Inheritance of anthocyanin pigmentation and characterization of R2R3-MYB genes and anthocyanin biosynthetic genes in guava (Psidium guajava L.)

• Main Authors: Chang, Nai-Tun, 張乃惇
• Other Authors: Chen, Yu-Kuang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/32m6z7

碩士 === 國立屏東科技大學 === 農園生產系所 === 105 === In order to understand the genetics and expression of anthocyanin pigmentation in guava, a green-leaf, green-exocarp, and pink-fleshed line V31 and its purple selfed progeny V31(x)-1 were compared. V31(x)-1 had the highest anthocyanin content at small fruit stage, but its anthocyanin content gradually decreased as the fruit developed. Anthocyanin was not detected in V31 at all developmental stages of the fruit. Among 93 R2R3 MYBs genes selected from the ‘Jen-Ju Ba’ genomic database, five guava PgMYBs were grouped into the same cluster as Arabidopsis MYB genes regulating anthocyanin biosynthesis and were named PgMYB1 to PgMYB5. R2R3 domains in guava PgMYB1 and many anthocyanin biosynthesis-controlled MYBs from other fruits exhibit high amino acid similarity. When compared with that of ‘Jen-Ju Ba’, the GA repeat number in the PgMYB1 promoter region of V31(x)-1 is larger by 31 repeats. Among the five PgMYBs, the expression of PgMYB1 in V31(x)-1 fruit flesh by qPCR analysis was consistent with the expression pattern of anthocyanin. The expressions of PgCHS, PgCHI, PgF3H and PgDFR in earlier anthocyanin biosynthesis were also concordant with anthocyanin content in general. However, the expressions of PgMYBs and anthocyanin biosynthetic genes in V31 were not correlated with the anthocyanin content of fruit. Genetic analysis in V31 selfed lines and their derived progeny has revealed that inheritance of anthocyanin pigmentation in this population is controlled by one single gene. The result indicated that the green allele is dominant to the purple allele and V31 is heterozygous. Fragments amplified by the specific primers designed from PgMYB1 promoter region showed high polymorphism in 28 guava genotypes. This primer pair can be used as a marker for cultivar identification.