坛紫菜抗细菌病害品系的筛选OA北大核心CSTPCD

In order to establish the screening criteria for bacterial resistance strains of Neoporphyra haitanensis,ten strains of N.haitanensis,including ZD-1,GS-1,MF-2 and others were used as the materials.With the pathogen Vibrio mediterranei 117-T6 and Phaeobacter sp.JN-W1 serving as the infectious sources,a disease evaluation system was constructed according to the rot rate,the extent of rot on the thalli and disease index,and based on which,the disease resistance grade was determined.Through the population selection method,the resistant strain GS-1 and the susceptible strain YS-W-01 were identified as the candidates.Moreover,changes in physiological and biochemical indicators such as antioxidant enzyme activity,soluble protein(SP),related genes,and photosynthetic pigment contents were analyzed before and after infection.It was observed that in the infected group,the activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT)were initially increased and then decreased.The SOD and POD activities of the resistant strain GS-1 were significantly higher than those of the susceptible strain(P<0.05).The content of SP was decreased with prolonged infection time.The content of free proline(Pro)in both strains was decreased after reaching peak levels,while malondialdehyde(MDA)remained at a higher level.The peak value of free Pro in the resistant strain was significantly higher than that in the susceptible strain(P<0.05),while MDA showed no difference.Additionally,the content of phycoerythrin and chlorophyll a(Chl a)were decreased continuously after a temporary increase with prolonged infection time.The statistical analysis indicated that the content of Chl a,free Pro,SP,SOD and POD activities,as well as relative expression of Mn-sod,had significant or extremely significant positive correlations with disease resistance(P<0.05 or P<0.01).It suggested that they could be used as effective indicators for screening resistant cultivars.The results of this study provide methodological references and data for the selection of superior cultivars of N.haitanensis resistant to bacterial diseases.