IDENTIFICATION OF PORPHYRA HAITANENSIS (BANGIALES, RHODOPHYTA) MEIOSIS BY SIMPLE SEQUENCE REPEAT MARKERS1

The simple sequence repeat (SSR) marks were employed to identify the stage at which meiosis occurs in the life cycle of Porphyra haitanensis T. J. Chang et B. F. Zheng. More than 90% of F1 blades of heterozygous conchocelis produced by the cross between a red mutant (R, female) and the wildtype (W, male) were color sectored. Two parental colors (R and W) and two new colors (R' and W') appeared in linear sectors in the color-sectored F1 blades. Two SSR primer pairs selected from a total of 52 primer pairs generated a specific paternal and maternal fragment, respectively. Co-occurrence of these two bands was detected in heterozygous conchocelis and in the color-sectored F1 blades with two to four sectors, such as R + W, R' + W', and R' + R + W + W'. However, the single-colored F1 blades exhibited only one band. In the sectors isolated from the color-sectored F1 blades, R and R' were the same, showing the maternal pattern, whereas W and W' were the same, showing the paternal pattern. These data suggested that the two different bands from heterozygous conchocelis originated from the parents and segregated in the F1 blades, whereas the two new colors, R' and W', in the F1 blades were produced by the exchange and recombination of alleles of the parental colors during meiosis. These results indicated that meiosis of P. haitanensis occurs during the first two cell divisions of a germinating conchospore, and, therefore, the initial four cells constitute a linear genetic tetrad, leading to the formation of a color-sectored blade.