Fusarium verticillioides, an important maize pathogen produces fumonisins and causes stalk and ear rot; thus, we are aimed to clarify its infection cycle by assessing enhanced green fluorescent protein (EGFP) expression in stalk and ear rot strains. Maize seeds were inoculated with stable and strongly pathogenic transformants. To investigate the degree of infection, inoculated plants were observed under a stereo fluorescence microscope, and affected tissue strains were detected using PCR. We found that both transformants infected maize. Hyphae infected the plants from radical to the stem and extended to the ear and infected ear kernels caused a second infection. This process formed the infection cycle.

This study aims to explore the protective effect of selenium (Se) on chronic zearalenone (ZEN)-induced reproductive system damage in male mice and the possible protective molecular mechanism against this. The chronic ZEN-induced injury mouse model was established with the continuous intragastric administration of 40 mg/kg body mass (B.M.) ZEN for 28 days. Then, interventions with different doses (0.1, 0.2, and 0.4 mg/kg B.M.) of Se were conducted on mice to analyse the changes in organ indexes of epididymis and testis, antioxidant capability of testis, serum level of testosterone, sperm concentration and motility parameters, and the expression levels of apoptosis-associated genes and blood testis barrier- (BTB) related genes. Our results showed that Se could greatly improve the ZEN-induced decrease of epididymis indexes and testis indexes. Results also showed that the decrease in sperm concentration, sperm normality rate, and sperm motility parameters, including percentage of motile sperm (motile), tropism percentage (progressive) and sperm average path velocity (VAP), caused by ZEN were elevated upon administration of the higher dose (0.4 mg/kg) and intermediate dose (0.2 mg/kg) of Se. Selenium also significantly reduced the content of malondialdehyde (MDA) but enhanced the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the testis tissue. Further research demonstrated that ZEN increased the level of mRNA expression of BCL2-associated X protein (Bax) and caspase 3 (Casp3), decreased the level of mRNA expression of B cell leukemia/lymphoma 2 (Bcl2), vimentin (Vim) and cadherin 2 (Cdh2), whereas the co-administration of Se reversed these gene expression levels. Our results indicated that high levels of Se could protect against reproductive system damage in male mice caused by ZEN and the mechanism might such be that Se improved mice antioxidant ability, inhibited reproductive cell apoptosis, and increased the decrease of BTB integrity-related genes caused by ZEN.

Isoxadifen-ethyl can effectively alleviate nicosulfuron injury in the maize. However, the effects of safener isoxadifen-ethyl on detoxifying enzymes in maize is unknown. The individual and combined effects of the sulfonylurea herbicide nicosulfuron and the safener isoxadifen-ethyl on the growth and selected physiological processes of maize were evaluated. Bioassays showed that the EC₅₀ values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for maize cultivar Zhengdan958 were 18.87 and 249.28 mg kg^-1, respectively, and were 24.8 and 275.51 mg kg^-1, respectively, for Zhenghuangnuo No. 2 cultivar. Evaluations of the target enzyme of acetolactate synthase showed that the I₅₀ values of nicosulfuron and nicosulfuron plus isoxadifen-ethyl for the ALS of Zhengdan958 were 15.46 and 28.56 μmol L^-1, respectively, and were 0.57 and 2.17 μmol L^-1, respectively, for the acetolactate synthase of Zhenghuangnuo No. 2. The safener isoxadifen-ethyl significantly enhanced tolerance of maize to nicosulfuron. The enhanced tolerance of maize to nicosulfuron in the presence of the safener, coupled with the enhanced injury observed in the presence of piperonyl butoxide, 1-aminobenzotriazole, and malathion, suggested cytochrome P450 monooxygenases may be involved in metabolism of nicosulfuron. We proposed that isoxadifen-ethyl increases plant metabolism of nicosulfuron through non-P450-catalyzed routes or through P450 monooxygenases not inhibited by piperonyl butoxide, 1-aminobenzotriazole, and malathion. Isoxadifen-ethyl, at a rate of 33 mg kg^-1, completely reversed the effects of all doses (37.5–300 mg kg^-1) of nicosulfuron on both of the maize cultivars. When the two compounds were given simultaneously, isoxadifen-ethyl enhanced activity of glutathione S-transferases (GSTs) and acetolactate synthase activity in maize. The free acid 4,5-dihydro-5,5-diphenyl-1,2-oxazole-3-carboxylic was equally effective at inducing GSTs as the parent ester and appeared to be the active safener. GST induction in the maize Zhenghuangnuo No. 2 was faster than in Zhengdan 958.

Setosphaeria turcica causes Northern corn leaf blight (NCLB). In this study, 92 isolates of S. turcica were collected from naturally infected corn fields at 57 sites within China to determine physiological race composition and genetic diversity. Based on the reaction of differential hosts, isolates were divided into 14 physiological races (0, 1, 2, 12, 3, 13, 23, N, 1N, 2N, 3N, 13N, 23N, 123N). Races 0 and 1 were dominant, found with frequencies of 34.78% and 28.26%, respectively. This study was the first to identify race 123N in Heilongjiang province, implying possible loss of corn variety resistance to the NCLB pathogen. A total of 64 loci were obtained from eight pairs of primers by sequence-related amplified polymorphism (SRAP), of which 44 were polymorphic, accounting for 68.75% of the loci. Molecular markers showed that 92 isolates could be categorized into four groups with a similarity coefficient of 0.82, indicating abundant genetic diversity. Further analysis of genetic similarity and genetic distance of each geographical population revealed that the populations from Northeast, North, and Northwest China exhibited high similarities to each other, while exhibiting a large genetic distance with those from Southwest China. Analysis of molecular variance indicated that 81.54% of the genetic variation among isolates was derived from individuals within the geographical population (P<0.001). The cluster analyses suggested that there was no distinct correlation among physiological races, genetic variation and geographic sources. This study provides a basis for understanding trends in S. turcica distribution and control of NCLB in China.

Fungi of the Fusarium oxysporum are widely distributed around the world in all types of soils, and they are all anamorphic species. In order to investigate the relationships and differences among Fusarium spp., 25 Fusarium spp. were isolated from greenhouse melon soils in Liaoning Province, China. With these 25 strains, three positive control Fusarium strains were analyzed using universally primed PCR (UP-PCR). Seventy-three bands appeared after amplification using 6 primers, and 66 of these bands (90.4%) were polymorphic. All strains were clustered into eight groups, though 14 strains of F. oxysporum were clustered into a single group. We concluded that UP-PCR could reveal the genetic relationships and differences among Fusarium strains. Moreover, the UP-PCR results suggested that F. oxysporum is distinguishable from other Fusarium spp. Thus, UP-PCR is a useful method for Fusarium classification. The pathogenicity of 13 strains of F. oxysporum to muskmelon, cucumber and watermelon seedlings was studied by infecting the seedlings with a spore suspension after cutting the root. The results showed that the F. oxysporum strains were pathogenic to all three melon types, although the pathogenicity differed significantly among the 13 strains. In addition, all strains had the greatest pathogenicity toward watermelon. Since the factors affecting pathogenicity vary widely, they should be considered in future studies on Fusarium spp. The results of such studies may then yield an accurate description of the pathogenicity of Fusarium spp.