Sideritiflavone

29951532

The ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), is one of the most economically devastating diseases impacting sugarcane. RSD causes significant yield losses and variety degradation. Diagnosis of RSD is challenging because it does not exhibit any discernible internal and external symptoms. Moreover, the Lxx bacteria are very small and difficult to isolate, cultivate, and detect. In this study, conventional polymerase chain reaction (PCR), real-time quantitative PCR (RT-qPCR), and Lxx-loop-mediated isothermal amplification (Lxx-LAMP) were utilized to specifically detect the presence of Lxx pathogens in the juice from Lxx-infected sugarcane stalks and an Lxx-pMD18-T recombinant plasmid. The results showed that Lxx was a highly specific causal pathogen for RSD. All three techniques provided great reproducibility, while Lxx-LAMP had the highest sensitivity. When the DNA extract from Lxx-infected sugarcane juice was used as a template, Lxx-LAMP was 10 and 100 times more sensitive than RT-qPCR and conventional PCR, respectively. When the Lxx-pMD18-T recombinant plasmid was used as a template, Lxx-LAMP was as sensitive as RT-qPCR but was 10 times more sensitive than conventional PCR. Based on the Lxx-LAMP detection system established, adding 0.4 μM loop primers (LF/LP) can accelerate the reaction and reduce the total time required. In addition, the optimal amount of Bst DNA polymerase for Lxx-LAMP reactions was determined to be 6.0 U. The results provide technical support for the detection of RSD Lxx pathogen that will help manage sugarcane RSD.

A Comparative Study of Three Detection Techniques for Leifsonia xyli Subsp. xyli, the Causal Pathogen of Sugarcane Ratoon Stunting Disease

Qibin Wu, Yong-Bao Pan, Dinggang Zhou, Michael P. Grisham, Shiwu Gao, Yachun Su, Jinlong Guo, Liping Xu, Youxiong Que

2018;

25045742

During sugarcane growth, the Early Elongation stage is critical to cane yield formation. In this study, parameters of 17 sugarcane varieties were determined at the Early Elongation stage using CI-301 photosynthesis measuring system and CI-100 digital plant canopy imager. The data analysis showed highly significant differences in leaf area index (LAI), mean foliage inclination angle (MFIA), transmission coefficient for diffused light penetration (TD), transmission coefficient for solar beam radiation penetration (TR), leaf distribution (LD), net photosynthetic rate (PN), transpiration rate (E), and stomatal conductance (GS) among sugarcane varieties. Based on the photosynthetic or canopy parameters, the 17 sugarcane varieties were classified into four categories. Through the factor analysis, nine parameters were represented by three principal factors, of which the cumulative rate of variance contributions reached 85.77%. A regression for sugarcane yield, with relative error of yield fitting less than 0.05, was successfully established: sugarcane yield = ?27.19 ? 1.69 × PN + 0.17 × E + 90.43 × LAI ? 408.81 × LD + 0.0015 × NSH + 101.38 × D (R 2 = 0.928**). This study helps provide a theoretical basis and technical guidance for the screening of new sugarcane varieties with high net photosynthetic rate and ideal canopy structure.

Photosynthetic and Canopy Characteristics of Different Varieties at the Early Elongation Stage and Their Relationships with the Cane Yield in Sugarcane

Jun Luo, Yong-Bao Pan, Liping Xu, Yuye Zhang, Hua Zhang, Rukai Chen, Youxiong Que

2014;