First Report of Leaf Spot Caused by Corynespora cassiicola on Acanthus ilicifolius in China.

Acanthus ilicifolius, also referred to as holly mangrove, usually grows in the coastal areas in southern China. It is not only a pioneer species of mangroves but also an important medicinal mangrove plant. In June 2019, leaf spots on A. ilicifolius with disease incidence of about 30 to 40% were observed in about 150 plants in a field located in Zhanjiang City, Guangdong Province, China. The disease mainly occurred on the leaf margins or tips. Initial symptoms of the disease were dark brown spots (5 to 9 mm) surrounded by a yellow halo, that expanded irregularly or semicircularly, until finally the leaves turned chlorotic and defoliated. Six samples of symptomatic leaves were excised, surface sterilized with 75% ethanol 30 s, 0.1% HgCl2 30 s, and rinsed three times with sterile water, and cut into small pieces (5 mm × 5 mm), placed on potato dextrose agar (PDA) at 25°C and darkness, and two isolates with different morphological characteristics were obtained after 3 days. For pathogenicity tests of the isolates, wounded and non-wounded leaves were inoculated. Fresh wounds were made with a sterile needle. Mycelial plugs from 8-day-old cultures of two isolates, ALY1 and ALY2, on PDA were inoculated on adaxial surface of wounded and non-wounded healthy young leaves of the A. ilicifolius seedlings (2 years old, 4 leaves per plant, 2 replicate plants per isolate), covered with wet cotton and kept in moist chambers at 25 ± 1°C, 80% relative humidity. Leaves inoculated with sterile PDA plugs were used as the control. After 3-5 days, the wounded and non-wounded leaves inoculated with ALY1 showed symptoms of leaf spots, similar to those observed in the field, while leaves inoculated with ALY2 and the control leaves remained symptomless. The pathogenicity tests were repeated three times under the same conditions and similar results were observed. ALY1 was confirmed as the pathogen causing the leaf spot. On PDA, ALY1 produced a gray to grayish brown colony. The conidia were obclavate to cylindrical, straight to slightly curved, pale brown, with 6 to 18 pseudosepta, 62.5 to 225.0×3.8 to 14.8 µm (n=17). According to the morphological characteristics, ALY1 was preliminarily identified as Corynespora cassiicola (Zhang et al.2018). For molecular identification, the internal transcribed spacer (ITS), the actin gene (ACT), the ß-tubulin gene (TUB2) and translation elongation factor 1-alpha gene (TEF1-α) of the three single-spore isolates from ALY1 (ALY1-1 to ALY1-3) were amplified and sequenced with primers ITS4/ITS5 (White et al.1990), ACT512F/ACT783R(Carbone and Kohn 1999), T1/T2 (Glass and Donaldson 1995), and EF1-728F/EF1-986R (O'Donnell et al.1998) respectively. The ITS region of ALY1 (-1, -2, -3) (GenBank accession number MN860006, -07, -08) was 99-100% identical (579/585, 586/586, 581/584 base pairs) to a corresponding ITS (MH255527) of C. cassiicola. Similarly, the ACT (MN887504, -05, -06), TUB2 (MN887507, -08, -09) and TEF1-α (MN887501, -02, -03) were 100% (342/342, 342/342, 342/342 base pairs), 100% (664/664, 662/662, 664/664 base pairs) and 100% (290/290, 290/290, 290/290 base pairs) to corresponding genes FJ853033, MH763700, and MK589886 sequences of C. cassiicola in GenBank, respectively. Phylogenetic tree generated with MEGA7 by the neighbor-joining analysis revealed that the isolate's ITS, ACT, TUB2 and TEF1-α sequences were grouped in the same clade to C. cassiicola. Based on both the morphological characteristics and sequences analyses, the pathogen causing leaf spot of A. ilicifolius was identified as C. cassiicola. This species had been reported on the A. ilicifolius in Guam America and Hong Kong China (Lu et al. 2000; Zhuang 2001; Dixon et al. 2009; Sumabat et al. 2018). The best of our knowledge, it is the first report of C. cassiicola causing leaf spot of A. ilicifolius in China. This disease may a potential threat to A. ilicifolius along the coastal regions of southern China.

Cardiovascular and metabolic phenotypes in relation to the ADRA2B insertion/deletion polymorphism in a Chinese population.

OBJECTIVE: The functional ADRA2B I/D polymorphism is associated with various cardiovascular and metabolic phenotypes in Caucasians. The purpose of our study was to investigate whether the ADRA2B I/D polymorphism is associated with such phenotypes in a Chinese population. METHODS: We enrolled 247 women and 234 men in a family-based Chinese study. Our statistical methods included generalized estimating equations and quantitative transmission disequilibrium test. RESULTS: The I allele (62.3 versus 50.8%, P = 0.015) and the II genotype (40.9 versus 23.4%, P = 0.017) were more prevalent among hypertensive than normotensive men. While adjusting for covariates and family clusters, male II homozygotes compared with D-allele carriers had higher systolic pressure (130.0 versus 125.0 mmHg, P = 0.016) and a 2.61 times greater (P = 0.008) risk of hypertension. On the other hand, II homozygous men had lower body weight (65.4 versus 69.6 kg, P = 0.008), body mass index (23.4 versus 24.5 kg/m2, P = 0.037), waist-to-hip ratio (0.838 versus 0.857, P = 0.024), serum insulin concentration (9.5 versus 13.2 mU/l, P = 0.026) and insulin resistance (homeostasis model assessment index 2.4 versus 3.2, P = 0.051). None of these associations reached statistical significance in women. In 65 informative male offspring, transmission of the I allele was associated with higher systolic pressure (+ 6.0 mmHg, P = 0.10), diastolic pressure (+ 5.5 mmHg, P = 0.021), and faster pulse rate (+ 5.8 beats/min, P = 0.019). CONCLUSION: In Chinese men, the I allele of the ADRA2B gene is associated with higher blood pressure, but also with a more favourable metabolic phenotype.

ADRA2B gene insertion/deletion polymorphism and artery compliance.

BACKGROUND: The ADRA2B gene insertion/deletion (I/D) polymorphism is associated with various cardiovascular and metabolic phenotypes. Large (C1) and small (C2) artery compliance, assessed by pulse wave analysis, is considered as sensitive markers or risk factors for cardiovascular disease. Therefore whether the ADRA2B I/D polymorphism is associated with C1 and C2 need to be investigated. METHODS: A total of 227 men and 243 women were enrolled in a Chinese family-based study. C1 and C2 were measured by pulse wave analysis. ADRA2B genotypes were determined by polymerase chain reaction. Statistical methods included generalized estimation equations and quantitative transmission disequilibrium test. RESULTS: The II (31.9%), ID (46.8%) and DD (21.3%) genotype frequencies were in Hardy-Weinberg equilibrium (P = 0.73). The covariates selected by stepwise regression for C1 and C2 were age, systolic pressure and gender. The population based association analysis showed that C1 and C2 were not associated with ADRA2B genotype both before (C1: P = 0.28; C2: P = 0.27) and after (C1: P = 0.58; C2: P = 0.18) the adjustment. The family-based analyses of 128 informative offspring showed that transmission of the D-allele was not associated with C1 or C2, both before (C1: P = 0.42; C2: P = 0.85) and after (C1: P = 0.31; C2: P = 0.82) the adjustment. CONCLUSION: The study do not support that the ADRA2B gene I/D polymorphism has a major gene effect on C1 or C2 in the Chinese population of current sample size.