Preliminary Study Of The Plantform To Study The Interacion Of Porphyra Spp. And Their Phycoshperes

We treated the thalli of Porphyra haitanensis with the mixture of 300μg/mL ammpicillin penicillin, 100μg/mL kanamycin and 100μg/mL gentamycin for 18-20hrs, in order to get the asepsis culture systems.According to the results of antibacterial analysis, we screened Polyketide synthase (PKS I) gene from the epiphytic bacteria of Porphyra spp. Three PKS I positive epiphytic bacteria were obtained from Wenzhou rotten Porphyra spp. these are the samples with high antibacterial activity. The BLAST results indicated that the Ketosynthase fragments of PKS I from the strains of WPhG3, WPySw1 and WPySw2 shared high similarities with the strains of Bacillus subtilis sub-sp. Subtilis str. 168 (NP₃89602), Bacillus subtilis (ABR19776) and Aspergillus carbonarius (AAZ99721), at the level of 98%, 99%, and 98% respectively. Furthermore, the phylogenetic analysis based on 16S rDNA sequences indicated that they belonged to the genus of Bacillus. The flora of Porphyra spp. epiphytic bacteria was complex, it regulated the phycosphere in many ways. The PKS I pathway might be a performance of antibacterial function of Bacillus from Wenzhou rotten samples.We screened 13 Pseudoalteronomas, 6 Bacillus and 7 fungi in order to find out the strains with promotion, inhibition or pathogeny functions. The microbial interactions were detected. The results showed that Porphyra fungi commly inhibited the epiphytic bacteria Pseudoaltermonas; while the three stains of Bacillus WPhS10, WPySW1, WPySW2, and one Pseudoaltermonas NPyS3 has the highest inhibition to fungi.We infected the thalli of Porphyra haitanensis with the screened four functional bacteria and fungi. The results showed that whether the thalli rotten depends more on the environment than on the infection of microbes, which indicated that the microbes might not be the pathogenies of Porphyra rotton, but they do will aggaravate the diease when the plants in adverse circumstances.,The result indicates that fungi are not necessarily the pathogenic bacteria, while the Porphyra spp. in bad environment may be more susceptible to pathogenic strains and lastly causing diseases.