusarium graminearum. This fungus is responsible for causing Fusarium head blight on cereal crops around the world. We investigated the effects of the major estrogen, β-estradiol, on the development of F. graminearum. β-estradiol increased the production of asexual conidia and sexual perithecia in this fungus. It also accelerated conidial germination of F. graminearum, Fusarium solani, and Fusarium oxysporum. Furthermore, it restored mycelial growth under membrane stress and enhanced survival under oxidative and cold stress conditions. It also affected mycotoxin production. These findings suggest that estrogen pollution would influence the life cycle of F. graminearum and the interactions between plant pathogens and plants.

The genus Botryosphaeria cause white rot disease on apple trees, and control of this pathogens were primary relied on the fungicide applications. To investigate the pyraclostrobin sensitivity of Botryosphaeria spp. in Korea, 329 isolates were collected from eight regions between 2005 and 2023. Phylogenetic analysis based on the concatenated sequences of internal transcribed spacer, tef1, and tub2 revealed B. sinensis (287 out of 329 isolates) and B. kuwatsukai (42 out of 329 isolates). EC50 values of isolates ranged from 0.01 to 34.16 μg/ml (average, 3.03 μg/ml). Mean EC50 values and frequency distributions were similar among isolate groups, indicating no significant differences in sensitivity. Twenty less-sensitive and 20 sensitive isolates were selected and their cytochrome b (cyt b) genes analyzed, revealing no mutations in codons 129, 137, and 143. Whole gene sequencing revealed three distinct cyt b gene structures among Botryosphaeria spp., and all strains, including those with different EC50 values and species, showed consistent amino acid sequences. Furthermore, control efficacy on pyraclostrobin-treated apple fruits indicated no significant differences between the five least sensitive and five most sensitive isolates. These results provide the baseline sensitivity of Botryosphaeria spp. to pyraclostrobin and highlight the structural characteristics of their cyt b gene. In conclusion, the assessment of Botryosphaeria isolates from various regions in Korea revealed no evidence of resistance to pyraclostrobin so far. However, the risk of resistance of Botryosphaeria populations still exists so it is assumed that continuous monitoring of risk assessment is necessary for Botryosphaeria in Korea.

The enzyme MGG_00097 from rice blast fungus (Magnaporthe grisea) is a NADPH-dependent oxidoreductase, involved in synthesizing glycerol from dihydroxyacetone phosphate and dihydroxyacetone. The 35.5-kDa monomer belongs to the aldo-keto reductase superfamily, characterized by a highly conserved catalytic tetrad. This study, elucidates the expression, purification, and kinetic properties of recombinant MGG_00097. The ternary complex of MGG_00097 with NADP+ and glycerol was refined to a 2.9 Å resolution, revealing critical insights into substrate binding and catalysis. NADP+ binds within the active site, with residues Ser221, Leu223, Ser225, Lys271, Ser272, Ser273, Thr274, Arg277, and Asn281 forming the substrate and cofactor-binding pockets. A Y56A mutation reveals the open conformation of the cofactor-binding pocket, with Glu29 and Gln226 functioning as hinge residues for the conformational changes upon cofactor binding. These findings contribute to the understanding of MGG_00097's catalytic mechanism and offer a basis for further biochemical and potential biotechnological applications.

Bacterial panicle blight and seedling rot diseases in rice plants (Oryza sativa L.) are caused by the pathogenic bacterial Burkholderia glumae. The nanosilicon treatment is gaining attraction but its effectiveness towards B. glumae infection in rice seedlings through regulating enzymatic activities remains largely unexplored. This study aimed to evaluate the bio-efficacy of nanosilicon in controlling seedling rot disease through regulation of peroxidase and polyphenol oxidase enzymes after challenge infected with B. glumae in rice variety MR297 and PadiU Putra. Nanosilicon was applied as seed priming in germination testing at 0, 300, 600, and 900 ppm on both rice varieties before B. glumae inoculation. Both rice seed varieties primed with nanosilicon at 600 ppm exhibited a significant increase in seedling germination performances over control. The rice seedling of MR297 was more responsive to nanosilicon at 600 ppm with only 17.78% of disease severity index over 26.67% in PadiU Putra and was therefore selected for the enzymatic activity screening. The results showed that the foliar spray of nanosilicon rice plants (MR297) significantly increased both peroxidase (POX) at 24 h and polyphenol oxidase (PPO) at 48 h after B. glumae inoculation with 20.44/min/g and 7.46/g activities, respectively. In addition, the plant growth performances were significantly increased compared with control under the same treatment. This demonstrates nanosilicon's potential to control rice seedling rot disease by regulating POX and PPO activities and hence promote plant growth. The application of nanosilicon is an environmentally friendly approach for controlling B. glumae infection at the early rice growing stage.