Isolation and Properties of a Biocidal Peptide from Hibiscus cannabinus Seeds

The fungitoxicity of a biocidal peptide from kenaf Hibiscus cannabinus L. seeds was investigated. Its influence on the distribution of calcium ions in mycelial cells of the fungus Verticilluim dahliae Kleb. was examined.     

A Compendium of the Most Promising Synthesized Organic Compounds against Several Fusarium oxysporum Species: Synthesis,Antifungal Activity,and Perspectives

Vascular wilt caused by F. oxysporum (FOX) is one of the main limitations of producing several agricultural products worldwide, causing economic losses between 40% and 100%. Various methods have been developed to control this phytopathogen, such as the cultural, biological, and chemical controls, the latter being the most widely used in the agricultural sector. The treatment of this fungus through systemic fungicides, although practical, brings problems because the agrochemical agents used have shown mutagenic effects on the fungus, increasing the pathogen’s resistance. The design and the synthesis of novel synthetic antifungal agents used against FOX have been broadly studied in recent years. This review article presents a compendium of the synthetic methodologies during the last ten years as promissory, which can be used to afford novel and potential agrochemical agents. The revision is addressed from the structural core of the most active synthetic compounds against FOX. The synthetic methodologies implemented strategies based on cyclo condensation reactions, radical cyclization, electrocyclic closures, and carbon–carbon couplings by metal–organic catalysis. This revision contributes significantly to the organic chemistry, supplying novel alternatives for the use of more effective agrochemical agents against F. oxysporum.     

Metabolite mass spectrometry profiling of cacao genotypes reveals contrasting resistances to Ceratocystis cacaofunesta phytopathogen

Ceratocystis wilt is a lethal disease of cacao, and the search for resistant genotypes may provide the best way to deal with the disease. Resistance or susceptibility behavior of some cacao genotypes when infected by Ceratocystis cacaofunesta is not yet understood. Herein, we report an LC-MS metabolomic screening analysis based on high-resolution MS to obtain comprehensive metabolic profile associated with multivariate data analysis of PLS-DA, which was effective to classify CCN-51 and TSH-1188 as resistant genotypes to C. cacaofunesta fungus, while CEPEC2002 was classified as a susceptible one. Using reversed-phase LC method, electrospray interface, and high-resolution tandem MS by the quadrupole-TOF analyzer, the typical profiles of metabolites, such as phenylpropanoids, flavonoids, lipids, alkaloids, and amino acids, were obtained. Untargeted metabolite profiles were used to construct discriminant analysis by partial least squares (PLS-DA)-derived loading plots, which placed the cacao genotypes into two major clusters related to susceptible or resistant groups. Linolenic, linoleic, oleic, stearic, arachidonic, and asiatic acids were annotated metabolites of infected, susceptible, and resistant genotypes, while methyl jasmonate, jasmonic acid, hydroxylated jasmonic acid, caffeine, and theobromine were annotated as constituents of the resistant genotypes. Trends of these typical metabolites levels revealed that CCN51 is susceptible, CEPEC2002 is moderately susceptible, and TSH1188 is resistant to C. cacaofunesta. Therefore, profiles of major metabolites as screened by LC-MS offer an efficient tool to reveal the level of resistance of cacao genotypes to C. cacaofunesta present in any farm around the world.     

高光谱的病害棉叶光合参数提取

应用高光谱遥感监测黄萎病胁迫下棉花叶片光合参数。在350～2 500 nm光谱波段获取207个不同时期不同病情严重度的棉叶样本光谱数据,同步利用光合仪测量样本光合参数。采用单因素方差和相关分析研究光合参数特征,提取样本叶片光合参数的敏感波段并筛选光谱特征参数,采用线性和非线性回归方法建立预测模型并检验。结果表明：随病情严重度增加,棉叶净光合速率、气孔导度、蒸腾速率均下降,胞间CO₂浓度先降后增,差异显著;病情严重度与光合参数均达到显著相关,与净光合速率、蒸腾速率、气孔导度、胞间 CO₂浓度相关系数分别为-0.97, -0.957, -0.886和0.715。选择与光合参数相关性最好的光谱敏感波段R704, R706, R699, R690, FD688, FD732, FD690, FD731, FD681组建新的光谱特征参数并与传统参数一起对净光合速率、蒸腾速率、气孔导度和胞间 CO₂浓度进行反演,其中是以光谱参数PRI[FD732, FD688]), R706, RVI[890, 670]), R690为自变量建立的净光合速率、蒸腾速率、气孔导度和胞间CO₂浓度反演方程精度最高,预测R2分别为0.827, 0.810, 0.658, 0.573;RMSE分别为5.466, 2.801, 109.500, 63.500;RE分别为0.041, 0.137, 0.158, 0.021。表明通过高光谱遥感可以实现棉花黄萎病叶片光合生理参数的提取。     

Role of chitin-specific peroxidase in wilt-resistant cotton

Chitin-specific isoforms of peroxidase with molecular weights 67 and 54.7 kDa that are involved in cotton wilt-resistance were obtained from sprouts of cotton variety AN-Bayaut-2 using chromatography. Electron microscopy showed that the morphology of the fungus V. dahliae changed under the influence of the chitin-specific isoforms of peroxidase. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 397–399, July–August, 2008     

Global dynamics of a pine wilt disease transmission model with nonlinear incidence rates

In this study, we investigate a pine wilt transmission model with nonlinear incidence rates. The stability of the system is analyzed for disease-free and endemic equilibria. It is proved that the global dynamics are completely by the basic reproduction number _R0$R_0$. If _R0$R_0$ is less than one, the disease-free equilibrium is globally asymptotically stable, and in such a case, the endemic equilibrium does not exist. If _R0$R_0$ is greater than one, the disease persists and the unique endemic equilibrium is globally asymptotically stable.     

Effect of cotton-seed biocidal peptides and gossypol on resistance to biotic factors

Peptide fractions were isolated from seeds of eight cotton varieties differing in resistance to fungal pathogens and cotton bollworm. Their ability to inhibit the growth of V. dahliae fungal conidiae and α-amylase from various sources was studied. A correlation was found between the fungicidal activity of the peptides and the resistance of the cotton varieties to the pathogens. α-Amylase of cotton bollworm was inhibited less by the isolated peptides than α-amylase of other insects that are not cotton pests. It was shown for the first time that gossypol inhibits α-amylase of insects. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 186-188, March-April, 2009.     

棉花单叶黄萎病病情严重度高光谱反演模型研究

对棉花单叶黄萎病病情严重度与原始及一阶微分光谱反射率、高光谱特征参数进行相关分析,构建病情严重度反演模型。结果表明：可见光和短波红外波段光谱反射率随病情严重度增加而增大,且可见光波段光谱反射率差异比短波红外波段更为显著。以红边面积为自变量的线性模型(r=0.669 6)及以波长694 nm处原始光谱反射率为自变量的对数模型(r=0.679 4)均能较好反演病情严重度。通过模型精度检验发现,以714 nm 处一阶微分光谱反射率为自变量的线性模型为病情严重度诊断的最佳模型,即y=-282.3x+3.811 2,该模型具有最大相关系数(拟合r=0.699 2,预测r=0.941 0),最小均方根误差(0.257 1)和相对误差(12.74%)。文章结果对深入研究棉花黄萎病遥感监测机理提供了理论依据,对利用高光谱遥感数据获取病害信息具有重要应用价值。     

Isolation of biocidal peptides from Daucus carota seeds

Two biocidal peptides were isolated from carrot seeds (Daucus carota). Their fungicidal activity toward the pathogenic fungus Verticillium dahliae was investigated. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 167–168, March–April, 2006.