Studies on breeding of Porphyra through cell-fusion and cell-line selection

通过对紫菜、紫菜、紫菜等野生种的筛选，发现不同品系对紫腐菌引起的红腐病的抗性水平不同。通过属内和门间原生质体融合，将抗病性状转移到感病栽培条斑病菌。在属内和门间原生质体融合后代中，条斑紫菜和细脚青霉的3个融合产物后代证实了抗性性状的传递和稳定遗传。红腐病抗性融合产物菌株也表现出对由Olpidiopsis sp.引起的栗疫病的抗性。与感病栽培菌株相比，抗赤腐病亲本和融合产物后代菌株的游动孢子包囊数和穿透率均较低。甚至在其他红藻角质层上也观察到包囊和原发感染，这表明宿主-病原菌相互作用…的调节更多的是寄主表面的半乳糖。要了解这种抗性机制的生化基础，还需要进一步的研究。不同的融合产物后代菌株表现出与培育的亲本融合伙伴几乎相似的生长速度。而它们的色素和游离氨基酸含量低于栽培亲本融合伙伴，但高于野生亲本融合伙伴。筛选出对蛋氨酸和胱氨酸具有氨基酸抗性的突变细胞系。与未处理的细胞系相比，抗性细胞系没有表现出任何特定或组的游离氨基酸的显著过度积累。而色素含量存在差异，蛋氨酸抗性品系的藻红蛋白和藻蓝蛋白含量增加。耐药细胞系也表现出比未经处理的菌体更高的生长速度。这项研究揭示了利用原生质体进行细胞系选择的新途径。较少

Screening of wild species of Porphyra (P.tenuipedalis, P.suburbiculata etc.), green algae (Ulvaceae) revealed different resistance levels among the strains to red rot disease caused by Pythium porphyrae. Intra-generic and inter-phylum protoplast fusion was carried out to transfer the disease resistant traits to the susceptible cultivated P.yezoensis. Of the Intra-generic and inter-phylum protoplast fusion progeny, the transfer and stable inheritance of resistant traits were confirmed in three fusion product progeny of P.yezoensis and P.tenuipedalis. The red rot resistant fusion product strains have also shown resistance to chytrid blight disease, caused by Olpidiopsis sp. The red rot resistant parent and fusion product progeny strains have shown less number of encysted Pythium zoospores and penetration rate in comparison to susceptible cultivated strain. Encystment and primary infection was observed even on other red algal cuticles suggesting the regulation of host-pathogen interaction … More by the surface galactans on the host surface. Further investigations are required to understand the biochemical basis of this resistance aechanism. The different fusion product progeny strains have displayed almost similar growth rates as the cultivated parent fusion partner. While in comparison, their pigment and free amino acid contents were less than the cultivated parent fusion partner, but were greater than the wild parent fusion partner.Protoplasts isolated from P.yezoensis were mutagenized with Ethyl methanesulphonate. Mutant cell lines with amino acid resistance to methionine and cystiene were selected. The resistant cell lines have not shown any significant over accumulation any particular or group of free amino acids, in comparison to the untreated lines. While, there were differences in pigmcnt contents, Methionine resistant lines had increased phycoerythrin and phycocyanin contents. The resistant cell lines have also shown higher growth rates than the untreated thalli. This study has revealed a new avenue of using protoplasts for cell line selection. Less