条斑紫菜耐高温杂交重组品系的筛选与特性分析

Selection and characterization of a high-temperature resistant strain by hybridization recombination in Pyropia yezoensis

为改善条斑紫菜优良品系TM-18藻体颜色偏红的弱点,本研究以红色型突变品系(TM-18,特点:藻体偏红色;生长快,色素蛋白含量高,具有一定的耐高温性)为父本;绿色型突变品系(OMO-1,特点:藻体绿色,生长较慢,色素蛋白含量低,耐高温性差)为母本进行种内杂交,从杂合丝状体的F1叶状体中,分离出了优良品系TW-9。通过比较它与亲本品系的特性,获得以下结果:在常温(18°C)和高温(24和25°C)下培养13 d,TW-9品系的壳孢子存活率分别为TM-18品系的1.0、1.1和1.1倍,以及OMO-1品系的1.1、4.7和7.2倍。在18°C组,3个品系的壳孢子苗畸形率无显著性差异,但在24和25°C组,TW-9品系的畸形苗率比TM-18品系分别降低了20.3%和29.5%,比OMO-1品系分别降低了74.8%和69.5%。将在18°C下培养40 d的叶状体分别置于18、24和25°C再培养10 d,TW-9品系的绝对生长率分别为TM-18品系的0.9、1.5和0.8倍,以及OMO-1品系的1.4、1.5和28倍。此外,在24°C下培养25 d或在25°C下培养10 d,OMO-1品系的藻体腐烂严重,最后完全解体;TM-18和TW-9品系藻体在24°C下培养25 d只出现轻微卷曲,但在25°C下,TM-18品系培养15 d就腐烂至完全解体,而TW-9品系培养30 d也只是轻微腐烂。在18°C下培养40 d的TW-9品系叶状体分别再在18和24°C下培养15 d,总藻胆蛋白含量分别为61.5和77.8 mg/g,分别为OMO-1品系的1.4和1.4倍,但与TM-18品系的含量相比无明显差异。在18°C下培养55 d的叶状体平均厚度,TW-9品系为25.6μm,分别比TM-18和OMO-1品系降低了13.5%和17.7%。另外,3个品系的壳孢子放散量无显著性差异。研究表明,TW-9品系不仅具有与TM-18品系相似的特性,如叶状体生长快、色素蛋白含量高、壳孢子放散量大等特性,并且它的藻体更薄、更耐高温,其颜色与野生色相近,符合生产栽培的要求,有望被培育成适宜栽培的新品种。

In this paper, a crossing-experiment of intraspecific hybridization in Pyropia yezoensis was done for breeding improved strains. The male parent was the red mutation strain （TM-18）, which was characterized by red blade, fast growing, high contents of photosynthetic pigments and with resistance to high temperature, and the female parent was the green mutation strain （OMO-1）, which was characterized by green blade, slow growing, low contents of photosynthetic pigments and poor resistance to high temperature. An improved strain （TW-9） was finally selected from the recombinant F1 blades. TW-9 strain showed some different characters from the parental strains. The result showed that at normal temperature （18 ℃） and high temperature （24 and 25 ℃） for 13 days of post-culture, the survival rates of conchospores in TW-9 strain were 1.0, 1.1, and 1.1 times those of TM-18 strain, and were 1.1, 4.7, and 7.2 times those of 01140-1 strain, respectively. At 18 ~C, the abnormal rates of conchospore germlings had no significant difference between different strains, but at 24 and 25 ℃, as compared with TM-18 and OMO-1 strains, the abnormal rates of conchospore germlings in TW-9 strain reduced by 20.3% and 29.5%, and by 78.4% and 69.5%, respectively. When the conchospore germlings （40-day-old, at 18 ℃） were cultured at 18, 24 and 25 ℃ for another 10 days, the absolute growth rates of TW-9 strain were 0.9, 1.5 and 0.8 times those of TM-18 strain, and were 1.4, 1.5 and 28 times those of OMO-1 strain, respectively. In addition, after being cultured at 24 ℃ for 25 days or at 25 ℃ for 10 days, OMO-1 strain blades decayed badly to complete disintegration. However, the blades of TM-18 and TW-9 strains were curl slightly when being cultured at 24℃ for 25 days, and TM-18 blades were decay badly to complete disintegration at 25 ℃ for 15 days, while TW-9 blades were only decay slightly at 25 ℃for 30 days. After being cultured at 18 and 24℃ for another 15 days, the phycobiliprotein contents of TW-9 strain were 61.5 and 77.8 mg/g which was almost the same to the TM-18 strain, and were 1.4 and 1.4 times those of OMO-1 strain, respectively. After being cultured at 18℃ for 55 days, the blades thickness of TW-9 strain was 25.6 μm, which was reduced by 13.5% and 17.7% compared with those of TM-18 and OMO-1 strains, respectively. Besides, there was no significant difference in quantity of conchospores released between the three strains. These results indicated that TW-9 strain has similar characteristics to TM-18 strain, such as fast growing, high contents of photosynthetic pigments and great quantity of conchospores released, as well as thinner blade and better high-temperature resistance, and its color is close to the wild-type, which could meet the demands for productive cultivation. Therefore, TW-9 strain is expected to become a superior new strain ofP. yezoensis.